Optimized Cu-doping in ZnO electro-spun nanofibers for enhanced photovoltaic performance in perovskite solar cells and photocatalytic dye degradation

Perovskite solar cells (PSCs) compete with conventional solar cells regarding their low-temperature processing and suitable power conversion efficiency. In PSCs, the electron transport layer (ETL) plays a vital role in charge extraction and avoiding recombination; however, poor charge transport of ETL leads to high internal resistance and associated low fill factors. To successfully resolve this challenge, copper-doped zinc oxide nanofibers as an electron transport layer are prepared with various doping levels of 1, 2, and 3 wt% using the electrospinning sol-gel method. The 3 wt% doping of Cu revealed the optimum performance as an ETL, as it offers an electrically efficient transporting structure. SEM images revealed a randomly oriented distribution of nanofibers with different sizes having mesoporous uniformity. Optical properties of doped nanofibers examined using UV-visible analysis showed an extended light absorption due to heteroatom-doping. Adding Cu into the ZnO leads to enhanced charge mobility across the electron transport material. According to Hall measurements, dopant concentration favors the conductivity and other features essentially required for charge extraction and transport. The solar cell efficiency of ZnO doped with 0%, 1%, 2%, and 3% Cu is 4.94%, 5.97%, 6.89%, and 9.79%, respectively. The antibacterial and photocatalytic activities of the prepared doped and undoped ZnO are also investigated. The better light absorption of Cu-ZnO showed a pronounced improvement in the photocatalytic activity of textile electrodes loaded with doped ZnO. The dye degradation rate reaches 95% in 180 min under visible light. In addition, these textile electrodes showed strong antibacterial activity due to the production of reactive oxygen species under light absorption.

The structural, optical and photovoltaic properties of Zn-doped MAPbI2Br perovskite solar cells

The spin coating method was used to deposit MAPbI2Br films on FTO-glass substrates. Zn2+ (zinc) doping was used for these films at intensity rates of 2% and 4%, respectively. XRD analysis proved that MAPbI2Br films had a cubic structure and a crystalline character. 2% Zn doping into the MAPbI2Br film had a modest large grain size (38.09 nm), Eg (1.95 eV), high refractive index (2.66), and low extinction coefficient (1.67), according to XRD and UV-vis analyses. To facilitate and enhance carrier transit, at contacts as well as throughout the bulk material, the perovskite's trap-state densities decreased. The predicted MAPbI2Br valence and conduction band edges are -5.44 and -3.52, respectively. The conduction band (CB) edge of the film that was exposed to Zn atoms has been pressed towards the lower value, assembly it a better material for solar cells. EIS is particularly useful for understanding charge carrier transport, recombination mechanisms, and the influence of different interfaces within the device structure. Jsc is 11.09 mA cm-2, Voc is 1.09, PCE is 9.372% and FF is 0.777. The cell made with the 2% Zn doped into the MAPbI2Br film demonstrated a superior device.

Public misconceptions and attitudes towards persons diagnosed with epilepsy in the Kingdom of Bahrain: A cross-sectional study

BACKGROUND

Despite significant advancements in the understanding and treatment of epilepsy, the quality of life for persons diagnosed with Epilepsy (PdwE) can still be negatively impacted due to prevalent misconceptions and societal attitudes. This study aimed to investigate the knowledge, misconceptions, and attitudes towards epilepsy in Bahrain.

METHODS

This cross-sectional study involved 1079 participants aged ≥ 18 years living in Bahrain. Data collection occurred between June and December 2023 through an online questionnaire. The questionnaire consisted of four sections: sociodemographic characteristics, sources of information, knowledge about epilepsy, and attitudes toward PdwE.

RESULTS

Most participants (1063 out of 1179) were familiar with epilepsy, with social media being the main source of information (56.7%). While 75.6% correctly recognized epilepsy as a nervous system disorder. About 30% of participants believed that body shaking and falling to the ground were the only types of seizures. In terms of attitudes, 47.9% believed that PdwE could achieve high levels of education, but 40% thought they might face job loss due to their condition. Additionally, 27.5% disagreed with the idea of marrying someone with epilepsy or allowing a family member to do so. Being female, young, highly educated, and having a family member with epilepsy were associated with significantly more positive attitudes compared to other groups.

CONCLUSION

The studied sample of the Bahraini public demonstrated a satisfactory level of knowledge about epilepsy. However, they still held certain misconceptions that could impact their attitudes towards PdwE. Community awareness campaigns can address this knowledge gap and reduce epilepsy stigma.

Sexual dysfunction in a sample of Egyptian patients with Parkinson's disease

BACKGROUND

Sexual dysfunction (SD) is a common, yet underdiagnosed problem in Parkinson Disease (PD) patients. It can negatively impact their quality of life (QoL) and clinical outcome. we tried to assess SD in a group of Egyptian PD patients.

METHODS

The study is a case-control, cross-sectional study that included 200 participants, consisting of 100 PD patients and 100 matched healthy controls. Social, demographic information, and clinical variables were collected from both groups. Sexual functions were assessed using the Arabic Female Sexual Function Index (ArFSFI), and the Arabic version of International Index of Erectile Function (IIEF).

RESULTS

Women with PD scored worse on FSFI total score compared to controls (p < 0.001). Regarding the FSFI domains, they scored significantly lower in individual domains of desire (p < 0.001), arousal (p < 0.001), lubrication (p = 0.006), orgasm (p < 0.001), satisfaction (p < 0.001), and pain (p = 0.003), compared with controls. Men with PD scored worse on IIEF total scores compared to controls (p < 0.001). They showed significantly worse scores of erectile functions (p < 0.001), orgasmic function (p < 0.001), sexual desire (p < 0.001), intercourse satisfaction (p < 0.001), and overall satisfaction (p < 0.001). Both groups reported significant effect of SD on their QoL. There was a significant correlation between disease severity and SD.

CONCLUSION

SD is common in PD patients. It negatively impacts their QoL and partnership. Healthcare professionals should initiate conversations about SD with the patients and provide appropriate education and treatment options.

Green synthesis of novel spiropyrazoline-indolinones in neutral deep eutectic solvents and DFT studies

Novel spiropyrazoline-indolinones (4a-t) have been synthesized successfully in neutral deep eutectic solvents by reacting 5-Cl/Br-isatin (1a-b) with aromatic ketones (2a-b) and a variety of substituted hydrazines (3a-e) in good to excellent yields. This eco-friendly straightforward synthetic protocol discloses good functional group compatibility. The conventional synthetic approach was compared with the greener route of microwave-assisted synthesis of spiropyrazolines using ethanol. This approach utilized mild reaction conditions which furnished high yields in short reaction time employing one pot two-step multicomponent. All new compounds were structurally confirmed by detailed spectroscopic analysis and density functional theory calculations. This method provides efficient access to spiropyrazole derivatives using biodegradable and green solvent.

Contemporary innovations in two-dimensional transition metal dichalcogenide-based P-N junctions for optoelectronics

Two-dimensional transition metal dichalcogenides (2D-TMDCs) with various physical characteristics have attracted significant interest from the scientific and industrial worlds in the years following Moore's law. The p-n junction is one of the earliest electrical components to be utilized in electronics and optoelectronics, and modern research on 2D materials has renewed interest in it. In this regard, device preparation and application have evolved substantially in this decade. 2D TMDCs provide unprecedented flexibility in the construction of innovative p-n junction device designs, which is not achievable with traditional bulk semiconductors. It has been investigated using 2D TMDCs for various junctions, including homojunctions, heterojunctions, P-I-N junctions, and broken gap junctions. To achieve high-performance p-n junctions, several issues still need to be resolved, such as developing 2D TMDCs of superior quality, raising the rectification ratio and quantum efficiency, and successfully separating the photogenerated electron-hole pairs, among other things. This review comprehensively details the various 2D-based p-n junction geometries investigated with an emphasis on 2D junctions. We investigated the 2D p-n junctions utilized in current rectifiers and photodetectors. To make a comparison of various devices easier, important optoelectronic and electronic features are presented. We thoroughly assessed the review's prospects and challenges for this emerging field of study. This study will serve as a roadmap for more real-world photodetection technology applications.

Correlation between the density of defect states (DDS) and cross-linking of corner/edge sharing GeSe4 tetrahedral structural units

We have estimated the DDS in the STSG [Se78-xTe20Sn2Gex (x = 0, 2, 4, 6)] system by using the Correlated Barrier Hopping (CBH) model by performing A.C. conduction measurements in the frequency range (1 kHz-10 kHz) and temperature underneath the glass transition temperature (303-333) K. The detailed analysis reveals that bi-polaron hopping is a leading conduction mechanism over single-polaron hopping. Further, there is a noticeable reduction in DDS with increasing concentration of Ge beyond the composition x = 2. A close inspection indicates that cross-linking of Se with Ge has an important role in controlling the DDS in terms of the corner/edge sharing configurations in the structural unit of GeSe4 tetrahedral.

Chitinase-3-like 1-protein in CSF: a novel biomarker for progression in patients with multiple sclerosis

BACKGROUND

Chitinase -3-like 1-protein (CHI3L1) is a glycoside secreted by monocytes, microglia, and activated astrocytes. Its distribution in inflammatory lesions denotes its role in astrocytic response to modulate CNS inflammation. In multiple sclerosis (MS), CHI3L1 levels have been found to be influenced by disease severity, activity, and progression. We aimed to measure CSF level of CHI3L1 in patients with MS and correlate its level with disability measures for a possible role as a biomarker for disease progression.

METHODS

Fifty-two MS patients (30 relapsing-remitting MS and 22 progressive MS) and thirty-five age and sex-matched healthy controls were included. They all underwent full clinical assessment (including disability and cognitive scales), radiological assessment, and CSF level of CHI3L1.

RESULTS

Patients with MS had higher CSF level of CHI3L1 than controls. Patients with progressive forms had higher levels than relapsing forms. There were positive correlations between disease duration, number of attacks, total EDSS, and CSF level of CHI3L1. Patients who had higher level of CSF CHI3L1 showed worse performance in MMSE and BICAMS and more lesions in T2 MRI brain. A cut off value of 154 ng/mL was found between patients with RRMS and PMS patients.

CONCLUSION

CHI3L1 can be considered as a biomarker of disease progression. CHI3L1 level increases in progressive MS more than RRMS. Also, high CSF level of CHI3L1 was associated with more disability including motor, cognitive, and radiological aspects.

Pre- and in-hospital delays in the use of thrombolytic therapy for patients with acute ischemic stroke in rural and urban Egypt

Background

Reducing pre- and in-hospital delays plays an important role in increasing the rate of intravenous thrombolysis (IVT) in patients with acute ischemic stroke. In Egypt, the IVT rate has increased steadily but is still far away from an ideal rate.

Aim

The study aimed to investigate the factors associated with pre- and in-hospital delays of IVT among patients with acute ischemic stroke coming from urban and rural communities.

Methods

This prospective, multicenter, observational cohort study was conducted from January 2018 to January 2019. Patients with acute ischemic stroke, who did not receive IVT, were included in the study. Patients were recruited from three large university stroke centers in Egypt, Assiut (south of Egypt), Tanta (north of Egypt), both serving urban and rural patients, and the University Hospital in Cairo (capital city), only serving an urban community. All participants underwent the National Institutes of Health Stroke Scale and full neurological assessment, urgent laboratory investigations, and computed tomography or magnetic resonance imaging to confirm the stroke diagnosis. The patients were subjected to a structured questionnaire that was designed to determine the parameters and time metrics for the pre- and in-hospital delays among patients from rural and urban regions.

Results

A total of 618 patients were included in the study, of which 364 patients (58.9%) lived in rural regions and 254 (41.1%) in urban regions. General demographic characteristics were similar between both groups. Approximately 73.3% of patients who arrived within the therapeutic time window were urban patients. The time from symptom onset till hospital arrival (onset to door time, ODT) was significantly longer among rural patients (738 ± 690 min) than urban patients (360 ± 342 min). Delayed onset to alarm time (OAT), initial misdiagnosis, and presentation to non-stroke-ready hospitals were the most common causes of pre-hospital delay and were significantly higher in rural patients. For patients arriving within the time window, the most common causes of in-hospital delays were prolonged laboratory investigations and imaging duration.

Conclusion

The limited availability of stroke-ready hospitals in rural Egypt leads to delays in stroke management, with subsequent treatment inequality of rural patients with acute stroke.

Multiple sclerosis patients’ response to COVID-19 pandemic and vaccination in Egypt

Background

On 11 March 2020, WHO declared COVID-19 has become a pandemic. This had an impact on everyday activity for every person. For special groups such as multiple sclerosis patients, the situation is a little bit confusing. In this study, COVID-19 infection impact on MS patients, willingness for vaccination, percentage of vaccinated patients and adverse effects of different vaccines were investigated. This cross-sectional descriptive study included 160 Egyptian MS patients. Demographic and clinical characteristics of all patients were extracted from their files MS unit archives. All these patients were contacted either by telephone and an oral informed consent was taken or in-person on their scheduled follow-up and informed written consent was taken to join this study. Patients were asked about: COVID-19 infection, severity of infection, and vaccination using a special questionnaire developed by the authors.

Results

Only 39 (24.3%) patients have had COVID-19 infection with confirmed diagnosis. Most of infected patients (84.6%) were treated at home with no need for hospital admission. Five patients (12.8%) reported symptom suggestive of relapses after COVID-19 infection. Sixty-five patients (40.6%) were vaccinated against COVID-19. Out of these vaccinated patients, 22 patients (33%) developed adverse events from vaccine. These adverse events were self-limiting and related to local injection site and general manifestations. MS relapse after vaccination was reported in 7.7% of the vaccinated group.

Conclusion

Prevalence of COVID-19 infection and severity of infection were equal to general population. Risk of relapse is low either with infection or vaccination. No severe adverse events were reported after vaccination.

Transcranial direct current stimulation for spasticity in patients with multiple sclerosis: Exploring novel routes

BACKGROUND

Patients with Multiple sclerosis (MS) usually suffer from severe neurological disabilities. Spasticity is one of the most bothering and disabling manifestations that MS patients suffer from. Owing to being a chronic inflammatory demyelinating disorder; finding new modalities to alleviate some of the disabilities related to MS became a desired objective. Transcranial direct current stimulation (tDCS), a relatively new tool for modulating cortical excitability has been recently considered as a tool to provide symptomatic treatment for many neurologic and psychiatric diseases. In our study, we used tDCS to assess its effect on spasticity in MS patients.

METHODS

5 consecutive daily sessions of 20 minutes duration of active anodal tDCS over the ipsilesional motor cortex were given to 10 relapsing remitting MS (RRMS) patients with at least 1 spastic lower limb (active group) who were compared with other matched10 RRMS patients who received sham stimulation (sham group). The outcome was to measure the effect on spasticity both clinically using the Modified Ashworth Scale (MAS) and through neurophysiological assessment (H reflex latency and H/M amplitude ratio).

RESULTS

Patients who received active anodal tDCS showed significant improvement (p< 0.05) in the H/M amplitude ratio as compared to the sham group. However, there was no significant difference between the two groups in the MAS. H latency showed significant stability in active group when compared to the sham group.

CONCLUSION

Anodal direct current stimulation of the ipsilesional motor cortex in patients with MS, resulted in reduced spasticity as per neurophysiological assessment.

Autoimmune encephalitis as a complication of COVID-19 infection: a case report

Background

During COVID-19 pandemic, a lot of newly discovered symptoms and presentations are emerging. Neurological symptoms of corona virus disease 19 (COVID19) have been reported including central nervous symptoms (CNS), peripheral nervous symptoms (PNS), and skeletal muscular symptoms; however, data are scarce about the exact occurrence of neurological affection during COVID-19 infection.

Case presentation

We present a case of a 67-year-old male patient with proven COVID-19 infection who developed acute confusion state, behavioral changes, agitation, and one attack of loss of consciousness 8 days following the infection. Laboratory profile, computed tomography (CT) brain, magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF) analysis all were normal, and the patients were highly suspicion of autoimmune encephalitis due to COVID-19 infection. The patient received pulse steroid therapy with complete regaining the conscious level.

Conclusion

This clinical case emphasizes the possible relationship between COVID-19 infection and autoimmune encephalitis.

Validation of the Arabic Version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale

BACKGROUND

The Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) has become the gold standard for evaluating different domains in Parkinson's disease (PD), and it is commonly used in clinical practice, research, and clinical trials.

OBJECTIVES

The objectives are to validate the Arabic-translated version of the MDS-UPDRS and to assess its factor structure compared with the English version.

METHODS

The study was carried out in three phases: first, the English version of the MDS-UPDRS was translated into Arabic and subsequently back-translated into English by independent translation team; second, cognitive pretesting of selected items was performed; third, the Arabic version was tested in over 400 native Arabic-speaking PD patients. The psychometric properties of the translated version were analyzed using confirmatory factor analysis (CFA) as well as exploratory factor analysis (EFA).

RESULTS

The factor structure of the Arabic version was consistent with that of the English version based on the high CFIs for all four parts of the MDS-UPDRS in the CFA (CFI ≥0.90), confirming its suitability for use in Arabic.

CONCLUSIONS

The Arabic version of the MDS-UPDRS has good construct validity in Arabic-speaking patients with PD and has been thereby designated as an official MDS-UPDRS version. The data collection methodology among Arabic-speaking countries across two continents of Asia and Africa provides a roadmap for validating additional MDS rating scale initiatives and is strong evidence that underserved regions can be energically mobilized to promote efforts that apply to better clinical care, education, and research for PD. © 2022 International Parkinson and Movement Disorder Society.

Relative Frequency and Risk Factors of COVID-19 Related Headache in a Sample of Egyptian Population: A Hospital-Based Study

Objectives

Headache is considered one of the most frequent neurological manifestations of COVID-19. This work aimed to identify the relative frequency of COVID-19 related headache and to clarify the impact of clinical, laboratory findings of COVID-19 infection on headache occurrence and its response to analgesics.

Design

Cross-sectional study

Setting

Recovered COVID-19 patients

Subjects

782 patients with a confirmed diagnosis of COVID-19 infection.

Methods

Clinical, laboratory and imaging data were obtained from the hospital medical records. Regarding patients who developed COVID-19 related headache, a trained neurologist performed an analysis of headache and its response to analgesics.

Results

The relative frequency of COVID-19 related headache among our sample was 55.1% with 95% CI (0.516–0.586) for the estimated population prevalence. Female gender, malignancy, primary headache, fever, dehydration, lower levels of hemoglobin and platelets and higher levels of neutrophil/lymphocyte ratio (NLR) and CRP were significantly associated with COVID-19 related headache. Multivariate analysis revealed that female gender, fever, dehydration, primary headache, high NLR, and decreased platelet count were independent predictors of headache occurrence. By evaluating headache response to analgesics, old age, diabetes, hypertension, primary headache, severe COVID-19, steroid intake, higher CRP and ferritin and lower hemoglobin levels were associated with poor response to analgesics. Multivariate analysis revealed that primary headache, steroids intake, moderate and severe COVID-19 were independent predictors of non-response to analgesics.

Discussion

Headache occurs in 55.1% of patients with COVID-19. Female gender, fever, dehydration, primary headache, high NLR, and decreased platelet count are considered independent predictors of COVID-19 related headache.

Characteristics of headache attributed to COVID-19 infection and predictors of its frequency and intensity: A cross sectional study

OBJECTIVE

To study the characteristics of headache attributed to COVID-19 infection and predictors of its severity.

METHODS

A cross-sectional study involved 172 individuals who had headache due to COVID-19 infection. A detailed analysis of such headache was done through a face-to-face interview. Patients with any other form of secondary headache were excluded. Labs, including lymphocytic count, C-reactive protein, D-dimer and ferritin and chest imaging, were made available.

RESULTS: THE

majority of our patients had a diffuse headache (52.9%). It was pressing in 40.7%, with median intensity of 7 (assessed by visual analogue scale) and median frequency of 7 days/week. Patients with preexisting primary headache (52.9%) had significantly more frequent COVID-19 related headache than those without (47.1%) (p = 0.001). Dehydrated patients (64.5%) had more frequent COVID-19 related headache than those who were not dehydrated (35.5%) (p = 0.029). Patients with fever (69.8%) had significantly higher frequency and intensity of COVID-19 related headache compared to those without fever (30.2%) (p = 0.003, 0.012). Patients with comorbidities (19.8%) had significantly higher frequency and intensity of headache than those without comorbidities (80.2%) (p = 0.006, 0.003). After multiple linear regression, primary headache disorders, dehydration and comorbidities were considered predictors of frequency of COVID-19 related headache. Meanwhile, fever and dehydration were predictors of pain intensity.

CONCLUSION

Healthcare providers of COVID-19 patients need to be aware of frequency and intensity predictors of COVID-19 related headache: Primary headache disorders, fever, dehydration, and comorbidities.

Evaluation of inflammatory markers and mean platelet volume as short-term outcome indicators in young adults with ischemic stroke

Background

Studying outcome predictors in patients with onset of cerebral infarction in early adult life may enhance our knowledge of disease pathophysiology and prognosis.

Aim

The aim is to identify independent predictors of short-term outcome of first-ever ischemic stroke in young adults with special emphasis on inflammatory and thrombogenic markers.

Methods

We enrolled 33 patients aged 19–44 years with first-ever ischemic stroke admitted to Kasr Alainy Stroke Unit and 33 matched controls. Clinical, radiological, and laboratory (adhesion molecules, C-reactive protein, prolactin, and mean platelet volume) evaluations were carried out. Functional outcome at 7 days after stroke onset was assessed using the modified Rankin scale, and independent predictors were identified.

Results

The most frequently identified risk factor was cardiac abnormality. Patients exhibited significantly higher levels of baseline inflammatory and thrombogenic markers compared with controls. These markers were significantly correlated with the stroke severity. Logistic regression model showed that high National Institutes of Health Stroke Scale (NIHSS) score (odds ratios [OR] = 0.13; 95% confidence interval [CI], 0.04–0.24; P = 0.01) and large infarction size (OR = 0.11; 95% CI, 0.09–0.17; P = 0.04) but not the laboratory markers were independent predictors of unfavorable outcome.

Conclusion

Our data suggested that higher NIHSS scores and large infarction size served as independent predictors of short-term unfavorable outcome, while inflammatory and thrombogenic markers did not.

Correction: Semiconducting quaternary chalcogenide glasses as new potential thermoelectric materials: an As–Ge–Se–Sb case

Correction for ‘Semiconducting quaternary chalcogenide glasses as new potential thermoelectric materials: an As–Ge–Se–Sb case’ by A. Dahshan, et al., Dalton Trans., 2015, 44, 14799–14804.

Semiconducting quaternary chalcogenide glasses as new potential thermoelectric materials: an As–Ge–Se–Sb case

The performance of chalcogenides as thermoelectric materials may be improved via complex structures, impurities, disorder etc.

Serious rectal bleeding complicating suction rectal biopsy in a child

Rectal suction biopsy is the first step in evaluating suspected Hirschsprung's disease before a full thickness rectal biopsy is planned. It has an excellent safety profile and generally good yield. However, there have been rare reports of serious complications with this procedure and at least one death, mostly in the neonatal period and under one year of age, at the time of diagnosis. We report a case of a 2 year old child with suspected Hirschsprung's disease who underwent rectal suction biopsy and developed delayed bleeding requiring a blood transfusion. To the best of our knowledge, this is the first report of an older child, greater than one year of age, developing this serious complication at the time of rectal suction biopsy. Discussion of the technique as well as the patient's presentation and his outcome are provided. Pediatric gastroenterologists and pediatric surgeons performing rectal suction biopsy may need to be aware of this risk even with older children.

Preparation and Mechanico-Optical Properties of Ultraviolet-Curable Transparent Polyurethane Elastomer Nanocomposites

Nanotechnology is presently seen as one of the most promising approaches in the field of materials science toward the development of advanced materials for future engineering applications. We report on the preparation of transparent elastomer based on polyurethane–PEG400/PEG2000–acrylate copolymers. UV curing was pursued. In order to render the polymer hydrophilic, a poly(ethylene glycol) (PEG) chain is used as the polyol portion of the polyurethane. The molecular weight of the PEG chain was matrix from PEG2000 g/mol and PEG400 at 1:3 ratio, respectively. An aliphatic di-isocyanate, namely, isophorone di-isocyanate (IPDI), was used to obtain transparent samples. A PEG-IPDI polymer was produced in the first step. 2-hydoxyethyl acrylate (HEA) was added to react with the excess of IPDI. Dibutyltin dilaureate (DBTL) was employed as the catalyst for formation of the urethane bond. Cross-linking occurred via free radical polymerization of the acrylate group. Nano dry silica powder (Aerosil R7200) is economical and widely used in the industry. The nanoparticles were dispersed in the polyurethane solution in the presence of photo-initaitor by using Ultra-Turrax homogenizer, and the resulting polyurethane nanocomposite solution was molded in the mold glass at room temperature. UV curing was achieved in few seconds. It is noticed that the inorganic filler can be used up to 5% (wt/wt) without affecting the transparency of the polyurethane elastomer sheets. Nanocomposites showed significantly enhanced mechanical properties at 3% (wt/wt). Optical absorption measurements show that the fundamental absorption edge obeys Tauc’s relation for the allowed nondirect transition. Optical band gap (Eg) of the polyurethane (PU)/Aerosil R7200 nanocomposites decreases with the increase of nanosilica content from 1% to 5%. Good mechanical and optical properties make the polyurethane nanocomposites good candidate for different applications such as thin film coating and photovoltaic.

Life threatening rectal bleeding due to a giant solitary juvenile polyp in a child. A case report and review of the literature

Juvenile polyps (JP) are a recognized cause of painless rectal bleeding in preschool age children. They are often solitary, pedunculated and small in size but may occasionally grow to large sizes or occur in great numbers, as in juvenile polyposis syndrome. A nine-year-old previously healthy Hispanic boy with prior history of recurrent abdominal pain and vomiting for 4 months presented with sudden onset of massive painless hematochezia and hemorrhagic shock. Following blood transfusion the bleeding spontaneously stopped. Though further evaluation was delayed due to family reticence, eventually colonoscopy was performed and revealed a giant pedunculated solitary polyp in the traverse colon. After resection, the polyp measured 3.2 x 2.2 x 1.7 cm. Histological evaluation revealed juvenile retention polyp. Giant juvenile polyps (greater than 30 mm) are exceedingly rare in children. Life threatening rectal bleeding due to giant solitary juvenile polyp has rarely been previously reported in children. Spontaneous cessation of bleeding should not delay the endoscopic evaluation. In a child with massive hematochesia, JP should still be considered in the differential diagnosis, as highlighted by this case.

Severe methemoglobinemia complicating topical benzocaine use during endoscopy in a toddler: a case report and review of the literature

Severe methemoglobinemia resulting from the use of topical benzocaine has been reported in adults as a rare complication. Here we report a case of severe acquired methemoglobinemia resulting from topical use of benzocaine spray during diagnostic upper gastrointestinal endoscopy in a 3-year-old boy with repeated episodes of hematemesis 3 weeks posttonsillectomy. He developed marked cyanosis and became increasingly agitated immediately after completion of his unremarkable endoscopic procedure, which was performed under intravenous sedation. He did not respond to maximum supplemental oxygen and had increased respiratory effort. His pulse oximetry dropped to 85%, but simultaneous arterial blood-gas analysis showed marked hypoxemia (Po2 = 29%) and severe methemoglobinemia (methemoglobin = 39%). His cyanosis and altered mental status promptly resolved after intravenous administration of methylene blue. In patients with methemoglobinemia, pulse oximetry tends to overestimate the actual oxygen saturation and is not entirely reliable. Posttonsillectomy bleeding is a rare but occasionally serious complication that could occur weeks after the surgery, although it more commonly occurs within the first few days. Physicians should remain aware of the possibility of its late onset. This case illustrates the severity of acquired methemoglobinemia that may result from even small doses of topical benzocaine and highlights the fact that prompt treatment of the disorder can be life saving. We question the rationale for routine use of topical anesthetic spray for sedated upper gastrointestinal endoscopy in children. By bringing the attention of pediatricians to this rare but serious complication, we hope that it will result in its improved recognition and possible prevention.

Helicobacter pylori and infantile hypertrophic pyloric stenosis: is there a possible relationship?

BACKGROUND

Recently, it has been suggested that Helicobacter pylori might be a cause of some cases of infantile hypertrophic pyloric stenosis (IHPS) in infancy on the basis of its epidemiologic and clinical features. We performed this study to evaluate the possible relationship between IHPS and H. pylori.

DESIGN

In consecutive infants with IHPS, we performed upper gastrointestinal endoscopy with biopsy before pyloromyotomy. The endoscopic appearance of the pylorus was noted to validate endoscopic features of IHPS.

RESULTS

Sixteen infants, 15 male, 14 white, mean age 42 days, range 21 to 104 days, were studied. The index case had chronic active gastritis on biopsy with organisms suspicious for H. pylori. Four others had chronic active gastritis, six more had focal or mild chronic gastritis, five were normal, and none had H. pylori on histology or immune histochemical staining in selected cases. All patients had negative rapid urease test. Most common endoscopic findings of IHPS were thickened prominent asymmetric pyloric folds and pin-hole pylorus that could not be intubated by the pediatric endoscope.

CONCLUSION

H. pylori was not specifically identified in our patients with IHPS. The presence of H. pylori-like organisms in the gastric mucosa in our index case and finding of chronic active gastritis in several others may indicate the possibility of an acquired infectious etiology for IHPS.

Isolated superior mesenteric artery thrombosis: a rare cause for recurrent abdominal pain in a child

A 4-year-old boy was evaluated for recurrent abdominal pain and failure to thrive over a 1-year period in a pediatric subspecialty clinic. Results of the extensive workup mostly were unremarkable. Eventually, imaging studies of the abdominal aorta revealed an isolated thrombosis of the superior mesenteric artery trunk and compensatory hypertrophy of the inferior mesenteric artery. He had been having abdominal angina symptoms and fear of eating. A detailed family history suggested a possible hypercoagulable state. However, an extensive hematologic evaluation did not reveal a recognizable defect that could produce thrombotic events. He was treated by arterial graft bypass surgery and started on conventional anticoagulants. Several months later, he developed repeat, near-total thrombosis of the graft with recurrence of his symptoms. After balloon dilation of the graft and starting him on appropriate anticoagulant maintenance regimen, he had good symptom relief, and the graft remained patent. This presentation was unusually prolonged for the type of vascular problem identified. The possibility of vascular problems in children, therefore, should be considered. Unidentified cause of hereditary clotting tendency is another challenging aspect of this case.

Gastroesophageal reflux disease and dental erosion in children

Recurrent exposure to gastric acid as in children with bulimia and gastroesophageal reflux disease (GERD) may contribute to dental erosion. We performed a prospective study to evaluate the presence of GERD and dental erosions in children with primary and permanent dentition. Children undergoing elective endoscopy for possible GERD (n = 37) underwent evaluation of their teeth for the presence, severity, and pattern of erosion and stage of dentition: 24 patients had GERD. Dental erosions were identified in 20; all had GERD. Erosion patterns showed more involvement of the posterior teeth. Many affected patients had primary dentition.

Management of ingested foreign bodies in children

This paper reviews the presentation, diagnosis, and management of ingested foreign bodies in children. It may help primary care physicians to recognize the wide spectrum of presentations of ingested foreign bodies in children, therefore emphasizing considering ingested foreign bodies in the differential diagnosis of many respiratory and vague gastrointestinal complaints. It also proposes an approach to handling asymptomatic children with foreign body ingestion and points out certain types of foreign bodies that require special consideration.

Correlation of endoscopy and histology in the gastroesophageal mucosa in children: are routine biopsies justified?

Guidelines for obtaining biopsies during endoscopy in children are needed. The endoscopic evaluation may be considered deficient on many occasions if not accompanied by a histopathologic evaluation. A retrospective review of our endoscopic records and biopsies was undertaken to determine the correlation of the visualized endoscopic appearance and the histopathologic findings in the upper gastrointestinal (GI) tract in children. Over a 1-year period, 204 patients, all of whom had esophageal biopsies and 59 of whom had gastric biopsies as well, were evaluated by an upper GI endoscopy. Endoscopic findings included erythema, granularity, abnormal vascular pattern, friability, erosions, plaques, ulceration, and strictures. Histologic evaluation of biopsies was undertaken by one pathologist according to the presence of and type of cellular infiltrate and cellular morphologic abnormalities in the mucosa and submucosa where available. In this study, the correlation of endoscopic appearance with histology was rather limited in both the esophagus and the gastric mucosa. Low specificity and sensitivity of endoscopy in both locations (41% and 81% for the esophagus; and 43% and 86% for the gastric mucosa, respectively) illustrated the discrepancy. The overall accuracy of endoscopic evaluation in matching the histologic diagnosis was not more than two out of three (63.8%). No single endoscopic finding had a reliable correlation with histologic diagnosis but some had higher predictive value than others. Of the multiple indications for endoscopy in children, recurrent abdominal pain had the least diagnostic yield. Endoscopic appearance correlates poorly with histologic diagnosis in the gastroesophageal mucosa in children. Regardless of the appearance of the mucosa, routine biopsy during upper GI endoscopy in children should be encouraged.

A randomized, prospective study to evaluate the efficacy and acceptance of three bowel preparations for colonoscopy in children

OBJECTIVE

We performed a prospective, randomized, single-blind study in children undergoing colonoscopy to evaluate the acceptance and efficacy of three different bowel preparations.

METHODS

Seventy patients (ages 3-20 yr, 38 males) were randomly assigned to one of the three study preparations: Magnesium citrate with X-prep and clear liquid diet for 2 days (group A); Dulcolax for 2 days and Fleet enema without dietary restriction (group B); and Golytely 20 ml/kg (up to 1 L) per hour for 4 h with clear liquid diet for 1 day (group C). Endoscopists blinded to bowel preparation graded the adequacy of colon cleansing. The preparations were rated by patients for tolerance, willingness to retake them, adverse effects, and compliance.

RESULTS

Data analysis using Fisher exact test and trend test showed that colon cleansing in groups A and C was superior to that in group B (p < 0.0001) and better in group C than A (p < 0.075). Overall tolerance and compliance were significantly better for groups A and B than group C (p < 0.003), but not different between A and B. More of group B patients were willing to retake the preparation than in group C (p < 0.002) and group A (p < 0.05), but this was not different between groups A and C. Adverse effects were reported more frequently by patients in group C than in groups A and B (p < 0.01).

CONCLUSIONS

Although the least well tolerated, Golytely provided the best cleansing. Dulcolax without dietary restriction provided unsatisfactory colon cleansing. Magnesium citrate with X-prep was acceptable and provided good cleansing.