Kamran Khan - Profile on Academia.edu (original) (raw)

Papers by Kamran Khan

Research paper thumbnail of Risk Factors Leading to Major Lower Limb Amputations in Diabetic Patients with Foot Ulcers

American Journal of Health, Medicine and Nursing Practice, 2022

Purpose: Foot ulceration in persons with diabetes is the most frequent precursor to amputation, w... more Purpose: Foot ulceration in persons with diabetes is the most frequent precursor to amputation, which impairs their activities. The aim of this study was to describe factors that lead to amputation of a diabetic foot, and propose a management strategy to prevent major amputation. Methods: Cross-sectional study was conducted at the Qazi Hussain Ahmad Hosptial, Nowshera Pakistan, from Jan, 2016, July 2021, and comprised patients of either gender having type 1 or type 2 diabetes and foot ulcers. The wounds were assessed according to Wagner wound staging and wound sepsis was evaluated in terms of local infection of the wound, leukocytosis and osteomyelitis of the bone. The glycemic control of these patients was assessed on presentation by measuring glaciated hemoglobin levels. Data was analyzed using SPSS 22. Findings: Out Of the 450 patients, 263(60%) were males and 187(40%) were females. Majority patients 193(43%) were aged 40-70 years. All 450(100%) patients underwent some type of am...

Research paper thumbnail of Effect of Architected Structural Members on the Viscoelastic Response of 3D Printed Simple Cubic Lattice Structures

Polymers

Three-dimensional printed polymeric lattice structures have recently gained interests in several ... more Three-dimensional printed polymeric lattice structures have recently gained interests in several engineering applications owing to their excellent properties such as low-density, energy absorption, strength-to-weight ratio, and damping performance. Three-dimensional (3D) lattice structure properties are governed by the topology of the microstructure and the base material that can be tailored to meet the application requirement. In this study, the effect of architected structural member geometry and base material on the viscoelastic response of 3D printed lattice structure has been investigated. The simple cubic lattice structures based on plate-, truss-, and shell-type structural members were used to describe the topology of the cellular solid. The proposed lattice structures were fabricated with two materials, i.e., PLA and ABS using the material extrusion (MEX) process. The quasi-static compression response of lattice structures was investigated, and mechanical properties were obt...

Research paper thumbnail of Surgeons Experience with the Conversion Rate of Laproscopic to Open Cholecystectomy in Patients with Previous Abdominal Surgery

Journal of University Medical & Dental College, 2019

BACKGROUND: Laparoscopic cholecystectomy is considered a gold standard management of gall stones.... more BACKGROUND: Laparoscopic cholecystectomy is considered a gold standard management of gall stones. Some cases are still converted into open cholecystectomy. Among many other factors, the most important factor is dense adhesions due to previous abdominal surgery. Surgical skills and experience of an operating surgeon plays a vital role in reducing the conversion rates. OBJECTIVE: We aim to determine the relation of surgeons experience with the conversion rate of laparoscopic to open cholecystectomy in patients of previous abdominal surgery. METHODS: This cross sectional study was conducted from December 2011 to December 2015. We included patients with previous abdominal surgery who were admitted with gall stone disease and planned to be operated by laparoscopic method. Those patients who have other factors responsible for conversion beside previous abdominal surgery were excluded from the study. A routine preoperative assessment, including biochemical liver assessment and abdominal ul...

Research paper thumbnail of Level of Pathogenic Escherichia Coli on Animal's Body Coat and in Meat under Slaughter House Environment

BACKGROUND Cattle slaughtering is performed in unhygienic conditions in local abattoirs. Therefor... more BACKGROUND Cattle slaughtering is performed in unhygienic conditions in local abattoirs. Therefore this study was conducted with the objective to investigate the level of Escherichia coli (E. coli) in various regions of live animal body coat, carcass and meat at the various stages of slaughtering processed.RESULTS Mean values of log Colony Forming Units (CFU) per square inch -1 of pathogenic E. coli was noted significantly higher on the body coat, carcass, meat and processing tools in untreated group of cattle. With application of hot water treatment, E. coli counts dropped both in body coat and on meat carcasses. In meat processing tools, chopper axe contained higher counts, while the washing water has slightly lesser count. In abattoir environment, lairage ground has high infection of pathogenic E. coli, and air samples also found positive with E coli. Conclusion: This study reveals that the level of pathogenic E. coli was high on animal's body coat, meat carcasses, processing tools and abattoir environment. Presently hot water (65.56 o C) application has significantly reduced the level of pathogen. However washing with some sanitizer will eliminate the pathogen from body coat thus resulting in little chances of meat contamination.

Research paper thumbnail of Systematic Review of Conceptual, Age, Measurement and Valuation Considerations for Generic Multidimensional Childhood Patient-Reported Outcome Measures

PharmacoEconomics

Background and Aims Patient-reported outcome measures (PROMs) for children (aged ≤ 18 years) pres... more Background and Aims Patient-reported outcome measures (PROMs) for children (aged ≤ 18 years) present methodological challenges. PROMs can be categorised by their diverse underlying conceptual bases, including functional, disability and health (FDH) status; quality of life (QoL); and health-related quality of life (HRQoL). Some PROMs are designed to be accompanied by preference weights. PROMs should account for childhood developmental differences by incorporating age-appropriate health/QoL domains, guidance on respondent type(s) and design. This systematic review aims to identify generic multidimensional childhood PROMs and synthesise their characteristics by conceptual basis, target age, measurement considerations, and the preference-based value sets that accompany them. Methods The study protocol was registered in the Prospective Register of Systematic Reviews (CRD42021230833), and reporting followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted systematic database searches for generic multidimensional childhood PROMs covering the period 2012-2020, which we combined with published PROMs identified by an earlier systematic review that covered the period 1992-2011. A second systematic database search identified preference-based value sets for generic multidimensional PROMs. The PROMs were categorised by conceptual basis (FDH status, QoL and HRQoL) and by target age (namely infants and pre-schoolers aged < 5 years, pre-adolescents aged 5-11, adolescents aged 12-18 and multi-age group coverage). Descriptive statistics assessed how PROM characteristics (domain coverage, respondent type and design) varied by conceptual basis and age categories. Involvement of children in PROM development and testing was assessed to understand content validity. Characteristics of value sets available for the childhood generic multidimensional PROMs were identified and compared. Results We identified 89 PROMs, including 110 versions: 52 FDH, 29 QoL, 12 HRQoL, nine QoL-FDH and eight HRQoL-FDH measures; 20 targeted infants and pre-schoolers, 29 pre-adolescents, 24 adolescents and 37 for multiple age groups. Domain coverage demonstrated development trajectories from observable FDH aspects in infancy through to personal independence and relationships during adolescence. PROMs targeting younger children relied more on informant report, were shorter and had fewer ordinal scale points. One-third of PROMs were developed following qualitative research or surveys with children or parents for concept elicitation. There were 21 preference-based value sets developed by 19 studies of ten generic multidimensional childhood PROMs: seven were based on adolescents' stated preferences, seven were from adults from the perspective of or on behalf of the child, and seven were from adults adopting an adult's perspective. Diverse preference elicitation methods were used to elicit values. Practices with respect to anchoring values on the utility scale also varied considerably. The range and distribution of values reflect these differences, resulting in value sets with notably different properties.

Research paper thumbnail of Project Proposal for an Intrusion Tolerant Threshold Cryptographic (ITTC) System

An ITTC system works on principles of distributive secret sharing. Instead of sharing a secret ke... more An ITTC system works on principles of distributive secret sharing. Instead of sharing a secret key among several parties which would be reconstructed upon re-quirement, threshold cryptography relies on sharing of cryptographic functions so that the secret key is never constructed in one place. This project aims to incorpo-rate threshold cryptographic functionalities in two of the most important crypto-graphic services: web servers and certificate authorities. 1

Research paper thumbnail of Experimental Characterization and Modeling Multifunctional Properties of Epoxy/Graphene Oxide Nanocomposites

Polymers

Thermomechanical modeling of epoxy/graphene oxide under quasi-static and dynamic loading requires... more Thermomechanical modeling of epoxy/graphene oxide under quasi-static and dynamic loading requires thermo-mechanical properties such as Young’s modulus, Poisson’s ratio, thermal conductivity, and frequency-temperature dependent viscoelastic properties. In this study, the effects of different graphene oxide (GO) concentrations (0.05, 0.1, and 0.2 wt%) within an epoxy matrix on several mechanical and thermal properties were investigated. The distribution of GO fillers in the epoxy was investigated using transmission electron microscopy (TEM). The digital image correlation (DIC) technique was employed during the tensile testing to determine Young’s modulus and Poisson’s ratio. Analytical models were used to predict Young’s modulus and thermal conductivity, with an error of less than 13% and 9%, respectively. Frequency–temperature dependent phenomenological models were proposed to predict the storage moduli and loss tangent, with a reasonable agreement with experimental data. A relativel...

Research paper thumbnail of Nanocomposite Conductive Bioinks Based on Low-Concentration GelMA and MXene Nanosheets/Gold Nanoparticles Providing Enhanced Printability of Functional Skeletal Muscle Tissues

ACS Biomaterials Science & Engineering

There is a growing need to develop novel wellcharacterized biological inks (bioinks) that are cus... more There is a growing need to develop novel wellcharacterized biological inks (bioinks) that are customizable for three-dimensional (3D) bioprinting of specific tissue types. Gelatin methacryloyl (GelMA) is one such candidate bioink due to its biocompatibility and tunable mechanical properties. Currently, only low-concentration GelMA hydrogels (≤5% w/v) are suitable as cellladen bioinks, allowing high cell viability, elongation, and migration. Yet, they offer poor printability. Herein, we optimize GelMA bioinks in terms of concentration and cross-linking time for improved skeletal muscle C2C12 cell spreading in 3D, and we augment these by adding gold nanoparticles (AuNPs) or a two-dimensional (2D) transition metal carbide (MXene nanosheets) for enhanced printability and biological properties. AuNP and MXene addition endowed GelMA with increased conductivity (up to 0.8 ± 0.07 and 0.9 ± 0.12 S/m, respectively, compared to 0.3 ± 0.06 S/m for pure GelMA). Furthermore, it resulted in an improvement of rheological properties and printability, specifically at 10°C. Improvements in electrical and rheological properties led to enhanced differentiation of encapsulated myoblasts and allowed for printing highly viable (97%) stable constructs. Taken together, these results constitute a significant step toward fabrication of 3D conductive tissue constructs with physiological relevance.

Research paper thumbnail of Traffic analyzer for differentiating BitTorrent handshake failures from port-scans

ArXiv, 2013

This paper aims to improve the accuracy of port-scan detectors by analyzing traffic of BitTorrent... more This paper aims to improve the accuracy of port-scan detectors by analyzing traffic of BitTorrent hosts and differentiating their respective BitTorrent connection (attempts) from port-scans. It is shown that by looking at BitTorrent coordination traffic and modelling port-scanning behavior the number of BitTorrent-related false positives can be reduced by 80% without any loss of IDS accuracy.

Research paper thumbnail of A Machine Learning Approach to Model Interdependencies between Dynamic Response and Crack Propagation

Sensors

Accurate damage detection in engineering structures is a critical part of structural health monit... more Accurate damage detection in engineering structures is a critical part of structural health monitoring. A variety of non-destructive inspection methods has been employed to detect the presence and severity of the damage. In this research, machine learning (ML) algorithms are used to assess the dynamic response of the system. It can predict the damage severity, damage location, and fundamental behaviour of the system. Fatigue damage data of aluminium and ABS under coupled mechanical loads at different temperatures are used to train the model. The model shows that natural frequency and temperature appear to be the most important predictive features for aluminium. It appears to be dominated by natural frequency and tip amplitude for ABS. The results also show that the position of the crack along the specimen appears to be of little importance for either material, allowing simultaneous prediction of location and damage severity.

Research paper thumbnail of Architected active metamaterials

Research paper thumbnail of Nutritive Value , Fiber Digestibility and Methane Production Potential of Tropical Forages in Rabbits : Effect of Species and Harvest Maturity

The aim of this study was to quantify the nutrient composition, neutral detergent fibre (NDF) dig... more The aim of this study was to quantify the nutrient composition, neutral detergent fibre (NDF) digestibility (in vitro) and methane (CH4) emission potential of commonly used tropical forages in rabbits. Seven fodder species, namely, Trifolium alexandrinum, Trifolium resupinatum, Avena sativa, Triticum aestivum, Hordeum vulgare, Brassica campestris, Cichorium intybus; and seven grass species, namely, Pennisetum purpureum, Panicum antidotale, Cenchrus ciliaris, Pennisetum orientale, Setaria anceps and Atriplex lentiformis were evaluated at early, mid and late stages of maturity. At each maturity, samples were collected from four replicate plots of each species, and subsequently analyzed for the contents of dry matter (DM) and nutrient composition. The DM and NDF degradability, and CH4 emission was measured using an in vitro gas production system. The CH4 concentration in the gas was measured using Gas Chromatography. Large variation (P < 0.001) was observed for contents of all measu...

Research paper thumbnail of Characterising Modal Behaviour of a Cantilever Beam at Different Heating Rates for Isothermal Conditions

Applied Sciences

The effect of temperature on structural response is a concern in engineering applications. The li... more The effect of temperature on structural response is a concern in engineering applications. The literature has highlighted that applied temperature loads change the system vibration behaviour. However, there is limited information available about temperature impacting the dynamic response. This paper investigated the heating rates effects on modal parameters for both with crack and without crack conditions in a cantilever beam. A beam subjected to three heating rates was considered: 2, 5, and 8 °C/min. The first one was assumed as a slow heating rate while the others were assumed as moderate and high, respectively. This controlled rate of heating was achieved by using a proportional-integral-derivative (PID) temperature controller. The results showed that heating at different rates has little impact on modal parameters. While this effect is minimal at lower temperatures and more evident at higher temperatures. The results of temperature ramped at 2, 5, and 8 °C/min were compared with...

Research paper thumbnail of Mechanical Properties and Energy Absorption Characteristics of Additively Manufactured Lightweight Novel Re-Entrant Plate-Based Lattice Structures

Polymers

In this work, three novel re-entrant plate lattice structures (LSs) have been designed by transfo... more In this work, three novel re-entrant plate lattice structures (LSs) have been designed by transforming conventional truss-based lattices into hybrid-plate based lattices, namely, flat-plate modified auxetic (FPMA), vintile (FPV), and tesseract (FPT). Additive manufacturing based on stereolithography (SLA) technology was utilized to fabricate the tensile, compressive, and LS specimens with different relative densities (ρ). The base material’s mechanical properties obtained through mechanical testing were used in a finite element-based numerical homogenization analysis to study the elastic anisotropy of the LSs. Both the FPV and FPMA showed anisotropic behavior; however, the FPT showed cubic symmetry. The universal anisotropic index was found highest for FPV and lowest for FPMA, and it followed the power-law dependence of ρ. The quasi-static compressive response of the LSs was investigated. The Gibson–Ashby power law (≈ρn) analysis revealed that the FPMA’s Young’s modulus was the high...

Research paper thumbnail of Structural change, modernization, total factor productivity, and natural resources sustainability: An assessment with quantile and non-quantile estimators

Structural change, modernization, total factor productivity, and natural resources sustainability: An assessment with quantile and non-quantile estimators

Resources Policy

Research paper thumbnail of Fat-Free Spindle Cell Lipoma of the Scalp

Fat-Free Spindle Cell Lipoma of the Scalp

Journal of Craniofacial Surgery

ABSTRACT Spindle cell lipoma (SCL) is a rare, benign subcutaneous neoplasm that typically occurs ... more ABSTRACT Spindle cell lipoma (SCL) is a rare, benign subcutaneous neoplasm that typically occurs on the upper trunk or neck of middle-aged men. The diagnosis of SCL is often straightforward due to its characteristic clinical presentation and classic histologic features of admixed mature adipocytes and CD-34 positive bland spindle cells. However, the diagnosis can be elusive when low-fat and free-fat patterns occur. Due to the lack of lipogenic content and morphologic overlap, this rare tumor is often mistaken for other benign and malignant soft tissue tumors. The authors present the case of a middle-aged man with a fat-free SCL of the temporal scalp. To our knowledge, this is the first reported case in the literature of a fat-free SCL involving the temporal scalp. With careful attention to the clinical context, histologic features, immunohistochemical profile, and cytogenetic abnormalities, the proper diagnosis of SCL without a lipogenic component can be achieved.

Research paper thumbnail of In vivo ranges of motion of cervical segments in patients with cervical spondylosis during dynamic neck motions

In vivo ranges of motion of cervical segments in patients with cervical spondylosis during dynamic neck motions

Chinese Medical Journal

Orthopaedic Bioengineering Research Center, Newton-Wellesley Hospital and Harvard Medical School,... more Orthopaedic Bioengineering Research Center, Newton-Wellesley Hospital and Harvard Medical School, Newton, MA, USA; Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Orthopaedics, Guizhou Provincial People’s Hospital, Guiyang, China; Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.

Research paper thumbnail of A Novel Twofold Symmetry Architected Metamaterials with High Compressibility and Negative Poisson's Ratio

Advanced Engineering Materials

The advancements in additive manufacturing (AM) technology make the fabrication of complex archit... more The advancements in additive manufacturing (AM) technology make the fabrication of complex architected materials and structures at multiple length scales possible to explore a new family of metamaterial. A metamaterial is an artificially engineered material to have a property not found in conventional materials. [1] Historically, the term "metamaterials" were limited to electromagnetism field, but, recently, it has been extended to photonic, phononic, and mechanical systems to design architected engineered materials that exhibit properties not usually found in conventional materials. [2] Mechanical metamaterials refer to a sort of metamaterials that designed artificial structural materials with counterintuitive mechanical properties derived from their tailored internal microstructure rather than the composition of base material. [3] The unusual properties include negative Poisson's ratio, negative modulus of elasticity, and negative compressibility. [4,5] Examples of mechanical metamaterials include acoustic metamaterials, auxetic materials, pentamode metamaterials, and micropolar metamaterials. The concept of metamaterials combined with AM opens new design avenues for the fabrication of complex microstructures over a wide range of length scales. [6-8] Auxetic mechanical metamaterials are recognized by a negative Poisson's ratio; i.e., materials will contract (expand) in the transverse direction when compressed uniaxially (stretched). Auxetic mechanical metamaterials are of interest because of their enhanced mechanical properties, such as increased indentation resistance, [9] shear modulus, [10] and fracture toughness. [11] They have a great potential in engineering applications, such as cellular materials with superior damping and acoustic properties, [12] piezoelectric metamaterials, [13] piezocomposites, [14] auxetic fasteners, [15] bioprostheses, [16] tissue engineering, [17] and mechanically tunable, elastically reversible, and transformable topological mechanical metamaterials. [18,19] The negative Poisson's ratio of auxetic material depends on the topology of auxetic building blocks and scaleindependent. [20,21] Several natural materials exhibit negative Poisson's ratio, such as silicates, [22] cubic elemental metals, [23] zeolites, [24] natural layered ceramics, [25] and monolithic ferroelectric polycrystalline ceramics. [26] Love [27] was the first to report the negative Poisson's ratio of naturally occurring cubic crystals of

Research paper thumbnail of Travel-driven emergence and spread of SARS-CoV-2 lineage B.1.620 with multiple VOC-like mutations and deletions in Europe

ABSTRACTMany high-income countries have met the SARS-CoV-2 pandemic with overwhelming sequencing ... more ABSTRACTMany high-income countries have met the SARS-CoV-2 pandemic with overwhelming sequencing resources and have identified numerous distinct lineages, including some with notably altered biology. Over a year into the pandemic following unprecedented reductions in worldwide human mobility, distinct introduced lineages of SARS-CoV-2 without sequenced antecedents are increasingly discovered in high-income countries as a result of ongoing SARS-CoV-2 genomic surveillance initiatives. We here describe one such SARS-CoV-2 lineage, carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Δ, Y144Δ, and LLA241/243Δ. This lineage – designated B.1.620 – is known to circulate in Lithuania and has now been found in several European states, but also in increasing numbers in central Africa owing to important recent increases in genome sequencing efforts on the continent. We provide evidence of likely o...

Research paper thumbnail of An electronic textile embedded smart cementitious composite

Engineering Reports

Structural health monitoring (SHM) using self-sensing cement-based materials has been reported be... more Structural health monitoring (SHM) using self-sensing cement-based materials has been reported before, where nano-fillers have been incorporated in cementitious matrices as functional sensing elements. A percolation threshold is always required in order for conductive nano-fillers modified concrete to be useful for SHM. Nonetheless, the best pressure/strain sensitivity results achieved for any self-sensing cementitious matrix are <0.01 MPa -1 . In this work, we introduce novel reduced graphene oxide (RGO) based electronic textile (e-textile) embedded in plain and polymer-binder-modified cementitious matrix for SHM applications. As a proof of concept, it was demonstrated that these coated fabric-based sensors can be successfully embedded within the cement-based structures, which are independent of any percolation threshold due to the interconnected fabric inside the host matrix. The piezo-resistive response was measured by applying direct and cyclic compressive loads (0.1 to 3.9 MPa). A pressure sensitivity of 1.5 MPa - 1 and an ultra-high gauge factor of 2000 was obtained for the system of the self-sensing cementitious structure with embedded e-textiles. The sensitivity of this new system with embedded e-textile is many orders of magnitude higher than nanoparticle based self-sensing of cementitious composites. The manufactured e-textile sensors showed mechanical stability and functional durability over long-term cyclic compression tests of 1000 cycles.

Research paper thumbnail of Risk Factors Leading to Major Lower Limb Amputations in Diabetic Patients with Foot Ulcers

American Journal of Health, Medicine and Nursing Practice, 2022

Purpose: Foot ulceration in persons with diabetes is the most frequent precursor to amputation, w... more Purpose: Foot ulceration in persons with diabetes is the most frequent precursor to amputation, which impairs their activities. The aim of this study was to describe factors that lead to amputation of a diabetic foot, and propose a management strategy to prevent major amputation. Methods: Cross-sectional study was conducted at the Qazi Hussain Ahmad Hosptial, Nowshera Pakistan, from Jan, 2016, July 2021, and comprised patients of either gender having type 1 or type 2 diabetes and foot ulcers. The wounds were assessed according to Wagner wound staging and wound sepsis was evaluated in terms of local infection of the wound, leukocytosis and osteomyelitis of the bone. The glycemic control of these patients was assessed on presentation by measuring glaciated hemoglobin levels. Data was analyzed using SPSS 22. Findings: Out Of the 450 patients, 263(60%) were males and 187(40%) were females. Majority patients 193(43%) were aged 40-70 years. All 450(100%) patients underwent some type of am...

Research paper thumbnail of Effect of Architected Structural Members on the Viscoelastic Response of 3D Printed Simple Cubic Lattice Structures

Polymers

Three-dimensional printed polymeric lattice structures have recently gained interests in several ... more Three-dimensional printed polymeric lattice structures have recently gained interests in several engineering applications owing to their excellent properties such as low-density, energy absorption, strength-to-weight ratio, and damping performance. Three-dimensional (3D) lattice structure properties are governed by the topology of the microstructure and the base material that can be tailored to meet the application requirement. In this study, the effect of architected structural member geometry and base material on the viscoelastic response of 3D printed lattice structure has been investigated. The simple cubic lattice structures based on plate-, truss-, and shell-type structural members were used to describe the topology of the cellular solid. The proposed lattice structures were fabricated with two materials, i.e., PLA and ABS using the material extrusion (MEX) process. The quasi-static compression response of lattice structures was investigated, and mechanical properties were obt...

Research paper thumbnail of Surgeons Experience with the Conversion Rate of Laproscopic to Open Cholecystectomy in Patients with Previous Abdominal Surgery

Journal of University Medical & Dental College, 2019

BACKGROUND: Laparoscopic cholecystectomy is considered a gold standard management of gall stones.... more BACKGROUND: Laparoscopic cholecystectomy is considered a gold standard management of gall stones. Some cases are still converted into open cholecystectomy. Among many other factors, the most important factor is dense adhesions due to previous abdominal surgery. Surgical skills and experience of an operating surgeon plays a vital role in reducing the conversion rates. OBJECTIVE: We aim to determine the relation of surgeons experience with the conversion rate of laparoscopic to open cholecystectomy in patients of previous abdominal surgery. METHODS: This cross sectional study was conducted from December 2011 to December 2015. We included patients with previous abdominal surgery who were admitted with gall stone disease and planned to be operated by laparoscopic method. Those patients who have other factors responsible for conversion beside previous abdominal surgery were excluded from the study. A routine preoperative assessment, including biochemical liver assessment and abdominal ul...

Research paper thumbnail of Level of Pathogenic Escherichia Coli on Animal's Body Coat and in Meat under Slaughter House Environment

BACKGROUND Cattle slaughtering is performed in unhygienic conditions in local abattoirs. Therefor... more BACKGROUND Cattle slaughtering is performed in unhygienic conditions in local abattoirs. Therefore this study was conducted with the objective to investigate the level of Escherichia coli (E. coli) in various regions of live animal body coat, carcass and meat at the various stages of slaughtering processed.RESULTS Mean values of log Colony Forming Units (CFU) per square inch -1 of pathogenic E. coli was noted significantly higher on the body coat, carcass, meat and processing tools in untreated group of cattle. With application of hot water treatment, E. coli counts dropped both in body coat and on meat carcasses. In meat processing tools, chopper axe contained higher counts, while the washing water has slightly lesser count. In abattoir environment, lairage ground has high infection of pathogenic E. coli, and air samples also found positive with E coli. Conclusion: This study reveals that the level of pathogenic E. coli was high on animal's body coat, meat carcasses, processing tools and abattoir environment. Presently hot water (65.56 o C) application has significantly reduced the level of pathogen. However washing with some sanitizer will eliminate the pathogen from body coat thus resulting in little chances of meat contamination.

Research paper thumbnail of Systematic Review of Conceptual, Age, Measurement and Valuation Considerations for Generic Multidimensional Childhood Patient-Reported Outcome Measures

PharmacoEconomics

Background and Aims Patient-reported outcome measures (PROMs) for children (aged ≤ 18 years) pres... more Background and Aims Patient-reported outcome measures (PROMs) for children (aged ≤ 18 years) present methodological challenges. PROMs can be categorised by their diverse underlying conceptual bases, including functional, disability and health (FDH) status; quality of life (QoL); and health-related quality of life (HRQoL). Some PROMs are designed to be accompanied by preference weights. PROMs should account for childhood developmental differences by incorporating age-appropriate health/QoL domains, guidance on respondent type(s) and design. This systematic review aims to identify generic multidimensional childhood PROMs and synthesise their characteristics by conceptual basis, target age, measurement considerations, and the preference-based value sets that accompany them. Methods The study protocol was registered in the Prospective Register of Systematic Reviews (CRD42021230833), and reporting followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted systematic database searches for generic multidimensional childhood PROMs covering the period 2012-2020, which we combined with published PROMs identified by an earlier systematic review that covered the period 1992-2011. A second systematic database search identified preference-based value sets for generic multidimensional PROMs. The PROMs were categorised by conceptual basis (FDH status, QoL and HRQoL) and by target age (namely infants and pre-schoolers aged < 5 years, pre-adolescents aged 5-11, adolescents aged 12-18 and multi-age group coverage). Descriptive statistics assessed how PROM characteristics (domain coverage, respondent type and design) varied by conceptual basis and age categories. Involvement of children in PROM development and testing was assessed to understand content validity. Characteristics of value sets available for the childhood generic multidimensional PROMs were identified and compared. Results We identified 89 PROMs, including 110 versions: 52 FDH, 29 QoL, 12 HRQoL, nine QoL-FDH and eight HRQoL-FDH measures; 20 targeted infants and pre-schoolers, 29 pre-adolescents, 24 adolescents and 37 for multiple age groups. Domain coverage demonstrated development trajectories from observable FDH aspects in infancy through to personal independence and relationships during adolescence. PROMs targeting younger children relied more on informant report, were shorter and had fewer ordinal scale points. One-third of PROMs were developed following qualitative research or surveys with children or parents for concept elicitation. There were 21 preference-based value sets developed by 19 studies of ten generic multidimensional childhood PROMs: seven were based on adolescents' stated preferences, seven were from adults from the perspective of or on behalf of the child, and seven were from adults adopting an adult's perspective. Diverse preference elicitation methods were used to elicit values. Practices with respect to anchoring values on the utility scale also varied considerably. The range and distribution of values reflect these differences, resulting in value sets with notably different properties.

Research paper thumbnail of Project Proposal for an Intrusion Tolerant Threshold Cryptographic (ITTC) System

An ITTC system works on principles of distributive secret sharing. Instead of sharing a secret ke... more An ITTC system works on principles of distributive secret sharing. Instead of sharing a secret key among several parties which would be reconstructed upon re-quirement, threshold cryptography relies on sharing of cryptographic functions so that the secret key is never constructed in one place. This project aims to incorpo-rate threshold cryptographic functionalities in two of the most important crypto-graphic services: web servers and certificate authorities. 1

Research paper thumbnail of Experimental Characterization and Modeling Multifunctional Properties of Epoxy/Graphene Oxide Nanocomposites

Polymers

Thermomechanical modeling of epoxy/graphene oxide under quasi-static and dynamic loading requires... more Thermomechanical modeling of epoxy/graphene oxide under quasi-static and dynamic loading requires thermo-mechanical properties such as Young’s modulus, Poisson’s ratio, thermal conductivity, and frequency-temperature dependent viscoelastic properties. In this study, the effects of different graphene oxide (GO) concentrations (0.05, 0.1, and 0.2 wt%) within an epoxy matrix on several mechanical and thermal properties were investigated. The distribution of GO fillers in the epoxy was investigated using transmission electron microscopy (TEM). The digital image correlation (DIC) technique was employed during the tensile testing to determine Young’s modulus and Poisson’s ratio. Analytical models were used to predict Young’s modulus and thermal conductivity, with an error of less than 13% and 9%, respectively. Frequency–temperature dependent phenomenological models were proposed to predict the storage moduli and loss tangent, with a reasonable agreement with experimental data. A relativel...

Research paper thumbnail of Nanocomposite Conductive Bioinks Based on Low-Concentration GelMA and MXene Nanosheets/Gold Nanoparticles Providing Enhanced Printability of Functional Skeletal Muscle Tissues

ACS Biomaterials Science & Engineering

There is a growing need to develop novel wellcharacterized biological inks (bioinks) that are cus... more There is a growing need to develop novel wellcharacterized biological inks (bioinks) that are customizable for three-dimensional (3D) bioprinting of specific tissue types. Gelatin methacryloyl (GelMA) is one such candidate bioink due to its biocompatibility and tunable mechanical properties. Currently, only low-concentration GelMA hydrogels (≤5% w/v) are suitable as cellladen bioinks, allowing high cell viability, elongation, and migration. Yet, they offer poor printability. Herein, we optimize GelMA bioinks in terms of concentration and cross-linking time for improved skeletal muscle C2C12 cell spreading in 3D, and we augment these by adding gold nanoparticles (AuNPs) or a two-dimensional (2D) transition metal carbide (MXene nanosheets) for enhanced printability and biological properties. AuNP and MXene addition endowed GelMA with increased conductivity (up to 0.8 ± 0.07 and 0.9 ± 0.12 S/m, respectively, compared to 0.3 ± 0.06 S/m for pure GelMA). Furthermore, it resulted in an improvement of rheological properties and printability, specifically at 10°C. Improvements in electrical and rheological properties led to enhanced differentiation of encapsulated myoblasts and allowed for printing highly viable (97%) stable constructs. Taken together, these results constitute a significant step toward fabrication of 3D conductive tissue constructs with physiological relevance.

Research paper thumbnail of Traffic analyzer for differentiating BitTorrent handshake failures from port-scans

ArXiv, 2013

This paper aims to improve the accuracy of port-scan detectors by analyzing traffic of BitTorrent... more This paper aims to improve the accuracy of port-scan detectors by analyzing traffic of BitTorrent hosts and differentiating their respective BitTorrent connection (attempts) from port-scans. It is shown that by looking at BitTorrent coordination traffic and modelling port-scanning behavior the number of BitTorrent-related false positives can be reduced by 80% without any loss of IDS accuracy.

Research paper thumbnail of A Machine Learning Approach to Model Interdependencies between Dynamic Response and Crack Propagation

Sensors

Accurate damage detection in engineering structures is a critical part of structural health monit... more Accurate damage detection in engineering structures is a critical part of structural health monitoring. A variety of non-destructive inspection methods has been employed to detect the presence and severity of the damage. In this research, machine learning (ML) algorithms are used to assess the dynamic response of the system. It can predict the damage severity, damage location, and fundamental behaviour of the system. Fatigue damage data of aluminium and ABS under coupled mechanical loads at different temperatures are used to train the model. The model shows that natural frequency and temperature appear to be the most important predictive features for aluminium. It appears to be dominated by natural frequency and tip amplitude for ABS. The results also show that the position of the crack along the specimen appears to be of little importance for either material, allowing simultaneous prediction of location and damage severity.

Research paper thumbnail of Architected active metamaterials

Research paper thumbnail of Nutritive Value , Fiber Digestibility and Methane Production Potential of Tropical Forages in Rabbits : Effect of Species and Harvest Maturity

The aim of this study was to quantify the nutrient composition, neutral detergent fibre (NDF) dig... more The aim of this study was to quantify the nutrient composition, neutral detergent fibre (NDF) digestibility (in vitro) and methane (CH4) emission potential of commonly used tropical forages in rabbits. Seven fodder species, namely, Trifolium alexandrinum, Trifolium resupinatum, Avena sativa, Triticum aestivum, Hordeum vulgare, Brassica campestris, Cichorium intybus; and seven grass species, namely, Pennisetum purpureum, Panicum antidotale, Cenchrus ciliaris, Pennisetum orientale, Setaria anceps and Atriplex lentiformis were evaluated at early, mid and late stages of maturity. At each maturity, samples were collected from four replicate plots of each species, and subsequently analyzed for the contents of dry matter (DM) and nutrient composition. The DM and NDF degradability, and CH4 emission was measured using an in vitro gas production system. The CH4 concentration in the gas was measured using Gas Chromatography. Large variation (P < 0.001) was observed for contents of all measu...

Research paper thumbnail of Characterising Modal Behaviour of a Cantilever Beam at Different Heating Rates for Isothermal Conditions

Applied Sciences

The effect of temperature on structural response is a concern in engineering applications. The li... more The effect of temperature on structural response is a concern in engineering applications. The literature has highlighted that applied temperature loads change the system vibration behaviour. However, there is limited information available about temperature impacting the dynamic response. This paper investigated the heating rates effects on modal parameters for both with crack and without crack conditions in a cantilever beam. A beam subjected to three heating rates was considered: 2, 5, and 8 °C/min. The first one was assumed as a slow heating rate while the others were assumed as moderate and high, respectively. This controlled rate of heating was achieved by using a proportional-integral-derivative (PID) temperature controller. The results showed that heating at different rates has little impact on modal parameters. While this effect is minimal at lower temperatures and more evident at higher temperatures. The results of temperature ramped at 2, 5, and 8 °C/min were compared with...

Research paper thumbnail of Mechanical Properties and Energy Absorption Characteristics of Additively Manufactured Lightweight Novel Re-Entrant Plate-Based Lattice Structures

Polymers

In this work, three novel re-entrant plate lattice structures (LSs) have been designed by transfo... more In this work, three novel re-entrant plate lattice structures (LSs) have been designed by transforming conventional truss-based lattices into hybrid-plate based lattices, namely, flat-plate modified auxetic (FPMA), vintile (FPV), and tesseract (FPT). Additive manufacturing based on stereolithography (SLA) technology was utilized to fabricate the tensile, compressive, and LS specimens with different relative densities (ρ). The base material’s mechanical properties obtained through mechanical testing were used in a finite element-based numerical homogenization analysis to study the elastic anisotropy of the LSs. Both the FPV and FPMA showed anisotropic behavior; however, the FPT showed cubic symmetry. The universal anisotropic index was found highest for FPV and lowest for FPMA, and it followed the power-law dependence of ρ. The quasi-static compressive response of the LSs was investigated. The Gibson–Ashby power law (≈ρn) analysis revealed that the FPMA’s Young’s modulus was the high...

Research paper thumbnail of Structural change, modernization, total factor productivity, and natural resources sustainability: An assessment with quantile and non-quantile estimators

Structural change, modernization, total factor productivity, and natural resources sustainability: An assessment with quantile and non-quantile estimators

Resources Policy

Research paper thumbnail of Fat-Free Spindle Cell Lipoma of the Scalp

Fat-Free Spindle Cell Lipoma of the Scalp

Journal of Craniofacial Surgery

ABSTRACT Spindle cell lipoma (SCL) is a rare, benign subcutaneous neoplasm that typically occurs ... more ABSTRACT Spindle cell lipoma (SCL) is a rare, benign subcutaneous neoplasm that typically occurs on the upper trunk or neck of middle-aged men. The diagnosis of SCL is often straightforward due to its characteristic clinical presentation and classic histologic features of admixed mature adipocytes and CD-34 positive bland spindle cells. However, the diagnosis can be elusive when low-fat and free-fat patterns occur. Due to the lack of lipogenic content and morphologic overlap, this rare tumor is often mistaken for other benign and malignant soft tissue tumors. The authors present the case of a middle-aged man with a fat-free SCL of the temporal scalp. To our knowledge, this is the first reported case in the literature of a fat-free SCL involving the temporal scalp. With careful attention to the clinical context, histologic features, immunohistochemical profile, and cytogenetic abnormalities, the proper diagnosis of SCL without a lipogenic component can be achieved.

Research paper thumbnail of In vivo ranges of motion of cervical segments in patients with cervical spondylosis during dynamic neck motions

In vivo ranges of motion of cervical segments in patients with cervical spondylosis during dynamic neck motions

Chinese Medical Journal

Orthopaedic Bioengineering Research Center, Newton-Wellesley Hospital and Harvard Medical School,... more Orthopaedic Bioengineering Research Center, Newton-Wellesley Hospital and Harvard Medical School, Newton, MA, USA; Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Orthopaedics, Guizhou Provincial People’s Hospital, Guiyang, China; Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.

Research paper thumbnail of A Novel Twofold Symmetry Architected Metamaterials with High Compressibility and Negative Poisson's Ratio

Advanced Engineering Materials

The advancements in additive manufacturing (AM) technology make the fabrication of complex archit... more The advancements in additive manufacturing (AM) technology make the fabrication of complex architected materials and structures at multiple length scales possible to explore a new family of metamaterial. A metamaterial is an artificially engineered material to have a property not found in conventional materials. [1] Historically, the term "metamaterials" were limited to electromagnetism field, but, recently, it has been extended to photonic, phononic, and mechanical systems to design architected engineered materials that exhibit properties not usually found in conventional materials. [2] Mechanical metamaterials refer to a sort of metamaterials that designed artificial structural materials with counterintuitive mechanical properties derived from their tailored internal microstructure rather than the composition of base material. [3] The unusual properties include negative Poisson's ratio, negative modulus of elasticity, and negative compressibility. [4,5] Examples of mechanical metamaterials include acoustic metamaterials, auxetic materials, pentamode metamaterials, and micropolar metamaterials. The concept of metamaterials combined with AM opens new design avenues for the fabrication of complex microstructures over a wide range of length scales. [6-8] Auxetic mechanical metamaterials are recognized by a negative Poisson's ratio; i.e., materials will contract (expand) in the transverse direction when compressed uniaxially (stretched). Auxetic mechanical metamaterials are of interest because of their enhanced mechanical properties, such as increased indentation resistance, [9] shear modulus, [10] and fracture toughness. [11] They have a great potential in engineering applications, such as cellular materials with superior damping and acoustic properties, [12] piezoelectric metamaterials, [13] piezocomposites, [14] auxetic fasteners, [15] bioprostheses, [16] tissue engineering, [17] and mechanically tunable, elastically reversible, and transformable topological mechanical metamaterials. [18,19] The negative Poisson's ratio of auxetic material depends on the topology of auxetic building blocks and scaleindependent. [20,21] Several natural materials exhibit negative Poisson's ratio, such as silicates, [22] cubic elemental metals, [23] zeolites, [24] natural layered ceramics, [25] and monolithic ferroelectric polycrystalline ceramics. [26] Love [27] was the first to report the negative Poisson's ratio of naturally occurring cubic crystals of

Research paper thumbnail of Travel-driven emergence and spread of SARS-CoV-2 lineage B.1.620 with multiple VOC-like mutations and deletions in Europe

ABSTRACTMany high-income countries have met the SARS-CoV-2 pandemic with overwhelming sequencing ... more ABSTRACTMany high-income countries have met the SARS-CoV-2 pandemic with overwhelming sequencing resources and have identified numerous distinct lineages, including some with notably altered biology. Over a year into the pandemic following unprecedented reductions in worldwide human mobility, distinct introduced lineages of SARS-CoV-2 without sequenced antecedents are increasingly discovered in high-income countries as a result of ongoing SARS-CoV-2 genomic surveillance initiatives. We here describe one such SARS-CoV-2 lineage, carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Δ, Y144Δ, and LLA241/243Δ. This lineage – designated B.1.620 – is known to circulate in Lithuania and has now been found in several European states, but also in increasing numbers in central Africa owing to important recent increases in genome sequencing efforts on the continent. We provide evidence of likely o...

Research paper thumbnail of An electronic textile embedded smart cementitious composite

Engineering Reports

Structural health monitoring (SHM) using self-sensing cement-based materials has been reported be... more Structural health monitoring (SHM) using self-sensing cement-based materials has been reported before, where nano-fillers have been incorporated in cementitious matrices as functional sensing elements. A percolation threshold is always required in order for conductive nano-fillers modified concrete to be useful for SHM. Nonetheless, the best pressure/strain sensitivity results achieved for any self-sensing cementitious matrix are <0.01 MPa -1 . In this work, we introduce novel reduced graphene oxide (RGO) based electronic textile (e-textile) embedded in plain and polymer-binder-modified cementitious matrix for SHM applications. As a proof of concept, it was demonstrated that these coated fabric-based sensors can be successfully embedded within the cement-based structures, which are independent of any percolation threshold due to the interconnected fabric inside the host matrix. The piezo-resistive response was measured by applying direct and cyclic compressive loads (0.1 to 3.9 MPa). A pressure sensitivity of 1.5 MPa - 1 and an ultra-high gauge factor of 2000 was obtained for the system of the self-sensing cementitious structure with embedded e-textiles. The sensitivity of this new system with embedded e-textile is many orders of magnitude higher than nanoparticle based self-sensing of cementitious composites. The manufactured e-textile sensors showed mechanical stability and functional durability over long-term cyclic compression tests of 1000 cycles.