Ejaz Ahmed - Academia.edu (original) (raw)
Papers by Ejaz Ahmed
Angewandte Chemie (International ed. in English), Jan 9, 2012
An emerging approach: In the ionothermal synthesis of transition-metal-oxide clusters an ionic li... more An emerging approach: In the ionothermal synthesis of transition-metal-oxide clusters an ionic liquid acts as a solvent, structure-directing agent, and charge-compensating species. The method may open new convenient routes for the synthesis of polyoxometalate-based materials.
Angewandte Chemie (International ed. in English), Jan 6, 2012
ABSTRACT One-dimensional conductor: Strong π interactions between ecliptically stacked tellurium ... more ABSTRACT One-dimensional conductor: Strong π interactions between ecliptically stacked tellurium squares in Te(4) [Bi(0.74) Cl(4) ] trigger excellent one-dimensional metallic conductivity as well as superconductivity below 7.15 K under ambient pressure. The electron-precise counterpart, Te(4) [Bi(0.67) Cl(4) ], is a semiconductor. The bismuth content and temperature- dependent competition of intra- and inter-ring bonding account for the electronic conduction.
Journal of nephropathology, 2013
The frequency and clinical and pathological characteristics associated with the Gly206Ala preseni... more The frequency and clinical and pathological characteristics associated with the Gly206Ala presenilin 1 (PSEN1) mutation in Puerto Rican and non-Puerto Rican Hispanics were evaluated at the University of Pennsylvania's Alzheimer's Disease Center. DNAs from all cohort subjects were genotyped for the Gly206Ala PSEN1 mutation. Carriers and non-carriers with neurodegenerative disease dementias were compared for demographic, clinical, psychometric, and biomarker variables. Nineteen (12.6%) of 151 unrelated subjects with dementia were discovered to carry the PSEN1 Gly206Ala mutation. Microsatellite marker genotyping determined a common ancestral haplotype for all carriers. Carriers were all of Puerto Rican heritage with significantly younger age of onset, but otherwise were clinically and neuropsychologically comparable to those of non-carriers with AD. Three subjects had extensive topographic and biochemical biomarker assessments that were also typical of non-carriers with AD. Neuropathological examination in one subject revealed severe, widespread plaque and tangle pathology without other meaningful disease lesions. The PSEN1 Gly206Ala mutation is notably frequent in unrelated Puerto Rican immigrants with dementia in Philadelphia. Considered together with the increased prevalence and mortality of AD reported in Puerto Rico, these high rates may reflect hereditary risk concentrated in the island which warrants further study.
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](Phosphate-based glasses have been investigated for tissue engineering applications. This study de... more Phosphate-based glasses have been investigated for tissue engineering applications. This study details the properties and structural characterization of titanium ultra-phosphate glasses in the 55(P 2 O 5 )-30(CaO)-(25 À x)(Na 2 O)-x(TiO 2 ) (0 6 x 6 5) system, which have been prepared via melt-quenching techniques. Structural characterization was achieved by a combination of X-ray diffraction (XRD), and solid-state nuclear magnetic resonance, Raman and Fourier transform infrared spectroscopies. Physical properties were also investigated using density, degradation and ion release studies; additionally, differential thermal analysis was used for thermal analysis of these glasses. The results show that with the addition of TiO 2 the density and glass transition temperature increased whereas the degradation and ion release properties are decreased. From XRD data, TiP 2 O 7 and CaP 2 O 6 were detected in 3 and 5 mol.% TiO 2 -containing glasses. Magic angle spinning nuclear magnetic resonance results confirmed that as TiO 2 is incorporated into the glass; the amount of Q 3 increases as the amount of Q 2 consequently decreases, indicating increasing polymerization of the phosphate network. Spectroscopy results also showed that the local structure of glasses changes with increasing TiO 2 content. As TiO 2 is incorporated into the glass, the phosphate connectivity increases, indicating that the addition of TiO 2 content correlates unequivocally with an increase in glass stability.
Kidney Diseases in the Developing World and Ethnic Minorities, 2005
Renal transplantation in developing countries. Healthcare in and from cadaver kidneys are 80% and... more Renal transplantation in developing countries. Healthcare in and from cadaver kidneys are 80% and 95%, respecdeveloping countries less funded than developed nations (0.8 tively. This success has been achieved as a result of unto 4% vs. 10 to 15%, respectively), and must contend against precedented advances in immunology, tissue matching, ϳ1/3 of the population living below the poverty line ($1US/ immunosuppression and surgical techniques. These were day), poor literacy (58% males/29% females), and less access
Progress in Natural Science: Materials International, 2013
ZnO and Cr-doped ZnO thin films are grown on to glass substrates using reactive electron beam (e-... more ZnO and Cr-doped ZnO thin films are grown on to glass substrates using reactive electron beam (e-beam) evaporation technique. Variation of structural, morphological, and optical properties with Cr doping is investigated. X-ray diffraction (XRD) studies show that the films are polycrystalline in nature with single phase. Energy dispersive spectroscopy (EDS) results demonstrate that Cr ions are substitutionally incorporated into ZnO. Atomic force microscopy (AFM) reveals that the films present a compact surface and root mean squared (RMS) roughness increased with Cr contents. The optical band gap energy E g of the films has been determined using Transmission data by spectrophotometer and ellipsometry. The band gap energy found to be decreased with increasing Cr doping concentration. The optical constants (refractive index, extinction coefficient) are calculated using ellipsometry and found to increase with Cr doping concentration.
Journal of nephropathology, 2014
Chronic allograft nephropathy (CAN) is a common cause of delayed allograft failure throughout the... more Chronic allograft nephropathy (CAN) is a common cause of delayed allograft failure throughout the world. Its prevalence and risk factors vary depending on a number of factors. There is little information on the prevalence and risk factors for early CAN in live related renal transplant patients. We aimed to determine the prevalence and the risk factors of early CAN in our setup. The study was conducted at Sindh Institute of Urology & Transplantation (SIUT), Karachi, from 2002 to 2005 on patients who had live related kidney transplantation and underwent at least one allograft biopsy within 18 months of transplantation. The biopsies were performed and prepared in accordance with established indications and guidelines. The Banff 97 classification and its updates were used to diagnose and categorize the biopsy pathology. Patients were divided into two groups depending on the presence or absence of CAN on biopsies. Following parameters were compared among the groups: age, sex, human leukocyte antigen (HLA) match, immunosuppression used, acute rejection (AR) episodes, urinary tract infections (UTIs), viral infections, cyclosporine levels, early and late graft function monitored by serum creatinine. A total of 164 patients fulfilled the study inclusion criteria. The mean age of recipients and donors was relatively young. The majority of the donors were siblings. The overall prevalence of CAN was 25.6% (42/164), between 3 and 18 months post transplantation. The median time to the appearance of CAN was 9 months post-transplant. The prevalence of CAN increased as post-transplant duration increased. In 39 (92.8%) subjects, CAN was detected on the second or subsequent graft biopsy. Only 3 (7.2%) patients showed CAN on the first graft biopsy. The majority of cases belonged to moderate degree or grade II CAN. The mean serum creatinine values were higher in the CAN group at the time of discharge and all times post-transplantation. In conclusion, the results show that serum creatinine at the time of discharge is a useful predictor of later development of chronic changes in the allograft. Further studies are needed to identify the risk factors for the early development of chronic changes in living related renal transplant program.
Nephro-urology monthly, 2013
Amyloidosis is a disorder of protein metabolism characterized by extracellular deposition of abno... more Amyloidosis is a disorder of protein metabolism characterized by extracellular deposition of abnormal protein fibrils. It may either be localized to any organ or systematically distributed throughout the body. The biochemical nature of proteins varies but the physical and tinctorial properties are shared by all the amyloidogenic proteins. In the West, it is mainly composed of amyloid light (AL) type immunoglobulin (Ig) light chains. Amyloidosis of the genitourinary tract is rare except for the kidney and isolated primary amyloidosis of the urinary bladder is even rarer. It mainly presents as intermittent painless gross hematuria. It mimics transitional cell carcinoma on imaging and endoscopic examination. We herein present a case of fifty six-years-old male with history of painless hematuria for three months. Cystoscopy revealed a 1 cm hyperemic area on the posterior wall of urinary bladder. The biopsy showed features of amyloidosis and amyloid A (AA) immunostaining was negative. Extensive workup was done to exclude other sites of involvement and a final diagnosis of primary localized amyloidosis of the urinary bladder was made. The patient is on regular follow-up.
Cheminform, 2005
For Abstract see ChemInform Abstract in Full Text.
Natural Product Research - NAT PROD RES, 2007
Haloxylase, the triglyceride (1), unsaturated fatty acid (2), and saturated fatty acid methyl est... more Haloxylase, the triglyceride (1), unsaturated fatty acid (2), and saturated fatty acid methyl ester (3) have been isolated from the chloroform-soluble fraction of Haloxylon recurvum. Their structures have been elucidated through spectroscopic studies and chemical transformation. All these compounds showed significant inhibitory activity against the enzyme chymotrypsin in a concentration dependent fashion.
Chemical & Pharmaceutical Bulletin, 2006
Two new sterols, halosterols A (1) and B (2), have been isolated from the CHCl(3) soluble fractio... more Two new sterols, halosterols A (1) and B (2), have been isolated from the CHCl(3) soluble fraction of Haloxylon recurvum, and their structures were elucidated by spectroscopic techniques including two dimensional-NMR. Both the compounds displayed chymotrypsin enzyme inhibitory potential.
Chemical & Pharmaceutical Bulletin, 2006
Hyperinols A (1) and B (2) are new taraxastane type triterpenes which have been isolated from the... more Hyperinols A (1) and B (2) are new taraxastane type triterpenes which have been isolated from the chloroform soluble fraction of Hypericum oblongifolium and their structures elucidated on the basis of spectroscopic data. Both showed significant inhibitory activity against chymotrypsin enzyme.
Chemical & Pharmaceutical Bulletin, 2006
Marianine, the new lanostane triterpene (1) and marianosides A (2) and B (3) have been isolated f... more Marianine, the new lanostane triterpene (1) and marianosides A (2) and B (3) have been isolated from the whole plant of Silybum marianum. Their structures were elucidated on the basis of extensive analysis of their one dimensional and two dimensional nuclear magnetic resonance (1D, 2D-NMR) spectral data. All inhibited chymotrypsin in a concentration-dependent manner.
Chemistry & Biodiversity, 2007
Calligonolides A (1) and B (2), two new butanolides, and a new steroidal ester, 3, have been isol... more Calligonolides A (1) and B (2), two new butanolides, and a new steroidal ester, 3, have been isolated from the whole plant of Calligonum polygonoides, together with four known compounds, tetracosan-4-olide, β-sitosterol and its glucoside, and ursolic acid. Their structures were elucidated by spectroscopic and mass-spectrometric studies. Compounds 1–3 showed moderate inhibitory potential against lipoxygenase from soybean.
Journal of the Physical …, 2009
We investigated the ordering behavior of ternary CuMPt 6 alloys with M ¼ Ti, V, Cr, Mn, Fe, Co, a... more We investigated the ordering behavior of ternary CuMPt 6 alloys with M ¼ Ti, V, Cr, Mn, Fe, Co, and Ni by high-temperature polycrystalline X-ray diffraction. The alloys undergo a phase transition from the fcc disordered state to the Cu 3 Au-type ordered state, except for the alloy with M ¼ Ni, in which only short-range order forms. The transition temperature T c is highest (1593 K) for M ¼ Ti and decreases almost monotonically with increasing atomic number to 1153 K for M ¼ Co. The observed dependence of ordering tendency on the atomic number of M is discussed in the light of the theory of ordering in transition-metal alloys and its significance for the study of ordering in ternary alloys.
Cheminform, 2007
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Archives of Pharmacal Research, 2005
Indigin, alkylated xanthene (1) and indigoferic acid (2) have been isolated from the chloroform s... more Indigin, alkylated xanthene (1) and indigoferic acid (2) have been isolated from the chloroform soluble fraction ofIndigofera oblongifolia, along with β-sitosterol (3) and 3-hydroxybenzoic acid (4), which are reported for the first time from this species. Their structures were determined through spectroscopic techniques. Both the new compounds1 and2 showed significant activity against enzyme lipoxygenase, while2 further showed moderate inhibition against BChE.
Angewandte Chemie (International ed. in English), Jan 9, 2012
An emerging approach: In the ionothermal synthesis of transition-metal-oxide clusters an ionic li... more An emerging approach: In the ionothermal synthesis of transition-metal-oxide clusters an ionic liquid acts as a solvent, structure-directing agent, and charge-compensating species. The method may open new convenient routes for the synthesis of polyoxometalate-based materials.
Angewandte Chemie (International ed. in English), Jan 6, 2012
ABSTRACT One-dimensional conductor: Strong π interactions between ecliptically stacked tellurium ... more ABSTRACT One-dimensional conductor: Strong π interactions between ecliptically stacked tellurium squares in Te(4) [Bi(0.74) Cl(4) ] trigger excellent one-dimensional metallic conductivity as well as superconductivity below 7.15 K under ambient pressure. The electron-precise counterpart, Te(4) [Bi(0.67) Cl(4) ], is a semiconductor. The bismuth content and temperature- dependent competition of intra- and inter-ring bonding account for the electronic conduction.
Journal of nephropathology, 2013
The frequency and clinical and pathological characteristics associated with the Gly206Ala preseni... more The frequency and clinical and pathological characteristics associated with the Gly206Ala presenilin 1 (PSEN1) mutation in Puerto Rican and non-Puerto Rican Hispanics were evaluated at the University of Pennsylvania's Alzheimer's Disease Center. DNAs from all cohort subjects were genotyped for the Gly206Ala PSEN1 mutation. Carriers and non-carriers with neurodegenerative disease dementias were compared for demographic, clinical, psychometric, and biomarker variables. Nineteen (12.6%) of 151 unrelated subjects with dementia were discovered to carry the PSEN1 Gly206Ala mutation. Microsatellite marker genotyping determined a common ancestral haplotype for all carriers. Carriers were all of Puerto Rican heritage with significantly younger age of onset, but otherwise were clinically and neuropsychologically comparable to those of non-carriers with AD. Three subjects had extensive topographic and biochemical biomarker assessments that were also typical of non-carriers with AD. Neuropathological examination in one subject revealed severe, widespread plaque and tangle pathology without other meaningful disease lesions. The PSEN1 Gly206Ala mutation is notably frequent in unrelated Puerto Rican immigrants with dementia in Philadelphia. Considered together with the increased prevalence and mortality of AD reported in Puerto Rico, these high rates may reflect hereditary risk concentrated in the island which warrants further study.
Phosphate-based glasses have been investigated for tissue engineering applications. This study de... more Phosphate-based glasses have been investigated for tissue engineering applications. This study details the properties and structural characterization of titanium ultra-phosphate glasses in the 55(P 2 O 5 )-30(CaO)-(25 À x)(Na 2 O)-x(TiO 2 ) (0 6 x 6 5) system, which have been prepared via melt-quenching techniques. Structural characterization was achieved by a combination of X-ray diffraction (XRD), and solid-state nuclear magnetic resonance, Raman and Fourier transform infrared spectroscopies. Physical properties were also investigated using density, degradation and ion release studies; additionally, differential thermal analysis was used for thermal analysis of these glasses. The results show that with the addition of TiO 2 the density and glass transition temperature increased whereas the degradation and ion release properties are decreased. From XRD data, TiP 2 O 7 and CaP 2 O 6 were detected in 3 and 5 mol.% TiO 2 -containing glasses. Magic angle spinning nuclear magnetic resonance results confirmed that as TiO 2 is incorporated into the glass; the amount of Q 3 increases as the amount of Q 2 consequently decreases, indicating increasing polymerization of the phosphate network. Spectroscopy results also showed that the local structure of glasses changes with increasing TiO 2 content. As TiO 2 is incorporated into the glass, the phosphate connectivity increases, indicating that the addition of TiO 2 content correlates unequivocally with an increase in glass stability.
Kidney Diseases in the Developing World and Ethnic Minorities, 2005
Renal transplantation in developing countries. Healthcare in and from cadaver kidneys are 80% and... more Renal transplantation in developing countries. Healthcare in and from cadaver kidneys are 80% and 95%, respecdeveloping countries less funded than developed nations (0.8 tively. This success has been achieved as a result of unto 4% vs. 10 to 15%, respectively), and must contend against precedented advances in immunology, tissue matching, ϳ1/3 of the population living below the poverty line ($1US/ immunosuppression and surgical techniques. These were day), poor literacy (58% males/29% females), and less access
Progress in Natural Science: Materials International, 2013
ZnO and Cr-doped ZnO thin films are grown on to glass substrates using reactive electron beam (e-... more ZnO and Cr-doped ZnO thin films are grown on to glass substrates using reactive electron beam (e-beam) evaporation technique. Variation of structural, morphological, and optical properties with Cr doping is investigated. X-ray diffraction (XRD) studies show that the films are polycrystalline in nature with single phase. Energy dispersive spectroscopy (EDS) results demonstrate that Cr ions are substitutionally incorporated into ZnO. Atomic force microscopy (AFM) reveals that the films present a compact surface and root mean squared (RMS) roughness increased with Cr contents. The optical band gap energy E g of the films has been determined using Transmission data by spectrophotometer and ellipsometry. The band gap energy found to be decreased with increasing Cr doping concentration. The optical constants (refractive index, extinction coefficient) are calculated using ellipsometry and found to increase with Cr doping concentration.
Journal of nephropathology, 2014
Chronic allograft nephropathy (CAN) is a common cause of delayed allograft failure throughout the... more Chronic allograft nephropathy (CAN) is a common cause of delayed allograft failure throughout the world. Its prevalence and risk factors vary depending on a number of factors. There is little information on the prevalence and risk factors for early CAN in live related renal transplant patients. We aimed to determine the prevalence and the risk factors of early CAN in our setup. The study was conducted at Sindh Institute of Urology & Transplantation (SIUT), Karachi, from 2002 to 2005 on patients who had live related kidney transplantation and underwent at least one allograft biopsy within 18 months of transplantation. The biopsies were performed and prepared in accordance with established indications and guidelines. The Banff 97 classification and its updates were used to diagnose and categorize the biopsy pathology. Patients were divided into two groups depending on the presence or absence of CAN on biopsies. Following parameters were compared among the groups: age, sex, human leukocyte antigen (HLA) match, immunosuppression used, acute rejection (AR) episodes, urinary tract infections (UTIs), viral infections, cyclosporine levels, early and late graft function monitored by serum creatinine. A total of 164 patients fulfilled the study inclusion criteria. The mean age of recipients and donors was relatively young. The majority of the donors were siblings. The overall prevalence of CAN was 25.6% (42/164), between 3 and 18 months post transplantation. The median time to the appearance of CAN was 9 months post-transplant. The prevalence of CAN increased as post-transplant duration increased. In 39 (92.8%) subjects, CAN was detected on the second or subsequent graft biopsy. Only 3 (7.2%) patients showed CAN on the first graft biopsy. The majority of cases belonged to moderate degree or grade II CAN. The mean serum creatinine values were higher in the CAN group at the time of discharge and all times post-transplantation. In conclusion, the results show that serum creatinine at the time of discharge is a useful predictor of later development of chronic changes in the allograft. Further studies are needed to identify the risk factors for the early development of chronic changes in living related renal transplant program.
Nephro-urology monthly, 2013
Amyloidosis is a disorder of protein metabolism characterized by extracellular deposition of abno... more Amyloidosis is a disorder of protein metabolism characterized by extracellular deposition of abnormal protein fibrils. It may either be localized to any organ or systematically distributed throughout the body. The biochemical nature of proteins varies but the physical and tinctorial properties are shared by all the amyloidogenic proteins. In the West, it is mainly composed of amyloid light (AL) type immunoglobulin (Ig) light chains. Amyloidosis of the genitourinary tract is rare except for the kidney and isolated primary amyloidosis of the urinary bladder is even rarer. It mainly presents as intermittent painless gross hematuria. It mimics transitional cell carcinoma on imaging and endoscopic examination. We herein present a case of fifty six-years-old male with history of painless hematuria for three months. Cystoscopy revealed a 1 cm hyperemic area on the posterior wall of urinary bladder. The biopsy showed features of amyloidosis and amyloid A (AA) immunostaining was negative. Extensive workup was done to exclude other sites of involvement and a final diagnosis of primary localized amyloidosis of the urinary bladder was made. The patient is on regular follow-up.
Cheminform, 2005
For Abstract see ChemInform Abstract in Full Text.
Natural Product Research - NAT PROD RES, 2007
Haloxylase, the triglyceride (1), unsaturated fatty acid (2), and saturated fatty acid methyl est... more Haloxylase, the triglyceride (1), unsaturated fatty acid (2), and saturated fatty acid methyl ester (3) have been isolated from the chloroform-soluble fraction of Haloxylon recurvum. Their structures have been elucidated through spectroscopic studies and chemical transformation. All these compounds showed significant inhibitory activity against the enzyme chymotrypsin in a concentration dependent fashion.
Chemical & Pharmaceutical Bulletin, 2006
Two new sterols, halosterols A (1) and B (2), have been isolated from the CHCl(3) soluble fractio... more Two new sterols, halosterols A (1) and B (2), have been isolated from the CHCl(3) soluble fraction of Haloxylon recurvum, and their structures were elucidated by spectroscopic techniques including two dimensional-NMR. Both the compounds displayed chymotrypsin enzyme inhibitory potential.
Chemical & Pharmaceutical Bulletin, 2006
Hyperinols A (1) and B (2) are new taraxastane type triterpenes which have been isolated from the... more Hyperinols A (1) and B (2) are new taraxastane type triterpenes which have been isolated from the chloroform soluble fraction of Hypericum oblongifolium and their structures elucidated on the basis of spectroscopic data. Both showed significant inhibitory activity against chymotrypsin enzyme.
Chemical & Pharmaceutical Bulletin, 2006
Marianine, the new lanostane triterpene (1) and marianosides A (2) and B (3) have been isolated f... more Marianine, the new lanostane triterpene (1) and marianosides A (2) and B (3) have been isolated from the whole plant of Silybum marianum. Their structures were elucidated on the basis of extensive analysis of their one dimensional and two dimensional nuclear magnetic resonance (1D, 2D-NMR) spectral data. All inhibited chymotrypsin in a concentration-dependent manner.
Chemistry & Biodiversity, 2007
Calligonolides A (1) and B (2), two new butanolides, and a new steroidal ester, 3, have been isol... more Calligonolides A (1) and B (2), two new butanolides, and a new steroidal ester, 3, have been isolated from the whole plant of Calligonum polygonoides, together with four known compounds, tetracosan-4-olide, β-sitosterol and its glucoside, and ursolic acid. Their structures were elucidated by spectroscopic and mass-spectrometric studies. Compounds 1–3 showed moderate inhibitory potential against lipoxygenase from soybean.
Journal of the Physical …, 2009
We investigated the ordering behavior of ternary CuMPt 6 alloys with M ¼ Ti, V, Cr, Mn, Fe, Co, a... more We investigated the ordering behavior of ternary CuMPt 6 alloys with M ¼ Ti, V, Cr, Mn, Fe, Co, and Ni by high-temperature polycrystalline X-ray diffraction. The alloys undergo a phase transition from the fcc disordered state to the Cu 3 Au-type ordered state, except for the alloy with M ¼ Ni, in which only short-range order forms. The transition temperature T c is highest (1593 K) for M ¼ Ti and decreases almost monotonically with increasing atomic number to 1153 K for M ¼ Co. The observed dependence of ordering tendency on the atomic number of M is discussed in the light of the theory of ordering in transition-metal alloys and its significance for the study of ordering in ternary alloys.
Cheminform, 2007
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Archives of Pharmacal Research, 2005
Indigin, alkylated xanthene (1) and indigoferic acid (2) have been isolated from the chloroform s... more Indigin, alkylated xanthene (1) and indigoferic acid (2) have been isolated from the chloroform soluble fraction ofIndigofera oblongifolia, along with β-sitosterol (3) and 3-hydroxybenzoic acid (4), which are reported for the first time from this species. Their structures were determined through spectroscopic techniques. Both the new compounds1 and2 showed significant activity against enzyme lipoxygenase, while2 further showed moderate inhibition against BChE.