Rotavirus trends and distribution of genotypes before and during COVID-19 pandemic era: Bangladesh, 2017-2021.

Rotavirus gastroenteritis is accountable for an estimated 128 500 deaths among children younger than 5 years worldwide, and the majority occur in low-income countries. Although the clinical trials of rotavirus vaccines in Bangladesh revealed a significant reduction of severe rotavirus disease by around 50%, the vaccines are not yet included in the routine immunization program. The present study was designed to provide data on rotavirus diarrhea with clinical profiles and genotypes before (2017-2019) and during the COVID-19 pandemic period (2020-2021). Fecal samples were collected from 2% of the diarrheal patients at icddr,b Dhaka hospital of all ages between January 2017 and December 2021 and were tested for VP6 rotavirus antigen using ELISA. The clinical manifestations such as fever, duration of diarrhea and hospitalization, number of stools, and dehydration and so on were collected from the surveillance database (n = 3127). Of the positive samples, 10% were randomly selected for genotyping using Sanger sequencing method. A total of 12 705 fecal samples were screened for rotavirus A antigen by enzyme immunoassay. Overall, 3369 (27%) were rotavirus antigen-positive, of whom children <2 years had the highest prevalence (88.6%). The risk of rotavirus A infection was 4.2 times higher in winter than in summer. Overall, G3P[8] was the most prominent genotype (45.3%), followed by G1P[8] (32.1%), G9P[8] (6.8%), and G2P[4] (6.1%). The other unusual combinations, such as G1P[4], G1P[6], G2P[6], G3P[4], G3P[6], and G9P[6], were also present. Genetic analysis on Bangladeshi strains revealed that the selection pressure (dN/dS) was estimated as <1. The number of hospital visits showed a 37% drop during the COVID-19 pandemic relative to the years before the pandemic. Conversely, there was a notable increase in the rate of rotavirus positivity during the pandemic (34%, p < 0.00) compared to the period before COVID-19 (23%). Among the various clinical symptoms, only the occurrence of watery stool significantly increased during the pandemic. The G2P[4] strain showed a sudden rise (19%) in 2020, which then declined in 2021. In the same year, G1P[8] was more prevalent than G3P[8] (40% vs. 38%, respectively). The remaining genotypes were negligible and did not exhibit much fluctuation. This study reveals that the rotavirus burden remained high during the COVID-19 prepandemic and pandemic in Bangladesh. Considering the lack of antigenic variations between the circulating and vaccine-targeted strains, integrating the vaccine into the national immunization program could reduce the prevalence of the disease, the number of hospitalizations, and the severity of cases.

Stacking Cyclophanes into Chiral Microvessels.

Engineering novel micro-/nanoscale systems and devices based on supramolecular assembly has tremendous potential from diverse applications perspective. However, controlling the size, shape, spatial arrangements, and hierarchical transcription by a dimensional organizing principle (1D-3D arrangement) without the help of templates remains a challenging task. In this vein, a recent study by Oki and colleagues reporting the stacking of chiral cyclophanes via intermolecular non-covalent interactions for crafting synchronous microcrystalline 3D chiral vessels with controlled conformational arrangements represents a truly remarkable illustration of molecular engineering. The microvessels bear stereocontrolled skeletal morphology, recognize stereoisomers and serve as containers to accommodate microcrystals, polymer particles, and fluorescent dyes. The full application scope of this fascinating research is far beyond non-covalent interactions, supramolecular self-assembly, and crystal engineering.

Diversity-Oriented Synthesis of [2.2]Paracyclophane-derived Fused Imidazo[1,2-a]heterocycles by Groebke-Blackburn-Bienaymé Reaction: Accessing Cyclophanyl Imidazole Ligands Library.

This report describes the synthesis of a [2.2]paracyclophane-derived annulated 3-amino-imidazole ligand library through a Groebke-Blackburn-Bienaymé three-component reaction (GBB-3CR) approach employing formyl-cyclophanes in combination with diverse aliphatic and aromatic isocyanides and heteroaromatic amidines. The GBB-3CR process gives access to skeletally-diverse cyclophanyl imidazole ligands, namely 3-amino-imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrazines. Additionally, a one-pot protocol for the GBB-3CR by an in situ generation of cyclophanyl isocyanide is demonstrated. The products were analyzed by detailed spectroscopic techniques, and the cyclophanyl imidazo[1,2-a]pyridine was confirmed unambiguously by single-crystal X-Ray crystallography. The cyclophanyl imidazole ligands can be readily transformed to showcase their useful utility in preparing N,C-palladacycles through regioselective ortho-palladation.

Metal-to-Metal Distance Modulation by Ligand Design: A Case Study of Structure-Property Correlation in Planar Chiral Cyclophanyl Metal Complexes.

Multinuclear metal complexes have seen tremendous progress in synthetic advances, their versatile structural features, and emerging applications. Here, we conceptualize Metal-to-Metal distance modulation in cyclophanyl metal complexes by bridging ligand design employing the co-facially stacked cyclophanyl-derived pseudo-geminal, -ortho, -meta, and -para constitutional isomers grafted with N-, O-, and P- containing chelates that allow the installation of diverse (hetero)metallic moieties in a distance-defined and spatially-oriented relation to one another. Metal-to-Metal distance modulation and innate transannular "through-space" π-π electronic interactions via the co-facially stacked benzene rings in cyclophanyl-derived complexes as well as their specific stereochemical structural features (element of planar chirality) are crucial factors that contribute to the tuning of structure-property relationships, which stand at the very center from the perspective of cooperative effects in catalysis as well as emerging material applications.

Metal-to-Metal Distance Modulated Au(I)/Ru(II) Cyclophanyl Complexes: Cooperative Effects in Photoredox Catalysis.

The modular synthesis of Au(I)/Ru(II) decorated mono- and heterobimetallic complexes with π-conjugated [2.2]paracyclophane is described. [2.2]Paracyclophane serves as a rigid spacer which holds the metal centers in precise spatial orientations and allows metal-to-metal distance modulation. A broad set of architectural arrangements of pseudo -geminal, -ortho, -meta, and -para substitution patterns were employed. Metal-to-metal distance modulation of Au(I)/Ru(II) heterobimetallic complexes and the innate transannular π-communication of the cyclophanyl scaffold provides a promising platform for the investigations of structure-activity relationship and cooperative effects. The Au(I)/Ru(II) heterobimetallic cyclophanyl complexes are stable, easily accessible, and exhibit promising catalytic activity in the visible-light promoted arylative Meyer-Schuster rearrangement.

Criegee Intermediates Beyond Ozonolysis: Synthetic and Mechanistic Insights.

After more than 70 years since their discovery, Criegee intermediates (CIs) are back at the forefront of modern chemistry of short-lived reactive intermediates. They play an important role in the mechanistic context of chemical synthesis, total synthesis, pharmaceuticals, and, most importantly, climate-controlling aerosol formation as well as atmospheric chemistry. This Minireview summarizes key aspects of CIs (from the mechanism of formation, for example, by ozonolysis of alkenes and photolysis methods employing diiodo and diazo compounds, to their electronic structures and chemical reactivity), highlights the most recent findings and some landmark results of gas-phase kinetics, and detection/measurements. The recent progress in synthetic and mechanistic studies in the chemistry of CIs provides a guide to illustrate the possibilities for further investigations in this exciting field.

Metal-Organic Framework-Templated Biomaterials: Recent Progress in Synthesis, Functionalization, and Applications.

The integration of a porous crystalline framework with soft polymers to create novel biomaterials has tremendous potential yet remains very challenging to date. Metal-organic framework (MOF)-templated polymers (MTPs) have emerged as persistent modular materials that can be tailored for desired biofunctions. These represent a novel class of hierarchically structured assemblies that combine the advantages of MOFs (precisely controlled structure, enormous diversity in framework topology, and high porosity) with the intrinsic behaviors of polymers (soft texture, flexibility, biocompatibility, and improved stability under physiological conditions). Transformation of surface-anchored MOFs (SURMOFs) via orthogonal covalent cross-linking yields surface-anchored polymeric gels (SURGELs) that open up exciting new opportunities to create soft nanoporous materials. SURGELs overcome the main drawbacks of SURMOFs, such as their limited stability under physiological conditions and their potential to release toxic metal ions, a substantial problem for applications in life sciences. MOF (SURMOF)-templated polymerization processes control the synthesis on a molecular level. Additionally, the morphology of the original MOF crystal template is replicated in the final network polymers. The MOF-templated polymerization can be induced by light, a catalyst, or temperature using several types of reactions, including thiol-ene, metal-free alkyne-azide click reactions, and Glaser-Hay coupling. In the case of photoinduced reactions, the cross-linking process can be locally confined, allowing control of the macroscopic patterning of the resulting network polymer. The use of layer-by-layer (lbl) techniques in the SURMOF synthesis serves the purpose of precise, layer-selective incorporation of functionalities via the combination of the postsynthetic modification and heteroepitaxy strategies. Transforming the functionalized SURMOF into a SURGEL allows the fabrication of polymers with desired bioactive functions at the internal or external surfaces. This Account highlights our ongoing research and inspiring progress in transforming SURMOFs into persistent, modular nanoporous materials tailored with biofunctions. Using cell culture studies, we present various aspects of SURGEL materials, such as the ability to deliver bioactive molecules to adhering cells on SURGEL surfaces, applications to advanced drug delivery systems, the ability to tune cell adhesion via surface modification, and the development of porphyrin-based SURGEL thin films with antimicrobial properties. Then we critically examine the challenges and limitations of current systems and discuss future research directions and new approaches for advancing MOF-templated biocompatible materials, emphasizing the need to include responsive and adaptive functionalities into the system. We emphasize that the hierarchical structure, ranging from the molecular to the macroscopic scale, allows for optimization of the material properties across all length scales relevant for cell-material interactions.

Controlling Regioselectivity in Palladium-Catalyzed C-H Activation/Aryl-Aryl Coupling of 4-Phenylamino[2.2]paracyclophane.

Selective activation/functionalization of C-H bonds has emerged as an atom- and step-economical process at the forefront of modern synthetic chemistry. This work reports palladium-catalyzed exclusively para-selective C-H activation/aryl-aryl bond formation with a preference over N-arylation under the Buchwald-Hartwig amination reaction of 4-phenylamino[2.2]paracyclophane. This innovative synthetic strategy allows a facile preparation of [2.2]paracyclophane derivatives featuring disparate para-substitutions at C-4 and C-7 positions in a highly selective manner, gives access to a series of potential candidates for [2.2]paracyclophane-derived new planar chiral ligands. The unprecedented behavior in reactivity and preferential selectivity of C-C coupling over C-N bond formation via C-H activation is unique to the [2.2]paracyclophane scaffold compared to the non-cyclophane analogue under the same reaction conditions. Selective C-H activation/aryl-aryl bond formation and sequential C-N coupling product formation is evidenced unambiguously by X-ray crystallography.

Polymerization in MOF-Confined Nanospaces: Tailored Architectures, Functions, and Applications.

This feature article describes recent trends and advances in structuring network polymers using a coordination-driven metal-organic framework (MOF)-based template approach to demonstrate the concept of crystal-controlled polymerization in confined nanospaces, forming tailored architectures ranging from simple linear one-dimensional macromolecules to tunable three-dimensional cross-linked network polymers and interwoven molecular architectures. MOF-templated network polymers combine the characteristics and advantages of crystalline MOFs (high porosity, structural regularity, and designability) with the intrinsic behaviors of soft polymers (flexibility, processability, stability, or biocompatibility) with widespread application possibilities and tunable properties. The article ends with a summary of the remaining challenges to be addressed, and future research opportunities in this field are discussed.

Regioselective Functionalization of [2.2]Paracyclophanes: Recent Synthetic Progress and Perspectives.

[2.2]Paracyclophane (PCP) is a prevalent scaffold that is widely utilized in asymmetric synthesis, π-stacked polymers, energy materials, and functional parylene coatings that finds broad applications in bio- and materials science. In the last few years, [2.2]paracyclophane chemistry has progressed tremendously, enabling the fine-tuning of its structural and functional properties. This Minireview highlights the most important recent synthetic developments in the selective functionalization of PCP that govern distinct features of planar chirality as well as chiroptical and optoelectronic properties. Special focus is given to the function-inspired design of [2.2]paracyclophane-based π-stacked conjugated materials by transition-metal-catalyzed cross-coupling reactions. Current synthetic challenges, limitations, as well as future research directions and new avenues for advancing cyclophane chemistry are also summarized.

Maternal BMI and nutritional status in early pregnancy and its impact on neonatal outcomes at birth in Bangladesh.

BACKGROUND: To assess the maternal characteristics and nutritional status according to body mass index (BMI) at 6-14 weeks of gestation and to examine the relationship between maternal nutritional status in early pregnancy and its impact on neonatal birth weight. METHODS: The investigation was conducted from April 2011 to June 2012 in Dhaka, Bangladesh. A total of 498 primigravida pregnant women participated in the study; women with known diabetes or previous gestational diabetes (GDM) were excluded. Maternal demographic details, pregnancy history and anthropometric measurements were obtained from the mother at the recruitment (6-14 weeks), 2nd visit between 24 and 28 week of gestation and 3rd visit at delivery. Cord venous blood samples of newborns (n = 138) were collected immediately after delivery for blood glucose, insulin, lipid profile, leptin and micronutrients including serum folate, ferritin, homocysteine, vitamin D, and vitamin B12. RESULTS: The prevalence at 6-14 weeks of pregnancy of anemia (Hb, < 11 g/dl), vitamin D deficiency (< 30 nmol/l), vitamin B12 deficiency (< 200 pg/ml), high homocysteine level (> 15 µmol/l), folate deficiency (< 3 ng/ml) and iron deficiency (ferritin < 13 ng/ml) were 19.5, 46.4, 15.1, 1.2, 0.4, and 12.7% respectively. GDM was found in 18.4% women. The prevalence of GDM was higher in overweight women (28.1%) than underweight (16.7%) and normal weight women (16.0%: p <  0.05). The incidence of low birth weight (LBW) and preterm delivery were 11.6 and 5.8% respectively and was not related to maternal BMI at 6-14 weeks of pregnancy. Maternal height was positively (p = 0.02), and homocysteine was negatively associated with neonatal birth weight (p = 0.02). In addition, the newborn's cord serum folate was positively (p = 0.03) and cord triglyceride was negatively (p = 0.03) associated with neonatal birth weight. CONCLUSION: Multiple maternal micronutrient deficiencies were present in early pregnancy. Maternal BMI in early pregnancy was not related to preterm deliveries or LBW. LBW was associated with lower folate, elevated cord triglyceride concentrations of the neonates and mother's height and increase in maternal homocysteine levels. The data has important implications for pregnancy care in Bangladesh and other similar communities.

Planar chiral [2.2]paracyclophanes: from synthetic curiosity to applications in asymmetric synthesis and materials.

Planar chiral [2.2]paracyclophane-based ligands and employment of such enantiopure representative ligands to facilitate selective transformation of prochiral or racemic substances into enantiopure products are rarely explored compared to the complex chiral scaffolds such as ferrocenes. This tutorial discusses recent findings and inspiring progress in design, synthetic tunability and applications of planar chiral [2.2]paracyclophane systems as a practical class of catalysts for asymmetric synthesis. Here, we summarize a series of planar chiral [2.2]paracyclophanes that are becoming an important new tool-box in asymmetric synthesis, employed in a variety of synthetic venues such as new chiral ligands and catalysts for stereo-controlled and enantioselective addition of alkyl, alkenyl, alkynyl and aryl zinc reagents to aliphatic and aromatic aldehydes, ketones, imines and many more. Besides, planar chiral [2.2]paracyclophanes are useful synthons, from a material perspective, can be incorporated into conjugated polymeric systems for chiroptical and optoelectronic properties, find broad applications in bio- and materials science, for instance, gold-based cytostatics, surface-mounted chiral MOF thin films for selective adsorption or in functionalized parylene polymer coatings, to name a few. This is an up-to-date tutorial review, written exclusively on planar chiral [2.2]paracyclophane chemistry, covering key aspects of synthesis, structures, properties, applications and future directions of chiral polymeric assemblies and novel biomaterials built with [2.2]paracyclophanes.

Planar Chiral [2.2]Paracyclophane-Based Bisoxazoline Ligands and Their Applications in Cu-Mediated N-H Insertion Reaction.

New catalysts for important C-N bond formation are highly sought after. In this work, we demonstrate the synthesis and viability of a new class of planar chiral [2.2]paracyclophane-based bisoxazoline (BOX) ligands for the copper-catalyzed N-H insertion of α-diazocarbonyls into anilines. The reaction features a wide substrate scope and moderate to excellent yields, and delivers the valuable products at ambient conditions.

Microsphaerol and seimatorone: two new compounds isolated from the endophytic fungi, Microsphaeropsis sp. and Seimatosporium sp.

A new polychlorinated triphenyl diether named microsphaerol (1), has been isolated from the endophtic fungus Microsphaeropsis sp. An intensive phytochemical investigation of the endophytic fungus Seimatosporium sp., led to the isolation of a new naphthalene derivative named seimatorone (2) and eight known compounds, i.e., 1-(2,6-dihydroxyphenyl)-3-hydroxybutan-1-one (3), 1-(2,6-dihydroxyphenyl)butan-1-one (4), 1-(2-hydroxy-6-methoxyphenyl)butan-1-one (5), 5-hydroxy-2-methyl-4H-chromen-4-one (6), 2,3-dihydro-5-hydroxy-2-methyl-4H-chromen-4-one (7), 8-methoxynaphthalen-1-ol (8), nodulisporins A and B (9 and 10, resp.), and daldinol (11). The structures of 1 and 2 were elucidated by detailed spectroscopic analysis including (1) H- and (13) C-NMR, COSY, HMQC, HMBC, and HR-EI-MS, while the structures of the known compounds were deduced from comparison of their spectral data with those in the literature. Preliminary studies revealed that microsphaerol (1) showed good antibacterial activities against B. Megaterium and E. coli, and good antilagal and antifungal activities against C. fusca, M. violaceum, respectively. On the other hand, seimatorone (2) exhibited moderate antibacterial, antialgal, and antifungal activities.

Seimisochromenes A and B: two new dihydroisochromenes from the endophytic fungus, Seimatosporium sp.

Two new dihydroisochromenes, named seimisochromenes A and B (1 and 2), were isolated from an endophytic fungus, Seimatosporium sp. The structures of seimisochromenes A and B have been determined from 1D ((1)H and (13)C NMR spectra) and 2D (COSY, HMQC, HMBC, and NOESY) NMR experiments.

A 3-dimensional model for teaching local flaps using porcine skin.

The European Working Time Directive and streamlined training has led to reduced training time. Surgery, as an experience-dependent craft specialty is affected more than other medical specialties. Trainees want to maximize all training opportunities in the clinical setting, and having predeveloped basic skills acquired on a simulated model can facilitate this.Here we describe the use of a novel model to design and raise local flaps in the face and scalp regions. The model consists of mannequin heads draped with porcine skin which is skewered with pins at strategic points to give a 3-dimensional model which closely resembles a cadaveric head.The advantages of this model are that it is life size and incorporates all the relevant anatomical features, which can be drawn on if required.This model was used on a recent course, Intermediate Skills in Plastic Surgery: Flaps Around the Face, at the Royal College of Surgeons England. The trainees found that practicing on the porcine skin gave them an opportunity to master the basics of flap design and implementation.In summary, this innovative 3-dimensional training model has received high levels of satisfaction and is currently as close as we can get to cadaveric dissection without the constraints and cost of using human tissue.

Highly stable, water-dispersible metal-nanoparticle-decorated polymer nanocapsules and their catalytic applications.

A facile synthesis of highly stable, water-dispersible metal-nanoparticle-decorated polymer nanocapsules (M@CB-PNs: M=Pd, Au, and Pt) was achieved by a simple two-step process employing a polymer nanocapsule (CB-PN) made of cucurbit[6]uril (CB[6]) and metal salts. The CB-PN serves as a versatile platform where various metal nanoparticles with a controlled size can be introduced on the surface and stabilized to prepare new water-dispersible nanostructures useful for many applications. The Pd nanoparticles on CB-PN exhibit high stability and dispersibility in water as well as excellent catalytic activity and recyclability in carbon-carbon and carbon-nitrogen bond-forming reactions in aqueous medium suggesting potential applications as a green catalyst.

Arsenic Contamination of Groundwater Is Determined by Complex Interactions between Various Chemical and Biological Processes.

At a great many locations worldwide, the safety of drinking water is not assured due to pollution with arsenic. Arsenic toxicity is a matter of both systems chemistry and systems biology: it is determined by complex and intertwined networks of chemical reactions in the inanimate environment, in microbes in that environment, and in the human body. We here review what is known about these networks and their interconnections. We then discuss how consideration of the systems aspects of arsenic levels in groundwater may open up new avenues towards the realization of safer drinking water. Along such avenues, both geochemical and microbiological conditions can optimize groundwater microbial ecology vis-à-vis reduced arsenic toxicity.

Use of Botulinum Toxin Injections in the Treatment of Cold Intolerance.

There is currently no consensus on the treatment of cold intolerance in extremities in post-trauma patients. We aim to present two cases where botulinum toxin type A injections were used to improve symptoms of cold intolerance. Botulinum toxin type A (Allergan) was injected into the area around the palmar digital neurovascular bundle on both sides of the affected finger. We performed this in two patients, and both had good improvement of symptoms. One patient was discharged, and the other remained under routine follow-up with potential yearly botulinum injections to aid symptoms during the winter months. Both patients are pleased with their outcomes and report significant improvement from the low-risk treatment. In both described cases, injections of botulinum toxin had a significant effect on their symptoms. We conclude that botulinum toxin type A may be used as a treatment modality to improve symptoms of cold intolerance after trauma.

Synthesis of Mono-, Di-, Tri-, and Tetra-cationic Pyridinium and Vinylpyridinium Modified [2.2]Paracyclophanes: Modular Receptors for Supramolecular Systems.

In this report, a new series of mono-, di-, tri-, and tetra-cationic pyridinium and vinyl pyridinium-modified [2.2]paracyclophanes as useful molecular tectons for supramolecular systems are described. Regioselective functionalization at specific positions, followed by resolution step and successive transformations through Pd-catalyzed Suzuki-Miyaura and Mizoroki-Heck cross-coupling chemistry furnish a series of modular PCP scaffolds. In our proof-of-concept study, on N-methylation, the PCPs bearing (cationic) pyridyl functionalities were demonstrated as useful molecular receptors in host-guest supramolecular assays. The PCPs on grafting with light-responsive azobenzene (-N=N-) functional core as side-groups impart photosensitivity that can be remotely transformed on irradiation, offering photo-controlled smart molecular functions. Furthermore, the symmetrical PCPs bearing bi-, and tetra-pyridyl functionalities at the peripheries have enormous potential to serve as ditopic and tetratopic 3D molecular tectons for engineering non-covalent supramolecular assemblies with new structural and functional attributes.