Rice Pangenome Genotyping Array: an efficient genotyping solution for pangenome-based accelerated genetic improvement in rice.

The advent of the pangenome era has unraveled previously unknown genetic variation existing within diverse crop plants, including rice. This untapped genetic variation is believed to account for a major portion of phenotypic variation existing in crop plants. However, the use of conventional single reference-guided genotyping often fails to capture a large portion of this genetic variation leading to a reference bias. This makes it difficult to identify and utilize novel population/cultivar-specific genes for crop improvement. Thus, we developed a Rice Pangenome Genotyping Array (RPGA) harboring probes assaying 80K single-nucleotide polymorphisms (SNPs) and presence-absence variants spanning the entire 3K rice pangenome. This array provides a simple, user-friendly and cost-effective (60-80 USD per sample) solution for rapid pangenome-based genotyping in rice. The genome-wide association study (GWAS) conducted using RPGA-SNP genotyping data of a rice diversity panel detected a total of 42 loci, including previously known as well as novel genomic loci regulating grain size/weight traits in rice. Eight of these identified trait-associated loci (dispensable loci) could not be detected with conventional single reference genome-based GWAS. A WD repeat-containing PROTEIN 12 gene underlying one of such dispensable locus on chromosome 7 (qLWR7) along with other non-dispensable loci were subsequently detected using high-resolution quantitative trait loci mapping confirming authenticity of RPGA-led GWAS. This demonstrates the potential of RPGA-based genotyping to overcome reference bias. The application of RPGA-based genotyping for population structure analysis, hybridity testing, ultra-high-density genetic map construction and chromosome-level genome assembly, and marker-assisted selection was also demonstrated. A web application (http://www.rpgaweb.com) was further developed to provide an easy to use platform for the imputation of RPGA-based genotyping data using 3K rice reference panel and subsequent GWAS.

Mass Spectrometry Identifies Taenia solium Proteins in Sera of Patients With and Without Parenchymal Neurocysticercosis.

Neurocysticercosis (NCC), a major cause of global acquired epilepsy, results from Taenia solium larval brain infection. T. solium adult worms release large numbers of infective eggs into the environment contributing to high levels of exposure in endemic areas. This study identifies T. solium proteins in the sera of individuals with and without NCC using mass spectrometry to examine exposure in endemic regions. Forty-seven patients (18-51 years), 24 parenchymal NCC (pNCC), 8 epilepsy of unknown aetiology, 7 glioma, 8 brain tuberculoma, and 7 healthy volunteers were studied. Trypsin digested sera were subject to liquid chromatography-tandem mass spectrometry and spectra of 375-1700 m/z matched against T. solium WormBase ParaSite database with MaxQuant software to identify T. solium proteins. Three hundred and nineteen T. solium proteins were identified in 87.5% of pNCC and 56.6% of non-NCC subjects. Three hundred and four proteins were exclusive to pNCC sera, seven to non-NCC sera and eight in both. Ten percent, exhibiting immune-modulatory properties, originated from the oncosphere and cyst vesicular fluid. In conclusion, in endemic regions, T. solium proteins are detected in sera of individuals with and without pNCC. The immunomodulatory nature of these proteins may influence susceptibility and course of infection.

Effect of administration of tranexamic acid on blood loss and transfusion requirements in children undergoing posterior fossa tumor excision: a retrospective cohort study.

BACKGROUND: Surgical resection of posterior fossa tumors (PFT) in the pediatric age group often results in significant intraoperative blood loss. The primary objective was to assess the effect of tranexamic acid (TXA) on blood loss and transfusion requirement in pediatric patients undergoing excision of PFT. METHODS: In this retrospective study, all pediatric patients ≤ 18 years, who underwent PFT resection over a period of 7 years, were included. The patient and surgical characteristics, estimated blood loss (EBL), the need for blood and blood product transfusion, use of crystalloids, vasopressors, and any adverse events like seizures and thromboembolic events were recorded and compared between Group A who received TXA and Group B who did not. RESULTS: The study included 50 patients, out of which 36 belonged to Group A and 14 to Group B. The median age was 8 years (IQR, 2-17) and the mean BMI was 16.46 ± 4.11 kg/m2. The mean EBL was 224.29 ± 110.36 ml in group A (n = 36) and 362 ± 180.11 ml in group B (n = 14) (p = 0.007). The intraoperative volume of crystalloid use was significantly higher in group B (p = 0.04). The requirement of blood and blood product transfusion was similar between the groups, but the volume of blood transfusion per kg body weight was higher in group B, 8.3 (IQR, 6.7-11.1) ml/kg in Group A versus 10.5 (IQR, 8.1-16.1) ml/kg in Group B (p-value 0.3). The rates of complications noted in the form of seizures and thromboembolic events were comparable. CONCLUSION: The use of TXA in the pediatric population undergoing PFT resection aids in reducing blood loss during the surgery without increasing complications.

Brain abscess following kidney transplantation: A single centre observational study from North India.

Background: Amongst the infections in kidney transplant recipients, brain abscess represents an uncommon life-threatening complication. Mortality continues to be high despite improvements in diagnostics and therapeutics. Method: We conducted an observational study, describing the incidence, presentation, implicating pathogen, management and outcome of brain abscess following kidney transplantation at our centre. Result: Amongst the 1492 patients who underwent kidney transplantation at our centre between June 1991 and January 2023 (cumulative follow-up: 4936 patient-years), five females and four males, developed brain abscesses. The incidence proportion (risk) is 0.6% with an incidence rate of 6.03 cases per 1000 patient years. The median duration from transplant to development of brain abscess was 5 weeks (range: 4 weeks to 9 years). The commonest presentation was a headache. A definitive microbiological diagnosis was established in eight out of nine patients. The commonest implicated organism was a dematiaceous fungus, Cladophialophora bantiana (3 patients, 33.3%). Despite the reduction in immunosuppression, surgical evacuation and optimal medical therapy, five (55.55%) patients succumbed to their illness. Conclusions: Brain abscesses following kidney transplantation is an uncommon, life-threatening condition. It usually occurs in the early post-transplant period and the presentation is often subtle. Unlike immunocompetent individuals, a fungus is the most common causative organism in those with solid organ transplants. The management includes a reduction in immunosuppression, early antimicrobial therapy, and surgical decompression.

Aligning time-resolved kinetics (TAP) and surface spectroscopy (AP-XPS) for a more comprehensive understanding of ALD-derived 2D and 3D model catalysts.

The spectro-kinetic characterization of complex catalytic materials, i.e. relating the observed reaction kinetics to spectroscopic descriptors of the catalyst state, presents a fundamental challenge with a potentially significant impact on various chemical technologies. We propose to reconcile the kinetic characteristics available from temporal analysis of products (TAP) pulse-response kinetic experiments with the spectroscopic data available from ambient pressure X-ray photoelectron spectroscopy (AP-XPS), using atomic layer deposition (ALD) to synthesize multicomponent model surfaces on 2D and 3D supports. The accumulated surface exposure to a key reactant (total number of collisions) is used as a common scale within which the results from the two techniques can be rigorously compared for microscopically-equivalent surfaces. This approach is illustrated by proof-of-principle TAP and AP-XPS experiments with PtIn/MgO/SiO2 catalysts for alkane dehydrogenation at 800 K. Similarly to industrially-relevant Pt-based bimetallic catalysts on high-surface area supports, the initial period of coke accumulation on the surface resulted in gradually decreased conversion and increased selectivity towards propylene. We were able to monitor the process of coke deposition with both AP-XPS and TAP. The evolution of the C 1s photoelectron spectra is aligned on the common exposure scale with the evolution of the coke amounts deposited per Pt site during a multi-pulse TAP experiment. Moreover, TAP provided quantitative kinetic descriptors of propane consumption and product mean residence time within this common exposure scale. The challenges and opportunities presented by this novel tandem methodology are discussed in the context of catalysis research.

Molecular profiling of BADH2 locus reveals distinct functional allelic polymorphism associated with fragrance variation in Indian aromatic rice germplasm.

Allelic variability of the aroma gene, betaine aldehyde dehydrogenase 2 (BADH2) was studied in a random subset of indigenous aromatic rice germplasm along with a few exotic aromatic accessions. Use of functional markers of four badh2 alleles identified that the test panel possessed only two alleles, badh2-E7 and badh2-p-5'UTR. Two other alleles, badh2.2 and badh2-E4-5.2 were absent. Based on the alleles present, four functional polymorphisms (FP) were detected, namely FP1 to FP4. 188 genotypes possessed FP1 having both the badh2-p-5'UTR and badh2-E7 (71.8%) alleles. The badh2 allele with FP1 is named badh2-E7-p. 39 genotypes (14.9%) possessed only the badh2-p-5'UTR allele (FP3), while three genotypes were found to carry only the badh2-E7 allele (FP2). We also found that 32 genotypes (12.2%) did not have any of the target aroma alleles tested in this study (FP4). Interestingly, for badh2-p-5'UTR marker, the expected 198 bp amplicon for the non-aromatic allele could not be detected among any of the genotypes tested. Instead, an amplicon of 456 bp length appeared with 100% presence in the non-aromatic checks. Notwithstanding, the 456 bp allele also showed a 16% presence among the aromatic lines. This article forms the first report of this allele, named badh2-p1, among aromatic rice. Quantification of 2-Acetyl-1-Pyrroline (2AP) content and sensory evaluation among the test genotypes showed that those with FP1 are highly aromatic than the genotypes carrying other types of FPs. But, a few strongly aromatic lines showed lower 2AP content. The BADH2 characterization carried out in this study is suggestive of identifying the additional gene(s)/ allele(s) governing aroma among the Indian fragrant rice. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-022-01181-9.

Effect of treatment regimens in severe COVID pneumonia at an Indian tertiary care hospital: An observational, real-world study.

Background: Corticosteroids have attracted attention as a treatment option for severe Coronavirus disease (COVID-19). However, published data on steroid therapy is debatable, and real-world data is lacking. This study evaluated the effect of treatment regimens, especially Pulse steroid therapy (Injection Methyl Prednisolone 250 mg iv once a day for three days) in severe-COVID-19 pneumonia at an Indian tertiary care hospital. Methods: This observational cross-sectional study included severe COVID-19 pneumonia patients aged >18 years, requiring assisted ventilation. As part of the hospital protocol, patients received either pulse steroid therapy, remdesivir or tocilizumab in addition to the recommended steroid doses i.e., injection of dexamethasone 6 mg iv once a day. The association of factors and treatment regimens to patient outcomes was evaluated. Results: Data of eighty-three patients were assessed, majority being above 60 years (n = 30, 36.14%) and males (n = 45/83, 54.21%). The commonest comorbidities were hypertension (n = 26), diabetes (n = 23) and obesity (n = 19), fifty-five patients (66.26%) reported at least one comorbidity. Sixty-one patients (73.49%) had received pulse steroid regimen, forty-eight patients (57.83%) were administered remdesivir-based regimen while twelve patients (14.46%) had received tocilizumab treatment. 54.1% patients managed with pulse steroid regimens were discharged after treatment, statistically similar to remdesivir-managed subgroup (62.5%, p > 0.05). On sub-group analysis, pulse steroids showed better outcomes in young males with no comorbidities. No comorbidity had significant relationship with patient outcomes (p > 0.05). Conclusion: Pulse steroid therapy is an effective therapy in management of patients with severe COVID-19 pneumonia in a real-world setting, with better outcomes in young males without comorbidities. Pulse steroids can be considered a viable option for severe-COVID-19 pneumonia management.

Controlled synthesis of Fe-Pt nanoalloys using atomic layer deposition.

We report the phase and size-controlled synthesis of Fe-Pt nanoalloys, prepared via a two-step synthesis procedure. The first step is the deposition of bilayers consisting of iron oxide and Pt films of desired thicknesses using atomic layer deposition, followed by a temperature-programmed reduction treatment of the film under H2/N2 atmosphere. This method enables the phase pure synthesis of all three Fe-Pt alloy phases, namely Fe3Pt, FePt, and FePt3, as revealed by in situ x-ray diffraction and x-ray fluorescence measurements. It is also demonstrated that by changing the total thickness of the bilayers while keeping the Pt/(Pt + Fe) atomic ratio constant, the size of the resulting bimetallic nanoparticles can be tuned, as confirmed by scanning electron microscopic measurements.

Early- and long-term surgical outcomes in 109 children with lipomyelomeningocele.

AIM: To determine the functional outcomes and risk factors for outcomes following surgery for lipomyelomeningocele (LMMC). METHODS: Data from 109 children with LMMC who underwent surgery from January 2008 to December 2017 were retrospectively studied to evaluate functional outcomes and possible risk factors for early- (at discharge from hospital or within 1 month of surgery) and long-term outcomes after surgery. RESULTS: There were 53 boys and 56 girls with median age of 36 months (IQR 12-90 months; range, 4 months to 18 years) at surgery. At presentation, neurological function was normal (asymptomatic group) in 28 (25.7%) children while there was neurological dysfunction (symptomatic group) in 81 (74.3%). Near total or radical excision of lipoma was done in 71 (65.1%) children. Six (5.8%) children had deterioration of neurological function in the post-operative period with recovery of function in three of them. There were no statistically significant risk factors for early outcomes. At a mean follow-up of 62.5 months (IQR 35-82 months; range, 12-146 months), 21 (27.6%) of the 76 symptomatic group children (including 59.3% with incomplete bladder dysfunction) showed improvement, 52 (68.4%) remained the same, while 3 (4%) deteriorated. In 31 children (symptomatic group) who developed symptoms after 1 year of age, early surgery after development of symptoms was associated with better chances of recovery (p = 0.0008). In the asymptomatic group, 23 (88.5%) had normal neurological function at mean follow-up of 57.5 months (IQR 30-77 months; range, 12-141 months) and 3 (11.5%) had neurological deterioration. The mean time to late deterioration (re-tethering) from surgery was 51.3 months (IQR 24-75 months; range, 24-84 months). Presence of syrinx on initial MRI (p = 0.008) and partial resection of the lipoma (p = 0.02) were independent risk factors for delayed deterioration. CONCLUSION: Radical resection of LMMC probably helps in preserving neurological function in > 90% of children at long-term follow-up. Fifty-five percent of children > 2 years of age with incomplete bladder dysfunction regained normal function following surgery. In children who develop symptoms after birth, early surgical intervention can reverse the neurological deficits.

Dry spinal tap during real-time ultrasound-guided paramedian spinal injection with patient in the lateral decubitus position: A single-centre retrospective study.

BACKGROUND: Real-time ultrasound-guided (USG) spinal injection is generally performed via the paramedian sagittal oblique (PMSO) ultrasound window. OBJECTIVE: The aim of this retrospective study was to draw attention to the occurrence of 'dry tap' during real-time USG spinal injection. DESIGN: Single-centre retrospective study. SETTING: University teaching hospital, Hong Kong, China. PATIENTS: Data from 113 patients (aged 69.2 ±â€Š18.0 years and BMI 22.3 ±â€Š3.6 kg m-2) of American Society of Anesthesiologists physical status 1 to 3 scheduled for surgery under neuraxial blockade between 2007 to 2017 were reviewed. INTERVENTIONS: Real-time USG spinal injections or combined spinal-epidural (CSE) using the PMSO ultrasound window with the patient in the lateral decubitus position and the spinal needle inserted from the nondependent side were studied. MAIN OUTCOME MEASURES: 'Dry tap' was defined as a failure of cerebrospinal fluid (CSF) to efflux from the hub of the needle, within 3 min, with the spinal needle visualised sonographically within the thecal sac. 'Slow CSF efflux' was defined as efflux of CSF within 1 to 3 min. Irrespective of whether it was a 'dry tap' or 'slow CSF efflux', the planned dose of local anaesthetic was injected through the spinal needle. RESULTS: The combined incidence of 'dry tap' and 'slow CSF efflux' was 23.8% (27/113) with an individual incidence for each event of 9.7% (11/113) and 14.2% (16/113), respectively. Under the conditions of this study, successful spinal anaesthesia developed in all patients. CONCLUSION: 'Dry tap' occurs in 9.7% of cases during real-time USG spinal injection using the PMSO ultrasound window, with the patient in the lateral decubitus position and the spinal needle inserted from the nondependent side. TRIAL REGISTRATION: ChiCTR-IOR-1800019011, Chinese Clinical Trials Registry (www.chictr.org.cn).

Use of immunoadsorption columns in ABO-incompatible renal transplantation: A prospective study at a tertiary care center in India.

BACKGROUND: We present our experience of ABO-incompatible renal transplant using immunoadsorption (IA) columns. We have compared efficacy of two commercially available columns. METHODS: This single-center prospective study was conducted at Army Hospital Research and Referral, Delhi. All consecutive ABO-incompatible renal transplants from January 2014 to February 2018 were analyzed. Of 30 patients who underwent transplantations, 28 underwent antibody depletion with immunoadsorption columns. Of them, 14 cases were in the "Glycosorb group," while 14 in the "Adsopak group." RESULTS: The donors in the Adsopak group were older than those in the Glycosorb group (p < 0.05). Both groups had spousal donors in majority. The cutoff for the antibody titer was 1:8. The median titer in the Adsopak group was 128 (range, 1:4 to 1:2048), while that in the Glycosorb group was 24 (range, 1:8 to 1:128). All patients in the Glycosorb group had baseline titers ≤1:128, while 13 patients in the Adsopak group had baseline titers ≤1:512. Nil titer was achievable with Glycosorb® (50%,7/14) but not with Adsopak® (P < 0.01). Around 4 sessions were required for the Glycosorb group, while around 8 sessions were required for the Adsopak group before transplantation (p < 0.001). The Glycosorb group was advantageous in terms of graft failure because no rejection was noticed in these patients in their follow-up period. Three patients in the Adsopak group developed rejection (two had mixed rejection, and one had antibody-mediated rejection). Four patients died of sepsis (three in the Glycosorb and one in the Adsopak group). Lower baseline serum creatinine level was achieved in the Glycosorb group. CONCLUSIONS: Results of ABO-incompatible renal transplantation were satisfactory, and the use of immunoadsorption columns could effectively deplete antibody titers. Glycosorb columns were more efficient than Adsopak columns. Graft survival was better with Glycosorb. Posttransplant infections were a major cause of mortality.

A single-center experience in use of tocilizumab in COVID-19 pneumonia in India.

BACKGROUND: IL-6 receptor antagonist tocilizumab (TCZ) has been used in several reported studies in the treatment of COVID-19 pneumonia and pieces of evidence are still emerging. METHODS: All patients with COVID-19 pneumonia showing features of hyperinflammatory syndrome receiving TCZ at a tertiary care center in India were included in the study and a retrospective descriptive analysis was done. RESULTS: Between May 2020 to August 2020, 21 patients received TCZ out of which 13 survived and 8 died. All non-survivors had longer duration (median 12 days, minimum 9, maximum 15 days compared to median 6 days, minimum 3 and maximum 14 days in survivors) of symptoms and severe disease requiring mechanical ventilation at the time of TCZ administration. Among survivors, 8 patients had severe disease, 3 had moderate disease, and 2 patients had mild disease. Six out of 8 (75%) among non-survivors and 8 out of 13 (62%) among survivors had preexisting medical comorbidities. The non-survivors had higher baseline neutrophil-to-leukocyte ratio (10.5 vs 8.8), serum ferritin (960 ng/ml vs 611 ng/ml), lactate dehydrogenase (795 IU/L vs 954 IU/L), and D-dimer (5900 µg/ml vs 1485 mg/ml) levels. No drug-related serious adverse effect was noted among the patients. CONCLUSION: In a scenario of emerging evidence for the role of TCZ in the management of severe COVID-19, our study provides useful data on its use in the Indian scenario. Deliberate patient selection and timing initiation of TCZ at a crucial stage of the disease may be beneficial in COVID-19 pneumonia with good safety returns.

Reaching Out to the Millions: A 5 Key Messages Rapid IEC Campaign During the COVID-19 Pandemic.

The ongoing COVID-19 pandemic has necessitated providing populations with simple and relevant, actionable informational messages for them to be informed on individual and community level measures to combat the pandemic. Distilling guidance from various sources into simple actionable message themes in a short time frame should be the hallmark of any rapid health promotion campaign. We developed and disseminated actionable Information, Education and Communication (IEC) messages on prevention and control during the ongoing COVID-19 pandemic by selecting five key message themes of prevention. A modified Delphi technique was used for the development process which was peer reviewed after consensus was generated. An online training model using specifically developed YouTube videos and Zoom Meetings was utilized to train Master Trainers and the further hierarchy reaching out to 6989 Community Resource Persons at the peripheral echelons. Conservatively the population reached out has been estimated to be more than 6 million (across 1.2 million households), over a two week period in April 2020. The implementing agency has created 300 videos in around 22 languages based on the 5 Key Messages, which are available online for universal access. A rapid IEC campaign that can be developed, designed and rolled out in a short span is required for emergency situations such as the ongoing pandemic. NGOs play an important role in reaching out relevant messages to the community, filling in the gaps by virtue of their relative systemic agility.

Gapless Quantum Spin Liquid in the Triangular System Sr_{3}CuSb_{2}O_{9}.

We report gapless quantum spin liquid behavior in the layered triangular Sr_{3}CuSb_{2}O_{9} system. X-ray diffraction shows superlattice reflections associated with atomic site ordering into triangular Cu planes well separated by Sb planes. Muon spin relaxation measurements show that the S=1/2 moments at the magnetically active Cu sites remain dynamic down to 65 mK in spite of a large antiferromagnetic exchange scale evidenced by a large Curie-Weiss temperature θ_{CW}≃-143 K as extracted from the bulk susceptibility. Specific heat measurements also show no sign of long-range order down to 0.35 K. The magnetic specific heat (C_{m}) below 5 K reveals a C_{m}=γT+αT^{2} behavior. The significant T^{2} contribution to the magnetic specific heat invites a phenomenology in terms of the so-called Dirac spinon excitations with a linear dispersion. From the low-T specific heat data, we estimate the dominant exchange scale to be ∼36 K using a Dirac spin liquid ansatz which is not far from the values inferred from microscopic density functional theory calculations (∼45 K) as well as high-temperature susceptibility analysis (∼70 K). The linear specific heat coefficient is about 18 mJ/mol K^{2} which is somewhat larger than for typical Fermi liquids.

Prevalence of smooth muscle dysfunction among children with Duchenne muscular dystrophy.

Smooth muscle dysfunction in Duchenne muscular dystrophy (DMD) has been rarely studied. A cross-sectional study was conducted to estimate the prevalence of smooth muscle dysfunction (vascular, upper gastrointestinal, and bladder smooth muscle) in children with DMD using questionnaires (Pediatric Bleeding Questionnaire, Pediatric Gastroesophageal Symptom Questionnaire, and Dysfunctional Voiding Symptom Score). Investigations included bleeding time estimation, nuclear scintigraphy for gastroesophageal reflux, and uroflowmetry for urodynamic abnormalities. Ninety-nine subjects were included in the study. The prevalence of vascular, upper gastrointestinal, and bladder smooth muscle dysfunction was 27.2%. Mean bleeding time was prolonged by 117.5 seconds. The prevalence of gastroesophageal reflux was 21%. Voided volume/estimated bladder capacity over 15% and abnormal flow curves on uroflowmetry were seen in 18.2% and 9.7% of the subjects, respectively. Our study highlights the need for addressing issues related to smooth muscle dysfunction in the routine clinical care of patients with DMD.

The co-reactant role during plasma enhanced atomic layer deposition of palladium.

Atomic layer deposition (ALD) of noble metals is an attractive technology potentially applied in nanoelectronics and catalysis. Unlike the combustion-like mechanism shown by other noble metal ALD processes, the main palladium (Pd) ALD process using palladium(ii)hexafluoroacetylacetonate [Pd(hfac)2] as precursor is based on true reducing surface chemistry. In this work, a thorough investigation of plasma-enhanced Pd ALD is carried out by employing this precursor with different plasmas (H2*, NH3*, O2*) and plasma sequences (H2* + O2*, O2* + H2*) as co-reactants at varying temperatures, providing insights in the co-reactant and temperature dependence of the Pd growth per cycle (GPC). At all temperatures, films grown with only reducing co-reactants contain a large amount of carbon, while an additional O2* in the co-reactant sequence helps to obtain Pd films with much lower impurity concentrations. Remarkably, in situ XRD and SEM show an abrupt release of the carbon impurities during annealing at moderate temperatures in different atmospheres. In vacuo XPS measurements reveal the remaining species on the as-deposited surface after every exposure. Links are established between the particular surface termination prior to the precursor pulse and the observed differences in GPC, highlighting hydrogen as the key growth facilitator and carbon and oxygen as growth inhibitors. The increase in GPC with temperature for ALD sequences with H2* or NH3* prior to the precursor pulse is explained by an increase in the amount of hydrogen species that reside on the Pd surface which are available for reaction with the Pd(hfac)2 precursor.

Surface mobility and impact of precursor dosing during atomic layer deposition of platinum: in situ monitoring of nucleation and island growth.

The increasing interest in atomic layer deposition (ALD) of Pt for the controlled synthesis of supported nanoparticles for catalysis demands an in-depth understanding of the nucleation controlled growth behaviour. We present an in situ investigation of Pt ALD on planar Si substrates, with native SiO2, by means of X-ray fluorescence (XRF) and grazing incidence small-angle X-ray scattering (GISAXS), using a custom-built synchrotron-compatible high-vacuum ALD setup and focusing on the thermal Pt ALD process, comprising (methylcyclopentadienyl)trimethylplatinum (MeCpPtMe3) and O2 gas at 300 °C. The evolution in key scattering features provides insights into the growth kinetics of Pt deposits from small nuclei to isolated islands and coalesced worm-like structures. An analysis approach is introduced to extract dynamic information on the average real space parameters, such as Pt cluster shape, size, and spacing. The results indicate a nucleation stage, followed by a diffusion-mediated particle growth regime that is marked by a decrease in average areal density and the formation of laterally elongated Pt clusters. Growth of the Pt nanoparticles is thus not only governed by the adsorption of Pt precursor molecules from the gas-phase and subsequent combustion of the ligands, but is largely determined by adsorption of migrating Pt species on the surface and diffusion-driven particle coalescence. Moreover, the influence of the Pt precursor dose on the particle nucleation and growth is investigated. It is found that the precursor dose influences the deposition rate (number of Pt atoms per cycle), while the particle morphology for a specific Pt loading is independent of the precursor dose used in the ALD process. Our results prove that combining in situ GISAXS and XRF provides an excellent experimental strategy to obtain new fundamental insights about the role of deposition parameters on the morphology of Pt ALD depositions. This knowledge is vital to improve control over the Pt nucleation stage and enable efficient synthesis of supported nanocatalysts.

Cadaveric renal transplantation: Our experience at a tertiary care centre in India.

BACKGROUND: Renal transplantation in developing countries like India is largely live donor transplantation. Cadaveric transplantation comprises <2% of all transplants in India. METHODS: Ninety-two cadaveric renal transplantations were included. Various donor and recipient characteristics were analysed along with graft and patient survival, using Kaplan-Meier method. RESULTS: The mean age of the recipients was 35.5 ± 10.9 years while that of cadaver was 43.9 ± 17.0 years. Proportion of females among recipients was 47.8% while that of donors was 34.8%. The most common underlying pathology was chronic glomerulonephritis (44.6%). Antithymocyte globulin was used as induction in 84.8% of cases. Tacrolimus-based triple-drug regimen was most commonly used as maintenance (80.4%). The mean follow-up time was 39.02 ± 28.24 months. The most common cause of death was sepsis (47%). More than 50% deaths (9/17) occurred within first 3 years, while 61.5% of graft loss occurred 5 years after transplantation. The mean graft survival time was 81.6 months (95% confidence interval [CI]: 72.8-90.4). Cumulative proportion of graft survival was 91.6% at 3 years and 77.1% at 5 years. Although females have better mean graft survival time (91.6 vs 73.5 months), it was not a significant difference as shown by log-rank test (p value = 0.062). Pretransplant haemodialysis has no significant effect on graft loss, but patients on peritoneal dialysis have significantly higher odds of graft loss (odds: 4.86, p value < 0.05 [0.018]). The mean patient survival time was 99.5 months (95% CI: 84.0-114.9). Cumulative proportion of patient survival was 83.3% at 3 years and 70.8% at 5 years. CONCLUSION: Graft and patient survival rate of cadaveric transplant at our centre was satisfactory. There is need to sensitise and augment the rate of cadaveric transplantation to increase the donor pool.

Postoperative intraventricular blood: a new modifiable risk factor for early postoperative symptomatic hydrocephalus in children with posterior fossa tumors.

OBJECTIVE: To analyze factors associated with the development of early symptomatic hydrocephalus following posterior fossa tumor (PFT) surgery in children. METHODS: In this retrospective study, data from 148 children (age < 18 years) who underwent primary resection of their PFTs without preoperative permanent CSF diversion procedures were collected. The incidence of symptomatic hydrocephalus within 30 days of tumor resection was studied and its association with various demographic, tumor-related, and surgery-related risk factors was analyzed. RESULTS: At presentation, 131 (89%) of the 148 patients had symptomatic hydrocephalus. There were 99 males and 49 females (mean age 8.7 years; range 1 to 17 years). Postoperatively, 14 (9.4%) patients required shunt placement for symptomatic hydrocephalus. The indications for shunt surgery were persistent symptoms of raised intracranial pressure (n = 6, 43%), CSF leak from the wound (n = 7, 50%), and tense pseudomeningocele (n = 1, 7%). On multivariate analysis, age < 6 years (OR 5.9, 95% CI 1.6-22.6, p = 0.009) and the presence of intraventricular blood (IVB) on postoperative CT (OR 6.4, 95% CI 1.7-23.7, p = 0.006) were independent risk factors for developing symptomatic hydrocephalus. CONCLUSIONS: The incidence of postoperative symptomatic hydrocephalus in our series (9.4%) is lower than that reported in most previous studies. Age < 6 years and the presence of postoperative IVB were independent risk factors for developing symptomatic hydrocephalus. Of these, postoperative IVB is probably the only modifiable risk factor.