Quantum chemical framework for tailoring N/B doped phenalene derivatives to achieve high performance nonlinear optical materials

Nonlinear optical (NLO) response materials are among the smartest materials of the era and are employed to modulate the phase and frequency of the laser. The present study presents a quantum chemical framework for tailoring nitrogen/boron doped derivatives of Dihydrodibenzo [de,op]pentacene through terminal and central core modifications. The derivatives of these compounds have been designed by introducing various π-conjugated connectors as well as B/N heteroatoms in the phenalene rings. Density functional theory (DFT) methods are used to optimize the ground state molecular geometries of designed compounds, represented as 1 to 4 (phenalene derivatives) and 1-BN to 4-BN (B/N doped phenalene derivatives) at the M06-2X/6-311G* level of theory. The highest value of 116.9 × 10-24 esu and 240.2 × 10-24 esu for isotropic and anisotropic linear polarizability is shown by compound 4. Among the designed compounds, 4-BN has achieved the highest γ amplitude of 1858 × 10-36 esu owing to its unique molecular structural design. Further analysis of electronic parameters, such as electron density difference (EDD) maps, the density of states, electrostatic potentials, transition density matrix (TDM) analysis, and frontier molecular orbitals analysis (FMOs), demonstrated the more effective intramolecular charge transfer (ICT) for the best compounds, resulting in a good NLO response. The compounds were also analyzed for their potential in photovoltaic applications based on factors such as open circuit voltage values determined to be between (0.14 eV and 1.82 eV), and light harvesting efficiency (0.425-0.909).

Computational prediction for designing novel ketonic derivatives as potential inhibitors for breast cancer: A trade-off between drug likeness and inhibition potency

Unlike simple molecular screening, a combined hybrid computational methodology has been applied which includes quantum chemical methods, molecular docking, and molecular dynamics simulations to design some novel ketonic derivatives. The current study contains the derivatives of an experimental ligand which are designed as a trade-off between drug likeness and inhibition strength. We investigate the interaction of various newly designed ketonic compounds with the breast cancer receptor known as the Estrogen Receptor Alpha (ERα). The molecular structures of all newly designed ligands were studied quantum chemically in terms of their fully optimized structures, 3-D molecular orbital distributions, global chemical descriptors, molecular electrostatic potentials and energies of frontier molecular orbitals (FMOs). All ligands under study show good binding affinities with the ERα protein. The ligands CMR2 and CMR4 exhibit improved molecular docking interactions. The intermolecular interactions indicate that CMR4 demonstrates better hydrophobic and hydrogen bonding interactions with protein (ERα). Furthermore, molecular dynamics simulations were conducted on ligands and reference drugs interacting with the ERα protein over a time span of 120 nanoseconds. The molecular dynamics results are interpreted in terms of ligand-protein stability and flexible behaviour based on their respective values of RMSD, RMSF, H-bonds, the radius of gyration, and SASA graphs. To analyse ligand-protein interactions throughout the entire 120 ns trajectory, a more advanced MM/PBSA method is utilized, where six selected ligands (CMR1, CMR2, CMR3, CMR4, CMR5 and CMR9) illustrate promising results for inhibition of the ERα receptor as assessed through MM/BBSA analysis. The CMR9 has the highest MM/BBSA binding free energy (-14.46 kcal/mol). The ADMET analysis reveals that CMR4 has maximum intestinal absorption (6.68) and clearance rate (0.1). All the compounds are non-toxic and safe to use. These findings indicate the potential of involving different computational techniques to design the ligand structures and to study the ligand-protein interactions for better understanding and achieving more potent synthetic inhibitors for breast cancer.

Exploration of nonlinear optical properties of 4-methyl-4H-1,2,4-triazol-3-yl)thio)-N-phenylpropanamide based derivatives: experimental and DFT approach

Triazoles, nitrogen-containing heterocycles, have gained attention for their applications in medicinal chemistry, drug discovery, agrochemicals, and material sciences. In the current study, we synthesized novel derivatives of N-substituted 2-((5-(3-bromophenyl)-4-methyl-4H-1,2,4-triazol-3-yl)thio)-N-phenylpropanamide and conducted a comprehensive investigation using density functional theory (DFT). These novel structural hybrids of 1,2,4-triazole were synthesized through the multi-step chemical modifications of 3-bromobenzoic acid (1). Initially, compound 1 was converted into its methyl-3-bromobenzoate (2) which was then transformed into 3-bromobenzohydrazide (3). The final step involved the cyclization of compound 3, producing its 1,2,4-triazole derivative (4). This intermediate was then coupled with different electrophiles, resulting in the formation of the final derivatives (7a-7c). Additionally, the characterization of these triazole-based compounds (7a, 7b, and 7c) were carried out using techniques such as IR, HNMR, and UV-visible spectroscopy to understand their structural and spectroscopic properties. The DFT study utilized M06/6-311G(d,p) functional to investigate geometrical parameters, HOMO-LUMO energies, natural bond orbital analyses, transition density matrix (TDM), density of states, and nonlinear optical (NLO) properties. The FMO analysis revealed that compound 7c exhibited the lowest band gap value (4.618 eV). Notably, compound 7c exhibited significant linear polarizability (4.195 >  × 10-23) and first and second hyperpolarizabilities (6.317 >  × 10-30, 4.314 × 10-35), signifying its potential for nonlinear optical applications. These NLO characteristics imply that each of our compounds, especially 7c, plays a crucial part in fabricating materials showing promising NLO properties for optoelectronic applications.

Exogenous Ca/Mg quotient reduces the inhibitory effects of PEG induced osmotic stress on Avena sativa L

Abstract Drought is one of the most damaging abiotic stress that hinder plant growth and development. The present study aimed to determine the effects of various Ca/Mg quotients under polyethylene glycol (PEG)–induced osmotic stress on growth, uptake and translocation of Ca and Mg in Avena sativa (L). Plants were grown in nutrient solution supplemented with three different Ca/Mg molar quotients (0.18, 2, and 4). After 30 days plants were exposed to two different PEG (Polyethylene glycol) concentrations (0.6 MPa & 0.2 MPa) for 8 days, and solutions were renewed after 4 days. A solution containing Ca and Mg nutrients has mitigated the negative impact caused via osmotic stress on relative growth rate (RGR), absolute growth rate (AGR), crop growth rate (CGR), leaf area ratio (LAR), Leaf index ratio (LAI), root-shoot ratio (RSR), water use efficiency (WUE) and net assimilation rate (NAR). In addition, it adversely affected germination parameters, including final emergence percentage (FEP), mean germination time (MGT), Timson germination Index (TGI), germination rate index (GRI) and percent field capacity (%FC), of oat (Avena sativa L.). Mg and Ca in shoot and root and Ca translocation factor decreased with increasing Ca in solution, while Mg translocation factor increased with increasing Ca in nutrient solution. In this work, the combined effects of various Ca/Mg quotients and osmotic stress produced by polyethylene glycol (PEG) in different concentrations (0.6 MPa, 0.2 MPa) on the growth and element uptake of Avena sativa L. are examined. As a result, the Ca/Mg Quotient may naturally combat the moderate drought stress experienced by field crops.

The human-wildlife conflict in Musk Deer National Park, Neelum Gureze Valley, Azad Jammu & Kashmir, Pakistan

Abstract Growing human population is a solemn risk to biodiversity at a global level. Massive anthropogenic pressure and invasion in the natural habitats initiated the human-wildlife conflict in rural areas. Present study aimed to assess human-wildlife conflict in Musk Deer National Park (MDNP) from 2013 to 2018. Results revealed an estimated 241784 nomadic and 5589 residential livestock heads grazed in different areas of MDNP during the summer season. A total of 126 heads were depredated by carnivores during the study period. Majority (n=39) of livestock heads were killed in May (n=29). Livestock depredation resulted in economic losses worth 3.115 million PKRs (25744 US$) to the herder community while farmers received 1.629 million PKRs (13466 US$) losses due to crop raiding. Most (64%) of the respondents believed human-wildlife conflict heightened due to scarcity of food or prey in the natural habitats of carnivores. Majority (92%) of the respondents did not like the presence of predators in MDNP. Loss compensation schemes could turn this negative attitude into the positive one and increase tolerance about the presence of carnivores in their vicinity. This study provides an insight into the human-wildlife conflict in MDNP and paves a way for understanding the conflict and conservation of carnivore species in the study area.

Comparative catalytic reduction and degradation with biodegradable sodium alginate based nanocomposite: Zinc oxide/N-doped carbon nitride/sodium alginate

Sodium alginate (SA) is a biodegradable macromolecule which is used to synthesize nanocomposites and their further use as catalysis. Zinc oxide (ZnO) and nitrogen doped carbon nitride (ND-C3N4) nanoparticles are prepared using solvothermal and hydrothermal methods, respectively. ZnO/ND-C3N4/SA nanocomposites are successfully synthesized by employing in-situ polymerization. The presence of essential functional groups is confirmed by Fourier transform infrared (FTIR) spectroscopic analysis. Controlled spherical morphology for ZnO nanoparticles, with an average diameter of ∼52 nm, is shown by Scanning electron microscopic (SEM) analysis, while rice-like grain structure with an average grain size ∼62 nm is exhibited by ND-C3N4 nanoparticles. The presence of required elements is confirmed by Energy dispersive X-ray spectroscopic (EDX) analysis. The crystalline nature of nanocomposites is verified by X-ray diffraction spectroscopic (XRD) analysis. The investigation of the catalytic efficiency for degradation and reduction of various organic dyes is carried out on nanoparticles and nanocomposites. Thorough examination and comparison of parameters, such as apparent rate constant (kapp), reduction time, percentage reduction, reduced concentration and half-life, are conducted for all substrates. The nanocomposites show greater efficiency than nanoparticles in both reactions: catalytic reduction and catalytic degradation.

Recent advances in synthesis and characterization of iron-nickel bimetallic nanoparticles and their applications as photo-catalyst and fuel additive

Iron-nickel bimetallic nanoparticles (Fe-Ni BMNPs) are prepared by combining two different metals by using the bottom-up approach. The resulting material has entirely different properties as compared to both the metals. The product is examined by using different analytical instruments such as.; scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), MDIJADE, ORIGIN pro to characterize their morphology, crystallinity and elemental composition and the final data has been statistically analyzed. SEM findings show that most nanoparticles are irregular in form and range in size from 10 nm to 100 nm. The findings of the TEM verified that the particles between 10 nm and 50 nm are irregular in size shape. The products acquired utilized as a fuel additive to monitor oil effectiveness by studying various parameters. The degradation of methylene blue dye depends directly on the concentration of the nanocatalyst. Different parameters also use the freshly prepared bimetallic nanocatalyst to investigate the efficacy of the kerosene fuel. By adding a tiny quantity of the nanocatalyst, the value of the flash point and fire point is significantly reduced. The nanocatalyst does not affect the cloud point and pour point to a large extent. The bimetallic nanocatalyst therefore has very excellent catalytic characteristics.

Transcriptomic response and immunological responses to chimpanzee adenovirus- and MVA viral-vectored vaccines for RSV in healthy adults

Cohorts of healthy younger adults (18-50yrs) and healthy older adults (60-75yrs) were immunized intramuscularly or intranasally with an adenovirus-vectored RSV vaccine (PanAd3-RSV) as a prime dose and boosted with PanAd3-RSV or a poxvirus-vectored vaccine (MVA-RSV) encoding the same insert. Whole blood gene expression was measured at baseline, 3- and 7-days post vaccination. Intramuscular prime vaccination with PanAd3-RSV induced differential expression of 643 genes (DEGs, FDR < 0.05). Intranasal prime vaccination with PanAd3-RSV did not induce any differentially expressed genes (DEGs) in blood samples at 3 days post vaccination. Intranasally primed participants showed greater numbers of DEGS on boosting than intramuscularly primed participants. The most highly enriched biological processes related to DEGs after both prime and boost vaccination were type-1 interferon related pathways, lymphocytic and humoral immune responses.

The Cost-effectiveness of Watch and Wait for Rectal Cancer

The existing literature suggests with a high degree of certainty that watch and wait is more cost-effective than initial total mesorectal excision. However, it is heavily reliant on poor-quality health-related quality of life data. Furthermore, the cost-effectiveness of organ preservation from a broader societal perspective has not been studied. Finally, the cost-effectiveness of emerging adjuncts to watch and wait for organ preservation, such as contact X-ray brachytherapy, local excision and total neoadjuvant therapy, need to be characterised.

Investigation of the adsorption properties of gemcitabine anticancer drug with metal-doped boron nitride fullerenes as a drug-delivery carrier: a DFT study

Anticancer-drug delivery is now becoming a challenging approach for researchers as it allows controlled drug delivery near cancerous cells with minimized generic collection and the avoidance of secondary side effects. Hence in this work, the applications of nanostructures as anticancer drug-delivery carriers were widely investigated to target cancerous tissues. Based on DFT calculations, we investigated the transition metal-doped boron nitride nanostructure as a drug-delivery agent for the gemcitabine drug utilizing the B3LYP/6-31G (d, p) level of theory. In this research, the adsorption energy and electronic parameters of gemcitabine on the interaction with the metal-doped BN nanostructures were studied. It has been observed that metal doping significantly enhances the drug-delivery properties of BN nanostructures. Among the investigated nanostructures, Ni–BN has been found to be the most prominent nanostructure to transport gemcitabine with an elevated value of adsorption energy in both the gas phase (−45.79) and water media (−32.46). The interaction between gemcitabine and BN nanostructures was confirmed through frontier molecular orbitals and stabilization energy analysis. The fractional charge transfer, MEP, NCI, and NBO analyses exposed the charge transfer from drug molecule to the BN nanostructures. Transition density maps and UV-VIS spectra were also plotted to investigate the excited-state properties of the designed complexes. Thus, the present study provides an in-depth interaction mechanism of the gemcitabine drug with BN, which reveals that metal-doped BN nanostructures can be a favorable drug-delivery vehicle for the gemcitabine anticancer drug.

Anticancer-drug delivery is now becoming a challenging approach for researchers as it allows controlled drug delivery near cancerous cells with minimized generic collection and the avoidance of secondary side effects.

Range of factors in the reduction of hyperhydricity associated with in vitro shoots of Salvia santolinifolia Bioss

Hyperhydricity is a serious physiological disorder and affects In vitro propagation of many plants and as well of Salvia santolinifolia. The donor material to initiate the in vitro culture was the callus taken from the in vitro shoots produced on Murashig and Skoogs (MS) medium at 4.0 mg/l BA. This callus formed numerous hyperhydric shoots on culturing upon the medium of the same composition. The aim was to systematically evaluate the effect of cytokinins (Benzyladnine (BA) and N6-(-2-isopentenyl) adenine (2iP), culture vessels magnitude, medium solidification, source of nitrogen and calcium chloride for the alleviation of hyperhydricity. In the tissue cultures of S. santolinifolia BA and 2iP induced severe hyperhydricity, when other factors i.e. culture vessels magnitude and a suitable concentration of agar, ammonium nitrate (NH4NO3), potassium nitrate (KNO3) & calcium chloride (CaCl2.2H2O) were not optimized. After 30 days' culture, we observed 83.82% hyperhydric shoots at increased level (1.5 mg/l 2iP) and 81.59% at decreased levels (1.0 mg/l 2iP). On the other hand, hyperhydricity percentage at decreased (0.4%) and at increased (0.8%) levels of agar were 72.37% and 39.08%, respectively. MS medium modification with NH4NO3 (412 mg/l), KNO3 (475 mg/l) and CaCl2.2H2O (880 mg/l) was found the best medium to reduced hyperhydricity (23.6%).

Gender-based incidence, recovery period, and mortality rate of COVID-19 among the population of district Attock, Pakistan

COVID-19 is reported as an extremely contagious disease with common symptoms of fever, dry cough, sore throat, and tiredness. The published literature on incidence and gender-wise prevalence of COVID-19 is scarce in Pakistan. Therefore, the present study was designed to compare the distribution, incubation period and mortality rate of COVID-19 among the male and female population of district Attock. The data were collected between 01 April 2020 and 07 December 2020 from the population of district Attock, Pakistan. A total of 22,962 individuals were screened and 843 were found positive for RT-qPCR for SARS-CoV-2. The confirmed positive cases were monitored carefully. Among the positive cases, the incidence of COVID-19 was 61.7% among males and 38.2% among females. The average recovery period of males was 18.89±7.75 days and females were 19±8.40 days from SARS-CoV-2. The overall mortality rate was 8.06%. The death rate of male patients was significantly higher (P<0.05) compared to female patients. Also, the mortality rate was higher (P<0.05) in male patients of 40-60 years of age compared to female patients of the same age group. Moreover, the mortality rate significantly increased (P<0.05) with the increase of age irrespective of gender. In conclusion, the incidence and mortality rate of COVID-19 is higher in males compared to the female population. Moreover, irrespective of gender the mortality rate was significantly lower among patients aged <40 years.

Chemically Modified Quinoidal Oligothiophenes for Enhanced Linear and Third-Order Nonlinear Optical Properties

In the present investigation, quantum chemical calculations have been performed in a systematic way to explore the optoelectronic, charge transfer, and nonlinear optical (NLO) properties of different bis(dicyanomethylene) end-functionalized quinoidal oligothiophenes. The effect of different conformations (linking modes of thiophene rings) on conformational, optoelectronic, and NLO properties are studied from the best-performed dimer to octamer. The optical and NLO properties of all the selected systems (1-7) are calculated by means of density functional theory (DFT) methods. Among all the designed compounds, the largest linear isotropic (αiso) polarizability value of 603.1 × 10-24 esu is shown by compound 7 which is ∼12, ∼16, ∼9, ∼11, ∼10, and ∼4 times larger as compared to compounds 1-6, respectively. A relative investigation is performed considering the expansion in third-order NLO polarizability as a function of size and conformational modes. Among all the investigated systems, system 7 shows the highest value of static second hyperpolarizability ⟨γ⟩ with an amplitude of 7607 × 10-36 esu at the M06/6-311G** level of theory, which is ∼521, ∼505, ∼38, ∼884, ∼185, and ∼15 times more than that of compounds 1-6, respectively. The extensively larger ⟨γ⟩ amplitude of compound 7 with higher oscillator strength and lower transition energy indicates that NLO properties are remarkably dependent upon linking modes of thiophene rings and its chain length. Furthermore, to trace the origin of higher nonlinearities, TD-DFT calculations are also performed at the same TD-M06/6-311G** level of theory. Additionally, a comprehensive understanding of the effect of structure/property relationship on the NLO polarizabilities of these investigated quinoidal oligothiophenes is obtained through the inspection of Frontier molecular orbitals, the density of states (TDOS and PDOS), and molecular electrostatic potential diagrams including the transition density matrix. Hence, the current examination will not just feature the NLO capability of entitled compounds yet additionally incite the interest of experimentalists to adequately modify the structure of these oligothiophenes for efficient optical and NLO applications.

Excited State Complexes of Coumarin Derivatives

Furocoumarins are the useful derivatives of coumarin, and they act as skin photosensitizing material due to their exciting exciplex states. Dendrimers also form exciplexes when they contain coumarin as core and used for light harvesting. A number of ingredients in human nutrition contain coumarins. The apiaceae family is the most common example of this class that contains carrots, celery and parsley etc. Rutaceae family is also an important food source that contains coumarins and provides citrus food. Besides fruits and vegetables, beverages like coffee, wine, black and green tea also incorporates coumarin derivatives. Few coumarin dyes show absorption and one emission peak but it can show a double amplified spontaneous emission band due to the generation of super exciplexes in coumarins. Exciplex formation of different coumarin derivatives including 7-methoxy coumarin, 7-hydroxy coumarin show wide application in synthesis of various other derivatives and they can be used as dye due to their prominent fluorescence properties. Exciplexes and excimers of coumarin are widely used in lasers. Both singlet and triplet state exciplexes are considered. Thus a comprehensive review of excited state complexes of coumarin derivatives is discussed here with emphases on the interaction and overlap of the energy levels.

Metal doped fullerene complexes as promising drug delivery materials against COVID-19

An outbreak of respiratory disorder caused by coronavirus has been named as coronavirus infection 2019 (COVID-19). To find a specific treatment against this disease researchers are at the frontline. To cure COVID-19, favipiravir (FPV) has been reported as an effective drug based on its high recovery rate. Among nanomaterials, fullerene C60 has achieved enormous attention as a drug delivery vehicle due to its good bioavailability and low toxicity. Hence, in this work, we have investigated the potential of metal-doped fullerene as a drug carrier, based on DFT calculations by using M06-2X functional and 6-31G(d) basis set in water media. In this research electronic parameters and adsorption energy of FPV on interaction with metal-doped (Cr, Fe, and Ni) fullerene is studied. The charge transfer between drug and doped fullerene has been studied through electrophilicity indexes. The structural and electronic properties are explored in terms of adsorption energy through frontier molecular orbital (FMO) and density of state (DOS). It is observed that doping of fullerene C60 with Cr, Fe, and Ni metals significantly enhances the drug delivery rate and provides numerous advantages including controlled drug release at specific target sites which minimize the generic collection in vivo and reduce the side effects. Thusly, it is suggested that our designed metal-doped complexes might be efficient candidates as drug delivery materials for COVID-19 infection.

Bioaccumulation of heavy metals in the tissues of Schizothorax plagiostomus at River Swat

Snow trout (Schizothorax plagiostomus) is an economically important freshwater fish, mostly found in northern areas of water reservoirs of Pakistan. The current study was conducted in River Swat to analyze the bioaccumulation of heavy metals (Pb, Cr, Ni, and Zn) in tissues of Schizothorax plagiostomus. Tissues were extracted and dissolved in perchloric acid (HClO4) and nitric acid (HNO3) along with hotplate. The heavy metals, zinc (Zn), lead (Pb), chromium (Cr), and Nickel (Ni) were determined using Perkin Elmer 2380 atomic absorption spectrophotometer. Results shows great variation in the content of the metal related to tissue type and sampling sites. A high concentration of bioaccumulation was reported at Charbagh, whereas lowest at Odigram: Charbagh>Landakai>Odigram. In the same way, Cr was the most accumulated heavy metal followed by lead, nickel, and Zinc.

Exploring the impact of central core modifications among several push-pull configurations to enhance nonlinear optical response

The present study explores a series of novel donor-π-acceptor (D-π-A) molecules containing 4,4'-dimethyldiphenylamine moiety as donor, 4,4'-dinitrodiphenylborane as acceptor while different π-bridges as efficient linkers between them, which comprises of (-HCCH-)_n, (-Ph-)_n and (-Ph ̶ HCCH-)_n combinations for compounds in series 1, 2 and 3, respectively. Quantum chemical computations are applied to calculate the linear polarizability (α), first (β) and second (γ) hyperpolarizabilities. A comparative analysis is performed considering an increase of NLO polarizabilities as a function of different π-linkers. Among the investigated compounds, 3c shows the largest first and second hyperpolarizabilities of 1378 × 10^-30 and 34971 × 10^-36 esu, respectively. Interestingly, an increase in NLO polarizability is observed by modifying the π-conjugated bridges and the largest NLO polarizability is observed for series 3 possessing (Ph ̶ HCCH-)_n π-linker which is found due to its lower transition energy and higher oscillator strengths. Furthermore, TD-DFT investigations, frontier molecular orbitals (FMOs) and electron density difference (EDD) maps analysis have shown a more efficient intramolecular charge transfer character from donor to acceptor moieties through (Ph ̶ HCCH-)_n π-linkers. The density of states (DOS) maps are showing explicit contributions of electronic states from different fragments of a molecular system where the partial contributions of (Ph ̶ HCCH-)_n π-linkers is seen significant in HOMO-LUMO orbitals of all the systems in series number 3. Thus, we believe that our study will highlight the importance of different D-π-A chromophores having variant types of π-conjugation cores as discussed in the present investigation.

The effect of different aromatic conjugated bridges on optoelectronic properties of diketopyrrolopyrrole-based donor materials for organic photovoltaics

A series of twelve Acceptor-π-Donor-π-Acceptor (A-π-D-π-A) topology-based donor molecules, where diketopyrrolopyrrole (DPP) as donor core unit is connected through furan which acts as conjugated π-bridge (CB) to aromatic derivatives (Ar) as acceptor units, have been investigated by making substitutions in acceptor units by using density functional theory(DFT) and time-dependent density functional theory (TD-DFT) for organic solar cell applications. The comparative study of optoelectronic properties indicates that thiadiazole with pyridine units containing molecules (M6b) exhibit lower energy of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels than those of oxadiazole and pyridine containing units (M6b). Among our investigated donors, the smallest Eg of 1.60 eV was observed for both M6a and M6b with distinctive broad absorption at 843 and 857 nm, respectively. Overall, smaller electron transfer (λ_e) values in contrast to hole transfer (λ_h) demonstrate that these donor compounds would be best for λ_e. The calculated open circuit voltage (Voc) is 2.45 and 2.17 eV, regarding bisPCBM and PC60BM (phenyl-C61-butyric acid methyl ester) acceptors. Thus, these theoretical calculations not only endorse the deep consideration between the chemical structures and optoelectronic characteristics of the donor-acceptor systems but also suggest appropriate materials for high-performance Organic Photovoltaics (OPV). Graphical abstract.

Techniques in the synthesis of organometallic compounds of tungsten

Tungsten is an elegant substance, and its compounds have great significance because of their extensive range of applications in diverse fields such as in gas sensors, photocatalysis, lithium ion batteries, H2production, electrochromic devices, dyed sensitized solar cells, microchip technology, and liquid crystal displays. Tungsten compounds exhibit a more efficient catalytic behavior, and tungsten-dependent enzymes generally catalyze the transfer of an oxygen atom to or from a physiological donor/acceptor with the metal center. Furthermore, tungsten has an n-type semiconductor band gap. Tungsten forms complexes by reacting with several elements such as H, C, N, O, and P as well as other numerous inorganic elements. Interestingly, all tungsten reactions occur at ambient temperature, usually with tetrahydrofuran and dichloromethane under vacuum. Tungsten has extraordinarily high-temperature properties, making it very useful for X-ray production and heating elements in furnaces. Tungsten coordinates with diverse nonmetallic elements and ligands and produces interesting compounds. This article describes an overview of the synthesis of various organometallic compounds of tungsten.

Theoretical Investigation of Perylene Diimide derivatives as Acceptors to Match with Benzodithiophene based Donors for Organic Photovoltaic Devices

Optoelectronic properties of PDI derivatives (PDI-1–PDI-28) have been studied by inserting functional groups (–CN, –NO2 and –SO2) at different positions, by using DFT and TD-DFT functional at CAM-B3LYP/6-31 (d) level of theory. Absorption spectra of investigated PDI derivatives cover whole UV-Visible region which indicate that studied molecules could be used efficiently for photovoltaics. The R*(λmax – λmin) value of PDI derivatives is red shifted due to CN substitution while it resulted in slightly blue shift due to NO2 substitution. In addition, reorganization energy (λ) values found to be lowered by all substituents but more efficiently by SO2 and CN substituents. Molecular electrostatic potential surfaces and chemical reactivity indices have also been calculated to verify results. Furthermore, investigated acceptor molecules have been matched with suitable donors (based on benzo [2.1-b:3.4-b′] dithiophene derivatives D1–D5) to verify their practical efficiency. The calculated open circuit voltage (Voc) of investigated PDI derivatives is fairly high with donors D1 (0.95–1.34) and D2 (0.54–0.92). This study can be beneficial in future investigations of donor-acceptor materials for organic photovoltaic devices.

Drug-induced inhibition of phosphorylation of STAT5 overrides drug resistance in neoplastic mast cells

Systemic mastocytosis (SM) is a mast cell (MC) neoplasm with complex pathology and a variable clinical course. In aggressive SM (ASM) and MC leukemia (MCL) responses to conventional drugs are poor and the prognosis is dismal. R763 is a multi-kinase inhibitor that blocks the activity of Aurora-kinase-A/B, ABL1, AKT and FLT3. We examined the effects of R763 on proliferation and survival of neoplastic MC. R763 produced dose-dependent inhibition of proliferation in the human MC lines HMC-1.1 (IC₅₀ 5-50 nM), HMC-1.2 (IC₅₀ 1-10 nM), ROSA^{KIT WT} (IC₅₀ 1-10 nM), ROSA^{KIT D816V} (IC₅₀ 50-500 nM) and MCPV-1.1 (IC₅₀ 100-1000 nM). Moreover, R763 induced growth inhibition in primary neoplastic MC in patients with ASM and MCL. Growth-inhibitory effects of R763 were accompanied by signs of apoptosis and a G2/M cell cycle arrest. R763 also inhibited phosphorylation of KIT, BTK, AKT and STAT5 in neoplastic MC. The most sensitive target appeared to be STAT5. In fact, tyrosine phosphorylation of STAT5 was inhibited by R763 at 10 nM. At this low concentration, R763 produced synergistic growth-inhibitory effects on neoplastic MC when combined with midostaurin or dasatinib. Together, R763 is a novel promising multi-kinase inhibitor that blocks STAT5 activation and thereby overrides drug-resistance in neoplastic MC.

The phosphorescence properties of a series of diarylethene-containing platinum complexes: the effect of ligand photoisomerization

Benefitting from isomerization in the ancillary-ligand diarylethene, a control of phosphorescence efficiency becomes available.

Theoretical studies to investigate the effect of different cores and two different topologies on the optical and charge transfer properties of donor materials for organic solar cells

Three dimensional conjugated three- and four-armed molecules with core-D–π–A and core-A–π–D topologies were designed and studied by DFT, revealing that molecules with the core-A–π–D topology and N or C cores would result low reorganization energies and broad absorption bands for organic solar cells.

The ratio and topology effects of benzodithiophene donor-benzooxadiazole acceptor fragments on the optoelectronic properties of donor molecules toward solar cell materials

A series of conjugated donor molecules (DmAnSq where m = 1-4, n = 1-7 while D = benzodithiophene, A = benzooxadiazole and S denotes ethyne spacers between D and A or D and D fragments) with various ratios of D/A fragments and topologies have been designed and investigated for OPV applications. An increase in the ratio of the acceptor fragment with respect to the donor fragment decreases the LUMO energy level and narrows the Eg for the designed molecule. More vertically (C4 and C8 substituted phenyl ring positions) bonded acceptor fragments than linearly (C2 and C6 substituted thiophene ring positions) bonded fragments result in a significant red shift in the maximum absorption wavelength. While, linearly bonded fragments lead to stronger absorption bands. Molecules with D-A-D topology exhibit more significant optical and electronic characteristics than those with D-D topology. All donor molecules (m = 2-4) of the D-A-D type show lower λh values than those of 1 donor containing (DAn) molecules. D-D type molecules show only lower λe values than DAn molecules because of the presence of a second donor fragment. The charge transfer phenomenon is shape dependent. The branched or anisotropic X, H, π, n, and square shaped molecules display higher charge transfer rates than the corresponding linear isomers due to better dimensionality. On the basis of these results, we suggest that designed donor and corresponding matched acceptor molecules have potential to act as promising candidates in solar cell devices.

Theoretical studies of heteroatom-doping in TiO2 to enhance the electron injection in dye-sensitized solar cells

Density functional calculations have been explored to analyze the structural, electronic and charge transfer properties of a doped TiO₂ substrate and catechol–TiO₂ interfaces for dye-sensitized solar cells.

Severe acute maternal morbidity and intensive care in a public sector university hospital of Pakistan

BACKGROUND

The study was planned to review the case series of pregnant women requiring intensive care due to severe acute maternal morbidity in the public sector university hospital, in order to identify failures and priorities in maternal health care provision in Pakistan.

METHODS

A retrospective case series study was performed of critically ill obstetrics patients admitted to general intensive care unit of Liaquat University Hospital Hyderabad, Pakistan, from January 1st to 31st December 2006. Data included demographics, disease responsible for critical illness, complications that prompted ICU admissions, intervention required, length of ICU stay and the resulting foeto-maternal mortality and morbidity.

RESULTS

Over the study period, 30 obstetric patients were transferred to general ICU, representing 1.34% of 2224 deliveries. Seventy three % of women belonged to rural areas, 96% were un-booked while history of surgical intervention was present in 87% of cases. Hypertensive disorders of pregnancy (50%) and sepsis (17%) were the two main obstetrical conditions responsible for maternal illness. Respiratory failure (57%) and haemodynamic instability (40%) were the major indications for ICU transfer. Mechanical ventilatory support was the commonest intervention required in the ICU followed by the ionotropic support (33%). The foetal mortality rate was 43%, while maternal mortality rate was 33%.

CONCLUSION

Maternal morbidity and mortality can be reduced by meticulous adaptation of safe motherhood initiative, provision of separate ICU services for critically ill obstetrical patients and early assessment and aggressive intervention through a team approach involving obstetricians, intensivists and anaesthetists.

Hypotensive action of coumarin glycosides from Daucus carota

Daucus carota (carrot) has been used in traditional medicine to treat hypertension. Activity-directed fractionation of aerial parts of D. carota resulted in the isolation of two cumarin glycosides coded as DC-2 and DC-3. Intravenous administration of these compounds caused a dose-dependent (1-10 mg/kg) fall in arterial blood pressure in normotensive anaesthetised rats. In the in vitro studies, both compounds caused a dose-dependent (10-200 microg/ml) inhibitory effect on spontaneously beating guinea pig atria as well as on the K+ -induced contractions of rabbit aorta at similar concentrations. These results indicate that DC-2 and DC-3 may be acting through blockade of calcium channels and this effect may be responsible for the blood pressure lowering effect of the compounds observed in the in vivo studies.

Central nervous system abscesses due to Coccidioides species

Meningitis occurs in one-third to one-half of patients with disseminated coccidioidomycosis, but mass lesions have rarely been described; these lesions are usually found at autopsy. We report six cases of disseminated coccidioidomycosis with central nervous system (CNS) abscesses. Four patients had cerebellar involvement, and two had spinal cord involvement. Four patients were diabetic, and two subsequently died. Review of the literature on CNS coccidioidomycosis indicated that parenchymal brain involvement occurs in 1%-33% of cases, and < 40 cases with mass lesions have been reported since 1905. Almost all patients were male and had other active disseminated foci of coccidioidomycosis. In approximately one-third of all cases, meningitis was absent. Brain lesions may be superficial or deep and multiple or single. In the absence of meningitis, serology of cerebrospinal fluid is negative. Hematogenous origin appears to be more common than direct extension from the meninges. Spinal cord involvement is rare. Diabetes was present in several cases, thus suggesting a vascular predisposition. We hope our experience will increase awareness of this entity, which appears to be more common than previously appreciated, and will facilitate diagnosis.

Detection of coliform organisms in drinking water by radiometric method

The radiometric method has been used for detection of coliform bacteria in water. The method is based on measuring the released metabolic 14CO2 from 14C-lactose in growth media containing coliform organisms incubated at 37 degrees C under continuous shaking. This rapid and sensitive radiometric method permits the detection of even single coliform organisms within 6 hours of incubation. Using this automated method, a total of 102 samples (in duplicate) collected from different areas in and around Rawalpindi and Islamabad were assessed for coliform bacteria. Of these 102 samples, 50 were tap water samples, 40 from wells and 6 each were from Rawal and Simly dams. About 47% and 67% tap water samples, while 62% and 74% well water samples were found unsatisfactory from around Islamabad and Rawalpindi areas, respectively. About 83% and 66% water samples from Rawal dam and Simly dam respectively were found to be unsatisfactory.