Contemporary advances in photocatalytic CO2 reduction using single-atom catalysts supported on carbon-based materials

The persistent issue of CO2 emissions and their subsequent impact on the Earth's atmosphere can be effectively addressed through the utilization of efficient photocatalysts. Employing a sustainable carbon cycle via photocatalysis presents a promising technology for simultaneously managing the greenhouse effect and the energy dilemma. However, the efficiency of energy conversion encounters limitations due to inadequate carrier utilization and a deficiency of reactive sites. Single-atom catalysts (SACs) have demonstrated exceptional performance in efficiently addressing the aforementioned challenges. This review article commences with an overview of SAC types, structures, fundamentals, synthesis strategies, and characterizations, providing a logical foundation for the design and properties of SACs based on the correlation between their structure and efficiency. Additionally, we delve into the general mechanism and the role of SACs in photocatalytic CO2 reduction. Furthermore, we furnish a comprehensive survey of the latest advancements in SACs concerning their capacity to enhance efficiency, long-term stability, and selectivity in CO2 reduction. Carbon-structured support materials such as covalent organic frameworks (COFs), graphitic carbon nitride (g-C3N4), metal-organic frameworks (MOFs), covalent triazine frameworks (CTFs), and graphene-based photocatalysts have garnered significant attention due to their substantial surface area, superior conductivity, and chemical stability. These carbon-based materials are frequently chosen as support matrices for anchoring single metal atoms, thereby enhancing catalytic activity and selectivity. The motivation behind this review article lies in evaluating recent developments in photocatalytic CO2 reduction employing SACs supported on carbon substrates. In conclusion, we highlight critical issues associated with SACs, potential prospects in photocatalytic CO2 reduction, and existing challenges. This review article is dedicated to providing a comprehensive and organized compilation of recent research findings on carbon support materials for SACs in photocatalytic CO2 reduction, with a specific focus on materials that are environmentally friendly, readily accessible, cost-effective, and exceptionally efficient. This work offers a critical assessment and serves as a systematic reference for the development of SACs supported on MOFs, COFs, g-C3N4, graphene, and CTFs support materials to enhance photocatalytic CO2 conversion.

Efficient structure tuning over the defective modulated zirconium metal organic framework with active coordinate surface for photocatalyst CO2 reduction

Structure engineering of zirconium-based metal organic frameworks (MOFs) aims to develop efficient catalysts for transforming intermittent renewable energy into value-added chemical fuels. In order to have a deeper understanding of industrial scaling, it is vital to ascertain the favourable operational parameters that are necessary for projecting at the atomic level. The proposed paradigm provides a robust basis for the efficient design of MOFs based heterogeneous photocatalysts. In this study, set of defective MOF (D-NUiO66) was effectively produced using a modular acidic method. Afterwards, the D-NUiO66 was combined with CeO2 to form the D-CeNUiO66 heterojunction for the purpose of carbon dioxide reduction. The morphological aspect of the composite investigation suggested that D-CeNUiO66 had a mesoporous structure with favourable adsorption properties. The optimized D-CeNUiO66 photocatalyst showed the high activity for the reduction of CO2 to CO, with a rate of 38.6 µmolg-1h-1 and demonstrated remarkable repeatability in terms of CO production. The incorporation of defect sites in the D-NUiO66 enhanced the light response to visible light, resulting in reduced band gap of 2.9 eV. The photoelectrochemical tests indicated that the introduction of defects in the UiO66 and coupling CeO2 in the D-CeNUiO66 composite induced fast charge transfer, therefore suppressing the charge recombination rate. This study provides valuable insights into the use of defective engineering and heterojunction approaches to metal-organic frameworks for photocatalytic applications.

First-principle calculations to investigate structural, electronic, mechanical, optical, and thermodynamic features of promising (La, In)-doped AlSb for optoelectronic applications

CONTEXT

A remarkable change in lattice parameters and bulk modulus is achieved by the suitable addition of Al (Al_1-x La_x Sb) and In (Al_1-x In_x Sb) atoms in the AlSb compound. Electronic responses like band structure, the total partial density of states, and the elemental density of states are thoroughly investigated. The computed values indicate that the binary compound AlSb is an indirect band gap and an optically inactive response. After increasing the doping concentrations (0.25, 0.5, 0.75) of La and In in AlSb, the band gap changes from indirect to direct nature. Hence, Al_1-0.75 La_0.25 Sb, Al_1-0.50 La_0.50 Sb, Al_1-0.75 In_0.25Sb, and Al_1-0.50 In_0.50Sb become optically active. The illustrious roles of Al-3p and In-4d states on the band gap and nonlinear responses of these compounds are extensively explored by the comparison between the computed results of ultra-soft and norm converging pseudopotentials. The excess specific heat (C_V), enthalpy of mixing (Hm), and phonon dispersion curves resulting from the concentrations "x" are estimated in order to investigate the thermodynamic stability responses of the pristine and doped AlSb. The obtained C_V and thermal coefficient statistics for Al_1-x La_x Sb and Al_1-x In_x Sb may be useful for a good mapping of experimental results and examining these compounds' enharmonic responses. There is a valuable change in optical characteristics like dielectric functional, absorption, conductivity, and refractive index due to the addition of (La, In) impurities in AlSb. It is further observed that Al_1-0.75 La_0.25 Sb, Al_1-0.50 La_0.50 Sb, Al_1-0.75 In_0.25Sb, and Al_1-0.50 In_0.50Sb are significantly mechanically stable compared to pristine AlSb. The above results suggest that Al_1-x La_x Sb and Al_1-x In_x Sb are high-performance optical materials and can be promising potential candidates for optoelectronic applications.

METHODS

The structural, electronic, mechanical, vibrational, and optical responses of the pure and doped Al_1-0.75 La_0.25 Sb, Al_1-0.50 La_0.50 Sb, Al_1-0.75 In_0.25Sb, and Al_1-0.50 In_0.50Sb are investigated, using Heydscuseria-Ernzerhof screened hybrid functional (HSEO6) and generalized gradient approximation (GGA) with norm-converging and ultra-soft pseudopotential techniques in the density functional theory.

Rice anther tapetum: a vital reproductive cell layer for sporopollenin biosynthesis and pollen exine patterning

The tapetum is the innermost layer of the four layers of the rice anther that provides protection and essential nutrients to pollen grain development and delivers precursors for pollen exine formation. The tapetum has a key role in the normal development of pollen grains and tapetal programmed cell death (PCD) that is linked with sporopollenin biosynthesis and transport. Recently, many genes have been identified that are involved in tapetum formation in rice and Arabidopsis. Genetic mutation in PCD-associated genes could affect normal tapetal PCD, which finally leads to aborted pollen grains and male sterility in rice. In this review, we discuss the most recent research on rice tapetum development, including genomic, transcriptomic and proteomic studies. Furthermore, tapetal PCD, sporopollenin biosynthesis, ROS activity for tapetum function and its role in male reproductive development are discussed in detail. This will improve our understanding of the role of the tapetum in male fertility using rice as a model system, and provide information that can be applied in rice hybridization and that of other major crops.

Synergistic catalytic enhancement of metal-organic framework derived nanoarchitectures decorated on graphene as a high-efficiency bifunctional electrocatalyst for methanol oxidation and oxygen reduction

Designing highly efficient, long-lasting, and cost-effective cathodic and anodic functional materials as a bifunctional electrocatalyst is essential for overcoming the bottleneck in fuel cell development. Herein, a novel two-step synthesis strategy is developed to synthesize metal-organic framework (MOF) derived nitrogen-doped carbon (NC) with improved spatial isolation and a higher loading amount of cobalt (Co) and nickel carbide (Ni₃C) nanocrystal decorated on graphene (denoted as Co@NC-Ni₃C/G). Benefiting from multiple active sites of high N-doping level, uniform dispersion of Co and Ni₃C nanocrystals, and a large active area of graphene, the Co@NC-Ni₃C/G hybrids exhibit excellent methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) efficiency in an alkaline environment. For MOR, the optimized Co@NC-Ni₃C/G-350 catalyst achieved a current density of 44.8 mA cm^-2 at an applied potential of 1.47 V (V vs. RHE), which is significantly higher than Co@NC-Ni₃C (42.07 mA cm^-2) and Co@NC (24.1 mA cm^-2) in 0.5 M methanol + 1.0 M KOH solutions. In addition, during the CO retention test, the Co@NC-Ni₃C/G-350 catalyst exhibits excellent CO tolerance capacity. Excitingly, the as-prepared Co@NC-Ni₃C/G-350 hybrid exhibits significantly improved ORR catalytic efficiency in terms of positive onset and half-wave potential (E_onset = 0.90 V, E_1/2 = 0.830 V vs. RHE), small Tafel slope (34 mV dec^-1) and excellent durability (only reduced 0.016 V after 5000 s test). This work provides new insights into MOF-derived functional nanomaterials for anode and cathode co-catalysts for methanol fuel cells.

Trigonella foenum-graecum Seeds Oil Attenuated Inflammation and Angiogenesis in vivo through Down-Regulation of TNF-α

INTRODUCTION

Inflammation is a vital reaction of the natural immune system that protects against encroaching agents. However, uncontrolled inflammation can lead to complications. Trigonella foenumgraecum is traditionally used as an anti-inflammatory herb.

OBJECTIVES

The current study was conducted to explore the antioxidant, anti-inflammatory, and antiangiogenic potentials of Trigonella foenum-graecum seeds oil.

METHODS

Oil was extracted from seeds of Trigonella foenum-graecum by cold press method and labelled as TgSO. Phytochemical (GC-MS, Folin-Ciocalteu method) and metal analyses were conducted to evaluate the metalo-chemical profile of TgSO. In vitro antioxidant assays (2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis-3- ethylbenzothiazoline-6-sulfonic acid and ferric reducing antioxidant power) were performed to assess its antioxidant potential. In vitro antimicrobial activity was evaluated using agar disc diffusion method and the safety profile of TgSO was assessed in acute toxicological studies following OECD 425 guidelines. In vivo antiinflammatory activities of TgSO were assessed in carrageenan, serotonin, histamine, formalin, and cotton pelletinduced oedema models. Serum TNF-α, Superoxide Dismutase (SOD) and, Catalases (CAT) levels were assessed by ELISA kits. In vivo antiangiogenic activity of TgSO was screened in chick Chorioallantoic Membrane (CAM) assay. Histopathological studies using excised paws were conducted to observe the effects of TgSO treatment at the tissue level. In silico docking studies were conducted to screen the binding potentials of identified compounds with TNF-α.

RESULTS

Extraction by cold press method yielded 16% of TgSO. Phytochemical analysis of TgSO through GCMS showed the presence of eugenol, dihydrocoumairn, heptadecanoic acid, tri- and tetradecanoic acid, and hexadecanoic acid, respectively. Total phenolic contents of TgSO were found to be 0.30±0.01mg/g gallic acid equivalent in Folin-Ciocalteu method. Metal analysis indicated the presence of different metals in TgSO. Findings of antioxidant models showed the moderate antioxidant potential of TgSO. Findings of antimicrobial assays showed that TgSO was active against bacterial (S. aureus, S. epidermidis) and fungal (C. albicans, and A. niger) strains. In vivo toxicity study data showed that TgSO was safe up to the dose of 5000 mg/kg. Data of oedema models showed a significant (p<0.05) reduction in oedema development in TgSO treated animals in both acute and chronic models. Histopathological evaluations of paws showed minimum tissue infiltration with inflammatory cells in TgSO-treated animals. Treatment with TgSO also significantly (p<0.05) down-regulated TNF-α in serum while levels of SOD and CAT were up-regulated. Findings of the CAM assay revealed the antiangiogenic activity of TgSO. Findings of in silico docking studies showed that identified phytoconstituents can bind with culprit cytokine (TNF-α).

CONCLUSION

Data obtained from the current study conclude that TgSO has antioxidant, anti-inflammatory, and antiangiogenic effects that validate its traditional uses. Synergistic actions of different phytoconstituents are proposed to be responsible for the observed effects.

55 Donor age has the least influence on recovery, quality, and in vitro developmental competence of ovum pickup–based Holstein Friesian oocytes under subtropical conditions

The use of oocytes obtained from younger donors for invitro fertilization followed by embryo transfer represents an opportunity to accelerate genetic gain by reducing generation interval. The present study was designed to evaluate the effect of age of donor on the follicular population, recovery, quality and invitro developmental competence of ovum pickup based Holstein Friesian oocytes under subtropical conditions. A total of eight (n=8) Holstein Friesian (with proper oestrus cyclicity) were selected for the study and divided into 2 groups based on animal age: (1) heifers (n=4), 1.5 to 2 years of age, and (2) adults (n=4), 5 to 6 years of age. The study was conducted near Lahore (31°33′ N, 74°19′ E), Punjab, Pakistan, from November 2019 to February 2020. The animals were wave synchronized using the physiological method of wave synchronization. After 4 days of second dominant follicle puncture, the first ovum pickup was carried out and a total of nine (n=9) OPU sessions were held for each group. The COCs from the follicles were aspirated using a transvaginal ultrasound–guided needle. Following searching and grading, COCs of grade A, B and C were processed for IVM in 100-µL droplets of BO-IVM under mineral oil at 37°C, 5% CO2, and 95% humidity for 24h. The frozen semen of a high-pedigree bull was thawed at 37°C and observed for post-thaw sperm motility. The semen samples of the same bull having motility &gt;50% were processed using the sperm swim-up method throughout the study. The IVF was carried out by placing the COCs and required amount of sperm in 100-µL droplets of BO-IVF at similar conditions for a maximum of 18h. The presumptive zygotes were denuded by gentle pipetting and cultured for a period of 7 days after placing in 100-µL drops of BO-IVC at 37°C, 5% CO2, 5% O2, and maximum humidity. The presumptive zygotes were observed for cleavage rate and blastocyst rate on Days 2 and 7 following COCs-sperm co-incubation. Data on the follicular population, oocytes recovered, and viable oocytes were analysed by the PROC GLIMMIX of SAS (SAS Institute Inc.), and proportional data were analysed by the Chi-squared method using SAS 9.1. COCs of grade AB (35.2 vs. 25.4%) were higher (P&gt;0.05) in the adult group than in the heifer group, respectively. Similarly, COCs with grade CD (57.5 vs. 71.9%) were lower (P&lt;0.05) in the adult group compared with the heifer group, respectively. However, the total follicles (6.55±0.42 vs. 6.39±0.39), number of COCs recovered (3.33±0.32 vs. 3.17±0.41), viable oocytes (3.08±0.29 vs. 3.08±0.39), cleavage rate (60.3 vs. 68.7%), and blastocyst rate (38.7 vs. 48.8%) did not differ (P&gt;0.05) between the groups. To conclude, donor age up to third lactation, under subtropical conditions, does not affect invitro embryo production in Holstein Friesian undergoing repeated OPU.

54 Effect of clinical endometritis on the follicle growth dynamics, oocyte recovery, oocyte quality, and invitro developmental competence of oocytes using ovum pickup in Sahiwal cattle

Sahiwal cattle is the premium quality milk breed of cattle in Pakistan. Uterine infections often lead to culling of valuable animals from a herd, resulting in genetic drain. The genetic potential of problematic females could be reaped by invitro embryo production. The objective of the present study was to evaluate the effect of clinical endometritis on follicle growth dynamics, recovery, quality, and invitro developmental competence of oocytes using ovum pickup (OPU) in Sahiwal cattle. The animals, 5–7 years of age, third or fourth parity, and 160 to 170 days in milk (DIM), were inspected for any discharge at the vulva or inside the vagina. Then, B-mode ultrasonography was performed to measure the diameter of cervix and to examine the uterus for the presence of pus. The animals (n=12) were divided into 2 groups: (1) healthy (n=6), and (2) clinical endometritis (n=6), based on the presence or absence of pus at the vulva or in the vagina. The first OPU was performed after 7 days of dominant follicle puncture and subsequently repeated OPUs (54 and 50), after every 7 days over 9 OPU sessions, were performed in the healthy group and clinical endometritis group, respectively. Follicles were aspirated using transvaginal ultrasound–guided needle. Viable COCs were considered for further processing only and were placed in the 100-µL droplets of BO-IVM medium and incubated at 37°C, 5% CO2, and 95% humidity for 24h. Nuclear maturation was estimated by staining the oocytes with Hoechst 33342. Frozen semen from the same Sahiwal bull was thawed and processed for IVF throughout the study. Sperm were prepared using swim-up protocol. Sperm and COCs were co-incubated in 100-µL droplets of BO-IVF for 18h. Finally, presumptive zygotes were cultured in 100-µL drops of BO-IVC medium at 37°C, 5% CO2, 5% O2, and 95% humidity for a period of 7 days. Cleavage rate and blastocyst rate were recorded on Day 2 and 7 following IVF, respectively. The data were analysed using the GLIMMIX procedure of SAS (SAS Institute Inc.). The results revealed that the number of medium-sized follicle (1.32±0.11 vs. 0.56±0.11) and total follicles (9.14±0.70 vs. 6.58±0.72) were higher (P&lt;0.05) in the healthy group than in the clinical endometritis group, respectively. Similarly, the number of oocytes recovered (5.05±0.39 vs. 2.78±0.41), viable oocytes (2.87±0.25 vs. 1.46±0.26), COCs with grade AB, having minimum of 2 cumulus cell layers and homogeneous cytoplasm, (33 vs. 20%) and nuclear maturation (68 vs. 55%) were also higher (P&lt;0.05) in the healthy group than in the clinical endometritis group, respectively. However, cleavage rate (55 vs. 46%) and blastocyst rate (29 vs. 26%) did not differ (P&gt;0.05) between the groups. In conclusion, clinical endometritis has a negative effect on follicle growth dynamics, oocyte recovery, oocyte quality, and nuclear maturation; however, the developmental competence of COCs is not compromised by it.

Methanolic extract of Ephedra ciliata promotes wound healing and arrests inflammatory cascade in vivo through downregulation of TNF-α

Chronic wounds may lead to the development of various pathological conditions such as diabetic foot ulcers and pressure sores. The current study evaluated wound healing and anti-inflammatory potentials of methanolic extract of Ephedra ciliata using series of in vivo models. Methanolic extract of Ephedra ciliata was prepared by maceration (Ec.Me). Qualitative and quantitative (HPLC) phytochemical and metal analyses were conducted to explore the chemical and metal profiles of Ec.Me. Safety profile (behavioural) and, antimicrobial, antioxidant, wound healing, anti-inflammatory and anti-angiogenic potentials of Ec.Me were evaluated using well-established in vitro and in vivo models. ELISA assay was performed to estimate the effects of Ec.Me treatment on serum levels of TNF-α. HPLC analysis identified quercetin as one of the major compounds in Ec.Me. Safety study data showed that Ec.Me was safe up to the dose of 2000 mg/kg. Antimicrobial assay data showed that Ec.Me was active against bacterial (Staphylococcus aureus) as well as fungal (Candida albicans and Aspergillus niger) strains. Ec.Me showed modertate antioxidant potential in in vitro and in vivo models. Data of excision and burn wound healing models showed that Ec.Me, promoted wound closure in a dose and time-dependent manner. Treatment with 20% Ec.Me cream and heparin showed almost the same effects with no statistical differences (p > 0.05). Ec.Me also showed time-dependent anti-inflammatory activities in both acute and chronic models. In carrageenan model, treatment with 200 mg/kg of Ec.Me showed comparable anti-inflammatory effects (p > 0.05) with quercetin and indomethacin throughout the study. In cotton pellet granuloma model treatment with 200 mg/kg of Ec.Me and indomethacin inhibited granuloma formation significantly better (p < 0.05) as compared with the rest of the treatment groups. Histopathological examination of skin samples showed marked improvement in architecture with minimal infiltration of inflammatory cells. Data of in vivo angiogenesis assay showed marked improvement in vessels length, density, branching points, total segments and total nets after treatment with Ec.Me, indicating no toxic effects towards vasculature development. Significant (p < 0.05) downregulation of TNF-α was observed in serum samples of animals treated with Ec.Me. Based on data of the current study, it is concluded that quercetin-rich extract of Ephedra ciliata has wound healing and anti-inflammatory potentials via downregulation of TNF-α. Moreover, it is suggested that the antimicrobial activity of Ec.Me prevented microbial invasion, thus promoted natural wound healing mechanisms as well.

Electron number density conservation model combined with a self-absorption correction methodology for analysis of nanostructure plasma using laser-induced breakdown spectroscopy

We studied laser ablation and plasma property evolution for a nickel (Ni) doped tin (Sn) oxide nanostructures target using laser-induced breakdown spectroscopy (LIBS). The transition metal Ni doped tin oxide nanostructures were synthesized by co-precipitation and hydrothermal methodologies. The size of prepared nanoparticles was verified by X-ray diffraction and transmission electron microscopy techniques. A frequency-doubled pulsed Nd:YAG laser with a wavelength of 532 nm was used to produce ablated plasma nanostructures. Ablation of doped and undoped nanostructures revealed salient-enhanced spectral emissions compared with their bulky counterparts. The emission lines of the constituent elements of doped material were used to find plasma parameters. The plasma temperature was estimated from a Boltzmann plot, and the electron number density was determined from the Saha-Boltzmann equation. The self-absorption effect has been observed in tiny plasma of nanostructures. The affected profiles of spectral lines of Ni and Sn nanoparticles due to self-absorption in LIBS spectra were corrected by the internal reference self-absorption correction (IRSAC) methodology. After correction of emitted line intensities by IRSAC, the electron number density (END) conservation approach was applied for quantitative analysis of doped nanostructures. In the END conservation approach, quantitative analysis of samples was carried out using electron number densities. Quantitative results derived from the END conservation approach at high and low concentrations exhibited good correlation when these were compared and validated with results from a conventional calibration free approach and the standard recognized energy dispersive X-ray technique.

Impact of human leukocyte antigen and calculated panel reactive antibody on BK viremia in kidney transplant recipients: A single-center experience and literature review

BACKGROUND

The aim of this retrospective analysis was to investigate the effect of human leukocyte antigen (HLA) and calculated panel reactive antibody (cPRA) on BK virus activation as evidenced by BK viremia (BKV).

PATIENTS AND METHODS

At our institution, 649 kidney transplant patients were screened for BKV from 2009 to 2017. Patients were considered to have BKV if they had >10 000 copies/mL of BK DNA in their blood. Donor and recipient HLA and cPRA, demographic, clinical and laboratory data, as well as immunosuppressive medications were collected.

RESULTS

We identified 122 BK positive and 527 BK negative patients. Only 25% of the patients had cPRA of 20% or more, and 64% had more than three HLA-A, -B, and -DR mismatches. In both univariate and multivariate analyses, male gender, age, and maintenance of steroid therapy significantly increased the risk of BKV (P = 0.005, 0.005 and <0.001, respectively). The degree of cPRA and the individual HLA allele and HLA allele matching did not significantly affect BKV.

CONCLUSION

Neither the degree of HLA mismatching nor cPRA appears to affect BKV. Moreover, no specific HLA allele, HLA allele matching, or cPRA were associated with BKV.

Impact of Recent Clinical Trials on Nephrology Practice: Are We in a Stagnant Era?

BACKGROUND

Although renal replacement therapy prevents death from uremia, survival among patients with acute and chronic kidney diseases (CKD) remains an imperative concern. The expected life span of US dialysis patients 60-64 years of age is approximately 4.5 years; this is similar to that of patients with lung cancer. Despite substantial progress in many medical specialties over the past decades (e.g., notable reductions in myocardial infarction, stroke, and mortality rates in the general population), survival among dialysis patients has not improved significantly over the same period. A few decades ago, HIV infection and AIDS were pretty much a death sentence. Because of progress in HIV treatment, now it can be controlled with a daily pill, and ongoing research is pushing treatment even further and controls the virus with longer-acting treatment. A cure is no longer impossible for HIV and other viral infections such as hepatitis B and C and many malignancies, but so far there is no cure for CKD.

SUMMARY

Billions of dollars have been spent on kidney disease research in the past decades, with no tangible progress in clinical practice. The challenges of improving the quantity and quality of trials in nephrology are enormous. The number of randomized controlled trials (RCTs) published in nephrology is lower than that in other medical subspecialties, and most of the big RCTs in nephrology yield negative results. Nephrology studies evaluating hard clinical endpoints or surrogate endpoints are scarce.

KEY MESSAGE

Herein we discuss the slow progress in nephrology research that has impacted clinical practice over the last couple of decades and highlight the major obstacles, challenges, and potential solutions.

Cardiac Arrest Due to Air Embolism: Complicating Image-guided Lung Biopsy

Cardiac arrest due to air embolism is an infrequent complication. Air embolism can be associated with procedures like endoscopic retrograde cholangiopancreatography, endoscopic variceal ligation, operative hysteroscopy, laparoscopic surgery, pacemaker placement, cardiac ablation, fiberoptic bronchoscopy, and decompression sickness. In rare cases, air embolus can be a catastrophic complication of computed tomography (CT) guided lung biopsy, which can lead to cardiac arrest. We present a case of a 67-year-old male chronic smoker with a left lower lobe pulmonary nodule who had a cardiac arrest due to air embolism as a consequence of CT guided biopsy of the pulmonary nodule found on a CT scan of the chest. He was successfully resuscitated and intubated for mechanical ventilation. He was managed conservatively and discharged home in a stable condition.

PTH assays in dialysis patients: Practical considerations

Parathyroid hormone (PTH) 1-84 is the main biologically active hormone produced by the parathyroid cells. Circulating PTH molecules include the whole PTH 1-84 along with amino (N) and carboxyl (C) terminal fragments. While PTH is the best available noninvasive biomarker to assess bone turnover in dialysis patients, the biological roles of individual circulating PTH fragments are still not completely known. The understanding that there is an enormous variation in the target specificity of currently available PTH assays for different circulating forms of PTH has led to the evolution of assays from first to second then third generation. With a reduction in kidney function, there is a preferential increase in circulating C fragments and non-PTH 1-84 forms, resulting in a decrease in the ratio of PTH 1-84/non-PTH 1-84. However, there are also substantial differences in between-assay measurements, with several fold variations in results. Targets based on multiples of the upper limit of normal (ULN) should be used rather than PTH ranges using absolute iPTH values. To date, the second-generation PTH remains the most widely used assay. Current guidelines recommend following iPTH trends rather than absolute values. Herein, we highlight problems and challenges in PTH assays/measurements and their interpretations in dialysis patients.

Factors affecting outcome after the use of the Ponseti method for the management of idiopathic clubfoot, a retrospective study in an orthopaedic referral institute

TIn the last few decades Ponseti method has replaced soft tissue releases as the gold standard in the management of idiopathic clubfoot. However, the recurrence of the deformity is common without post tenotomy bracing. The purpose of this study was to retrospectively see various attributes of the patients associated with poor outcome after use of Ponseti method in idiopathic clubfoot management. Seventy nine consecutive patients with one hundred and twenty three idiopathic clubfeet treated with Ponseti method by single orthopaedic surgeon were followed for a period of two years and recurrence of the deformity was studied in relation to age of patient at presentation (< 3 months or more), sex of the patient, severity of the deformity ( moderate to severe verses (Vs.) very severe), compliance to post tenotomy bracing (compliant Vs. non compliant), educational level of parents (high school or less) and access of parents to internet (Yes or No) and odds ratio for recurrence and level of significance determined for each using Fisher's exact t-test. Non compliance in seventeen patients (17.7%) with post tenotomy bracing was the most important factor related to the recurrence, with an odds ratio of 6.22 (P =0.0059). Educational level (less than high school) of parents (36.7%) was the second most important factor with odds ratio of 5.5 (P=0.0073). Fifteen patients with severe Demiglio scoring feet had an odds ratio of 5.3 (P= 0.0097) for the recurrence of the deformity. Inaccess of the parents to the internet had an odds ratio of 6.33 (P =0.011) for the recurrence of the deformity. Age and sex of the patients was not found to have a significant effect on the recurrence of the deformity. In conclusion, the risk factors associated with recurrence of the idiopathic clubfoot deformity except severity of the deformity are modifiable and extra minutes can be spent with risk group parents during follow up visits to prevent a recurrence by making them understand natural history of the corrected foot without post tenotomy bracing, encouraging them for regular follow up visits, arranging interactive sessions with other patients who are regular in their follow up and compliant with bracing, and encouraging the literate parents to update their information about clubfoot from internet.

Hand amputations: epidemiology, management and resurfacing options for soft tissue coverage

OBJECTIVE

Agricultural hand injuries occur mainly among young adults, many affecting the dominant hand, thereby impeding patients' ability to work or cope with social obligations. This study was carried out with the aim of collecting data on the epidemiology and management of agricultural hand injuries in Indian subjects.

METHOD

The study was conducted in the Department of Plastic and Reconstructive Surgery, JN Medical College, AMU, Aligarh, India, from October 2009 to December 2013. Patients with agricultural hand injuries were included. Data collected included socio-demographic details, mode and type of injury, type of reconstruction, complications, length of hospital stay and assessment of post-reconstruction status. These data were tabulated and analysed.

RESULTS

The typical patient was young (mean 33.2 years), of lower socio-economic status and with a total disregard for safety regulations. There is clustering of cases during the wheat harvest season (April-June). Wheat thresher injuries were the most common cause of partial hand amputation (51%), especially during this season. This was followed by fodder cutting (kutti/chara) machine injury, especially in females and children (36%). A simple classification for these injuries has been described and Grade II injury was the commonest. Reverse radial forearm flap was the most suitable regional flap for coverage, whereas thoraco-umbilical flap was the most commonly used distant flap. Patients who had the single-stage procedure had a significantly shorter stay.

CONCLUSION

Agricultural hand injuries are not totally avoidable and their incidence can be reduced by proper education, but the low economic and literacy status of the patients is a big hurdle. The forearm offers many flaps for reconstruction of hand, which can be used in defects on dorsal or palmar aspect of hand and results in early discharge from the hospital and early rehabilitation. In patients with associated injury to the forearm, abdominal flaps can be used for cover.

Application of Heavy Metal Rich Tannery Sludge on Sustainable Growth, Yield and Metal Accumulation by Clarysage (Salvia sclarea L.)

A field experiment was conducted to evaluate the effective utilization of tannery sludge for cultivation of clarysage (Salvia sclarea) at CIMAP research farm, Lucknow, India during the year 2012-2013. Six doses (0, 20, 40, 60, 80, 100 tha(-1)) of processed tannery sludge were tested in randomised block design with four replications. Results revealed that maximum shoot, root, dry matter and oil yield were obtained with application of 80 tha(-1)of tannery sludge and these were 94, 113 and 61% higher respectively, over control. Accumulation of heavy metals (Cr, Ni, Fe, Pb) were relatively high in shoot portion of the plant than root. Among heavy metals, magnitude of chromium accumulation was higher than nickel, iron and lead in shoot as well as in root. Linalool, linalyl acetate and sclareol content in oil increased by 13,8 and 27% respectively over control, with tannery sludge application at 80 tha(-1). Heavy metals such as chromium, cadmium and lead content reduced in postharvest soil when compared to initial status. Results indicated that clarysage (Salvia sclarea) can be grown in soil amended with 80 tha(-1)sludge and this can be a suitable accumulator of heavy metals for phytoremediation of metal polluted soils.

Genotypic variability for root/shoot parameters under water stress in some advanced lines of cotton (Gossypium hirsutum L.)

Research pertaining to genetic variability parameters, heritability, and genotypic, phenotypic, simple, and environmental correlations for various seedling traits in five elite advanced cotton (Gossypium hirsutum L.) lines (FH-113, FH-114, FH-941, FH-942, and FH-2015) and one check (CIM-496) was carried out during October and November 2010 under greenhouse conditions at the Cotton Research Institute (Faisalabad, Pakistan). Material was raised in plastic tubes with a randomized complete block design replicated three times. Three drought shocks were applied by withholding water from the tube-sown plants for 8-, 10-, and 12-day intervals. After 60 days of sowing, data on root/shoot traits like root length (cm), shoot length (cm), root weight (g), shoot fresh weight (g), lateral root number, root dry weight (g) shoot dry weight (g), and total plant weight (g) were recorded. Considerable genotypic variations existed between genotypes for all seedling characters. Higher broad-sense heritability estimates were found for all traits studied. Maximum broad-sense heritability coupled with high genetic advance in root length (0.99, 17.34), lateral root number (0.91, 2.89), and shoot length (0.90, 4.35) suggested a potential for genetic improvement through breeding and selection. The correlation coefficients among root length, shoot length, root dry weight, fresh shoot weight, and total plant weight were positively and significantly correlated; thus, they can be selected simultaneously as drought tolerance selection indexes owing to the absence of undesired relationships. Genotypes FH-942 and FH-113 had the lowest excised leaf water loss during the first 4 h and also for the next 4 h. Therefore, these two advanced lines (FH-942 and FH-113) with high initial water content and lower excised leaf water loss had better adaptation to water stress.

Alar base resection - Medial flap technique

The primary goal of alar base resection is the narrowing of nasal base while preserving or recreating normal contour. The standard wedge resection, as proposed by Weir, does narrow the base but too open at the expense of normal appearing nostrils. 25 patients were taken up for corrective septo-rhinoplasty of which 5 patients needed alar base resection. The medial flap technique as proposed by Jack Sheen was adopted and normal appearing nasal base achieved in all cases.

Determinants influencing prevalence of louse infestations on layers of district Faisalabad (Pakistan)

1. This paper describes the influence of some epidemiological determinants on the prevalence of louse infestation on layers in Faisalabad (Pakistan). 2. Seventy layer farms were screened to determine the prevalence of louse infestation and its determinants including age of the bird, availability of space per bird and frequency of litter change. Prevalence of Lipeurus caponis was highest (53.2%), followed by Menacanthus stramineus (22.16%), Goniodes dissimilis (12.37%) and Goniodes gallinae (12.37%). 3. Older birds (36 to 74 weeks of age) were found with a significantly higher prevalence of louse infestation than younger birds. 4. Month-wise prevalence of louse infestation was higher during the summer months (from April to August) and at older age. 5. Birds kept at floor area allowances ranging from 0.43 to 0.55 m(2) were highly infested with lice as compared to those provided with a space of 0.61 m(2) or higher per bird. 6. Litter change frequency after every 8 weeks resulted in a reduced chance of louse infestation as compared to less frequent litter changing practice. 7. It was concluded from the study that the louse infestation is a menace for the poultry production industry in Pakistan and age, space per bird and litter change frequency are the influencing determinants. 8. Further research on the chemotherapeutic trials and resistance in poultry should be continued for an effective lice control program.

Peritoneal dialysis for adults with acute renal failure: an underutilized modality

In order to evaluate the effects of peritoneal dialysis as a modality of renal replacement therapy for adults with acute renal failure (ARF) of varied etiologies, we studied 43 ARF patients who underwent peritoneal dialysis at our hospital from April 2004 to November 2005. The age of the patients ranged from 18 to 75 years with a mean of 35 years. There was no significant difference in the incidence of ARF between males and females. Acute tubular necrosis secondary to acute gastroenteritis was the cause of ARF in 32 (80%) patients; four (10%) patients expired secondary to ARF. There was an average fall of around 60% in the S. creatinine at the end of PD. We did not notice any significant complications related to the procedure. We conclude that peritoneal dialysis is still a good option for the treatment of patients with ATN.

The structure of zwitterionic phosphocholine surfactant monolayers

The structure of a zwitterionic phosphocholine (PC) surfactant monolayer adsorbed on the surface of water has been determined using neutron reflectivity in combination with H/D isotopic substitution. The most significant results of this study are the level of hydration of the PC headgroup and the lack of dehydration with increasing temperature and salt addition. The fraction of the alkyl chain (f(c)) immersed in water for all three chain isomers studied was found to be around 0.15, suggesting that the PC headgroup geometries influenced not only the headgroup hydration but also the degree of immersion of the alkyl chain in water. At the critical micelle concentration (CMC), the number of water molecules associated with the PC headgroup in C(m)PC (m = 12, 14, 16) was on order of 15. This value was significantly greater than that obtained for nonionic and ionic surfactants with similar limiting area per molecule at the CMC (A(cmc)). However, the fraction of the chain immersed in water for the ionic and nonionic surfactants was much greater. This suggests that the unique surface biocompatibility of PC surfactants arises from their strong affinity for water, and the relatively low fraction of mixing with the alkyl chain arises from the higher structural order within the PC monolayer. As surface coverage decreased, the number of water molecules associated with each PC headgroup increased, but f(c) remained constant for all the surfactants. This observation was consistent with the small variation in the thickness of the headgroup region, and the entire layer changed little with surfactant concentration. This is attributed to the role of PC headgroup geometries to maintain the conformational order within the layer as packing density varies. Further structural analysis based on a kinematic approach showed that, as the chain length was increased from C12 to C14 to C16 at the CMC, the angle of tilt for the alkyl chain increased from 40 degrees to 48 degrees to 53 degrees , respectively, whereas the thickness of the whole layer and that of the PC head region was largely constant. The almost vertical projection of the PC headgroup from these single alkyl chain surfactants is in sharp contrast to its strongly tilted conformation, as reported for dichain phospholipids such as dipalmitoyl glycerol phosphocholine (DPPC).

Neutron reflection from the liquid-liquid interface: adsorption of hexadecylphosphorylcholine to the hexadecane-aqueous solution interface

Adsorption of water-soluble, zwitterionic n-hexadecylphosphorylcholine (C(16)PC) amphiphiles has been examined at the hexadecane-aqueous solution interface using neutron reflectivity (NR) and interfacial tension measurements. The results of both methods indicate that the limiting area per surfactant molecule at the interface at the critical micelle concentration (cmc) is 40 +/- 5 Angstroms(2). In the NR measurements, two isotopic contrasts have been employed to determine the adsorption isotherm and to explore the structure of the interfacial region. Single-layer model fitting to both isotopic contrasts was only possible for the single sub-cmc concentration studied, where a film thickness of 60 +/- 5 Angstroms was obtained; consistent single-layer model fits to both contrasts for concentrations greater than the cmc were not possible, leading to the requirement of a two-layer model with an overall film thickness close to 60 +/- 2 Angstroms. This film thickness is appreciably greater than the fully extended C(16)PC molecular length and cannot be explained purely in terms of thermal broadening. A further result is that the reflectivity data indicate that, as the C(16)PC concentration increases, the amount of water on the hexadecane side of the interfacial region increases, in contrast to intuitive expectation. These findings are interpreted by conjecturing a structural model in which a trilayer of C(16)PC molecules is formed at the interface with the water concentrated in the region occupied by the headgroups.

Adsorption of single chain Zwitterionic phosphocholine surfactants: Effects of length of alkyl chain and head group linker

The adsorption of a range of single chain zwitterionic phosphocholine surfactants (C(n)P(m)C) at the air/liquid interface has been studied by a combination of surface tension and neutron reflectivity. The critical micellar concentration (CMC) for C(n)PC (or C(n)P(2)C), where n varied from 12, 14 to 16, was found to be 0.91, 0.14, and 1.2 x 10(-2) mM respectively, and followed the same trend as observed for other zwitterionic and non-ionic surfactants. The area per molecule at the CMC, A(cmc), for C(n)PC was found to remain constant between 50 and 53 A(2), indicating that the increase in the alkyl chain length had little effect on A(cmc) at the interface. The neutron reflection measurement also showed an almost constant layer thickness (tau) of 20+/-2 A from all the alkyl chain deuterated PC surfactants (dC(n)hPC) in null reflecting water (NRW), suggesting that the alkyl chains of the surfactant responded to changes in either chain length or solution concentration by varying their angle of tilt. In contrast, increasing the length of head group linker between P and N atoms in C(12)P(m)C, where m=2, 4, to 6, resulted in a much slower decrease of CMC from 0.91, 0.7, to 0.5 mM, consistent with a different contribution to the free energy of micellization. A(cmc) for C(12)P(m)C did not vary when m was increased from 2 to 4, and this observation together with the thickness of the head group region indicated an almost perpendicular projection of the head group in C(12)P(2)C and C(12)P(4)C. A further increase in m to 6 resulted in an A(cmc) of 70 A(2). This increase in A(cmc) however did not result in any change in either the total layer thickness or the fraction of the head group region submerged in the aqueous subphase, suggesting that the head group in C(12)P(6)C was bent away from the surface normal direction. Both increase in temperature from 25 to 40 degrees C and the addition of 0.1 M NaCl had little effect on the area per molecule or the thickness of C(12)P(m)C surfactant layer, showing that the C(12)P(m)C series behaved like C(n)P(2)C series. The main conclusion from this study is that for all the C(n)P(m)C surfactants studied, change in m or n has little effect on the total thickness, the thickness of the alkyl chain or that of the head group region.

Surface adsorption of zwitterionic surfactants: n-alkyl phosphocholines characterised by surface tensiometry and neutron reflection

The surface adsorption of n-dodecyl phosphocholine (C12PC) has been characterised by a combined measurement of surface tension and neutron reflectivity. The critical micellar concentration (CMC) was found to be 0.91 mM at 25 degrees C in pure water. At the CMC, the limiting area per molecule (A(cmc)) was found to be 52+/-3 A2 and the surface tension (gamma(cmc)) to be ca. 40.0+/-0.5 mN/m. The parallel study of chain isomer n-hexadecyl phosphocholine (C16PC) showed a decrease of the CMC to 0.012 mM and a drop of gamma(cmc) to 38.1+/-0.5 mN/m. However, A(cmc) for C16PC was found to be 54+/-3 A2, showing that increase in alkyl chain length by four methylene groups has little effect on A(cmc). The almost constant A(cmc) suggested that the limiting area per molecule was determined by the bulky PC head group. It was further found that the surface tension and related key physical parameters did not vary much with temperature, salt addition, solution pH or any combination of these, thus showing that surface adsorption and solution aggregation from PC surfactants is largely similar to the zwitterionic betaine surfactants and is distinctly different from ionic and non-ionic surfactants. The thickness of the adsorbed monolayers measured from both dC12hPC and dC16hPC was found to be 20-22 A at the CMC from neutron reflectivity. Neither A(cmc) nor layer thickness varied with alkyl chain length, indicating that as the alkyl chain length became longer it was further tilted away from the surface normal direction and the layer packing density increased. It was also observed that the thickness of the layer varied little with surfactant concentration, indicating that the average conformational orientation of the alkyl chain remained unchanged against varying surface coverage.

Cockayne syndrome

We report four cases of Cockayne Syndrome in a family of seven children. Apart from the usual clinical and laboratory features, sparse eye lashes and high arched palate in two patients, conjunctival and corneal edema in one, and proximal muscle weakness in one patient were noticed as additional findings.

Nonendoscopic removal of percutaneous endoscopic gastrostomy tubes: morbidity and mortality in children

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) tubes are often removed by cutting the tubing at skin level and allowing the internal components to pass through the gastrointestinal tract. This technique is commonly used in adults, but little information is available concerning its safety in younger patients.

METHODS

To assess the safety of this approach in children, the clinical courses of all patients who had undergone PEG tube removal in our pediatric gastroenterology unit over a 3-year period were reviewed.

RESULTS

Five of 11 patients in whom the internal components were allowed to pass developed significant complications. Three required subsequent endoscopic removal of the internal component due to persistent vomiting, one died from complications of esophageal perforation caused by the retained internal component, and one developed a gastrocutaneous fistula containing the retained bumper 2 years after PEG tube removal. Significant complications occurred more often in the younger and smaller patients.

CONCLUSIONS

Small children are at greater risk than adults for developing serious complications associated with unremoved PEG tube internal components. If passage of the internal components cannot be confirmed after 2 weeks, chest and abdominal radiographs should be obtained.

Seroprevalence of antibodies to Toxoplasma gondii, with particular reference to obstetric history of patients in Rawalpindi-Islamabad, Pakistan

Six hundred and forty blood samples were obtained from Rawalpindi-Islamabad to determine the frequency of Toxoplasma gondii antibodies using indirect immunofluorescent antibody (IFA) test. Two hundred and forty samples were from suspected cases of Toxoplasmosis. Forty (17%) cases were positive for IgG antibody. Seven (3%) of these cases showed antibody titre greater than 1:320. Of 65 children tested, 8 (12.30%) were positive. Four (6%) children had a rising titre from 1:160 to 1:1025. Prevalence of Toxoplasma antibodies was correlated to mode of living, maternal obstetric history, their animal contact and age of the children.