Exposure to NO2 in occupational built environments in urban centre in Lahore

Increased economic growth, urbanisation and substantial rise in automobile vehicles has contributed towards the elevated levels of air pollution in major cities in Pakistan. Aone week study was conducted by using passive samplers to assess NO2 concentration in occupational built environments at two most congested and populated sites of Lahore. Both sites were locatedon the busy roads of Lahore. At Site-I the highest concentration was in outdoors followed by corridor and indoor. While at Site II all the sampling location wereindoors and level were comparable to that of outdoor levelsat Site I. The results suggest the likely contribution of ambient sources in exposure to indoor NO2 in educational and other occupational built environments in urban centres

Exposure to NO<inf>2</inf> in occupationalbuilt environmnets in urban centre in Lahore

Increased economic growth, urbanisation and substantial rise in automobile vehicles has contributed towards the elevated levels of air pollution in major cities in Pakistan. Aone week study was conducted by using passive samplers to assess NO2 concentration in occupational built environments at two most congested and populated sites of Lahore. Both sites were locatedon the busy roads of Lahore. At Site-I the highest concentration was in outdoors followed by corridor and indoor. While at Site II all the sampling location wereindoors and level were comparable to that of outdoor levelsat Site I. The results suggest the likely contribution of ambient sources in exposure to indoor NO2 in educational and other occupational built environments in urban centres

Mechanistic Studies for Palladium Catalyzed Copolymerization of Ethylene with Vinyl Ethers

The mechanism of ethylene with vinyl ether (VE, CH2=CHOEt) copolymerization catalyzed by phosphine-sulfonate palladium complex (A) was investigated by density functional theory (DFT) calculation. On achieving an agreement between theory and experiment, it is found that the favorable 1,2-selective insertion of VE into the complex A originates from stronger hydrogen interaction between the oxygen atom of VE and the ancillary ligand of catalyst A. Additionally, VE insertion is easier into the ethylene pre-inserted intermediate than that into the catalyst to form the resultant copolymers with the major units of OEt in chain and minor units of OEt at the chain end. The effect of β-OEt and β-H elimination was explored to elucidate chain termination and the molecular weight of copolymers. Furthermore, a family of cationic catalysts has been demonstrated to copolymerize ethylene with VE along with our modified cationic complex B with higher incorporation of VE and reactivity in comparison with complex A, which was modelled computationally by increasing the strong interactions between the catalyst and monomer moiety. Other than VE, the activity of cationic complex B for copolymerization of vinyl chloride and methacrylate is also computed successfully

Computational Studies on the Selective Polymerization of Lactide Catalyzed by Bifunctional Yttrium NHC Catalyst

A theoretical investigation of the ring-opening polymerization (ROP) mechanism of rac-lactide (LA) with an yttrium complex featuring a N-heterocyclic carbine (NHC) tethered moiety is reported. It was found that the carbonyl of lactide is attacked by N(SiMe3)2 group rather than NHC species at the chain initiation step. The polymerization selectivity was further investigated via two consecutive insertions of lactide monomer molecules. The insertion of the second monomer in different assembly modes indicated that the steric interactions between the last enchained monomer unit and the incoming monomer together with the repulsion between the incoming monomer and the ligand framework are the primary factors determining the stereoselectivity. The interaction energy between the monomer and the metal center could also play an important role in the stereocontrol

Methicillin resistant Staphylococcus aureus: A brief review of virulence and resistance

Staphylococcus aureus is a common gram-positive human pathogen involved in both community-acquired and nosocomial infections ranging from localized superficial lesions to food poisoning and fatal systemic infections owing to its impressive array of virulence factors responsible for attaching, colonizing, invading, and avoiding host immune system. The discovery of antibiotics effectively checked the once deadly infections. However, resistance started soon after their discovery and first methicillin resistant strain of S. aureus was reported in early sixties. The most important attribute of MRSA resistance to penicllins is its acquisition of mecA gene coding for penicillin-binding protein PBP2a that blocks inhibitory action on peptidoglycan cross-linking. Now MRSA presents a serious global healthcare concern being responsible for prolonged hospital stays and increased mortality. The precise information of virulence factors and resistant traits of MRSA and their interplay in a community is key to minimize the intermixing of resistant and susceptible pathogens in the communit

Effectiveness of a Lytic Phage SRG1 against Vancomycin-Resistant Enterococcus faecalis in Compost and Soil

Nosocomial infections caused by vancomycin-resistant Enterococcus have become a major problem. Bacteriophage therapy is proposed as a potential alternative therapy. Bacteriophages are viruses that infect bacteria and are ubiquitous in nature. Lytic bacteriophage was isolated from sewage water that infects VREF, the causative agent of endocarditis, bacteraemia, and urinary tract infections (UTIs). The phage produced clear plaques with unique clear morphology and well-defined boundaries. TEM results of phage revealed it to be 108±0.2 nm long and 90±0.5 nm wide. The characterization of bacteriophage revealed that infection process of phage was calcium and magnesium dependent and phage titers were highest under optimum conditions for VREF, with an optimal temperature range of 37–50°C. The maximum growth was observed at 37°C, hence having 100% viability. The latent period for phage was small with a burst size of 512 viral particles per bacterial cell. The phage was tested against various clinical strains and results proved it to be host specific. It can be used as a potential therapeutic agent for VREF infections. The phage efficiently eradicated VREF inoculated in cattle compost, poultry compost, and a soil sample which makes it a potential agent for clearing compost and soil sample

Isolation and Characterization of a Phage to Control Vancomycin Resistant Enterococcus faecium

Enterococcus faecium, is an important nosocomial pathogen with increased incidence of multidrug resistance (MDR) – specifically Vancomycin resistance. E. faecium constitutes the normal microbiota of the human intestine as well as exists in the hospitals and sewage, thus making the microorganism difficult to eliminate. Phage therapy has gained attention for controlling bacterial MDR infections and contaminations. We have successfully isolated from waste water and characterized a lytic bacteriophage STH1 capable of targeting Vancomycin resistant Enterococcus faecium (VREF) with high specificity. The phage was isolated from sewage water of a hospital at district Dera Ismail Khan, Pakistan. Initial characterization showed that magnesium and calcium ions significantly increased phage adsorption to the host. One step growth experiment showed a latent period of 18 min with burst size of 334 virions per cell. Optimal temperature and pH of the phage was 37°C and 7.0, respectively. Phage application to host strain grown in milk and water (treated and untreated) showed that the phage efficiently controlled bacterial growth. The study suggests that the phage STH1 can serve as potential control agent for E. faecium infections in medical facilities and in other environmental contaminations

A systematic review of biosynthesized metallic nanoparticles as a promising anti-cancer-strategy

Cancer is one of the foremost causes of death worldwide. Cancer develops because of mutation in genes that regulate normal cell cycle and cell division, thereby resulting in uncontrolled division and proliferation of cells. Various drugs have been used to treat cancer thus far; however, conventional chemotherapeutic drugs have lower bioavailability, rapid renal clearance, unequal delivery, and severe side effects. In the recent years, nanotechnology has flourished rapidly and has a multitude of applications in the biomedical field. Bio-mediated nanoparticles (NPs) are cost effective, safe, and biocompatible and have got substantial attention from researchers around the globe. Due to their safe profile and fewer side effects, these nanoscale materials offer a promising cure for cancer. Currently, various metallic NPs have been designed to cure or diagnose cancer; among these, silver (Ag), gold (Au), zinc (Zn) and copper (Cu) are the leading anti-cancer NPs. The anticancer potential of these NPs is attributed to the production of reactive oxygen species (ROS) in cellular compartments that eventually leads to activation of autophagic, apoptotic and necrotic death pathways. In this review, we summarized the recent advancements in the biosynthesis of Ag, Au, Zn and Cu NPs with emphasis on their mechanism of action. Moreover, nanotoxicity, as well as the future prospects and opportunities of nano-therapeutics, are also highlighted

Vitamin D Receptor Gene Polymorphism: An Important Predictor of Arthritis Development

Vitamin D is an anti-inflammatory molecule and has a role in prevention of arthritis development. Biologically active form 1, 25(OH)2D3 of vitamin D can only exert its action after binding its definite vitamin D receptor encoded by VDR gene. VDR gene polymorphism leads to dysfunctioning of 1, 25(OH)2D3 ultimately disease onset. The purpose of current study was to evaluate the effect of vitamin D level and VDR gene polymorphism on rheumatoid arthritis and osteoarthritis. Blood samples were collected from case and control after taking written consent. Serum was separated and vitamin D level as determined from each sample by ELISA. DNA was extracted from each blood sample and amplified by using gene specific primers. Genotyping was performed by Sangers sequencing and PCR-RFLP technique. It was found that vitamin D level was not significantly different among patients and controls. The rs10735810, rs1544410, rs7975232, and rs731236 were associated with the onset of arthritis at both allelic and genotypic level (p < 0.01). Nucleotide change on rs10735810 site leads to change of tryptophan with arginine. The frequencies of haplotype CGAT, CGGA, CGGT, CTAA, CTAT, TGAA, TGAT, TGGA, and TTGA were higher in patients and act as risk factors of RA onset, whereas haplotypes CGAT, CGAT, CGGT, CTGA, TGAT, TGGA, TTAA, and TTGA were associated with OA onset. In conclusion, serum vitamin D level may be normal among arthritis patients but polymorphism on VDR gene restricts vitamin D to perform its anti-inflammatory function by altering the 1, 25(OH)2 D3 binding sites