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1.
Nano Lett ; 24(1): 16-25, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38109350

RESUMO

The anomalous Hall effect (AHE) is an important transport signature revealing topological properties of magnetic materials and their spin textures. Recently, MnBi2Te4 has been demonstrated to be an intrinsic magnetic topological insulator. However, the origin of its intriguing AHE behaviors remains elusive. Here, we demonstrate the Berry curvature-dominated intrinsic AHE in wafer-scale MnBi2Te4 films. By applying back-gate voltages, we observe an ambipolar conduction and n-p transition in ∼7-layer MnBi2Te4, where a quadratic relation between the AHE resistance and longitudinal resistance suggests its intrinsic AHE nature. In particular, for ∼3-layer MnBi2Te4, the AHE sign can be tuned from pristine negative to positive. First-principles calculations unveil that such an AHE reversal originated from the competing Berry curvature between oppositely polarized spin-minority-dominated surface states and spin-majority-dominated inner bands. Our results shed light on the underlying physical mechanism of the intrinsic AHE and provide new perspectives for the unconventional sign-tunable AHE.

2.
Birth ; 51(1): 3-12, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37766494

RESUMO

AIMS: This study aims to comprehensively explore the decision-making requirements of women contemplating vaginal birth after cesarean (VBAC). DESIGN & METHODS: A meta-synthesis approach was employed for this study. Using an integrative methodology, we conducted a systematic assessment of women's experiences and needs related to VBAC decision-making. A comprehensive search was conducted across The Cochrane Library, PubMed, EMBASE, Ovid Medline, SCOPUS, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, and Wan Fang databases to identify pertinent studies between 2000 and 2022. Furthermore, the reference lists of the included studies were thoroughly examined. RESULTS: Fifteen studies were incorporated, from which seven themes emerged: emotional changes, preference for vaginal birth, unmet information needs, influences on decision-making, decision-making autonomy, aligning information provision with decision-support needs, and the requirement for support systems. Two primary syntheses were constructed on the decision-making process and the need for decision-making aids, respectively. CONCLUSION: Women opting for VBAC experienced emotional shifts during their decision-making process in pregnancy. There remains a need for an enhanced decision-making tool to guide them in their choice. Recommendations for implementation in VBAC decision aids include facilitating women's involvement in decision-making, satisfying their information needs, and delivering appropriate emotional support.


Assuntos
Nascimento Vaginal Após Cesárea , Gravidez , Feminino , Humanos , Nascimento Vaginal Após Cesárea/psicologia , Tomada de Decisões , Técnicas de Apoio para a Decisão
3.
Small ; 19(43): e2302878, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37376847

RESUMO

Electrochemical reduction of CO2 (CO2 RR) into value-added products is a promising strategy to reduce energy consumption and solve environmental issues. Formic acid/formate is one of the high-value, easy-to-collect, and economically viable products. Herein, the reconstructed Bi2 O2 CO3 nanosheets (BOCR NSs) are synthesized by an in situ electrochemical anion exchange strategy from Bi2 O2 SO4 as a pre-catalyst. The BOCR NSs achieve a high formate Faradaic efficiency (FEformate ) of 95.7% at -1.1 V versus reversible hydrogen electrode (vs. RHE), and maintain FEformate above 90% in a wide potential range from -0.8 to -1.5 V in H-cell. The in situ spectroscopic studies reveal that the obtained BOCR NSs undergo the anion exchange from Bi2 O2 SO4 to Bi2 O2 CO3 and further promote the self-reduction to metallic Bi to construct Bi/BiO active site to facilitate the formation of OCHO* intermediate. This result demonstrates anion exchange strategy can be used to rational design high performance of the catalysts toward CO2 RR.

4.
Aesthetic Plast Surg ; 47(2): 825-832, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36075983

RESUMO

BACKGROUND: Fat transplantation supported by supplementation with ASCs has become a reliable procedure for treating soft tissue defects. However, the unpredictable survival rates for grafted fat remains a challenge with post-transplantation ischemia causing tissue loss. MiR126, which regulates VEGF signaling, is an endothelial cell-specific miRNA known to play an essential role in angiogenesis. We hypothesized that increased miR126 expression in grafted ASCs may promote fat survival within an autologous fat transfer model. METHODS: Rat adipose-derived stem cells were isolated, expanded ex vivo for three passages and then transduced with miR126. We used PCR to verify lentiviral transduction and ELISA to confirm VEGF expression. We then mixed autologous fat tissues from our rat model with transduced ASCs, augmented with a nonsense control or miR126 expression vector. These mixtures were used in the fat grafting procedure, completed via subcutaneous injection at three paravertebral points in each rat. Fat grafts were then harvested on days 4, 7, 14, and 28 post-transplant and evaluated for survival, neovascularization, and protein expression via western blot. RESULTS: VEGF expression levels in ASCs, Con-ASCs, and miR126-ASCs were not significantly different. However, miR126-ASCs experienced significantly improved survival on days 7, 14, and 28 when compared with the other groups. These ASCs also presented with the greatest capillary density on days 7, 14, and 28 post-transplantation as well as increased p-ERK and p-AKT expression when compared to the other groups. CONCLUSION: This data suggests that miR126 augmentation of ASCs may help to enhance the survival and angiogenic capacity of transplanted fat tissues, and that this augmentation was not dependent on VEGF but rather the activation of the ERK/AKT pathway. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .


Assuntos
Sobrevivência de Enxerto , MicroRNAs , Ratos , Animais , Fator A de Crescimento do Endotélio Vascular/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Tecido Adiposo/transplante , Células-Tronco , MicroRNAs/genética
5.
Aesthetic Plast Surg ; 47(2): 654-665, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36203097

RESUMO

BACKGROUND: The number of publications on blepharoplasty is increasing rapidly. Bibliometric analysis can help surgeons quickly and systematically understand the current state of development. To our knowledge, there are no bibliometric studies on blepharoplasty, and therefore, we conducted this study to reveal research trends and perspectives of blepharoplasty. METHODS: Relevant publications from 2002 to 2021 were extracted from the Web of Science Core Collection database. After manual screening, VOSviewer software and CiteSpace software were used to collect and analyze the acquired data. RESULTS: A total of 1125 publications were included and the publications per year increased annually. Contributions from the USA led both quantity and quality. The University of California System was one of the most influential academic institutions. Aesthetic Plastic Surgery had the most publications, and Plastic and Reconstructive Surgery was the most frequently cited or co-cited journal. Massry GG and Hamra ST were the most prolific and co-cited authors, respectively. Additionally, Rohrich RJ had the highest number of citations per publication. References co-cited analysis identified that lower eyelid research was a hotspot. Keywords were mainly divided into 6 clusters, namely "lower lid blepharoplasty," "complications," "facial rejuvenation," "blepharoptosis," "upper blepharoplasty," and "Asian blepharoplasty and epicanthoplasty." CONCLUSIONS: Blepharoplasty research is flourishing, and three clusters may be the hotspots: "Lower blepharoplasty and mid-face rejuvenation," "overall facial outcome and quality-of-life," and "Asian blepharoplasty and epicanthoplasty." LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .


Assuntos
Blefaroplastia , Humanos , Resultado do Tratamento , Estudos Retrospectivos , Povo Asiático , Pálpebras/cirurgia , Bibliometria
6.
Inorg Chem ; 60(9): 6167-6175, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33331784

RESUMO

We investigate giant magnetoelectric coupling at a Mn3+ spin crossover in [MnIIIL]BPh4 (L = (3,5-diBr-sal)2323) with a field-induced permanent switching of the structural, electric, and magnetic properties. An applied magnetic field induces a first-order phase transition from a high spin/low spin (HS-LS) ordered phase to a HS-only phase at 87.5 K that remains after the field is removed. We observe this unusual effect for DC magnetic fields as low as 8.7 T. The spin-state switching driven by the magnetic field in the bistable molecular material is accompanied by a change in electric polarization amplitude and direction due to a symmetry-breaking phase transition between polar space groups. The magnetoelectric coupling occurs due to a γη2 coupling between the order parameter γ related to the spin-state bistability and the symmetry-breaking order parameter η responsible for the change of symmetry between polar structural phases. We also observe conductivity occurring during the spin crossover and evaluate the possibility that it results from conducting phase boundaries. We perform ab initio calculations to understand the origin of the electric polarization change as well as the conductivity during the spin crossover. Thus, we demonstrate a giant magnetoelectric effect with a field-induced electric polarization change that is 1/10 of the record for any material.

7.
BMC Infect Dis ; 21(1): 1137, 2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34742247

RESUMO

BACKGROUND: Liposuction is one of the most commonly performed aesthetic procedures. Toxic shock syndrome(TSS) is a rare, life-threatening complication. The incidence rate of TSS is very low in the plastic surgery field, especially after liposuction and fat transfer. CASE PRESENTATION: A 23-year-old female patient was transferred to our emergency department from an aesthetic clinic with sepsis shock features after received liposuction and fat transfer. The patient underwent TSS, disseminated intravascular coagulation(DIC), multiple organ dysfunction syndrome (MODS), symmetrical peripheral gangrene (SPG), and necrotizing soft tissue infection of the buttocks in the next 10 days. Authors used a series of debridement and reconstructive surgery including vacuum sealing drainage (VSD) treatment, artificial dermis grafts,split-thickness skin grafts, amputation surgeries when her vital signs were stable. The patient experienced desquamation of the hand on the 26th day. The skin grafts survived and the function of both fingers and toes recovered. She was discharged 2 months after admission and was in good health. CONCLUSION: TSS is extremely rare in the field of liposuction and autologous fat transfer. The mortality rate of TSS is very high. Early diagnosis and operative treatment, as well as correction of systemic abnormalities, are the important keys to save a patient's life.


Assuntos
Coagulação Intravascular Disseminada , Lipectomia , Choque Séptico , Adulto , Feminino , Gangrena/etiologia , Mãos , Humanos , Lipectomia/efeitos adversos , Choque Séptico/etiologia , Adulto Jovem
8.
J Cell Physiol ; 235(3): 2171-2182, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31468534

RESUMO

Curcumin (CUR) shows a remarkable antitumor activity against a wide range of cancers such as glioma, but its underlying mechanism remains elusive. In this study, we aimed to explore the potential role of H19/miR-675/vitamin D receptor (VDR) in the effect of CUR against glioma. Real-time polymerase chain reaction and western-blot analysis were used to study the effect of CUR or 1,25-dihydroxyvitamin D (1,25(OH)2 D3 ) on the expression of H19, miR-675, and VDR. In addition, the effect of H19 on VDR expression was also studied. Furthermore, the expression of H19, miR-675, and VDR between CUR-loaded nanoparticles (NPs) and NP groups was compared, and the interaction among H19, miR-675, and VDR was analyzed by in-silicon and luciferase assays. In a dose-dependent manner, CUR and 1,25(OH)2 D3 both downregulated the expression of H19 and miR-675 but increased the expression of VDR. In addition, H19 evidently reduced the mRNA and protein levels of VDR. Furthermore, VDR was confirmed as a target gene of miR-675, which significantly reduced the expression of VDR. Finally, the administration of CUR evidently decreased tumor volume. CUR-loaded NP group exhibited lower levels of H19 and miR-675, while the NP group showed higher levels of VDR mRNA and protein. In summary, it is the first time that the involvement of a negative feedback loop of H19/miR-675/VDR has been demonstrated in the development of glioma. Therefore, H19 might serve as a new biomarker for the diagnosis and treatment of glioma.


Assuntos
Curcumina/farmacologia , Glioma/tratamento farmacológico , Glioma/genética , MicroRNAs/genética , RNA Longo não Codificante/genética , Receptores de Calcitriol/genética , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Retroalimentação , Feminino , Humanos , RNA Mensageiro/genética , Ratos , Ratos Wistar
9.
Phys Rev Lett ; 124(22): 227201, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32567894

RESUMO

Three high-spin phases recently discovered in the spin-crossover system Mn(taa) are identified through analysis by a combination of first-principles calculations and Monte Carlo simulation as a low-temperature Jahn-Teller ordered (solid) phase, an intermediate-temperature dynamically correlated (liquid) phase, and an uncorrelated (gas) phase. In particular, the Jahn-Teller liquid phase arises from competition between mixing with low-spin impurities, which drive the disorder, and intermolecular strain interactions. The latter are a key factor in both the spin-crossover phase transition and the magnetoelectric coupling. Jahn-Teller liquids may exist in other spin-crossover materials and materials that have multiple equivalent Jahn-Teller axes.

10.
Phys Rev Lett ; 122(10): 106602, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30932676

RESUMO

We show that the spin-orbit coupling (SOC) in α-MnTe impacts the transport behavior by generating an anisotropic valence-band splitting, resulting in four spin-polarized pockets near Γ. A minimal k·p model is constructed to capture this splitting by group theory analysis, a tight-binding model, and ab initio calculations. The model is shown to describe the rotation symmetry of the zero-field planer Hall effect (PHE). The PHE originates from the band anisotropy given by SOC, and is quantitatively estimated to be 25%-31% for an ideal thin film with a single antiferromagnetic domain.

11.
Appl Opt ; 57(33): 9789-9796, 2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30462011

RESUMO

A dual concave grating imaging spectrometer with anastigmatic imaging has been presented for remote sensing. The optimal arrangements of the gratings and the addition of a cylindrical lens have been determined based on different aberrations and the major corresponding parameter analysis. The advanced Wadsworth mounting can eliminate coma and astigmatism and realize high spectral resolution with low ruling density gratings. The design presents excellent optical performance: the spectral resolution is 0.6 nm, and spatial resolution is 1 mrad/pixel over the waveband of 400 nm centered at 600 nm with NA 0.1. The manufacture and testing of the prototype prove the principle of design and the engineering practicality.

12.
Mol Med ; 21: 134-42, 2015 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-25587856

RESUMO

The host tolerance mechanisms to avian influenza virus (H5N1) infection that limit tissue injury remain unknown. Emerging evidence indicates that cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-dependent Cl(-) channel, modulates airway inflammation. Janus tyrosine kinase (JAK) 3, a JAK family member that plays a central role in inflammatory responses, prominently contributes to the dysregulated innate immune response upon H5N1 attachment; therefore, this study aims to elucidate whether JAK3 activation induced by H5N1 hemagglutinin (HA) inhibits cAMP-dependent CFTR channels. We performed short-circuit current, immunohistochemistry and molecular analyses of the airway epithelium in Jak3(+/+) and Jak3(+/-) mice. We demonstrate that H5N1 HA attachment inhibits cAMP-dependent CFTR Cl(-) channels via JAK3-mediated adenylyl cyclase (AC) suppression, which reduces cAMP production. This inhibition leads to increased nuclear factor-kappa B (NF-κB) signaling and inflammatory responses. H5N1 HA is detected by TLR4 expressed on respiratory epithelial cells, facilitating JAK3 activation. This activation induces the interaction between TLR4 and Gαi protein, which blocks ACs. Our findings provide novel insight into the pathogenesis of acute lung injury via the inhibition of cAMP-dependent CFTR channels, indicating that the administration of cAMP-elevating agents and targeting JAK3 may activate host tolerance to infection for the management of influenza virus-induced fatal pneumonia.


Assuntos
AMP Cíclico/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Virus da Influenza A Subtipo H5N1/fisiologia , Janus Quinase 3/metabolismo , Pneumonia Viral/metabolismo , Pneumonia Viral/virologia , Receptor 4 Toll-Like/metabolismo , Animais , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Modelos Animais de Doenças , Ativação Enzimática , Expressão Gênica , Humanos , Influenza Humana/metabolismo , Influenza Humana/virologia , Janus Quinase 3/genética , Camundongos , Camundongos Knockout , NF-kappa B/metabolismo , Pneumonia Viral/patologia , Ligação Proteica , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , Mucosa Respiratória/virologia , Transdução de Sinais
13.
Heliyon ; 10(4): e25351, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38379982

RESUMO

Taraxacum kok-saghyz (TKS) latex is a natural latex produced from its root, and its extraction optimization process is mainly studied in the present paper. The composition of fresh roots of TKS was quantitatively analyzed, and the results showed that the moisture content of the fresh root was approximately 70 %, and the rubber content averaged to 6 % (dry weight ratio). An optimal process route for extracting the TKS latex was finally determined, making the extraction efficiency reach about 80 %, and a new latex extraction process was established and optimized and named "the process of Buffer Extraction TKS Latex (BETL)". Hevea latex, extracted TKS latex and TKS latex collected directly from the broken roots were compared for study. The results showed that, like Hevea latex, the appearance of TKS latex was milky white; and after centrifugation, both showed four layers from top to bottom: rubber particles, Frey-Wyssling particles, C-serum and lutoids. The results of the composition analysis showed that the concentration of TKS latex ranged from 54.54 % to 68.25 %, which is close to that of concentrated Hevea latex; the moisture content of TKS latex was between 31.75 % and 45.46 %. The protein content of TKS latex was 13.51 mg/mL, which was lower than that of Hevea latex at the same rubber hydrocarbon concentration. The molecular structures and properties of Hevea latex, the extracted TKS latex, and the collected TKS latex were characterized by FTIR, 13C NMR, GPC, TG, SEM and LPSA, and the results showed that the main components and structure of the three latexes were similar, which are all cis-1,4-polyisoprene, and include the proteins and lipids. The distributions molecular weights of the three latexes all showed a bimodal distribution, but the molecular weight of the latex collected from TKS was lower, which indicates the larger molecules were difficult to flow outside the root automatically. The Hevea latex and TKS latex rubber particles were both core-shell structure and the size distribution were bimodal, which was consistent with the GPC analysis results.

14.
J Tradit Chin Med ; 43(1): 175-180, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36640010

RESUMO

We want to explore the analgesic brain effect of the moxibustion at heat-sensitized Yaoyangguan (GV3) in patients with lumbar disc herniation (LDH) and myofascial pain syndrome (MPS). In an assessor-blinded observational study, we will include 15 LDH and 15 MPS. They will accept same treatment of heat-sensitive moxibustion at Yaoyangguan (GV3). The resting-state functionality magnetic resonance imaging image data of brain activities before and after treatment will be analyzed by mean fractional amplitude of low-frequency fluctuation, regional homogeneity analysis and brain functional connection. We select seed of first sensory cortex, second sensory cortex, insula cortex, periaqueductal gray and anterior cingulate cortex as the regions of interest to analyse the relationship between brain functional connectivity of pain-related networks and clinical data. Our study could disclose key brain targets and central response characteristics of the analgesic brain effect and the brain functional connection of heat-sensitive moxibustion.


Assuntos
Deslocamento do Disco Intervertebral , Moxibustão , Síndromes da Dor Miofascial , Humanos , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Deslocamento do Disco Intervertebral/terapia , Temperatura Alta , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Analgésicos , Estudos Observacionais como Assunto
15.
Plast Reconstr Surg ; 152(2): 341-345, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-36728189

RESUMO

SUMMARY: Autologous fat injection is one of the most popular methods for the treatment of temporal depression; however, accurate puncture into the target layer without vascular compromise is hard to achieve. With the aid of high-frequency ultrasonography, the authors performed autologous fat transplantation after visualization in five cases, with satisfactory results. The authors observed the course of superficial temporal vessels, the orbitozygomatic artery, and sentinel veins preoperatively, and used high-frequency ultrasonography to guide lipotransfer into the desired layer intraoperatively, to avoid intravascular injection. With the aid of high-frequency ultrasonography, the authors can easily prevent vascular complications and personalize surgical procedures, as anatomical variations of vasculature can also be detected by means of this method.


Assuntos
Punções , Veias , Humanos , Ultrassonografia , Ultrassonografia de Intervenção
16.
ACS Omega ; 8(27): 24185-24197, 2023 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-37457490

RESUMO

Taraxacum kok-saghyz(TKS) rubber is considered the most ideal alternative source of natural rubber (NR). Extracting rubber from TKS with high quality, low cost, and low pollution is the basis of commercial development. The TKS roots were subjected to morphological observation and detailed compositional analysis. Scanning electron microscopy (SEM) images confirm that rubber filaments are physically entangled with plant tissues due to differences in molecular polarity. Compared with the traditional solvent TKS rubber extraction process, a new rubber extraction process developed in this study, namely, the microbial extraction (″ME″) process, is less harmful to the environment and lower in cost. The ″ME″ process is divided into three steps: dilute acid pretreatment process, enzyme degradation process, and fermentation process. After each step is completed, the purity of TKS rubber will gradually increase from 84.8% to 93.8 to 95.5%. The TKS rubber finally obtained fully meets the requirements of the traditional rubber industry, especially the tire industry. Besides, the yield of biofuel ethanol, a by-product of cellulose fermentation, reaches 2.05 g/100 g of TKS roots (dry weight), which can effectively reduce the production cost of TKS rubber. In the rubber extraction process, microorganisms have little effect on the quality of TKS rubber. The results show that the molecular weight and chemical structure of TKS rubber is very close to NR, so the ″ME″ process can be used as a new method for large-scale extraction of TKS rubber.

17.
Nat Commun ; 14(1): 219, 2023 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-36639704

RESUMO

Human-sensitive mechanosensation depends on ionic currents controlled by skin mechanoreceptors. Inspired by the sensory behavior of skin, we investigate zwitterionic hydrogels that generate ions under an applied force in a mobile-ion-free system. Within this system, water dissociates as the distance between zwitterions reduces under an applied pressure. Meanwhile, zwitterionic segments can provide migration channels for the generated ions, significantly facilitating ion transport. These combined effects endow a mobile-ion-free zwitterionic skin sensor with sensitive transduction of pressure into ionic currents, achieving a sensitivity up to five times that of nonionic hydrogels. The signal response time, which relies on the crosslinking degree of the zwitterionic hydrogel, was ~38 ms, comparable to that of natural skin. The skin sensor was incorporated into a universal throat-worn silent-speech recognition system that transforms the tiny signals of laryngeal mechanical vibrations into silent speech.


Assuntos
Hidrogéis , Fala , Humanos , Íons , Pele
18.
Front Bioeng Biotechnol ; 11: 1282512, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38260754

RESUMO

Screw loosening is a widely reported issue after spinal screw fixation and triggers several complications. Biomechanical deterioration initially causes screw loosening. Studies have shown that incomplete insertion of pedicle screws increases the risk of screw breakage by deteriorating the local mechanical environment. However, whether this change has a biomechanical effect on the risk of screw loosening has not been determined. This study conducted comprehensive biomechanical research using polyurethane foam mechanical tests and corresponding numerical simulations to verify this topic. Pedicle screw-fixed polyurethane foam models with screws with four different insertion depths were constructed, and the screw anchoring ability of different models was verified by toggle tests with alternating and constant loads. Moreover, the stress distribution of screw and bone-screw interfaces in different models was computed in corresponding numerical mechanical models. Mechanical tests presented better screw anchoring ability with deeper screw insertion, but parameters presented no significant difference between groups with complete thread insertion. Correspondingly, higher stress values can be recorded in the model without complete thread insertion; the difference in stress values between models with complete thread insertion was relatively slight. Therefore, incomplete thread insertion triggers local stress concentration and the corresponding risk of screw loosening; completely inserting threads could effectively alleviate local stress concentration and result in the prevention of screw loosening.

19.
Front Pharmacol ; 14: 1293130, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38044941

RESUMO

Cancer poses a substantial risk to human life and wellbeing as a result of its elevated incidence and fatality rates. Endoplasmic reticulum stress (ERS) is an important pathway that regulates cellular homeostasis. When ERS is under- or overexpressed, it activates the protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK)-, inositol-requiring enzyme 1 (IRE1)- and activating transcription Factor 6 (ATF6)-related apoptotic pathways to induce apoptosis. Tumor cells and microenvironment are susceptible to ERS, making the modulation of ERS a potential therapeutic approach for treating tumors. The use of natural products to treat tumors has substantially progressed, with various extracts demonstrating antitumor effects. Nevertheless, there are few reports on the effectiveness of natural products in inducing apoptosis by specifically targeting and regulating the ERS pathway. Further investigation and elaboration of its mechanism of action are still needed. This paper examines the antitumor mechanism of action by which natural products exert antitumor effects from the perspective of ERS regulation to provide a theoretical basis and new research directions for tumor therapy.

20.
Huan Jing Ke Xue ; 44(10): 5546-5555, 2023 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-37827771

RESUMO

The release of nitrogen and phosphorus from sediments into lake water will exacerbate the eutrophication of lakes and endanger ecological safety and human health. Microorganisms are indispensable in nitrogen and phosphorus conversion, and accurate analysis of the distribution characteristics and sources of nitrogen and phosphorus in sediments as well as their relationship with microorganisms is an important prerequisite for lake eutrophication control. Taking Taihu Lake as the study area, 30 surface sediment samples were collected, and the grain size, pH, organic matter (OM), dissolved organic carbon (DOC), total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3--N), and dissolved organic nitrogen (DON) along with some other index contents were measured and analyzed; accordingly, spatial distribution characteristics were analyzed. While using nutrient agar (NA), the number of aerobic bacteria (AB) was determined by plate counting in the medium. Combined with principal component analysis (PCA) and Pearson correlation analysis, the spatial distribution characteristics and sources of sediments and AB in Taihu Lake were explored. The characteristics of sediment pollution in Taihu Lake were studied using the comprehensive pollution index and the organic pollution index methods. The results revealed that the average sediment indicators of the surface layer of Taihu Lake were as follows:AB was 9.25×104 CFU·g-1, average particle size (MZ) was 17.59 µm, pH was 7.62, ω(OM) was 15.05 g·kg-1, ω(DOC) was 71.60 mg·kg-1, ω(TP) was 598.13 mg·kg-1, ω(TN) was 1113.92 mg·kg-1, ω(NO3--N) was 3.22 mg·kg-1, and ω(DON) was 22.60 mg·kg-1. The comprehensive pollution index (FF) showed that 13% of the Taihu Lake was moderately polluted, while 87% was heavily polluted. Excluding the area in the center of the lake, the southern lake area, and some lakes in the western part of the East Taihu Lake, TN in the rest of the area was moderately and severely polluted. In addition to the heavy pollution of Zhushan Bay, the TP in Taihu Lake was generally at light and moderate pollution. The organic pollution index (OI) showed that the organic pollution of the sediments of Taihu Lake was relatively light, majorly caused by organic nitrogen (ON) pollution. DOC, DON, TN, and OM in Taihu Lake were primarily derived from the influence of aquatic plants, and TP And AB were primarily derived from the influence of the external input of rivers. This research will provide theoretical support for lake eutrophication treatment and also provide new ideas for further analysis of AB to remove nitrogen and phosphorus pollution from sediments.


Assuntos
Bactérias Aeróbias , Poluentes Químicos da Água , Humanos , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Nitrogênio/análise , Fósforo/análise , Lagos/química , Eutrofização , Matéria Orgânica Dissolvida , China , Sedimentos Geológicos/química
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