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1.
Food Sci Nutr ; 12(8): 5722-5733, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39139927

ABSTRACT

Kombucha tea is a traditional beverage originating from China and has recently gained popularity worldwide. Kombucha tea is produced by the fermentation of tea leaves and is characterized by its beneficial properties and varied chemical content produced during the fermentation process, which includes organic acids, amino acids, vitamins, minerals, and other biologically active compounds. Kombucha tea is often consumed as a health drink to combat obesity and inflammation; however, the bioactive effects of kombucha tea have not been thoroughly researched. In this study, we reveal the underlying mechanisms of the beneficial properties of kombucha tea and how they protect against obesity and inflammation by studying Drosophila models. We established an inflammatory Drosophila model by knocking down the lipid storage droplet-1 gene, a human perilipin-1 ortholog. In this model, dysfunction of lipid storage droplet-1 induces inflammation by enhancing the infiltration of hemocytes into adipose tissues, increasing reactive oxygen species production, elevating levels of proinflammatory cytokines, and promoting the differentiation of hemocytes into macrophages. These processes are regulated by the c-Jun N-terminal Kinase (JNK) pathway. Using this unique Drosophila model that mimics mammalian inflammation, we verified the beneficial effects of kombucha tea on reducing tissue inflammation. Our data confirms that kombucha tea effectively improves inflammatory conditions by suppressing the expression of cytokines and proinflammatory responses induced by lipid storage droplet-1 dysfunction. It was found that kombucha tea consumption alleviated the production of reactive oxygen species and activated the JNK signaling pathway, signifying its potential as an anti-inflammatory agent against systemic inflammatory responses connected to the JNK pathway. Kombucha tea reduced triglyceride accumulation by increasing the activity of Brummer (a lipase), thereby promoting lipolysis in third-instar larvae. Therefore, kombucha tea could be developed as a novel, functional beverage to protect against obesity and inflammation. Our study also highlights the potential use of this innovative model to evaluate the effects of bioactive compounds derived from natural products.

2.
Materials (Basel) ; 17(13)2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38998392

ABSTRACT

The last two decades have witnessed significant progress in the development of severe plastic deformation techniques to produce ultrafine-grained materials with new and superior properties. This review examines works and achievements related to the low-temperature superplasticity of ultrafine-grained aluminum alloys. The examples are provided of the possibility to observe low-temperature superplasticity in aluminum alloys at temperatures less than 0.5 Tmelt and even at room temperature, and herein, we demonstrate the cases of achieving high ductility and high strength in aluminum alloys from processing utilizing severe plastic deformation. Special emphasis is placed on recent studies of the formation of segregations of alloying elements at grain boundaries in UFG Al alloys and their influence on the development of grain boundary sliding and manifestation of low-temperature superplasticity. In addition, the current status and innovative potential of low-temperature superplasticity in aluminum alloys are observed.

3.
Materials (Basel) ; 17(11)2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38893992

ABSTRACT

In order to facilitate the prediction of some physical properties, we propose several simple formulas based on two parameters only, the metallic valence and metallic atomic radii. Knowing the composition, for single-phase alloys, the average parameters can be calculated by the rule of mixture. The input parameters can be obtained from tabulated databases. Adopting from the literature the results of Coulomb crystal model for metals and single-phase high-entropy alloys, we have derived formulas for the shear modulus (G) and the cohesion energy (Ecoh). Based on these parameters separately, we set up two formulas to estimate the hardness in the case of pure metals. For single-phase (solid-solution) HEAs, by simplifying the Maresca and Curtin model, we obtained a formula for estimating the hardness, which takes into account the atomic misfit in addition to G. The maximal hardness for single-phase HEA is approximately 600 kg/mm2 and is obtained for a composition with a valence electron concentration of approximately 6 ÷ 7.

4.
Materials (Basel) ; 17(3)2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38591455

ABSTRACT

A homogenized, supersaturated AlZnMgZr alloy was processed via severe plastic deformation (SPD) using a high-pressure torsion (HPT) technique for different revolutions at room temperature to obtain an ultrafine-grained (UFG) microstructure. The microstructure and mechanical properties of the UFG samples were then studied using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and tensile and hardness measurements. The main purpose was to study the effect of shear strain on the evolution of the microstructure of the investigated alloy. We found a very interesting evolution of the decomposed microstructure in a wide range of shear strains imposed by HPT. While the global properties, such as the average grain size (~200 nm) and hardness (~2200 MPa) appeared unchanged, the local microstructure was continuously transformed. After 1 turn of HPT, the decomposed UFG structure contained relatively large precipitates inside grains. In the sample processed by five turns in HPT, the segregation of Zn atoms into grain boundaries (GBs) was also observed. After 10 turns, more Zn atoms were segregated into GBs and only smaller-sized precipitates were observed inside grains. The intensive solute segregations into GBs may significantly affect the ductility of the material, leading to its ultralow-temperature superplasticity. Our findings pave the way for achieving advanced microstructural and mechanical properties in nanostructured metals and alloys by engineering their precipitation and segregation by means of applying different HPT regimes.

5.
Nat Mater ; 23(3): 363-368, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38302742

ABSTRACT

Crystal lattice fluctuations, which are known to influence phase transitions of quantum materials in equilibrium, are also expected to determine the dynamics of light-induced phase changes. However, they have only rarely been explored in these dynamical settings. Here we study the time evolution of lattice fluctuations in the quantum paraelectric SrTiO3, in which mid-infrared drives have been shown to induce a metastable ferroelectric state. Crucial in these physics is the competition between polar instabilities and antiferrodistortive rotations, which in equilibrium frustrate the formation of long-range ferroelectricity. We make use of high-intensity mid-infrared optical pulses to resonantly drive the Ti-O-stretching mode at 17 THz, and we measure the resulting change in lattice fluctuations using time-resolved X-ray diffuse scattering at a free-electron laser. After a prompt increase, we observe a long-lived quench in R-point antiferrodistortive lattice fluctuations. Their enhancement and reduction are theoretically explained by considering the fourth-order nonlinear phononic interactions to the driven optical phonon and third-order coupling to lattice strain, respectively. These observations provide a number of testable hypotheses for the physics of light-induced ferroelectricity.

6.
Materials (Basel) ; 16(19)2023 Oct 07.
Article in English | MEDLINE | ID: mdl-37834730

ABSTRACT

A supersaturated Al-4.8%Zn-1.2%Mg-0.14%Zr (wt%) alloy was processed by the equal-channel angular pressing (ECAP) technique at room temperature in order to obtain an ultrafine-grained (UFG) microstructure having an average grain size of about 260 nm. The hardness and microstructural characteristics, such as the phase composition and precipitations of this UFG microstructure were studied using depth-sensing indentation (DSI), transmission electron microscopy (TEM), as well as non-isothermal scanning of differential scanning calorimetry (DSC), and compared to the properties of the un-deformed sample. Emphasis was placed on the effect of the UFG microstructure on the subsequent thermal processes in DSC measurements. It has been shown that the ECAP process resulted in not only an ultrafine-grained but also a strongly precipitated microstructure, leading to a hardness (2115 MPa) two and a half times higher than the initial hardness of the freshly quenched sample. Because of the significant changes in microstructure, ECAP has also a strong effect on the dissolution (endothermic) and precipitation (exothermic) processes during DSC measurements, where the dissolution and precipitation processes were quantitatively characterized by using experimentally determined specific enthalpies, ΔH and activation energies, Q.

7.
Phys Chem Chem Phys ; 25(32): 21468-21478, 2023 Aug 16.
Article in English | MEDLINE | ID: mdl-37539527

ABSTRACT

Two-dimensional (2D) Janus materials with extraordinary properties are promising candidates for utilization in advanced technologies. In this study, new 2D Janus XWSiP2 (X = S, Se, Te) monolayers were constructed and their properties were systematically analyzed by using first-principles calculations. All three structures of SWSiP2, SeWSiP2, and TeWSiP2 exhibit high energetic stability for the experimental fabrication with negative and high Ecoh values, the elastic constants obey the criteria of Born-Huang, and no imaginary frequency exists in the phonon dispersion spectra. The calculated results from the PBE and HSE06 approaches reveal that the XWSiP2 are semiconductors with moderate direct band-gaps varying from 1.01 eV to 1.06 eV using the PBE method, and 1.39 eV to 1.44 eV using the HSE06 method. In addition, the electronic band structures of the three monolayers are significantly affected by the applied strains. Interestingly, the transitions from a direct to indirect semiconductor are observed for different biaxial strains εb. The transport parameters including the carrier mobility values along the x direction µx and y direction µy were also calculated to study the transport properties of the XWSiP2. The results indicate that the XWSiP2 monolayers not only have high carrier mobilities but also anisotropy in the transport directions for both holes and electrons. Together with the moderate and tunable energy gaps, the XWSiP2 materials are found to be potential candidates for application in the photonic, photovoltaic, optoelectronic, and electronic fields.

8.
Ultramicroscopy ; 250: 113750, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37178606

ABSTRACT

X-ray photoelectron diffraction (XPD) is a powerful technique that yields detailed structural information of solids and thin films that complements electronic structure measurements. Among the strongholds of XPD we can identify dopant sites, track structural phase transitions, and perform holographic reconstruction. High-resolution imaging of kll-distributions (momentum microscopy) presents a new approach to core-level photoemission. It yields full-field kx-ky XPD patterns with unprecedented acquisition speed and richness in details. Here, we show that beyond the pure diffraction information, XPD patterns exhibit pronounced circular dichroism in the angular distribution (CDAD) with asymmetries up to 80%, alongside with rapid variations on a small kll-scale (0.1 Å-1). Measurements with circularly-polarized hard X-rays (hν = 6 keV) for a number of core levels, including Si, Ge, Mo and W, prove that core-level CDAD is a general phenomenon that is independent of atomic number. The fine structure in CDAD is more pronounced compared to the corresponding intensity patterns. Additionally, they obey the same symmetry rules as found for atomic and molecular species, and valence bands. The CD is antisymmetric with respect to the mirror planes of the crystal, whose signatures are sharp zero lines. Calculations using both the Bloch-wave approach and one-step photoemission reveal the origin of the fine structure that represents the signature of Kikuchi diffraction. To disentangle the roles of photoexcitation and diffraction, XPD has been implemented into the Munich SPRKKR package to unify the one-step model of photoemission and multiple scattering theory.

9.
J Chem Phys ; 158(20)2023 May 28.
Article in English | MEDLINE | ID: mdl-37232440

ABSTRACT

Water is vital for life, and without it, biomolecules and cells cannot maintain their structures and functions. The remarkable properties of water originate from its ability to form hydrogen-bonding networks and dynamics, which the connectivity constantly alters because of the orientation rotation of individual water molecules. Experimental investigation of the dynamics of water, however, has proven challenging due to the strong absorption of water at terahertz frequencies. In response, by employing a high-precision terahertz spectrometer, we have measured and characterized the terahertz dielectric response of water from supercooled liquid to near the boiling point to explore the motions. The response reveals dynamic relaxation processes corresponding to the collective orientation, single-molecule rotation, and structural rearrangements resulting from breaking and reforming hydrogen bonds in water. We have observed the direct relationship between the macroscopic and microscopic relaxation dynamics of water, and the results have provided evidence of two liquid forms in water with different transition temperatures and thermal activation energies. The results reported here thus provide an unprecedented opportunity to directly test microscopic computational models of water dynamics.

10.
Materials (Basel) ; 16(6)2023 Mar 13.
Article in English | MEDLINE | ID: mdl-36984190

ABSTRACT

The relationship between the tendencies towards rigidity (measured by shear modulus, G) and hardness (measured by Vickers hardness, HV) of early transition metal (ETM)-based refractory high-entropy alloys (RHEA) and bond parameters (i.e., valence electron concentration (VEC), enthalpy of mixing (ΔHmix)) was investigated. These bond parameters, VEC and ΔHmix, are available from composition and tabulated data, respectively. Based on our own data (9 samples) and those available from the literatures (47 + 27 samples), it seems that for ETM-based RHEAs the G and HV characteristics have a close correlation with the bonding parameters. The room temperature value of G and HV increases with the VEC and with the negative value of ΔHmix. Corresponding equations were deduced for the first time through multiple linear regression analysis, in order to help design the mechanical properties of ETM refractory high-entropy alloys.

11.
Sci Rep ; 12(1): 21355, 2022 12 09.
Article in English | MEDLINE | ID: mdl-36494427

ABSTRACT

We compared seven node vaccination strategies in twelve real-world complex networks. The node vaccination strategies are modeled as node removal on networks. We performed node vaccination strategies both removing nodes according to the initial network structure, i.e., non-adaptive approach, and performing partial node rank recalculation after node removal, i.e., semi-adaptive approach. To quantify the efficacy of each vaccination strategy, we used three epidemic spread indicators: the size of the largest connected component, the total number of infected at the end of the epidemic, and the maximum number of simultaneously infected individuals. We show that the best vaccination strategies in the non-adaptive and semi-adaptive approaches are different and that the best strategy also depends on the number of available vaccines. Furthermore, a partial recalculation of the node centrality increases the efficacy of the vaccination strategies by up to 80%.


Subject(s)
Epidemics , Humans , Epidemics/prevention & control , Vaccination
12.
SAR QSAR Environ Res ; 33(10): 753-778, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36318662

ABSTRACT

Since interleukin-8 (IL-8/CXCL8) and its receptor, CXCR1 and CXCR2, were known in the early 1990s, biological pathways related to these proteins were proven to have high clinical value in cancer and inflammatory/autoimmune conditions treatment. Recently, IL-8 has been identified as biomarker for severe COVID-19 patients and COVID-19 prognosis. Boyles et al. (mAbs 12 (2020), pp. 1831880) have published a high-resolution X-ray crystal structure of the LY3041658 Fab in a complex human CXCL8. They described the ability to bind to IL-8 and the blocking of IL-8/its receptors interaction by the LY3041658 monoclonal antibody. Therefore, the study has been designed to identify potential small molecules inhibiting interleukin-8 by targeting LY3041658/IL-8 complex structure using an in silico approach. A structure­based pharmacophore and molecular docking models of the protein active site cavity were generated to identify possible candidates, followed by virtual screening with the ZINC database. ADME analysis of hit compounds was also conducted. Molecular dynamics simulations were then performed to survey the behaviour and stability of the ligand-protein complexes. Furthermore, the MM/PBSA technique has been utilized to evaluate the free binding energy. The final data confirmed that one newly obtained compound, ZINC21882765, may serve as the best potential inhibitor for IL-8.


Subject(s)
COVID-19 Drug Treatment , Interleukin-8 , Humans , Molecular Docking Simulation , Quantitative Structure-Activity Relationship , Molecular Dynamics Simulation , Ligands
13.
Dalton Trans ; 51(37): 14338-14344, 2022 Sep 26.
Article in English | MEDLINE | ID: mdl-36069507

ABSTRACT

Motivated by the successful synthesis of two-dimensional MoSi2N4 [Y.-L. Hong et al., Science, 2020, 369, 670-674] and Janus MoSSe [A.-Y. Lu et al., Nat. Nanotechnol., 2017, 12, 744-749], in this work, we propose novel 2D Janus XMoGeN2 (X = S, Se and Te) monolayers using first-principles prediction. The controllable electronic features of Janus XMoGeN2 (X = S, Se and Te) monolayers under an external electric field and strain are also examined. Our predictions demonstrated that 2D XMoGeN2 materials are structurally and dynamically stable. All these 2D XMoGeN2 materials are indirect semiconductors with band gaps of 1.60/2.10, 1.54/2.07 and 1.05/1.56 eV obtained by the PBE/HSE functional for SMoGeN2, SeMoGeN2 and TeMoGeN2 monolayers, respectively. Furthermore, the electronic band gap and band structures of these monolayers are controllable under an external electric field and strain, making them promising candidates for flexible optoelectronics and nanoelectronics. The electric field tunes the TeMoGeN2 monolayer from semiconductor to metal and leads to a change in the band gap. While strain modifies the band gap of the TeMoGeN2 monolayer, giving rise to a shift in the CB from the Γ-M path to the M point and a tendency to transform from semiconductor to metal. Our findings suggest that these novel 2D XMoGeN2 materials are potential candidates for use in future high-performance applications.

14.
J Chem Phys ; 157(5): 054501, 2022 Aug 07.
Article in English | MEDLINE | ID: mdl-35933214

ABSTRACT

Dynamic fluctuations in the hydrogen-bond network of water occur from femto- to nanosecond timescales and provide insight into the structural/dynamical aspects of water at ion-water interfaces. Employing terahertz spectroscopy assisted with molecular dynamics simulations, we study aqueous chloride solutions of five monovalent cations, namely, Li, Na, K, Rb, and Cs. We show that ions modify the behavior of the surrounding water molecules and form interfacial layers of water around them with physical properties distinct from those of bulk water. Small cations with high charge densities influence the kinetics of water well beyond the first solvation shell. At terahertz frequencies, we observe an emergence of fast relaxation processes of water with their magnitude following the ionic order Cs > Rb > K > Na > Li, revealing an enhanced population density of weakly coordinated water at the ion-water interface. The results shed light on the structure breaking tendency of monovalent cations and provide insight into the properties of ionic solutions at the molecular level.


Subject(s)
Terahertz Spectroscopy , Water , Cations, Monovalent , Hydrogen Bonding , Lithium/chemistry , Sodium/chemistry , Water/chemistry
15.
Front Immunol ; 13: 911873, 2022.
Article in English | MEDLINE | ID: mdl-35967449

ABSTRACT

The ability to study cancer-immune cell communication across the whole tumor section without tissue dissociation is needed, especially for cancer immunotherapy development, which requires understanding of molecular mechanisms and discovery of more druggable targets. In this work, we assembled and evaluated an integrated experimental framework and analytical process to enable genome-wide scale discovery of ligand-receptors potentially used for cellular crosstalks, followed by targeted validation. We assessed the complementarity of four different technologies: single-cell RNA sequencing and Spatial transcriptomic (measuring over >20,000 genes), RNA In Situ Hybridization (RNAscope, measuring 4-12 genes) and Opal Polaris multiplex protein staining (4-9 proteins). To utilize the multimodal data, we implemented existing methods and also developed STRISH (Spatial TRanscriptomic In Situ Hybridization), a computational method that can automatically scan across the whole tissue section for local expression of gene (e.g. RNAscope data) and/or protein markers (e.g. Polaris data) to recapitulate an interaction landscape across the whole tissue. We evaluated the approach to discover and validate cell-cell interaction in situ through in-depth analysis of two types of cancer, basal cell carcinoma and squamous cell carcinoma, which account for over 70% of cancer cases. We showed that inference of cell-cell interactions using scRNA-seq data can misdetect or detect false positive interactions. Spatial transcriptomics still suffers from misdetecting lowly expressed ligand-receptor interactions, but reduces false discovery. RNAscope and Polaris are sensitive methods for defining the location of potential ligand receptor interactions, and the STRISH program can determine the probability that local gene co-expression reflects true cell-cell interaction. We expect that the approach described here will be widely applied to discover and validate ligand receptor interaction in different types of solid cancer tumors.


Subject(s)
Single-Cell Analysis , Transcriptome , Ligands , RNA , Sequence Analysis, RNA/methods , Single-Cell Analysis/methods
16.
ACS Omega ; 7(25): 22020-22031, 2022 Jun 28.
Article in English | MEDLINE | ID: mdl-35785325

ABSTRACT

Protein dynamics is strongly influenced by the surrounding environment and physiological conditions. Here we employ broadband megahertz-to-terahertz spectroscopy to explore the dynamics of water and myoglobin protein on an extended time scale from femto- to nanosecond. The dielectric spectra reveal several relaxations corresponding to the orientational polarization mechanism, including the dynamics of loosely bound, tightly bound, and bulk water, as well as collective vibrational modes of protein in an aqueous environment. The dynamics of loosely bound and bulk water follow non-Arrhenius behavior; however, the dynamics of water molecules in the tightly bound layer obeys the Arrhenius-type relation. Combining molecular simulations and effective-medium approximation, we have determined the number of water molecules in the tightly bound hydration layer and studied the dynamics of protein as a function of temperature. The results provide the important impact of water on the biochemical functions of proteins.

17.
RSC Adv ; 12(30): 19115-19121, 2022 Jun 29.
Article in English | MEDLINE | ID: mdl-35865616

ABSTRACT

In this work, we systematically examine the electronic features and contact types of van der Waals heterostructures (vdWHs) combining single-layer boron phosphide (BP) and Janus Ga2SSe using first-principles calculations. Owing to the out-of-plane symmetry being broken, the BP/Ga2SSe vdWHs are divided into two different stacking patterns, which are BP/SGa2Se and BP/SeGa2S. Our results demonstrate that these stacking patterns are structurally and mechanically stable. The combination of single-layer BP and Janus Ga2SSe gives rise to an enhancement in the Young's modulus compared to the constituent monolayers. Furthermore, at the ground state, the BP/Ga2SSe vdWHs possess a type-I (straddling) band alignment, which is desired for next-generation optoelectronic applications. The interlayer separation and electric field are effectively used to tune the electronic features of the BP/Ga2SSe vdWH from the type-I to type-II band alignment, and from semiconductor to metal. Our findings show that the BP/Ga2SSe vdWH would be appropriate for next-generation multifunctional optoelectronic and photovoltaic devices.

18.
Eur Rev Med Pharmacol Sci ; 26(8): 2960-2969, 2022 04.
Article in English | MEDLINE | ID: mdl-35503640

ABSTRACT

OBJECTIVE: This report aimed to characterize clinical and imaging characteristics and outcomes of the patients with lower cervical spine injury combined with spinal cord paralysis who underwent posterior cervical spine surgery. PATIENTS AND METHODS: Between January 2019 and December 2020, a retrospective evaluation of prospectively collected data at one institution was conducted. We included all patients who were diagnosed with subaxial cervical spine injuries (C3-7), had spinal cord paralysis, and underwent posterior cervical spine surgery. Clinical profile, preoperative characteristics, intraoperative data, and postoperative outcomes were retrieved from prospective patients' medical records and computerized database. RESULTS: Among 70 selected patients, most were male (66, 94.29%) and the average age was 48.41 ± 14.33 years. Most of them worked in agriculture (90.4%). Clinical symptoms included neck pain (58, 82.86%), cervical radiculopathy (50, 71.43%), loss of sensation (44, 62.86%), and decreased sensation (21, 30.00%). The most frequent cervical spinal injuries involved C5 (28.57%), followed by C7 (14.29%). Circular muscle dysfunction was present in 65 (92.86%) patients. Early complications included respiratory failure (12.85%), pneumonia (11.42%), bedsores (8.57%), and urinary tract infection (7.14%). Common late complications included movement disorder (48.21%), muscle weakness and stiffness (37.50%), sensory disturbances (32.14%), urinary tract infection (17.86%), bedsores (16.07%), and pneumonia (5.36%). Patients after surgery and at follow-up had a significant improvement compared to preoperative assessment according to the AIS classification, and recovery of smooth muscle. Three patients died within 1 month following surgery, 3 within 1-3 month(s), 2 within 3-6 months, and 1 case beyond 6 months. CONCLUSIONS: In hospital-based clinical condition with limited practice approach, our study indicated specific clinical and imaging characteristics of Vietnamese patients with lower cervical spine injury combined with spinal cord paralysis. With high postoperative mortality rate, commonly late complications after posterior cervical spine surgical approach were pain and difficulty in neck movement, muscle weakness and stiffness, and nerve root pain.


Subject(s)
Pressure Ulcer , Spinal Diseases , Spinal Injuries , Adult , Cervical Vertebrae/diagnostic imaging , Cervical Vertebrae/surgery , Female , Humans , Male , Middle Aged , Muscle Weakness , Pain , Paralysis , Postoperative Complications , Prospective Studies , Retrospective Studies , Spinal Cord , Treatment Outcome
19.
J Hosp Infect ; 125: 60-66, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35460799

ABSTRACT

BACKGROUND: Enterobacter kobei is an emerging cause of outbreak of nosocomial infections in neonatal intensive care units (NICUs). Between July and September 2016, a NICU in a tertiary care hospital of Nepal observed an abrupt increase in the number of neonatal sepsis cases caused by Enterobacter spp. infecting 11 out of 23 admitted neonates, five of whom died of an exacerbated sepsis. AIM: To confirm the suspected outbreak, identify environmental source of infection, and characterize genetic determinants of antimicrobial resistance (AMR) and virulence of the pathogen. METHODS: Whole-genome sequencing of all Enterobacter spp. isolated from blood cultures of septic neonates admitted to NICU between May 2016 and December 2017 was performed. Also, an environmental sampling was intensified from fortnightly to weekly during the outbreak. FINDINGS: The genomic analysis revealed that 10 out of 11 non-duplicated E. kobei isolated from neonatal blood cultures between July and September 2016 were clonal, confirming the outbreak. The isolates carried AMR genes including blaAmpC and mcr-10 conferring reduced susceptibility to carbapenem and colistin respectively. The environmental sampling, however, failed to isolate any Enterobacter spp. Reinforcement of aseptic protocols in invasive procedures, hand hygiene, environmental decontamination, fumigation, and secluded care of culture-positive cases successfully terminated the outbreak. CONCLUSION: Our study underscored the need to implement stringent infection control measures to prevent infection outbreaks. For the first time, we report the emergence of carbapenem and colistin non-susceptible E. kobei carrying mcr-10 gene as a cause of nosocomial neonatal sepsis in a NICU.


Subject(s)
Cross Infection , Enterobacteriaceae Infections , Neonatal Sepsis , Carbapenems , Colistin , Cross Infection/epidemiology , Disease Outbreaks/prevention & control , Enterobacter , Enterobacteriaceae Infections/epidemiology , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Microbial Sensitivity Tests , Neonatal Sepsis/epidemiology , Nepal/epidemiology , Tertiary Care Centers
20.
Biophys J ; 121(4): 540-551, 2022 02 15.
Article in English | MEDLINE | ID: mdl-35074392

ABSTRACT

Proteins and water couple dynamically over a wide range of time scales. Motivated by their central role in protein function, protein-water dynamics and thermodynamics have been extensively studied for structured proteins, where correspondence to structural features has been made. However, properties controlling intrinsically disordered protein (IDP)-water dynamics are not yet known. We report results of megahertz-to-terahertz dielectric spectroscopy and molecular dynamics simulations of a group of IDPs with varying charge content along with structured proteins of similar size. Hydration water around IDPs is found to exhibit more heterogeneous rotational and translational dynamics compared with water around structured proteins of similar size, yielding on average more restricted dynamics around individual residues of IDPs, charged or neutral, compared with structured proteins. The on-average slower water dynamics is found to arise from excess tightly bound water in the first hydration layer, which is related to greater exposure to charged groups. The more tightly bound water to IDPs correlates with the smaller hydration shell found experimentally, and affects entropy associated with protein-water interactions, the contribution of which we estimate based on the dielectric measurements and simulations. Water-IDP dynamic coupling at terahertz frequencies is characterized by the dielectric measurements and simulations.


Subject(s)
Intrinsically Disordered Proteins , Intrinsically Disordered Proteins/chemistry , Molecular Dynamics Simulation , Protein Conformation , Thermodynamics , Water/chemistry
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