Muhammad Aamir - Academia.edu (original) (raw)
Papers by Muhammad Aamir
Mixed metal halide perovskites are gaining paramount interest due to efficient band gap tenabilit... more Mixed metal halide perovskites are gaining paramount interest due to efficient band gap tenability and improved optical properties compared to their single metal halide perovskites. It is thus valuable to investigate compositional changes in lead halide perovskites to explore energy changes. Herein, we report the synthesis of a lead to lead free hybrid perovskite solid solution (CH 3 NH 3 Pb 1Àx Cu x Br 3) as nanoparticles and films. The increasing concentration of Cu 2+ ions in the site of the Pb 2+ ion in the perovskite shifted the diffraction peaks to a larger angle. Uniform spherically shaped nanoparticles were synthesized by a wet chemical method, the higher Cu 2+ concentration leads to agglomeration, producing sheet like morphologies. However, the deposition of thin films of CH 3 NH 3 Pb 1Àx Cu x Br 3 perovskite solid solution shows that well defined morphologies begin to appear with increasing concentrations of Cu 2+ in the perovskite structure. The as-prepared bulk lead free CH 3 NH 3 CuBr 3 perovskite shows a band gap of 1.65 eV. A blue shift in photoluminescence (PL) was observed with copper enriched hybrid perovskites.
Inorganic halide perovskite (CsPbX 3) nanostructures have gained considerable interest in recent ... more Inorganic halide perovskite (CsPbX 3) nanostructures have gained considerable interest in recent years owing to their enhanced stability and optoelectronic applications. Recent developments in the synthesis of nanostructures are reviewed. The impact of the precursor and ligand nature, temperature and growth time on the morphology and shape tuning of CsPbX 3 nanostructures is described in relation to their optical properties. The presynthetic and postsynthetic anion exchange strategies to retain pre-existing crystal phase and shape are discussed in this minireview.
Soil and Sediment Contamination: An International Journal, 2016
Latin American Journal of Pharmacy, Aug 1, 2011
Latin American Journal of Pharmacy, 2010
Iranian Polymer Journal, 2009
African Journal of Pharmacy and Pharmacology, Oct 22, 2011
Environmental geochemistry and health, Jan 29, 2016
Hexachlorocyclohexane (HCH) isomers and dichlorodiphenyltrichloroethane (DDT) metabolites were an... more Hexachlorocyclohexane (HCH) isomers and dichlorodiphenyltrichloroethane (DDT) metabolites were analyzed in sediments of three different depths (0-10, 10-20 and 20-30 cm) collected from Kabul River, Pakistan, in February 2014. The occurrence levels, enantiomer fractions and potential ecological risk of these organochlorine pesticides (OCPs) were evaluated. The total concentrations of ∑HCHs and ∑DDTs in surface sediments ranged from 4.9-23.9 ng g(-1) and from 6.4-18.8 ng g(-1) (dry weight basis), respectively. The vertical contamination profile of DDTs was found in order of 20-30 cm >10-20 cm >0-10 cm, indicated that the residue levels of DDTs gradually decreased after it was banned. The ratios of β-HCH/HCHs ranged from 0.04 to 0.73 (69 % of samples below 0.5) suggesting the fresh input of HCHs, while isomeric ratios of α-HCH/γ-HCH (ranged from 0.02 to 7.94), with 76 % of samples less than 3, indicating the cocktail use of technical grade HCH and lindane in the study area. The r...
Latin American Journal of Pharmacy, 2010
Journal of the College of Physicians and Surgeons Pakistan Jcpsp, Sep 1, 2004
Latin American Journal of Pharmacy, 2011
Latin American Journal of Pharmacy, 2010
Latin American Journal of Pharmacy, 2012
Materials Science in Semiconductor Processing, 2017
A B S T R A C T Hybrid perovskite have shown a potential as structurally and chemically tunable m... more A B S T R A C T Hybrid perovskite have shown a potential as structurally and chemically tunable materials with interesting optical properties. Herein, We describe the synthesis and characterization of two new perovskites, hydroxyl ammonium lead iodo chloride, OHNH 3 PbI 2 Cl (1) and hydroxyl ammonium lead chloride, OHNH 3 PbCl 3 (2) by wet-chemical route. The as-prepared (1) and (2) have shown promising optical properties with suitable band gaps 3.7 eV and 3.9 eV respectvely. Time resolved Photoluminescence (PL) results showed that hybride pervoskite (2) had a long lived PL whereas (1) exhibited a short PL lifetime. Thermo-gravimetrical analysis (TGA) in nitrogen gas environment revealed that (1) and (2) are stable and do not show any sign of decomposition up to ~200 o C. Photocatalytical performance of as-prepared materials (1) and (2) under sunlight were mointerted using textile dye direct yellow. The compound (1) degraded dye in 20 min while (2) in 55 min with superior recyclablity.
Latin American Journal of Pharmacy, 2011
Monatshefte für Chemie - Chemical Monthly, 2016
Three derivatives of arylazapyrazole ((E)-4-(phenyldiazenyl)-3,5-dimethyl-1H-pyrazole, (E)-4-[(4-... more Three derivatives of arylazapyrazole ((E)-4-(phenyldiazenyl)-3,5-dimethyl-1H-pyrazole, (E)-4-[(4-flu-orophenyl)diazenyl]-3,5-dimethyl-1H-pyrazole, and (E)-4-[(4-iodophenyl)diazenyl]-3,5-dimethyl-1H-pyrazole) were synthesized, characterized, and further investigated for their electrochemical behavior at glassy carbon electrode using cyclic voltammetry. All compounds were reduced following E i C i mechanism giving single cathodic peak in potential range 0 to-2 V vs. Ag/AgCl. The plots of log i P vs. log m showed that the electrode process is mixed adsorption-diffusion controlled. The kinetic parameters such as transfer coefficient (an), diffusion coefficients (D o), and standard heterogeneous rate constants (k s) were determined from the electrochemical data. The values of D o were determined and found greater for the smallest among the three compounds. k s values were calculated by Laviron formalism which lies in the order of 10-2 s-1. Temperature and pH effects were studied and thermody-namic parameters such as change in free energy of activation (DG #), apparent activation energy (E a), enthalpy (DH #), and entropy (DS #) of activation were determined. Negative values of E a , DH # , and DS # imply that the electrode process needs lesser over potential with temperature rise, pre-adsorption of the analyte onto the electrode surface and the activated complex has a more organized structure than the reactants, respectively. Graphical abstract Keywords Arylazapyrazole Á Cyclic voltammetry Á Temperature and pH effect Á Kinetics Á Thermodynamics
Acta Poloniae Pharmaceutica, 2010
The objective of this study was to formulate stable and controlled release microparticles for sim... more The objective of this study was to formulate stable and controlled release microparticles for simultaneous delivery and UV spectrophotometric detection in combined dosage of an non-steroidal anti-inflammatory drug (NSAID) (nimesulide, NMS) and a spasmolytic agent (tizanidine, TZN) to maintain plasma concentration that may increase patients compliance, improved therapeutic efficacy, The aim was also to reduce severity of upper GI side effects of NMS because of alteration in delivery pattern via slow release of drug from microparticles and to increase the benefits of spasticity and disability for spastic patients by administering TZN in a modified release formulation as these two drugs are often prescribed in combination for the management of pain associated with muscles spasm. Ethyl cellulose was used as a retardant polymer. Drug-polymer and drug-drug compatibility study were conducted by different analytical tests. Microparticles were prepared by coacervation thermal change method. The prepared microparticles were characterized for their micromeritics and drug loading. The prepared microparticles were light yellow, free flowing and spherical in shape. The drug-loaded microparticles showed 87% and 91% entrapment efficiency of NMS and TZN, respectively, and release was extended up to 10 h. The infrared spectra, differential scanning calorimetry thermograms and XRD spectra showed the stable character of both the drugs in the drug-loaded microparticles. The in vitro release study of microparticles was performed in phosphate buffer pH 6.8. Linearity was observed in the concentration range of 5.0-30.0 microg/mL of NMS and 0.5-3.0 microg/mL of TZN. The microparticles have a potential for the prolongation and simultaneous delivery of the NIM and TIZ. The proposed UV method for simultaneous detection can be used for routine analysis of combined dosage form.
Journal of the College of Physicians and Surgeons Pakistan Jcpsp, Mar 1, 2004
OBJECTIVE: To evaluate the risk of malignancy index (RMI) for pre-operative diagnosis of ovarian ... more OBJECTIVE: To evaluate the risk of malignancy index (RMI) for pre-operative diagnosis of ovarian mass.DESIGN: Observational study.PLACE AND DURATION OF STUDY: Department of Chemical Pathology and Endocrinology at Armed Forces Institute of Pathology (AFIP), Rawalpindi from January 2001 to January 2002.SUBJECTS AND METHODS: The study consisted of 100 female patients consecutively admitted for surgical exploration of ovarian mass. Pre-operatively ultrasonic evaluation of ovarian mass, menopausal status and serum cancer-associated antigen 125 (CA 125) levels were carried out. Postoperatively histopathology of the resected ovarian mass was done to confirm the diagnosis. To increase the sensitivity and specificity of CA 125 for early detection of ovarian cancer, a combination of serum CA 125 with ultrasonography and menopausal status, designated as risk of malignancy index (RMI) for each patient, was calculated.RESULTS: The sensitivity and specificity of CA 125 alone for the diagnosis of ovarian cancer, at cutoff level of 35 U/ml, were 83% and 82% respectively. Using RMI, at cutoff level of 125, the sensitivity was 87%, and specificity was 88%. Receiver operating characteristic (ROC) curves reveal that RMI was a better discriminant than CA 125 alone for differentiating between benign lesions and malignant ovarian tumors.CONCLUSION: The risk of malignancy index (RMI) is a better diagnostic marker as compared to CA 125 alone because of its high specificity and sensitivity in differentiating ovarian cancer from ovarian benign lesions. It is a simple scoring system and, therefore, its application is recommended to evaluate ovarian masses in clinical practice.
Environmental science and pollution research international, Jan 14, 2016
This study aimed to investigate the potential health risk associated with toxic metals in contami... more This study aimed to investigate the potential health risk associated with toxic metals in contaminated foodstuffs (fruits, vegetables, and cereals) collected from various agriculture fields present in chromite mining-affected areas of mafic and ultramafic terrains (northern Pakistan). The concentrations of Cr, Ni, Zn, Cd, and Pb were quantified in both soil and food samples. The soil samples were highly contaminated with Cr (320 mg/kg), Ni (108 mg/kg), and Cd (2.55 mg/kg), which exceeded their respective safe limits set by FAO/WHO. Heavy metal concentrations in soil were found in the order of…
Mixed metal halide perovskites are gaining paramount interest due to efficient band gap tenabilit... more Mixed metal halide perovskites are gaining paramount interest due to efficient band gap tenability and improved optical properties compared to their single metal halide perovskites. It is thus valuable to investigate compositional changes in lead halide perovskites to explore energy changes. Herein, we report the synthesis of a lead to lead free hybrid perovskite solid solution (CH 3 NH 3 Pb 1Àx Cu x Br 3) as nanoparticles and films. The increasing concentration of Cu 2+ ions in the site of the Pb 2+ ion in the perovskite shifted the diffraction peaks to a larger angle. Uniform spherically shaped nanoparticles were synthesized by a wet chemical method, the higher Cu 2+ concentration leads to agglomeration, producing sheet like morphologies. However, the deposition of thin films of CH 3 NH 3 Pb 1Àx Cu x Br 3 perovskite solid solution shows that well defined morphologies begin to appear with increasing concentrations of Cu 2+ in the perovskite structure. The as-prepared bulk lead free CH 3 NH 3 CuBr 3 perovskite shows a band gap of 1.65 eV. A blue shift in photoluminescence (PL) was observed with copper enriched hybrid perovskites.
Inorganic halide perovskite (CsPbX 3) nanostructures have gained considerable interest in recent ... more Inorganic halide perovskite (CsPbX 3) nanostructures have gained considerable interest in recent years owing to their enhanced stability and optoelectronic applications. Recent developments in the synthesis of nanostructures are reviewed. The impact of the precursor and ligand nature, temperature and growth time on the morphology and shape tuning of CsPbX 3 nanostructures is described in relation to their optical properties. The presynthetic and postsynthetic anion exchange strategies to retain pre-existing crystal phase and shape are discussed in this minireview.
Soil and Sediment Contamination: An International Journal, 2016
Latin American Journal of Pharmacy, Aug 1, 2011
Latin American Journal of Pharmacy, 2010
Iranian Polymer Journal, 2009
African Journal of Pharmacy and Pharmacology, Oct 22, 2011
Environmental geochemistry and health, Jan 29, 2016
Hexachlorocyclohexane (HCH) isomers and dichlorodiphenyltrichloroethane (DDT) metabolites were an... more Hexachlorocyclohexane (HCH) isomers and dichlorodiphenyltrichloroethane (DDT) metabolites were analyzed in sediments of three different depths (0-10, 10-20 and 20-30 cm) collected from Kabul River, Pakistan, in February 2014. The occurrence levels, enantiomer fractions and potential ecological risk of these organochlorine pesticides (OCPs) were evaluated. The total concentrations of ∑HCHs and ∑DDTs in surface sediments ranged from 4.9-23.9 ng g(-1) and from 6.4-18.8 ng g(-1) (dry weight basis), respectively. The vertical contamination profile of DDTs was found in order of 20-30 cm >10-20 cm >0-10 cm, indicated that the residue levels of DDTs gradually decreased after it was banned. The ratios of β-HCH/HCHs ranged from 0.04 to 0.73 (69 % of samples below 0.5) suggesting the fresh input of HCHs, while isomeric ratios of α-HCH/γ-HCH (ranged from 0.02 to 7.94), with 76 % of samples less than 3, indicating the cocktail use of technical grade HCH and lindane in the study area. The r...
Latin American Journal of Pharmacy, 2010
Journal of the College of Physicians and Surgeons Pakistan Jcpsp, Sep 1, 2004
Latin American Journal of Pharmacy, 2011
Latin American Journal of Pharmacy, 2010
Latin American Journal of Pharmacy, 2012
Materials Science in Semiconductor Processing, 2017
A B S T R A C T Hybrid perovskite have shown a potential as structurally and chemically tunable m... more A B S T R A C T Hybrid perovskite have shown a potential as structurally and chemically tunable materials with interesting optical properties. Herein, We describe the synthesis and characterization of two new perovskites, hydroxyl ammonium lead iodo chloride, OHNH 3 PbI 2 Cl (1) and hydroxyl ammonium lead chloride, OHNH 3 PbCl 3 (2) by wet-chemical route. The as-prepared (1) and (2) have shown promising optical properties with suitable band gaps 3.7 eV and 3.9 eV respectvely. Time resolved Photoluminescence (PL) results showed that hybride pervoskite (2) had a long lived PL whereas (1) exhibited a short PL lifetime. Thermo-gravimetrical analysis (TGA) in nitrogen gas environment revealed that (1) and (2) are stable and do not show any sign of decomposition up to ~200 o C. Photocatalytical performance of as-prepared materials (1) and (2) under sunlight were mointerted using textile dye direct yellow. The compound (1) degraded dye in 20 min while (2) in 55 min with superior recyclablity.
Latin American Journal of Pharmacy, 2011
Monatshefte für Chemie - Chemical Monthly, 2016
Three derivatives of arylazapyrazole ((E)-4-(phenyldiazenyl)-3,5-dimethyl-1H-pyrazole, (E)-4-[(4-... more Three derivatives of arylazapyrazole ((E)-4-(phenyldiazenyl)-3,5-dimethyl-1H-pyrazole, (E)-4-[(4-flu-orophenyl)diazenyl]-3,5-dimethyl-1H-pyrazole, and (E)-4-[(4-iodophenyl)diazenyl]-3,5-dimethyl-1H-pyrazole) were synthesized, characterized, and further investigated for their electrochemical behavior at glassy carbon electrode using cyclic voltammetry. All compounds were reduced following E i C i mechanism giving single cathodic peak in potential range 0 to-2 V vs. Ag/AgCl. The plots of log i P vs. log m showed that the electrode process is mixed adsorption-diffusion controlled. The kinetic parameters such as transfer coefficient (an), diffusion coefficients (D o), and standard heterogeneous rate constants (k s) were determined from the electrochemical data. The values of D o were determined and found greater for the smallest among the three compounds. k s values were calculated by Laviron formalism which lies in the order of 10-2 s-1. Temperature and pH effects were studied and thermody-namic parameters such as change in free energy of activation (DG #), apparent activation energy (E a), enthalpy (DH #), and entropy (DS #) of activation were determined. Negative values of E a , DH # , and DS # imply that the electrode process needs lesser over potential with temperature rise, pre-adsorption of the analyte onto the electrode surface and the activated complex has a more organized structure than the reactants, respectively. Graphical abstract Keywords Arylazapyrazole Á Cyclic voltammetry Á Temperature and pH effect Á Kinetics Á Thermodynamics
Acta Poloniae Pharmaceutica, 2010
The objective of this study was to formulate stable and controlled release microparticles for sim... more The objective of this study was to formulate stable and controlled release microparticles for simultaneous delivery and UV spectrophotometric detection in combined dosage of an non-steroidal anti-inflammatory drug (NSAID) (nimesulide, NMS) and a spasmolytic agent (tizanidine, TZN) to maintain plasma concentration that may increase patients compliance, improved therapeutic efficacy, The aim was also to reduce severity of upper GI side effects of NMS because of alteration in delivery pattern via slow release of drug from microparticles and to increase the benefits of spasticity and disability for spastic patients by administering TZN in a modified release formulation as these two drugs are often prescribed in combination for the management of pain associated with muscles spasm. Ethyl cellulose was used as a retardant polymer. Drug-polymer and drug-drug compatibility study were conducted by different analytical tests. Microparticles were prepared by coacervation thermal change method. The prepared microparticles were characterized for their micromeritics and drug loading. The prepared microparticles were light yellow, free flowing and spherical in shape. The drug-loaded microparticles showed 87% and 91% entrapment efficiency of NMS and TZN, respectively, and release was extended up to 10 h. The infrared spectra, differential scanning calorimetry thermograms and XRD spectra showed the stable character of both the drugs in the drug-loaded microparticles. The in vitro release study of microparticles was performed in phosphate buffer pH 6.8. Linearity was observed in the concentration range of 5.0-30.0 microg/mL of NMS and 0.5-3.0 microg/mL of TZN. The microparticles have a potential for the prolongation and simultaneous delivery of the NIM and TIZ. The proposed UV method for simultaneous detection can be used for routine analysis of combined dosage form.
Journal of the College of Physicians and Surgeons Pakistan Jcpsp, Mar 1, 2004
OBJECTIVE: To evaluate the risk of malignancy index (RMI) for pre-operative diagnosis of ovarian ... more OBJECTIVE: To evaluate the risk of malignancy index (RMI) for pre-operative diagnosis of ovarian mass.DESIGN: Observational study.PLACE AND DURATION OF STUDY: Department of Chemical Pathology and Endocrinology at Armed Forces Institute of Pathology (AFIP), Rawalpindi from January 2001 to January 2002.SUBJECTS AND METHODS: The study consisted of 100 female patients consecutively admitted for surgical exploration of ovarian mass. Pre-operatively ultrasonic evaluation of ovarian mass, menopausal status and serum cancer-associated antigen 125 (CA 125) levels were carried out. Postoperatively histopathology of the resected ovarian mass was done to confirm the diagnosis. To increase the sensitivity and specificity of CA 125 for early detection of ovarian cancer, a combination of serum CA 125 with ultrasonography and menopausal status, designated as risk of malignancy index (RMI) for each patient, was calculated.RESULTS: The sensitivity and specificity of CA 125 alone for the diagnosis of ovarian cancer, at cutoff level of 35 U/ml, were 83% and 82% respectively. Using RMI, at cutoff level of 125, the sensitivity was 87%, and specificity was 88%. Receiver operating characteristic (ROC) curves reveal that RMI was a better discriminant than CA 125 alone for differentiating between benign lesions and malignant ovarian tumors.CONCLUSION: The risk of malignancy index (RMI) is a better diagnostic marker as compared to CA 125 alone because of its high specificity and sensitivity in differentiating ovarian cancer from ovarian benign lesions. It is a simple scoring system and, therefore, its application is recommended to evaluate ovarian masses in clinical practice.
Environmental science and pollution research international, Jan 14, 2016
This study aimed to investigate the potential health risk associated with toxic metals in contami... more This study aimed to investigate the potential health risk associated with toxic metals in contaminated foodstuffs (fruits, vegetables, and cereals) collected from various agriculture fields present in chromite mining-affected areas of mafic and ultramafic terrains (northern Pakistan). The concentrations of Cr, Ni, Zn, Cd, and Pb were quantified in both soil and food samples. The soil samples were highly contaminated with Cr (320 mg/kg), Ni (108 mg/kg), and Cd (2.55 mg/kg), which exceeded their respective safe limits set by FAO/WHO. Heavy metal concentrations in soil were found in the order of…