Electrochromic Os-based metallo-supramolecular polymers: electronic state tracking by in situ XAFS,IR, and impedance spectroscopies

In this study, the electronic states of Os-based metallo-supramolecular polymers (poly(OsL)²⁺) during electrochromism were tracked by in situ X-ray absorption fine structure (XAFS), infrared (IR), and impedance spectroscopies. The XAFS spectra suggested electronic charge migration in the polymer, and the in situ spectra revealed reversible changes caused by electrochemical redox reactions. The IR spectra of the polymers showed an IVCT band, and we also confirmed the reversible changes by applying a voltage to the redox cell. During the impedance measurements, we found a drastic decrease in the charge transfer resistance (R_CT) of the polymer films near the electrochemical redox potential.

In this study, the electronic states of Os-based metallo-supramolecular polymers (poly(OsL)²⁺) during electrochromism were tracked by in situ X-ray absorption fine structure (XAFS), infrared (IR), and impedance spectroscopies.     

Clinical profile and follow-up of 51 pediatric neurocysticercosis cases: A study from Eastern India

Introduction:

Our present observational study attempted to evaluate the clinical profiles, diagnosis, treatment and follow-up results of 51 pediatric neurocysticercosis patients over a mean duration of five years (from January 2006 to December 2010).

Materials and Methods:

Diagnosis was mainly based on clinical features, computed tomography (CT)/magnetic resonance imaging scan and exclusion of other causes. Patients with active, transitional cysts and seizure were treated with albendazole for 28 days, steroids and anticonvulsants.

Results:

A total of 38 patients completed this study. Mean age of the presentation was 8.47 ± 3.19 years 52.6% of the patients were female. Overall patients presented with generalized seizure in 55.3%, focal in 31.6%, headache ± vomiting in 63.2%, focal neurodeficit in 10.5% and combination of symptoms in 60.5% cases. Contrast CT brain showed a solitary lesion in 27 (71.1%) and multiple in the rest. At presentation lesions were transitional in 58.2%, inactive in 20% and mixed in 14.6%. After a mean of 2 years, seizure persisted in 9 (23.7%) and headache in 8 (21.1%) of whom six had normal electroencephalography (EEG) while one each showed focal slowing, generalized slowing and epileptiform discharges. During the follow-up, CT scan brain 44.7% lesions calcified, 31.6% disappeared, 10.5% regressed and the rest persisted.

Conclusion:

Solitary ring enhancing lesions (transitional stage) involving the parietal lobe was the commonest CT picture at presentation. Generalized tonic-clonic seizure was the most common type of seizure. Number of lesions, persistence of lesion, number of seizures, EEG abnormality at presentation were not found to be prognostically significant (P > 0.05).Key Words: Brain, epilepsy, lesion, neurocysticercosis, parenchyma, solitary     

In silico decryption of serotonin–receptor binding: local non-covalent interactions and long-range conformational changes

Serotonin–receptor binding is the key step in the process behind serotonin functionality, including several psychological and physiological behaviours. This study is focused on identifying the main non-covalent interactions controlling the stability of serotonin–receptor complexes as well as the main conformational changes in the receptor due to serotonin–receptor binding using classical molecular dynamics simulations and quantum chemical calculations. A qualitative analysis based on two order parameters ((i) the centre of mass distance and (ii) the angle between the surface normals of each aromatic residue and serotonin in the binding site) on the serotonin–receptor complex trajectory suggests that the T-type stacking interaction is predominant in the binding site. Quantum chemical calculations of the stacking interaction energy provide the quantitative contributions of important aromatic residues to the stabilization of the complex. Furthermore, a three body stacking interaction (named ‘L’-type) was observed and likely contributes to the stability of the complex. Direct and water-mediated hydrogen bonding between the residues in the binding site and serotonin contributes to the complex stability. Principal component analysis of the molecular dynamics simulation trajectory of the serotonin–receptor complex and the apo-receptor in water indicates that the whole receptor is significantly stabilized due to serotonin binding. An analysis based on the dynamic cross correlation function reflects the strong correlation between trans-membrane (TM)3, TM5, TM6 (containing residues responsible for the stacking interaction and hydrogen bonding) and mini-G₀ which may participate in signal transduction leading to the functionality of serotonin.

This study is focused on identifying the main non-covalent interactions controlling the stability of serotonin–receptor complexes as well as the main conformational changes in the receptor due to serotonin–receptor binding.     

Highly fluorescent aryl-cyclopentadienyl ligands and their tetra-nuclear mixed metallic potassium–dysprosium clusters

Two alkyl substituted triaryl-cyclopentadienyl ligands [4,4′-(4-phenylcyclopenta-1,3-diene-1,2-diyl)bis(methylbenzene) (1) and 4,4′,4′′-(cyclopenta-1,3-diene-1,2,4-triyl)tris(methylbenzene) (2)] have been synthesized via cross-aldol condensation followed by Zn-dust mediated cyclization and acid catalyzed dehydration reactions. The fluorescence properties of 1 and 2 have been studied in solution and solid state. The ligands exhibited aggregation-induced emission enhancement (AIEE) in THF/water solution. 1 and 2 have been found to be significantly more fluorescent in the solid state than in their respective solutions. This phenomenon can be attributed to the strong intermolecular CH⋯π interactions present in 1 and 2 which leads to the tight packing of molecules in their solid-state. Both 1, 2 and their corresponding anions have been studied by theoretical calculations. Ligands 1 and 2 have been shown to react with anhydrous DyCl₃ in the presence of potassium metal at high temperature to afford two fluorescent chloride-bridged tetra-nuclear mixed potassium–dysprosium metallocenes [(Me₂Cp)₄Dy₂^IIICl₄K₂]·3.5(C₇H₈) (5) and [(Me₃Cp)₄Dy₂^IIICl₄K₂]·3(C₇H₈) (6), respectively in good yields.

Alkyl substituted triaryl-cyclopentadienyl ligands with aggregation-induced emission enhancement (AIEE) properties and their applications in the syntheses of novel chloride bridged tetra-nuclear mixed potassium–dysprosium metallocenes.     

Frequency and features of nocturnal enuresis in Pakistani children aged 5 to 16 years based on ICCS criteria: a multi-center cross-sectional study from Karachi,Pakistan

Background

Nocturnal enuresis (NE) is a common symptom in children worldwide. International Children’s Continence Society (ICCS) defines enuresis as either mono-symptomatic, NE with lower urinary tract symptoms and NE with co-morbid conditions. The objectives of this study were to determine the frequencies and types of NE and associated symptoms and conditions in children aged 5 to 16?years based on ICCS criteria.

Methods

A multi-center cross sectional study was conducted between November 2012 and December 2013 in the primary care clinics of four hospitals in Karachi. Children aged five to fifteen years were included through consecutive sampling. Informed consent was obtained from the parents and a pre-coded semi-structured questionnaire was used to obtain the information. Data was entered on SPSS version 20.0 and multivariable logistic regression analysis was used for data analysis.

Results

Out of 429 children aged between five and sixteen years, 243(56.9%) were boys and the remaining 186(43.1%) were girls. One hundred and eighty three children (43%) had nocturnal enuresis (NE). Forty four (10.3%), had mono-symptomatic NE, 57(31.1%) had associated lower urinary tract symptoms (NE-LUTS), whereas 30 (16.3%) had NE with a co-morbid condition. Fifty two (28.4%) NE’s had at least one of both LUTS and a co-morbid condition. Out of the 246(57%) non-enuretic’s, 31(12.6%) had a LUTS, 95(38.6%) had a co-morbid condition and 57(23.2%) had at least one of both LUTS and a co-morbid condition. The remaining 63 (25.6%) were symptom free. Increased voiding frequency, urgency, dysuria, suprapubic pain and daytime incontinence were the LUTS significantly associated with NE. Co-morbid conditions significantly associated with NE included constipation, congenital defects, developmental delay, and learning and sleep problems.

Conclusion

Although NE can be an only symptom, it is often associated with lower urinary tract symptoms like dysuria, urgency, suprapubic pain, and daytime incontinence. Children presenting with NE often have co-morbid conditions like constipation, urinary tract infection, sleep disorders, and developmental delay. Many children presenting with these conditions as the primary complaint may also have NE. It should be addressed as unrecognized and untreated NE can cause additional morbidity and distress.

     

A dipodal molecular probe for naked eye detection of trivalent cations (Al3+, Fe3+and Cr3+) in aqueous medium and its applications in real sample analysis and molecular logic gates

A simple and low cost multifunctional colorimetric receptor L has been designed, synthesized and characterized by ¹H-NMR, IR spectroscopy, ESI-MS spectrometry and elemental analysis. The chemosensor L can selectively detect three biologically and environmentally important trivalent metal ions (Al³⁺, Fe³⁺and Cr³⁺) both visually and spectrophotometrically in CH₃CN–H₂O (1 : 1, v/v) solution in the presence of other biologically relevant metal ions. The Job''s plot analyses indicate the 2 : 2 binding stereochemistry for Al³⁺, Fe³⁺ and Cr³⁺ ions with L, which was further confirmed by ¹H-NMR and ESI-MS studies. The binding constant values were found to be 2.9 × 10⁴ M⁻¹ for Al³⁺, 1.079 × 10⁵ M⁻¹ for Fe³⁺ and 1.366 × 10⁵ M⁻¹ for Cr³⁺ respectively. The detections limits of the sensor for Al³⁺ (2.8 × 10⁻⁷ M), Fe³⁺ (1.9 × 10⁻⁷ M) and Cr³⁺ (2.5 × 10⁻⁷ M) are far below than the limit set by the World Health Organization (WHO) for drinking water. Moreover, colorimetric test kits for rapid detection of Al³⁺, Fe³⁺, and Cr³⁺ could be successively applied for all practical purposes, indicating its potential use in environmental samples. It has also been used in building molecular logic gates.

A dipodal reversible colorimetric trivalent metal ion chemosensor (L) has been designed and synthesized. The chemosensor L successfully detects Al³⁺, Fe³⁺ and Cr³⁺ based on binding site-signaling approach and it has practical application.     

Chronic Administration of Bacopa Monniera Increases BDNF Protein and mRNA Expressions: A Study in Chronic Unpredictable Stress Induced Animal Model of Depression

Objective

The present study aimed to investigate whether graded doses of Bacopa Monniera (BM) extract could produce antidepressant-like effects in chronic unpredictable stress (CUS) induced depression in rats and its possible mechanism(s).

Methods

Rats were subjected to an experimental setting of CUS. The effect of BM extract treatment in CUS-induced depression was examined using behavioral tests including the sucrose consumption, open field test and shuttle box escape test. The mechanism underlying the antidepressant-like action of BM extract was examined by measuring brain-derived neurotrophic factor (BDNF) protein and mRNA expression in brain tissues of CUS-exposed rats.

Results

Exposure to CUS for 4 weeks caused depression-like behavior in rats, as indicated by significant decreases in sucrose consumption, locomotor activity and escape latency. In addition, it was found that BDNF protein and mRNA levels in the hippocampus and frontal cortex were lower in CUS-treated rats, as compared to controls. Daily administration of the graded doses of BM extract during the 4-week period of CUS significantly suppressed behavioral changes and attenuated the CUS-induced decrease in BDNF protein and mRNA levels in the hippocampus and frontal cortex.

Conclusion

The results suggest that BM extract alleviates depression induced by CUS. Present study also confirms that 80-120 mg/kg doses of BM extract have significantly higher antidepressant-like activity.     

Oral polio vaccine response in breast fed infants with malnutrition and diarrhea

Oral vaccines for polio (OPV) and rotavirus are less effective in children in the developing world. The reasons for this are not well understood. We tested for risk factors for poor response to OPV in infants from an urban slum of Dhaka, Bangladesh. Diminished serum neutralizing response to OPV, but not failure of intramuscularly administered vaccines, was associated with malnutrition, diarrhea, and shorter breastfeeding duration. Children with malnutrition (WAZ <−2) had significantly lower OPV 3 titers (p = 0.029). Children who had 2 or more diarrhea episodes during the 1st months of life were more than twice as likely to experience OPV failure as those who had 1 diarrhea episode or no diarrhea (p = 0.0245). In contrast, each additional month in exclusive breastfeeding was associated with an increase in OPV 3 titer by 0.41 (p = 0.0072) and 0.16 (p = 0.0065) at the 25th and 50th percentiles of OPV 3 titers respectively. These data are consistent with a defect in induction of immunity in the gut for OPV but not parenteral vaccines, a defect that may be amenable to intervention in part via promotion of exclusive breastfeeding.