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

Papers by Kamran Khan

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...

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...

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...

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

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...

ACS Biomaterials Science & Engineering

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.

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.

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...

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...

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...

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.

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.

Advanced Engineering Materials

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...

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...

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...

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...

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

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...

ACS Biomaterials Science & Engineering

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.

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.

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...

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...

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...

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.

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.

Advanced Engineering Materials

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...