Double-side 2D/3D heterojunctions for inverted perovskite solar cells.

Defects at the top and bottom interfaces of three-dimensional (3D) perovskite photoabsorbers diminish the performance and operational stability of perovskite solar cells owing to charge recombination, ion migration and electric-field inhomogeneities1-5. Here we demonstrate that long alkyl amine ligands can generate near-phase-pure 2D perovskites at the top and bottom 3D perovskite interfaces and effectively resolve these issues. At the rear-contact side, we find that the alkyl amine ligand strengthens the interactions with the substrate through acid-base reactions with the phosphonic acid group from the organic hole-transporting self-assembled monolayer molecule, thus regulating the 2D perovskite formation. With this, inverted perovskite solar cells with double-side 2D/3D heterojunctions achieved a power conversion efficiency of 25.6% (certified 25.0%), retaining 95% of their initial power conversion efficiency after 1,000 h of 1-sun illumination at 85 °C in air.

wnt16 regulates spine and muscle morphogenesis through parallel signals from notochord and dermomyotome.

Bone and muscle are coupled through developmental, mechanical, paracrine, and autocrine signals. Genetic variants at the CPED1-WNT16 locus are dually associated with bone- and muscle-related traits. While Wnt16 is necessary for bone mass and strength, this fails to explain pleiotropy at this locus. Here, we show wnt16 is required for spine and muscle morphogenesis in zebrafish. In embryos, wnt16 is expressed in dermomyotome and developing notochord, and contributes to larval myotome morphology and notochord elongation. Later, wnt16 is expressed at the ventral midline of the notochord sheath, and contributes to spine mineralization and osteoblast recruitment. Morphological changes in wnt16 mutant larvae are mirrored in adults, indicating that wnt16 impacts bone and muscle morphology throughout the lifespan. Finally, we show that wnt16 is a gene of major effect on lean mass at the CPED1-WNT16 locus. Our findings indicate that Wnt16 is secreted in structures adjacent to developing bone (notochord) and muscle (dermomyotome) where it affects the morphogenesis of each tissue, thereby rendering wnt16 expression into dual effects on bone and muscle morphology. This work expands our understanding of wnt16 in musculoskeletal development and supports the potential for variants to act through WNT16 to influence bone and muscle via parallel morphogenetic processes.

Safety and efficacy of direct percutaneous endoscopic jejunostomy tube placement compared with surgical jejunostomy: a tertiary care analysis.

BACKGROUND AND AIMS: Jejunostomy tube placements provides enteral access for feeding in eligible patients who cannot meet their nutritional needs by mouth. They can be surgically placed laparoscopically (lap-J) or with the use of a conventional open laparotomy approach (open-J). Recently, direct percutaneous endoscopic jejunostomy (DPEJ) has emerged as an alternative owing to its low cost and shorter recovery times. We sought to retrospectively compare the procedural success rates and adverse events of these methods. METHODS: Patients were identified by querying our health system patient database and the departmental database of patients who underwent DPEJ. The patients were divided into 3 cohorts based on the procedure: DPEJ, lap-J, or open-J. Patient age and body mass index, procedural success rate, and adverse event rate were compared among the 3 groups. RESULTS: A total of 201 patients met inclusion criteria (65 DPEJ, 111 lap-J, and 25 open-J). Procedural success rates were similar among the 3 groups (DPEJ 96.9%, lap-J 99.1%, open-J 100%; P = .702). Rates of infection and bleeding were also similar among the 3 groups. There were no cases of GI perforation. Tube dysfunction for any reason that required complete removal or replacement within 90 days occurred more often in the surgical groups than in the DPEJ group (DPEJ 0%, lap-J 35.1%, open-J 40.0%; P < .001). This was driven largely by increased rates of tube clogging and tube dislodgement in the surgical groups. CONCLUSIONS: DPEJ is a safe and effective alternative to surgical jejunostomy in eligible patients and may be associated with decreased adverse event rates at 90 days.

Effects of Glucagon-Like Peptide-1 Receptor Agonists on Gastric Mucosal Visibility and Retained Gastric Contents During Esophagogastroduodenoscopy.

BACKGROUND AND AIMS: Glucagon-like peptide-1 receptor agonists (GLP-1RA) are increasingly utilized in diabetes and obesity management. GLP-1RAs delay gastric emptying; however, their impact on visibility during esophagogastroduodenoscopy (EGD) remains uncertain. METHODS: A 1:1 matched case-control study was conducted. Individuals undergoing EGD on GLP-1RAs were matched to non-users based on demographics and diabetes status. A validated scale (POLPREP) was used to determine gastric mucosal visibility scores. RESULTS: A total of 84 pairs (n=168) were included. GLP-1RA users showed significantly lower visibility scores, with a 2.54 times higher likelihood of lower scores compared to non-users. Additionally, GLP-1RA users had a higher incidence of retained gastric contents (13.1% vs. 4.8%, aOR:4.62, p=0.025) and aborted procedures due to this issue. No anesthesia-related adverse events were observed. CONCLUSIONS: GLP-1RA use at the time of endoscopy exhibited higher odds of lower gastric mucosal visibility scores, retained contents and aborted procedures. Further research is warranted.

Safety, Efficacy and Clinical Utility of the 5.1mm EndoRotor Powered Debridement Catheter for Treatment of Walled-Off Pancreatic Necrosis.

BACKGROUND AND AIMS: Direct endoscopic necrosectomy (DEN) is a recommended strategy for treatment of walled-off-necrosis (WON). DEN uses a variety of devices including the EndoRotor (Interscope, Inc.) debridement catheter. Recently, a 5.1 mm EndoRotor with increased chamber size and rate of tissue removal was introduced. The aim of this study was to assess the efficacy and safety of this device. METHODS: A multi-center cohort study was conducted at eight institutions including patients who underwent DEN with the 5.1 mm EndoRotor. The primary outcome was the number of DEN sessions needed for WON resolution. Secondary outcomes included the average percent reduction in solid WON debris and decrease in WON area per session, total time spent performing EndoRotor therapy for WON resolution, and adverse events. RESULTS: 64 procedures in 41 patients were included. For patients in which the 5.1 mm EndoRotor catheter was the sole therapeutic modality, an average of 1.6 DEN sessions resulted in WON resolution with an average cumulative time of 85.5 minutes. Of the 21 procedures with data regarding percent of solid debris, the average reduction was 85% +/- 23% per session. Of the 19 procedures with data regarding WON area, the mean area significantly decreased from 97.6 +/- 72.0 cm2 to 27.1 +/- 35.5 cm2 (p<0.001) per session. Adverse events included two intra-procedural LAMS dislodgements managed endoscopically and three perforations none of which were related to EndoRotor. Bleeding was reported in seven cases, none required embolic or surgical therapy and two required blood transfusions. CONCLUSIONS: This is the first multi-center retrospective study to investigate the efficacy and safety of the 5.1 mm EndoRotor catheter for WON. Results from this study showed an average of 1.6 DEN sessions were needed to achieve WON resolution with an 85% single session reduction in solid debris and a 70% single session decrease in WON area with minimal adverse events.

Experts' recommendations in laser use for the treatment of bladder cancer: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training and Research in Urological Surgery and Technology (TRUST)-Group.

PURPOSE: To identify laser settings and limits applied by experts during laser vaporization (vapBT) and laser en-bloc resection of bladder tumors (ERBT) and to identify preventive measures to reduce complications. METHODS: After a focused literature search to identify relevant questions, we conducted a survey (57 questions) which was sent to laser experts. The expert selection was based on clinical experience and scientific contribution. Participants were asked for used laser types, typical laser settings during specific scenarios, and preventive measures applied during surgery. Settings for a maximum of 2 different lasers for each scenario were possible. Responses and settings were compared among the reported laser types. RESULTS: Twenty-three of 29 (79.3%) invited experts completed the survey. Thulium fiber laser (TFL) is the most common laser (57%), followed by Holmium:Yttrium-Aluminium-Garnet (Ho:YAG) (48%), continuous wave (cw) Thulium:Yttrium-Aluminium-Garnet (Tm:YAG) (26%), and pulsed Tm:YAG (13%). Experts prefer ERBT (91.3%) to vapBT (8.7%); however, relevant limitations such as tumor size, number, and anatomical tumor location exist. Laser settings were generally comparable; however, we could find significant differences between the laser sources for lateral wall ERBT (p = 0.028) and standard ERBT (p = 0.033), with cwTm:YAG and pulsed Tm:YAG being operated in higher power modes when compared to TFL and Ho:YAG. Experts prefer long pulse modes for Ho:YAG and short pulse modes for TFL lasers. CONCLUSION: TFL seems to have replaced Ho:YAG and Tm:YAG. Most laser settings do not differ significantly among laser sources. For experts, continuous flow irrigation is the most commonly applied measure to reduce complications.

Stenotrophomonas riyadhensis sp. nov., isolated from a hospital floor swab.

During the analysis of a collection of Pseudomonas strains linked to an outbreak in an intensive care unit at King Faisal Specialist Hospital and Research Center in 2019, one isolate (CFS3442T) was identified phenotypically as Pseudomonas aeruginosa. However, whole-genome sequencing revealed its true identity as a member of the genus Stenotrophomonas, distinct from both P. aeruginosa and Stenotrophomonas maltophilia. The isolate demonstrated: (i) a significant phylogenetic distance from P. aeruginosa; (ii) considerable genomic differences from several S. maltophilia reference strains and other Stenotrophomonas species; and (iii) unique phenotypic characteristics. Based on the combined geno- and phenotypic data, we propose that this isolate represents a novel species within the genus Stenotrophomonas, for which the name Stenotrophomonas riyadhensis sp. nov. is proposed. The type strain is CFS3442T (=NCTC 14921T=LMG 33162T).

Conversion of Failed J-Pouch to Kock Pouch: Indications, Contraindications, and Outcomes.

BACKGROUND: The IPAA has been successful in restoring intestinal continuity and preserving continence in the majority of patients requiring a proctocolectomy. However, a subset of individuals experience significant complications that might result in pouch failure. The conversion of the J-pouch to a continent ileostomy pouch represents a significant surgical procedure. In this article, we discuss the indications and contraindications, present the technical principles applied for the conversion, and describe the outcomes of such conversion in the literature. OBJECTIVE: The main objective during the conversion of the J-pouch to a continent ileostomy is the creation of a sufficiently sized reservoir with a high-quality valve mechanism while preserving as much small bowel as possible. CONCLUSIONS: The conversion of the J-pouch to a continent ileostomy represents a significant surgical procedure. When performed in centers of expertise, it can be a good option for patients who otherwise will require an end ileostomy. Indications for conversion include most cases of J-pouch failure, with a few important exceptions. See video from symposium .

A new perspective on therapies involving B-cell depletion in autoimmune diseases.

It has been rediscovered in the last fifteen years that B-cells play an active role in autoimmune etiology rather than just being spectators. The clinical success of B-cell depletion therapies (BCDTs) has contributed to this. BCDTs, including those that target CD20, CD19, and BAFF, were first developed to eradicate malignant B-cells. These days, they treat autoimmune conditions like multiple sclerosis and systemic lupus erythematosus. Particular surprises have resulted from the use of BCDTs in autoimmune diseases. For example, even in cases where BCDT is used to treat the condition, its effects on antibody-secreting plasma cells and antibody levels are restricted, even though these cells are regarded to play a detrimental pathogenic role in autoimmune diseases. In this Review, we provide an update on our knowledge of the biology of B-cells, examine the outcomes of clinical studies employing BCDT for autoimmune reasons, talk about potential explanations for the drug's mode of action, and make predictions about future approaches to targeting B-cells other than depletion.

Highly efficient mica-incorporated graphene oxide-based membranes for water purification and desalination.

Graphene oxide (GO) has become the most attractive material for membrane technology owing to its potential application as a nanofiller in water treatment, purification, and desalination. In this study, we incorporated mica as a cross-linking reagent to increase the interlayer spacing and stability of GO sheets and fabricated a mica/GO (MGO) membrane for the first time. The MGO membrane (260 ± 10 nm) exhibits 100% rejection for biomolecules such as tannic acid (TA) and bovine serum albumin (BSA) and >99% rejection for multiple probe molecules, such as methylene blue, methyl orange, congo red, and rhodamine B. The high rejection of membranes can be attributed to the surface interaction of mica with GO nanosheets through covalent interaction, which enhances the stability and separation efficiency of the membranes for probe ions and molecules. This ultrathin MGO membrane also exhibits much better water permeability at 870 ± 5 L m-2 h-1 bar-1, which is 10-100 times greater than that reported for pure GO and GO-based composite membranes. Additionally, the membrane shows high rejection for salt ions (70%). Furthermore, the stability of the MGO membranes was evaluated under various conditions, and the membranes demonstrated remarkable stability for up to 60 days in a neutral environment.

Remimazolam versus propofol for sedation in gastrointestinal endoscopy and colonoscopy within elderly patients: a meta-analysis of randomized controlled trials.

PURPOSE: Propofol has become the sedative of choice for endoscopy and colonoscopy. However, it has shown associations with various adverse effects, specifically in the geriatric population. In contrast, remimazolam is a novel benzodiazepine, demonstrating a superior clinical safety profile. Hence, this systematic review and meta-analysis aims to clarify the efficacy and safety of remimazolam versus propofol in elderly patients (≥ 60 years) undergoing gastrointestinal endoscopic and colonoscopy procedures. METHODS: Electronic databases including PubMed, Cochrane Library, ScienceDirect, and Google Scholar were explored from inception till January 7, 2024. The Cochrane Risk of Bias Tool for Randomized Controlled Trials (RoB-2) was utilized to evaluate the quality of each included study reported in this meta-analysis. RESULTS: Seven randomized control trials were included, resulting in the pooling of 1,466 patients (remimazolam: 731 patients; propofol: 735 patients). Propofol demonstrated a significantly lower time to loss of consciousness (P < 0.00001, 4 studies, 784 patients) and a greater sedation success after first dose (P = 0.05, 5 studies, 1,271 patients). Remimazolam reported a significantly lower risk of bradycardia (P = 0.02, 5 studies, 1,323 patients), hypoxemia (P < 0.00001, 6 studies, 1,389 patients), and pain on injection site (P < 0.00001, 5 studies, 1,184 patients). No statistically significant differences in sedation time, number of supplemental doses, procedural parameters, and other adverse outcomes were reported. CONCLUSION: As per the results of our analyses, propofol demonstrated comparatively superior efficacy, however, remimazolam demonstrated comparatively superior safety. The debatable evidence generated from this meta-analysis may not currently be powerful enough to advocate for the use of remimazolam in elderly patients undergoing gastrointestinal procedures; hence, further comprehensive studies are necessary in order to arrive at a robust conclusion.

Designing Energy-Efficient Buildings in Urban Centers through Machine Learning and Enhanced Clean Water Management.

Rainwater Harvesting (RWH) is increasingly recognized as a vital sustainable practice in urban environments, aimed at enhancing water conservation and reducing energy consumption. This study introduces an innovative integration of nano-composite materials as Silver Nanoparticles (AgNPs) into RWH systems to elevate water treatment efficiency and assess the resulting environmental and energy-saving benefits. Utilizing a regression analysis approach with Support Vector Machines (SVM) and K-Nearest Neighbors (KNN), this study will reach the study objective. In this study, the inputs are building attributes, environmental parameters, sociodemographic factors, and the algorithms SVM and KNN. At the same time, the outputs are predicted energy consumption, visual comfort outcomes, ROC-AUC values, and Kappa Indices. The integration of AgNPs into RWH systems demonstrated substantial environmental and operational benefits, achieving a 57% reduction in microbial content and 20% reductions in both chemical usage and energy consumption. These improvements highlight the potential of AgNPs to enhance water safety and reduce the environmental impact of traditional water treatments, making them a viable alternative for sustainable water management. Additionally, the use of a hybrid SVM-KNN model effectively predicted building energy usage and visual comfort, with high accuracy and precision, underscoring its utility in optimizing urban building environments for sustainability and comfort.

Population mortality before and during the COVID-19 epidemic in two Sudanese settings: a key informant study.

BACKGROUND: Population mortality is an important metric that sums information from different public health risk factors into a single indicator of health. However, the impact of COVID-19 on population mortality in low-income and crisis-affected countries like Sudan remains difficult to measure. Using a community-led approach, we estimated excess mortality during the COVID-19 epidemic in two Sudanese communities. METHODS: Three sets of key informants in two study locations, identified by community-based research teams, were administered a standardised questionnaire to list all known decedents from January 2017 to February 2021. Based on key variables, we linked the records before analysing the data using a capture-recapture statistical technique that models the overlap among lists to estimate the true number of deaths. RESULTS: We estimated that deaths per day were 5.5 times higher between March 2020 and February 2021 compared to the pre-pandemic period in East Gezira, while in El Obeid City, the rate was 1.6 times higher. CONCLUSION: This study suggests that using a community-led capture-recapture methodology to measure excess mortality is a feasible approach in Sudan and similar settings. Deploying similar community-led estimation methodologies should be considered wherever crises and weak health infrastructure prevent an accurate and timely real-time understanding of epidemics' mortality impact in real-time.

Impact of Blood Sampling Methods on Blood Loss and Transfusion After Pediatric Cardiac Surgery: An Observational Study.

OBJECTIVES: The aims of this study were to assess the impact of the closed-loop sampling method on blood loss and the need for blood transfusion in pediatric patients following cardiac surgery. DESIGN: Retrospective observational study. SETTING: A single tertiary center. PARTICIPANTS: All pediatric patients younger than 4 years old who were admitted to the pediatric intensive care unit (PICU) after cardiac surgery were enrolled. The study included 100 pediatric patients in the conservative (postimplementation) group and 43 pediatric patients in the nonconservative group (preimplementation). INTERVENTIONS: Observational. MEASUREMENTS: The primary outcome was the volume of blood loss during the PICU follow-up period. The secondary outcomes were the requirement for blood transfusion in each group, duration of mechanical ventilation, length of intensive care unit (ICU) stay, length of hospital stay, and mortality. MAIN RESULTS: In the conservative (postimplementation) group, blood loss during the follow-up period was 0.67 (0.33-1.16) mL/kg/d, while it was 0.95 (0.50-2.30) mL/kg/d in the nonconservative (preimplementation) group, demonstrating a significant reduction in blood loss in the conservative group (p = 0.012). The groups showed no significant differences in terms of the required blood transfusion volume postoperatively during the first 24 hours, first 48 hours, or after 48 hours (p = 0.061, 0.536, 0.442, respectively). The frequency of blood transfusion was comparable between the groups during the first 24 hours, first 48 hours, or after 48 hours postoperatively (p = 0.277, 0.639, 0.075, respectively). In addition, the groups did not show significant differences in the duration of mechanical ventilation, length of ICU stay, length of hospital stay, or mortality. CONCLUSIONS: The closed-loop sampling method can be efficient in decreasing blood loss during postoperative PICU follow-up for pediatric patients after cardiac surgeries. However, its application did not reduce the frequency or the volume of blood transfusion in these patients.

High Interest in the Use of mHealth Platform for HIV Prevention among Men Who Have Sex with Men in Nepal.

Mobile technology growth in Nepal offers promising opportunities for using mobile health (mHealth) interventions to facilitate HIV prevention efforts. However, little is known about access and utilization of communication technology and their willingness to use mHealth for HIV prevention services in Nepal. We conducted a cross-sectional respondent-driven sampling survey of 250 MSM in Kathmandu Valley of Nepal from October to December 2022. We collected information on participant characteristics, HIV risk-related behaviors, ownership, or access to and frequency of use of communication technology (phones, tablets, laptops, and computers), and willingness to use mHealth to access HIV prevention services. Descriptive, bivariate, and multivariate linear regression analyses were performed. Almost all participants had smartphones with the internet (231/250, 92.4%) and accessed the internet daily (219/250, 87.6%) on the smartphone (236/250, 94.4%). The median score for willingness to use mHealth for HIV prevention was 10 (IQR: 3 to 17). Willingness to use mHealth was higher among those participants with a high school or above education (ß = 0.223, p = < 0.001), had experienced violence (ß = 0.231, p = 0.006), and had moderate to severe depressive symptoms (ß = 0.223, p = < 0.001). However, monthly income above NPR 20,000 (USD 150) (ß= -0.153, p = 0.008), disclosure of their sexual orientation to anyone (ß= -0.159, p = < 0.007), and worry about being negatively judged by health care workers (ß= -0.136, p = 0.023) were less willing to use mHealth strategies. The findings from this study suggest that there is a high willingness for utilizing mHealth interventions for HIV prevention in MSM population who are at higher risk of HIV acquisition.

Endoscopic assisted microscopic posterior cordotomy for bilateral abductor vocal fold paralysis using radiofrequency versus coblation.

PURPOSE: To assess the outcomes of endoscopic assisted microscopic posterior cordotomy for bilateral abductor vocal fold paralysis (BAVFP) using radiofrequency versus coblation. METHODS: This was a randomized prospective cohort study that carried out on 40 patients with BAVFP who were subjected to endoscopic/assisted microscopic posterior cordotomy. The patients were randomly allocated into two groups: group (A) patients were operated with radiofrequency, and group (B) patients were operated with coblation. Glottic chink, grade of dyspnea, voice handicap index 10 (VHI10), and aspiration were evaluated pre-operatively and 2 weeks and 3 months post-operatively. RESULTS: There was a significant improvement in the glottic chink and VHI10 scores postoperatively with a non-significant difference between both groups regarding the degree of improvement. In addition, there was a significant improvement of the grade of dyspnea with a non-significant impact on the degree of aspiration in both groups post operatively. There was a lower incidence of oedema and granulation formation in the coblation group but without a statistical significance. CONCLUSION: Both techniques are effective alternatives for performing posterior transverse cordotomy in cases of BAVFP.

Superficial Temple Lymphatic Malformation Appeared 13 Years after Initial Presentation With Orbital Lymphatic Malformation.

A 26-year-old male with a history of orbital lymphangioma and compressive optic neuropathy presented with recurrent proptosis in the OS. After examination and imaging, a left orbital lymphatic malformation and a new subcutaneous temporal-parietal vasculo-lymphatic malformation were diagnosed. The patient underwent a bleomycin injection for the orbital malformation and an excisional biopsy for the temporal lesion, leading to symptom resolution. Recurrence of lymphatic malformations and hemorrhage typically occurs at the same site, here we report a patient with the appearance of a new site lesion with orbital recurrence.

Detecting Psychological Interventions Using Bilateral Electromyographic Wearable Sensors.

This study investigated the impact of auditory stimuli on muscular activation patterns using wearable surface electromyography (EMG) sensors. Employing four key muscles (Sternocleidomastoid Muscle (SCM), Cervical Erector Muscle (CEM), Quadricep Muscles (QMs), and Tibialis Muscle (TM)) and time domain features, we differentiated the effects of four interventions: silence, music, positive reinforcement, and negative reinforcement. The results demonstrated distinct muscle responses to the interventions, with the SCM and CEM being the most sensitive to changes and the TM being the most active and stimulus dependent. Post hoc analyses revealed significant intervention-specific activations in the CEM and TM for specific time points and intervention pairs, suggesting dynamic modulation and time-dependent integration. Multi-feature analysis identified both statistical and Hjorth features as potent discriminators, reflecting diverse adaptations in muscle recruitment, activation intensity, control, and signal dynamics. These features hold promise as potential biomarkers for monitoring muscle function in various clinical and research applications. Finally, muscle-specific Random Forest classification achieved the highest accuracy and Area Under the ROC Curve for the TM, indicating its potential for differentiating interventions with high precision. This study paves the way for personalized neuroadaptive interventions in rehabilitation, sports science, ergonomics, and healthcare by exploiting the diverse and dynamic landscape of muscle responses to auditory stimuli.

Catalytic innovations: Improving wastewater treatment and hydrogen generation technologies.

The effective reduction of hazardous organic pollutants in wastewater is a pressing global concern, necessitating the development of advanced treatment technologies. Pollutants such as nitrophenols and dyes, which pose significant risks to both human and aquatic health, making their reduction particularly crucial. Despite the existence of various methods to eliminate these pollutants, they are not without limitations. The utilization of nanomaterials as catalysts for chemical reduction exhibits a promising alternative owing to their distinguished catalytic activity and substantial surface area. For catalytically reducing the pollutants NaBH4 has been utilized as a useful source for it because it reduces the pollutants quiet efficiently and it also releases hydrogen gas as well which can be used as a source of energy. This paper provides a comprehensive review of recent research on different types of nanomaterials that function as catalysts to reduce organic pollutants and also generating hydrogen from NaBH4 methanolysis while also evaluating the positive and negative aspects of nanocatalyst. Additionally, this paper examines the features effecting the process and the mechanism of catalysis. The comparison of different catalysts is based on size of catalyst, reaction time, rate of reaction, hydrogen generation rate, activation energy, and durability. The information obtained from this paper can be used to steer the development of new catalysts for reducing organic pollutants and generation hydrogen by NaBH4 methanolysis.

Development of In-Needle SPME Devices for Microextraction Applied to the Quantification of Pesticides in Agricultural Water.

The chemical industry explosion in the 20th century has led to increased environmental pollution, affecting fauna, flora, and waterways. These substances alter water's taste, color, and smell, making it unfit for consumption or toxic. Agricultural water networks face threats from pollution before and after treatment. Some chemical contaminants, like pesticides, are embedded in natural biogeochemical cycles. In this study, we developed a simple and low-cost procedure for the fabrication of needles coated with polydimethylsiloxane (PDMS) as an efficient sorbent for the microextraction of organic pollutant traces from water. The prepared needles were used as an alternative for commercial solid-phase micro-extraction (SPME) devices in analytical chemistry. The PDMS polymeric phase was characterized by Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and scanning electron microscopy (SEM). The PDMS-coated needles were used for extraction of thirteen pesticides by direct-immersion solid-phase microextraction (DI-SPME) from contaminated waters, followed by determination with gas chromatography-mass spectrometry (GC-MS). The developed analytical method showed limits of detection (LODs) between 0.3 and 2.5 ng mL-1 and RSDs in the range of 0.8-12.2%. The homemade needles were applied for the extraction of pesticides in surface and ground aqueous samples collected from an agricultural area. Several target pesticides were identified and quantified in the investigated water samples.