SciCombinator

Discover the most talked about and latest scientific content & concepts.

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The increasing global prevalence of the symptoms of constipation adversely affects the quality of life (QOL) of symptomatic patients. An acceptable universal definition of constipation does not exist and a detailed history taking form each patient with various complaints including stool consistency, sensing of incomplete evacuation or a manual need to assist evacuation is required. Complexity of obtaining etiologic diagnosis and the wide range of therapeutic options can mislead physicians in choosing correct treatment.

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Constipation is a common, treatable condition that can be experienced by all age groups. This article outlines the different types of constipation and explains how the condition is diagnosed. A comprehensive and person-centred assessment is fundamental to identifying constipation, and should include taking the patient’s clinical history and discussing any lifestyle factors that may be causing or contributing to the condition. This article also details the pharmacological and non-pharmacological interventions that nurses can employ in the management of constipation, including providing advice on lifestyle changes and the use of laxatives.

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Little is understood about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the COVID-19 pandemic. Furthermore, there is limited literature available and few case studies exploring the observations of colleagues involved in managing patients with COVID-19. Children represent a small sample of the confirmed cases of COVID-19 in the UK but the reasons for this are relatively unknown. Most children are asymptomatic or exhibit mild symptoms from COVID-19 infection. However, a small number have been identified who develop a significant systemic inflammatory response, referred to as paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS). PIMS-TS involves persistent fever and organ dysfunction. PIMS-TS can also share clinical features with other conditions including toxic shock syndrome, septic shock and Kawasaki disease. This article presents a case study to explore the resuscitative care provided to a ten-year-old child with suspected PIMS-TS.

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In this work, we demonstrate the tunable luminescence of newly synthesized SDC/OS Mg/Al-LDH composites (SDC is 4,4'-stilbenedicarboxylic acid; OS is 1-octanesulfonic acid sodium; LDH is layered double hydroxide) and their application in fluorescence sensing to detect Fe(iii) ions. Through an ion-exchange method, the SDC2- and OS- anions with changed molar ratios are intercalated into the LDH interlayers to obtain composites of SDCxOS1-x-LDH (x = 0.02, 0.05, and 0.10). In the solid state, the optimized SDC0.05OS0.95-LDH exhibits a blue emission (441 nm) with a 54 nm blue-shift compared with SDC-Na solid salt (495 nm). In a delaminated state, the colloidal suspension of SDC0.05OS0.95-LDH in formamide (FM) also gives a blue emission at 444 nm in comparison to the 451/468 nm emissions of the FM solution of free SDC2- anions, and the luminescence intensity of the exfoliated composite is ∼28 times higher than that of the SDC2- anions. The SDC0.05OS0.95-LDH composite could be utilized in chemical fluorescence sensing for detecting Fe3+ ions. In aqueous solutions with extremely low Fe3+ concentrations of 0.18-1.78 μM (0.01-0.1 ppm), the composite gives a large quenching constant of 2.34 × 105 M-1, and an ultralow detection limit of 6.12 × 10-8 M. This work may provide a highly effective while simple method for the detection of Fe3+ in a small concentration range.

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Three complexes based on an Ir-M (M = FeII, CoII, and NiII) heterobimetallic core and 2-(diphenylphosphino)pyridine (Ph2PPy) ligand were synthesized via the reaction of trans-[IrCl(CO)(Ph2PPy)2] and the corresponding metal chloride. Their structures were established by single-crystal X-ray diffraction as [Ir(CO)(μ-Cl)(μ-Ph2PPy)2FeCl2]·2CH2Cl2 (2), [IrCl(CO)(μ-Ph2PPy)2CoCl2]·2CH2Cl2 (3), and [Ir(CO)(μ-Cl)(μ-Ph2PPy)2NiCl2]·2CH2Cl2 (4). Time-dependent DFT computations suggest a donor-acceptor interaction between a filled 5dz2 orbital on iridium and an empty orbital on the first-row metal atom, which is supported by UV-vis studies. Magnetic moment measurements show that the first-row metals are in their high-spin electronic configurations. Cyclic voltammetry data show that all the complexes undergo irreversible decomposition upon either reduction or oxidation. Reduction of 4 proceeds through an ECE mechanism. While these complexes are not stable to electrocatalysis conditions, the data presented here refine our understanding of the bonding synergies of the first-row and third-row metals.

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The major risk factors to fatal outcome in COVID-19 patients, i.e., elderliness and pre-existing metabolic and cardiovascular diseases (CVD), share in common the characteristic of being chronic degenerative diseases of inflammatory nature associated with defective heat shock response (HSR). The molecular components of the HSR, the principal metabolic pathway leading to the physiological resolution of inflammation, is an anti-inflammatory biochemical pathway that involves molecular chaperones of the heat shock protein (HSP) family during homeostasis-threatening stressful situations (e.g., thermal, oxidative and metabolic stresses). The entry of SARS coronaviruses in target cells, on the other hand, aggravates the already-jeopardized HSR of this specific group of patients. In addition, cellular counterattack against virus involves interferon (IFN)-mediated inflammatory responses. Therefore, individuals with impaired HSR cannot resolve virus-induced inflammatory burst physiologically, being susceptible to exacerbated forms of inflammation, which leads to a fatal “cytokine storm”. Interestingly, some species of bats that are natural reservoirs of zoonotic viruses, including SARS-CoV-2, possess an IFN-based antiviral inflammatory response perpetually activated but do not show any sign of disease or cytokine storm. This is possible because bats present a constitutive HSR that is by far (hundreds of times) more intense and rapid than that of human, being associated with a high core temperature. Similarly in humans, fever is a physiological inducer of HSR while antipyretics, which block the initial phase of inflammation, impair the resolution phase of inflammation through the HSR. These findings offer a rationale for the reevaluation of patient care and fever reduction in SARS, including COVID-19.

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The substantial part of the water-soluble hemicellulose fraction, obtained when processing cellulose to produce paper and other products, has so far been discarded. The aim of this work is to reveal the interfacial properties of softwood hemicellulose (galactoglucomannan, GGM) in relation to their molecular and solution structure. In this study the sugar composition of GGM was characterised by chemical analysis as well as 1D and 2D NMR spectroscopy. Previously it has been demonstrated that hemicellulose has high affinity towards cellulose and has the ability to alter the properties of cellulose based products. This study is focused on the interactions between hemicellulose and the cellulose surface. Therefore, adsorption to hydrophobized silica and cellulose surfaces of two softwood hemicellulose samples and structurally similar seed hemicelluloses (galactomannans, GMs) was studied with ellipsometry, QCM-D and neutron reflectometry. Aqueous solutions of all samples were characterized with light scattering to determine how the degree of side-group substitution and molecular weight affect the conformation and aggregation of these polymers in the bulk. In addition, hemicellulose samples were studied with SAXS to investigate backbone flexibility. Light scattering results indicated that GM polymers form globular particles while GGMs were found to form rod-like aggregates in the solution. The polysaccharides exhibit higher adsorption to cellulose than on hydrophobic surfaces. A clear correlation between the increase in molecular weight of polysaccharides and increasing adsorbed amount on cellulose was observed, while the adsorbed amount on the hydrophobic surface was fairly independent of the molecular weight. The obtained layer thickness was compared with bulk scattering data and the results indicated flat conformation of the polysaccharides on the surface.

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Electrolytic diffusiophoresis is the movement of colloidal particles in response to a concentration gradient of an electrolyte. The diffusiophoretic velocity vDP is typically predicted through the relation vDP = DDP ∇log cs, where DDP is the diffusiophoretic mobility and cs is the concentration of the electrolyte. The logarithmic dependence of vDP on cs may suggest that the strength of diffusiophoretic motion is insensitive to the magnitude of the electrolyte concentration. In this article, we emphasize that DDP is intimately coupled with cs for all electrolyte concentrations. For dilute electrolytes, the finite double layer thickness effects are significant such that DDP decreases with a decrease in cs. In contrast, for concentrated electrolytes, charge screening could result in a decrease in DDP with an increase in cs. Therefore, we predict a maximum in DDP with cs for moderate electrolyte concentrations. We also show that for typical colloids and electrolytes , where Ds is the solute ambipolar diffusivity. To validate our model, we conduct microfluidic experiments with a wide range of electrolyte concentrations. The experimental data also reveals a maximum in DDP with cs, in agreement with our predictions. Our results have important implications in the broad areas of electrokinetics, lab-on-a-chip, active colloidal transport and biophysics.

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Multiplex detection and quantification of bacteria in water by using portable devices are particularly essential in low and middle-income countries where access to clean drinking water is limited. Addressing this crucial problem, we report a highly sensitive immunoassay sensor system utilizing the fluorescence technique with magnetic nanoparticles (MNPs) to separate target bacteria and two different types of quantum dots (CdTe and Ni doped CdTe QDs) incorporated into a passive microfluidic chip to transport and to form sandwich complexes for the detection of two target bacteria, namely Escherichia coli (E. coli) and Salmonella enteritidis (S. enteritidis) in less than 60 min. The assay is carried out on a capillary driven microfluidic chip that can be operated by merely pipetting the samples and reagents, and fluorescence measurements are done by using a handheld fluorescence spectrophotometer, which renders the system portable. The linear range of the method was found to be 101 to 105 cfu mL-1 for both E. coli and S. enteritidis. The limit of detection (LOD) was calculated to be 5 and 3 cfu mL-1 for E. coli and S. enteritidis, respectively. The selectivity of the method was examined by testing Enterobacter dissolvens (E. dissolvens) and Staphylococcus aureus (S. aureus) samples, and no significant interference was observed. The method was also demonstrated to detect bacteria in tap water and lake water samples spiked with target bacteria.

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This study presents the development of disposable biosensors employed in the determination of histamine in fish samples. Screen printed carbon electrodes (SPCEs) were first modified with a mixture of titanium dioxide nanoparticles (TiO2), carboxylated multiwalled carbon nanotubes (c-MWCNTs), hexaammineruthenium(iii) chloride (RU) and chitosan (CS). Diamine oxidase (DAO) or monoamine oxidase (MAO) enzymes were further immobilized onto the TiO2-c-MWCNT-RU-CS/SPCEs via 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC) and hydroxysuccinimide (NHS) chemistry for the fabrication of the biosensors. The morphological and electrochemical properties of the proposed biosensors were studied using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). A performance comparison of two biosensors indicated that the one based on DAO had a linear concentration range from 9.9 × 10-6 to 1.1 × 10-3 M and the other based on MAO, from 5.6 × 10-5 to 1.1 × 10-3 M for histamine. The sensitivity of the DAO based biosensor was almost 1.5 times higher than that of the MAO based biosensor. The proposed biosensors were successfully employed to determine histamine in fish samples and the recoveries were between 100.0% and 104.6%.