Irfan Ahmad

Followers

Following

Public Views

Interests

Uploads

Papers by Irfan Ahmad

Room temperature chemical synthesis of Bi 2 O 3 nanoparticles

Micro & Nano Letters, 2021

In this article, room temperature synthesis of Bi 2 O 3 nanoparticles in a single-pot reaction is... more In this article, room temperature synthesis of Bi 2 O 3 nanoparticles in a single-pot reaction is reported. The nanoparticles were synthesized by reducing Bi(NO 3) 3 ⋅5H 2 O with NaBH 4 as a reducing agent, SDS and oleic acid as stabilizing agents. The synthesized nanoparticles were characterized using UV-vis absorption spectroscopy, FTIR spectroscopy, XRD, and HR-TEM. The crystalline nature of the synthesized nanoparticles was confirmed through XRD and HRTEM data analysis. An average particle size of 14 nm (with quasispherical morphology) and a wide band gap were measured for the synthesized nanoparticles. HRTEM image confirmed a highly crystalline growth at individual nanoparticle level. Dielectric measurement indicates a rapid reduction of both real and imaginary dielectric constants as the frequency increases to higher values. The potential application of the synthesized nanoparticles has been demonstrated in photocatalytic degradation of pollutants present in the industrial waste-water. 1 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Download

Transplantation of ocular stem cells: the role of injury in incorporation and differentiation of grafted cells in the retina

Vision Research, 2003

The incorporation of transplanted cells into the host retina is one of the prerequisites for succ... more The incorporation of transplanted cells into the host retina is one of the prerequisites for successful cell replacement therapy to treat retinal degeneration. To test the hypothesis that injury promotes cell incorporation, stem cells/progenitors were isolated from the retina, ciliary epithelium or limbal epithelium and transplanted into the eyes of rats with retinal injury. Different stem cell/ progenitor populations incorporated into traumatized or diseased retina but not into the normal retina. The proportion of cells incorporated into the inner retina was consistently higher than in the outer retina. The transplanted cells expressed markers specific to cells of the lamina into which they were incorporated suggesting that cues for specific differentiation are localized within the inner and outer retina. These findings demonstrate that injury-induced cues play a significant role in promoting the incorporation of ocular stem cells/progenitors regardless of their origin or their differentiation along specific retinal sublineage.

Download

Predictors of fatal outcome in fulminant hepatic failure

Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2006

To determine prognostic indicators for morbidity and mortality in patients with fulminant hepatic... more To determine prognostic indicators for morbidity and mortality in patients with fulminant hepatic failure. Observational study. Department of Gastroenterology and Hepatology, Shaikh Zayed Postgraduate Medical Institute, Lahore, from April 2003 to June 2005. Forty five patients with confirmed diagnosis of fulminant hepatic failure were included in this study. They were investigated for acute viral serology, complete blood count, liver function tests, renal function tests, serum electrolytes, arterial blood gases, initially daily and then on alternate days. Patients were followed in high dependency/ICU at the Shaikh Zayed Postgraduate Medical Institute. Data were analyzed by logistic regression analysis to identify predictors of mortality and morbidity. Of the 45 subjects, 31 were males and 14 females. Twenty four patients were positive for acute hepatitis E. Twenty patients recovered fully, whereas 25 died with mortality rate of 55.6 %. Variables i.e. presence of non-A non-B viral he...

A study of colorectal polyps

Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2006

To determine various features of colorectal polyps and to evaluate the safety of colonoscopic pol... more To determine various features of colorectal polyps and to evaluate the safety of colonoscopic polypectomy. Case series. The Department of Gastroenterology and Hepatology, Federal Postgraduate Medical Institute, Shaikh Zayed Hospital, Lahore, from January 1987 to January 2004. This study was based on data analysis of 393 patients who underwent colonoscopic polypectomy at our institution during 17 years from January 1987 to January 2004. Presenting complaints of patients were noted. Polyps were evaluated in terms of size, site, number and histopathology. Among 393 patients, 268 were male and 125 female. Presenting complaints were bleeding per rectum in 339 patients, diarrhea with blood in 34 and without blood in 6 patients, and lower abdominal pain in 12 patients. Two patients were being investigated for iron deficiency anemia. Two hundred and sixty-four patients had juvenile polyps, 39 had adenomatous polyps, 39 hyperplastic polyps, 39 inflammatory polyps, 3 malignant polyps and 2 pa...

Serum alanine aminotransferase level and response to interferon-ribavirin combination therapy in patients with chronic hepatitis C

Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2006

To determine the difference in sustained virological response to interferon-ribavirin combination... more To determine the difference in sustained virological response to interferon-ribavirin combination therapy between patients with normal ALT and those with raised ALT in chronic hepatitis C. Quasi-experimental study. Department of Gastroenterology and Hepatology, Shaikh Zayed Postgraduate Medical Institute, Lahore, from February 2004 to June 2005. Patients with positive HCV RNA by PCR and compensated liver disease were included and divided in two groups. One group with ALT below upper normal limit (UNL= 65U/L) and second group with raised ALT (> 1x UNL). After treatment with standard interferon alpha 2a and ribavirin, both groups were checked for sustained viral response (SVR) six months after end of treatment and compared for response to therapy with Chi square test. Of the 70 patients included, 25 had normal ALT (< 1 x upper normal limit UNL) and 45 had ALT above upper normal limit (> 1 x UNL). Of these, 63 patients completed treatment. Sustained viral response (SVR) was se...

A cascade framework for unoccluded and occluded pedestrian detection

Proceedings of the 2014 IEEE Students' Technology Symposium, 2014

This paper presents a novel pedestrian detection framework for efficient detection of both unoccl... more This paper presents a novel pedestrian detection framework for efficient detection of both unoccluded and occluded pedestrians, thereby proposing an efficient technique for pedestrian detection in real-time environment. Our framework consists of two layers of detection, the first layer using full body detectors for accurate detection of unoccluded pedestrians and then a cascaded layer of part based detectors to efficiently detect the occluded pedestrians. The full body detectors based techniques are state-of-the art for unoccluded pedestrian detection and the part based model is a viable choice for partially occluded pedestrian detection. In our part based model, we use six parts; three horizontal parts and three vertical parts thereby creating a model that is robust to varying degrees and types of occlusions. Each detection layer utilizes multiple modalities (cues) namely; intensity, dense stereo and dense flow. The use of part based detectors as the cascaded layer also increases the unoccluded pedestrian detection rate by correctly detecting the pedestrians that had been misclassified by the first layer. Thus, the second layer of part based detectors has a synergic effect on the first layer.

Download

Cyst Nematodes in India

Cyst Nematodes, 1986

Nineteen species of cyst nematodes have been recorded from many areas in India since 1958 when th... more Nineteen species of cyst nematodes have been recorded from many areas in India since 1958 when the first species, Heterodera avenae Woll. was reported (Vasudeva, 1958). The golden cyst nematode, Globodera rostochiensis (Woll.) Behr., was first discovered by Jones (1961) and since then both G. rostochiensis and G. pallida (Stone) Behr. have been found extensively in potato crops in southern India (Seshadri & Sivakumar, 1962; Thangaraju, 1983). The other seventeen species have been found in association with major crops: wheat, barley, ragi, pulses, rice, sugarcane, maize, and others (Table 1). Cyst nematodes have been recorded from 13 states and the union territory of Delhi. In eleven states two or more species have been found, while in seven states three or more species have been recorded. The highest number of seven species from Delhi is probably accounted for by the greater number of surveys made there than other parts of the country. Cyst nematodes are also likely to be present in the rest of the states but few surveys have been carried out to detect them.

Protection of growth and photosynthesis of Brassica juncea genotype with dual type sulfur transport system against sulfur deprivation by coordinate changes in the activities of sulfur metabolism enzymes and cysteine and glutathione production

Russian Journal of Plant Physiology, 2011

plants is initiated by its activation, and the reaction is catalyzed by the enzyme ATP sulfurylas... more plants is initiated by its activation, and the reaction is catalyzed by the enzyme ATP sulfurylase (ATP S) and finally leads to the formation of cysteine (Cys) [1, 3]. Cys serves as a precursor for a range of further reduced S containing compounds, including glu tathione (GSH). GSH represents a major S storage capacity in plants and performs several essential func tions within the plant cell, serving as a redox regulator and antioxidant [4-6]. As a component of the ascor bate-GSH cycle, it takes part in the removal of H 2 O 2 excess, in a reaction, in which GSH is oxidized to glu tathione disulfide (GSSG). The high ratio of GSH to its oxidized form, GSSG, occurring under optimal growth conditions can be restored by means of higher glutathione reductase (GR) activity, increased GSH synthesis, decreased GSH degradation, or the trans port of GSH and GSSG [7]. In addition, by affecting

Download

Effects of cadmium stress upon activities of antioxidative enzymes, photosynthetic rate, and production of phytochelatins in leaves and chloroplasts of wheat cultivars differing in yield potential

Photosynthetica, 2009

We tested the mode of action of Cd on photosynthesis and activities of ATP-sulfurylase (ATP-S), c... more We tested the mode of action of Cd on photosynthesis and activities of ATP-sulfurylase (ATP-S), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), and on contents of phytochelatins (PCs) and glutathione (GSH) in two cultivars of wheat (Triticum aestivum L.) PBW-343 and WH-542 differing in yield potential. Cd treatment increased Cd content and photosynthetic activity in PBW-343 more than in WH-542. The activities of APX, GR, ATP-S, and synthesis of PCs and GSH were also increased by Cd, but the CAT and SOD activities were inhibited in both the cultivars. The efficient functioning of antioxidative enzymes, production of PCs and GSH, helped in counteracting the effects of Cd namely in PBW-343, protected photosynthetic ability, and increased the tolerance to Cd.

Download

Characterization and density functional theory study of the antioxidant activity of quercetin and its sugar-containing analogues

European Food Research and Technology, 2013

Download

A study of the intestinal contents of some mononchs

Revue Nérnatol, 1986

SUMMARY The intestinal contents of over one thousand specimens of thirty three species belonging ... more

Download

Digital dental photography. Part 4: choosing a camera

British Dental Journal, 2009

The fi rst is an intra-oral or fi bre optic camera. This is an excellent tool for a cursory tour ... more The fi rst is an intra-oral or fi bre optic camera. This is an excellent tool for a cursory tour of the oral cavity, showing patients gingival infl ammation, decay and defective restorations. While its quality is adequate for displaying on a monitor, it is insuffi cient for permanent documentation or for archiving.

Download

Risk management in clinical practice. Part 5. Ethical considerations for dental enhancement procedures

BDJ, 2010

Download

High Prevalence of Carbapenem-Resistant Acinetobacter baumannii Carrying the blaOXA-143 Gene in Brazilian Hospitals

Antimicrobial Agents and Chemotherapy, 2010

High Prevalence of Carbapenem-Resistant Acinetobacter baumannii Carrying the bla OXA-143 Gene in ... more High Prevalence of Carbapenem-Resistant Acinetobacter baumannii Carrying the bla OXA-143 Gene in Brazilian Hospitals ᰔ A recent article by Higgins et al. reported the identification of a novel carbapenem-hydrolyzing class D ␤-lactamase (CHDL), defined as OXA-143, in a carbapenem-resistant Acinetobacter baumannii strain isolated in Brazil in 2004 (5). This enzyme, which has 88% identity with OXA-40, is the first representative of a novel subgroup of CHDLs whose prevalence remains to be determined (5). In an attempt to carry out this task, we have conducted a surveillance study of carbapenem-resistant A. baumannii isolates in order to determine the antimicrobial susceptibility patterns and prevalence of bla OXAtype carbapenemase genes in medical centers in both the southeastern and southern regions of Brazil. We report here a

Download

Single-Cell RNA Sequencing with Spatial Transcriptomics of Cancer Tissues

International Journal of Molecular Sciences, 2022

Single-cell RNA sequencing (RNA-seq) techniques can perform analysis of transcriptome at the sing... more Single-cell RNA sequencing (RNA-seq) techniques can perform analysis of transcriptome at the single-cell level and possess an unprecedented potential for exploring signatures involved in tumor development and progression. These techniques can perform sequence analysis of transcripts with a better resolution that could increase understanding of the cellular diversity found in the tumor microenvironment and how the cells interact with each other in complex heterogeneous cancerous tissues. Identifying the changes occurring in the genome and transcriptome in the spatial context is considered to increase knowledge of molecular factors fueling cancers. It may help develop better monitoring strategies and innovative approaches for cancer treatment. Recently, there has been a growing trend in the integration of RNA-seq techniques with contemporary omics technologies to study the tumor microenvironment. There has been a realization that this area of research has a huge scope of application i...

Download

Irfan Ahmad

Uploads

Papers by Irfan Ahmad

Log In