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

Papers by Tahir Khan

Seasonal distribution of algae determined in three research sites of river Jindi, Pakistan. Sampl... more Seasonal distribution of algae determined in three research sites of river Jindi, Pakistan. Samples of 5 classes having 46 families, 54 genera, 107 spp., out of 107 spp. 46.72% collected in winter, 53.27% in summer seasons. The most abundant class Bacillariophyta with 24 genera, 46 spp. (46.9%), followed by Chlorophyceae with 18genera, 33 spp. (30.8%), Cyanophyceae with 8 genera, 20 spp. (18.69%), Euglenophyceae with 3 genera, 6 spp. (5.60%), Charophyceae with 1genus, 1 spp. (0.93%) in both seasons. In winter season, abundant class Bacillariophyceae with 14 genera, 24 spp. (48.97%), followed by Chlorophyceae with 11genera, 22 spp. (44.89%), Euglenophyceae 2 genera, 1 spp. Charophyceae with 1 genus, 1 spp. (2.04%). In summer season, abundant class Bacillariophyceae with 10 genera, 22 spp. (38.59%), followed by Cyanophceae 7 genera, 19 spp. (33.33%), Chlorophyceae 7 genera, 11 spp. (19.29%), Euglenophyceae 2 genera, 5 spp. (8.77%). The genus spirogyra is abundant among all sites, shows wide range ecological amplitude, thus found in different habitats. The diatom, bluegreen algae dominated, summer season (38.59%), and (33.33%) respectively, followed by green algae 19.29%). The diatoms registered high numbers in summer (48.97%), winter (38.59%) respectively. The pH of water samples varied 7.35-8.89, more or less alkaline in nature. High pH is positively correlated with algal growth. Turbidity ranged from 5-18 NTU. High turbidity decreases oxygenation, high penetration. TDS, TSS were positively correlated with number of species. TDS were 212.9-297.9 mg/L. The amount of TSS varied from 17-37 mg/L, EC value 365-812 µS/cm. The optimum amount of EC favours growth, distribution of algae. Salinity value 0.5-2.1 mg/L suitable for the growth, distribution of algae. The total CO2 in water was 7.04-54.08 shows more respiration, results algal growth. The amount of DO varied from 2.5-3.8 mg/L. Nitrate as N2 content 0.05-1.8 mg/L, Phosphate as TP range from 0.5-1.4 mg/L and Ca Hardness as CaCO3 227-440 mg/L.

The present study was aimed to evaluate the effect of naphthyl acetic acid (NAA) on chlorophyll, ... more The present study was aimed to evaluate the effect of naphthyl acetic acid (NAA) on chlorophyll, protein, proline, sugar and carotenoid contents along with certain enzymatic activities, namely peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APOX) in two selected varieties i.e. Iqbal and Pahari of maize crop induced under salt stress of different concentrations (100mM, 80mM, 60mM, 40mm and 20mM). The experiment was conducted at the Department of Botany, Bacha Khan University Charsadda, Pakistan during maize growing season, 10-09-2015. The result of the study revealed that different concentrations of NaCl affect the physiological and biochemical parameters. The anti-oxidative enzymes, such as peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APOX), and sugar, proline, and proteins were found maximum in treatment T2, T4, T10 and T12 in the Pahari variety which on physiological basis was found more tolerant to the saline condition and regarding the response to exogenous application of naphthyl acetic acid (NAA) the variety Iqbal was more sensitive to salt stresses.

Mycobuology, 2023

Cordyceps fumosorosea is an important species in the genus of Cordyceps, containing a variety of ... more Cordyceps fumosorosea is an important species in the genus of Cordyceps, containing a variety of bioactive compounds, including fumosorinone (FU). This study was a groundbreaking assessment of FU levels in liquid and solid cultures. The present study focused on the impacts of solid-state fermentation (SSF) using solid substrates (wheat, oat, and rice), as well as the effects of fermentation parameters (pH, temperature, and incubation period), on the generation of FU. All the fermentation parameters had significant effects on the synthesis of FU. In a study of 25 C, 5.5 pH, and 21 days of incubation period combinations calculated-to give maximal FU production, it was found that the optimal values were 25 C, 5.5 pH, and 21 days, respectively. In a solid substrate medium culture, FU could be produced from SSF. At 30 days, a medium composed of rice yielded the most FU (798.50 mg/L), followed by a medium composed of wheat and oats (640.50 and 450.50 mg/L), respectively. An efficient method for increasing FU production on a large scale could be found in this approach. The results of this study might have multiple applications in different industrial fermentation processes.

Journal of Materials Chemistry, 2002

$Research paper thumbnail of Solution of fractional order heat equation via triple Laplace transform in 2 dimensions$

Mathematical Methods in the Applied Sciences, 2017

In this article, we introduce the triple Laplace transform for the solution of a class of fractio... more In this article, we introduce the triple Laplace transform for the solution of a class of fractional order partial differential equations. As a consequence, fractional order homogeneous heat equation in 2 dimensions is investigated in detail. The corresponding solution is obtained by using the aforementioned triple Laplace transform, which is the generalization of double Laplace transform. Numerical plots to the concerned solutions are provided to demonstrate our results.

Advances in Materials Science and Engineering, 2019

Functionally graded materials (FGMs) are novel materials whose properties change gradually with r... more Functionally graded materials (FGMs) are novel materials whose properties change gradually with respect to their dimensions. It is the advanced development of formerly used composite materials and consists of two or more materials in order to achieve the desired properties according to the application where an FGM is used. FGMs have obtained a great attention of researchers in the past decade due to their graded properties at every single point in various dimensions. The properties of an FGM are not identical to the materials that constitute it. This paper aims to present an overview of the existing literature on stability, buckling, and free vibration analysis of FGM carried out by numerous authors in the past decade. Moreover, the analyses of mathematical models adopted for the aforementioned analyses are not the core purpose of this paper. At the end, future work is also suggested in this review paper.

Theoretical biology & medical modelling, Jan 5, 2017

Hepatitis B infection caused by the hepatitis B virus is one of the most serious viral infections... more Hepatitis B infection caused by the hepatitis B virus is one of the most serious viral infections and a global health problem. In the transmission of hepatitis B infection, three different phases, i.e. acute infected, chronically infected, and carrier individuals, play important roles. Carrier individuals are especially significant, because they do not exhibit any symptoms and are able to transmit the infection. Here we assessed the transmissibility associated with different infection stages of hepatitis B and generated an epidemic model. To demonstrate the transmission dynamic of hepatitis B, we investigate an epidemic model by dividing the infectious class into three subclasses, namely acute infected, chronically infected, and carrier individuals with both horizontal and vertical transmission. Numerical results and sensitivity analysis of some important parameters are presented to show that the proportion of births without successful vaccination, perinatally infected individuals, ...

Sarhad Journal of Agriculture, 2016

Clinics in Podiatric Medicine and Surgery, 2013

A retrospective review of 7 patients (8 total feet) was conducted by the authors to determine the... more A retrospective review of 7 patients (8 total feet) was conducted by the authors to determine the effects of combined 1st metatarsal Reverdin-Laird and opening base wedge osteotomy in the management of hallux valgus deformity. Postoperative radiographs were compared with preoperative radiographs for improvement in the 1st intermetatarsal angle, proximal articular set angle, hallux abductus angle, and tibial sesamoid position.

2008 20th International Symposium on Power Semiconductor Devices and IC's, 2008

In this paper, a novel structure based on the Floating RESURF LDMOSFET is proposed for enhanced o... more In this paper, a novel structure based on the Floating RESURF LDMOSFET is proposed for enhanced off-state blocking capability. The new structure facilitates the implementation of FRESURF concept in thicker epi technologies for higher voltage tiers. An additional floating island is introduced, sandwiched between the standard drift region and heavily doped buried layer, which makes the Incremental FRESURF action feasible.

Nephrology Dialysis Transplantation, 2004

Background. The molecular basis for the alteration of glomerular podocyte phenotype in nephrotic ... more Background. The molecular basis for the alteration of glomerular podocyte phenotype in nephrotic syndrome probably involves adaptive changes of the actin cytoskeleton.-Actinin-4 is an actin cross-linking protein that also interacts with intra-and intercellular adhesion molecules and elements of the transmembrane signal transduction pathway and is implicated in nephrotic syndrome by animal models and human genetic studies. Methods. We have performed the first quantitative immunoelectron microscopy study of-actinin-4 expression in humans, analysing 12 cases of minimal change nephrosis (MCNS) and 16 cases of idiopathic membranous nephropathy (MGN), and comparing this with expression in normal tissue from seven nephrectomies (Nx).-Actinin-4 was visualized by immunogold labelling of plastic-embedded whole glomerular cross-sections, and analysed using LUCIA software. Results. Despite podocyte effacement,-actinin-4 expression (group mean±1 SD) in MCNS was similar to that seen in normal Nx podocytes. In contrast,-actinin-4 expression in MGN was significantly higher than in MCNS or Nx (P<0.001). Furthermore, in MGN cases showing a segmental deposition, expression of-actinin-4 was significantly higher only in those capillary loop segments containing deposits, whereas in those segments without deposits expression was unchanged compared with that seen in Nx (P<0.001).-Actinin-4 expression was higher in MGN cases where subepithelial deposits abutted podocyte cytoplasm, and lower in disease stages where deposits were contained within the glomerular basement membrane or were being reabsorbed. Conclusions. Elevated-actinin-4 expression is observed only in MGN, and only in areas of subepithelial deposits. Further investigation into the cause of this may reveal insights into the pathogenesis of acquired nephrosis.

Medical Principles and Practice, 2011

Objective: To evaluate the incidence, treatment and clinical outcomes of tuberculous (TB) lymphad... more Objective: To evaluate the incidence, treatment and clinical outcomes of tuberculous (TB) lymphadenitis at Penang General Hospital, Malaysia. Materials and Methods: Penang General Hospital is the referral center for all tuberculosis patients in the state of Penang. Patient records were reviewed to identify patients with confirmed diagnosis of TB lymphadenitis between January 2006 and December 2008. Data were analyzed using SPSS version 15. Results: Of 1,548 tuberculosis cases, 109 (7.0%) patients had TB lymphadenitis. The mean age was 36.4 ± 12.87 years and of the 109 patients with TB lymphadenitis, 35 (33.0%), 37 (34.0%) and 36 (33.0%) were observed for 2006, 2007 and 2008, respectively. Ethnically, 45 (41.3%) were Malay followed by 37 Chinese (33.9%). Among risk factors for TB lymphadenitis, HIV and diabetes mellitus were seen in 17 (15.6%) and 11 (10.0%) patients, respectively. Cough and fever were the most frequently reported symptoms. In a majority of cases (n = 90, 82.5%) posi...

Journal of the American Podiatric Medical Association, 2013

Background:We explored gait differences in patients with diabetes and peripheral neuropathy (DPN)... more Background:We explored gait differences in patients with diabetes and peripheral neuropathy (DPN) and aged-matched controls over short and long walking distances. The potential benefit of footwear for improving gait in patients with DPN was also explored.Methods:Twelve patients with DPN and eight controls walked at their habitual speed over short (7 m) and long (20 m) distances under two conditions: barefoot and regular shoes. A validated system of body-worn sensors was used to extract spatiotemporal gait parameters. Neuropathy severity was quantified using vibratory perception threshold measured at the great toe.Results:Gait deterioration in the DPN group was observed during all of the walking trials. However, the difference between patients with DPN and participants in the control group achieved statistical significance only during long walking distance trials. Shod and barefoot double support times were longer in the DPN group during long walking distances (>20%,P= .03). Gait ...

Journal of Strength and Conditioning Research, 2009

Few studies have focused upon the physiological responses to circuit weight training (CWT) in men... more Few studies have focused upon the physiological responses to circuit weight training (CWT) in men and women, and an investigation of possible gender differences could lead to optimal exercise prescriptions and improved adaptation outcomes. The purpose of the study was to determine the effects of gender on cardiovascular and metabolic responses to CWT and consequent recovery. Ten healthy men and 10 healthy women completed an initial session to collect descriptive data and determine a 12 repetition maximum (12RM) for 6 different upper- and lower-body resistance exercises. This was followed by 2 identical sessions of a CWT protocol on 2 separate days at least 48 hours apart. The first session was used to familiarize subjects with the equipment and the testing protocol. The second session was used to determine physiological responses. Each subject performed 10 repetitions of 6 exercises for 3 circuits at a 12RM load. Vo2 and respiratory exchange ratio (RER) were continuously monitored, whereas heart rate (HR) and blood pressure (BP) were taken at the end of each circuit. Across the exercise session, men revealed greater absolute and relative Vo2, relative lean body mass Vo2, systolic BP (SBP), RER, and recovery Vo2 when compared with the female subjects. There were no differences in HR, diastolic BP (DBP), or recovery RER. The present study provides a greater insight into gender differences in cardiovascular and metabolic responses to circuit weight training. These gender differences should be taken into consideration for development of CWT protocols for men and women.

Journal of Pediatric Orthopaedics, 1989

Eighteen patients with slipped upper femoral epiphyses were treated by internal fixation using si... more Eighteen patients with slipped upper femoral epiphyses were treated by internal fixation using single pins in the centre of the femoral head. In 15 patients, prophylactic pinning of the unaffected side was performed; therefore, 33 hips were pinned. Results were encouraging in that no slip progressed following fixation, no pins broke, and no late reslips occurred. The optimum position for a pin is in the centre of the femoral head, with subsequent pins in suboptimal sites. The method of single pinning is simple and, theoretically, minimizes the risk of joint penetration.

Journal of Materials Science & Technology, 2011

The excellent corrosion resistance, formability and strength make stainless steels versatile for ... more The excellent corrosion resistance, formability and strength make stainless steels versatile for diverse applications. However, its high specific strength and good crashworthiness make it suitable for transportation and aerospace industry. On the other hand, the need to ...

Journal of Automated Methods and Management in Chemistry, 2005

Clinical chemistry analyser is a high-performance microcontroller-based photometric biochemical a... more Clinical chemistry analyser is a high-performance microcontroller-based photometric biochemical analyser to measure various blood biochemical parameters such as blood glucose, urea, protein, bilirubin, and so forth, and also to measure and observe enzyme growth occurred while performing the other biochemical tests such as ALT (alkaline amino transferase), amylase, AST (aspartate amino transferase), and so forth. These tests are of great significance in biochemistry and used for diagnostic purposes and classifying various disorders and diseases such as diabetes, liver malfunctioning, renal diseases, and so forth. An inexpensive clinical chemistry analyser developed by the authors is described in this paper. This is an open system in which any reagent kit available in the market can be used. The system is based on the principle of absorbance transmittance photometry. System design is based around 80C31 microcontroller with RAM, EPROM, and peripheral interface devices. The developed sy...

International Journal of Urology, 2007

A 30-year old male who had a non-related cadaveric renal transplant at the age of 12 years, prese... more A 30-year old male who had a non-related cadaveric renal transplant at the age of 12 years, presented with generalised CNS symptoms and meningeal enhancement on CT scan of the brain, 18 years after the transplantation. Autopsy revealed renal cell carcinoma in the transplanted kidney and metastatic tumour in a variety of organs including the brain. Prior ultrasound scans done at various post-transplant periods had all been normal.

IEEE Wireless Communications, 2011

IEEE Transactions on Electron Devices, 2008

The effect of different gate oxide processes on the performance of 4H-SiC MOSFETs has been studie... more The effect of different gate oxide processes on the performance of 4H-SiC MOSFETs has been studied. These processes include different gate oxide depositions (high-temperature oxide, low-temperature oxide, and plasma-enhanced chemical vapor deposition oxide) and annealing processes (oxygen, NO, and CO 2). Various MOS device parameters, particularly, threshold voltage, subthreshold slope, field-effect electron mobility, sheet electron carrier concentration, and Hall mobility, are correlated with various process steps.