Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 62
Filtrar
1.
Cureus ; 16(2): e55119, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38558642

RESUMO

The flu, often known as influenza, is a dangerous public health hazard for the pediatric population. Immunization is essential for decreasing the burden of the disease and avoiding complications related to influenza. However, the immunogenicity, efficacy, and safety of different influenza vaccines in children warrant careful evaluation. The purpose of this narrative review is to give a summary of the existing literature on the immunogenicity, efficacy, and safety of several vaccinations against influenza viruses in children. The review incorporates evidence from a range of studies focusing on the outcomes of interest. Immunogenicity studies have shown that influenza vaccines induce a robust immune response in children, primarily through neutralizing antibodies' formation. However, variations in vaccine composition influence the duration and magnitude of immune responses. Safety is a crucial consideration in pediatric vaccination. In children, influenza vaccinations have generally shown a high safety profile, with mild and temporary side effects being the most common. Vaccinations against influenza have shown a modest level of efficacy in avoiding hospitalizations linked to influenza, laboratory-confirmed influenza infections, and serious consequences in children. Live attenuated vaccines have shown higher effectiveness against matched strains compared to inactivated vaccines. In conclusion, this narrative review highlights that receiving influenza vaccination in children aged six to 47 months is very important. While different vaccines exhibit varying immunogenicity, safety profiles, and effectiveness, they all contribute to reducing the burden of influenza among children. Future research should focus on optimizing vaccine strategies, improving vaccine coverage, and evaluating long-term protection.

2.
Nucleic Acids Res ; 52(3): 1341-1358, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38113276

RESUMO

MTU1 controls intramitochondrial protein synthesis by catalyzing the 2-thiouridine modification of mitochondrial transfer RNAs (mt-tRNAs). Missense mutations in the MTU1 gene are associated with life-threatening reversible infantile hepatic failure. However, the molecular pathogenesis is not well understood. Here, we investigated 17 mutations associated with this disease, and our results showed that most disease-related mutations are partial loss-of-function mutations, with three mutations being particularly severe. Mutant MTU1 is rapidly degraded by mitochondrial caseinolytic peptidase (CLPP) through a direct interaction with its chaperone protein CLPX. Notably, knockdown of CLPP significantly increased mutant MTU1 protein expression and mt-tRNA 2-thiolation, suggesting that accelerated proteolysis of mutant MTU1 plays a role in disease pathogenesis. In addition, molecular dynamics simulations demonstrated that disease-associated mutations may lead to abnormal intermolecular interactions, thereby impairing MTU1 enzyme activity. Finally, clinical data analysis underscores a significant correlation between patient prognosis and residual 2-thiolation levels, which is partially consistent with the AlphaMissense predictions. These findings provide a comprehensive understanding of MTU1-related diseases, offering prospects for modification-based diagnostics and novel therapeutic strategies centered on targeting CLPP.


Assuntos
Mitocôndrias , Proteínas Mitocondriais , Peptídeo Hidrolases , tRNA Metiltransferases , Humanos , Endopeptidase Clp/genética , Endopeptidase Clp/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mutação , Peptídeo Hidrolases/genética , Proteólise , RNA Mitocondrial/metabolismo , RNA de Transferência/metabolismo , tRNA Metiltransferases/genética , Proteínas Mitocondriais/metabolismo
3.
Cells Tissues Organs ; 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37944499

RESUMO

It is apparent that whilst many reports are available regarding Platelet-Rich-Plasma (PRP), the larger majority of these have been mainly focused on autologous sources, and for good reason. Issues relating to allogenic source have been consciously avoided owing to concerns of cross infectivity and immune rejection. However, this topic today is now revisited and is of interest since progress over the year have demonstrated its safety, efficacy and its abundance of supply. The present systematic review was thus conducted to elucidate advances made in this area, with the aim to provide a wider and deeper understanding of studies relevant to the application of allogenic PRP in cartilage repair. Literature search was conducted systematically using Medline, ProQuest, Web of Science, Cochrane Central Register of Controlled Trials, and snowballing searching strategy to identify relevant studies using topic-specific keywords in various combinations including "allogenic, platelet, rich, plasma" OR "allogeneic, platelet, rich, plasma" OR "allogenic platelet-rich plasma" OR "allogeneic platelet-rich plasma" OR "allogenic platelet rich plasma" OR "allogeneic platelet rich plasma AND cartilage OR chondrocytes OR synoviocytes OR stem cells. Studies that used allogenic PRP in an attempt to facilitate cartilage repair were included. The risk of bias was assessed by the SYRCLE's checklist. Of 206 studies identified, 12 were found eligible. Only those studies that are clearly related and specific to allogenic PRP were included. Of these, nine investigated the efficacy of allogenic PRP in animal models, while three articles employed an in vitro model. Allogenic PRP promotes cell proliferation, cartilage matrix production and anti-inflammatory effects in vitro. The in vivo studies reported histological evidence of significant acceleration of cartilage repair in treated animals. Despite several conflicting findings, all studies agreed that allogenic PRP is safe and potentially efficacious for cartilage repair, with the advantages of allogenic sources apparent.

4.
Cureus ; 15(8): e44191, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37767255

RESUMO

Topical estrogen is effective for treating postmenopausal vaginal atrophy. However, there is a potential risk of estrogen-related adverse effects. There is a need for finding effective non-hormonal treatment for vaginal atrophy. The topical application of moisturising agents, such as hyaluronic acid (HA), represents a promising non-hormonal treatment for the relief of vaginal atrophy. This study aimed to summarize the evidence regarding the efficacy of topical HA compared to topical estrogen in postmenopausal women with vaginal atrophy. The literature search covered English-published studies from database inception till February 2023. The search included the electronic databases of MEDLINE/PubMed, Cochrane Library, Web of Science, ProQuest, and Scopus, using the terms "Hyaluronic Acid" AND "Postmenopause" AND "Vagina" AND "Atrophy". Due to the diversity in reporting outcomes, meta-analysis was not feasible. A narrative synthesis with a systematic approach was conducted by vote counting of studies that included a direct comparison between topical HA and topical estrogen. Six studies were included. Intra-group comparisons showed that both interventions were significantly effective in alleviating the symptoms of vaginal atrophy and dyspareunia as well as improving vaginal pH and cell maturation index. However, inter-group comparisons in most studies showed that estrogen was superior to HA in relieving vaginal symptoms and improving vaginal pH, dyspareunia, and the cell maturation index. There is no evidence to show the superiority of HA to estrogen in the treatment of postmenopausal vaginal atrophy. However, the therapeutic efficacy of HA seems to be comparable to estrogen and considering its safety, HA can be used as an alternative to estrogen in patients who do not want to use estrogen. The available studies have several limitations, and the reporting of outcomes was considerably heterogeneous.

5.
Joint Bone Spine ; 91(3): 105642, 2023 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-37739213

RESUMO

Osteoarthritis (OA) is the most prevalent chronic joint disease with an immense socioeconomic burden; however, no treatment has achieved complete success in effectively halting or reversing cartilage degradation, which is the central pathophysiological feature of OA. Chondrocytes loss or dysfunction is a significant contributing factor to the progressive cartilage deterioration as these sole resident cells have a crucial role to produce extracellular matrix proteins, thus maintaining cartilage structure and homeostasis. It has been previously suggested that death of chondrocytes occurring through apoptosis substantially contributes to cartilage degeneration. Although the occurrence of apoptosis in osteoarthritic cartilage and its correlation with cartilage degradation is evident, the causes of chondrocyte apoptosis leading to matrix loss are still not well-understood. Autophagy, an intracellular degradative mechanism that eliminates dysfunctional cytoplasmic components to aid cell survival in unfavourable conditions, is a potential therapeutic target to inhibit chondrocyte apoptosis and reduce OA severity. Despite accumulating evidence indicating significant cytoprotective effects of autophagy against chondrocyte apoptosis, the mechanistic link between autophagy and apoptosis in chondrocytes remains to be further explored. In this review, we summarize the relevant mechanistic events that perpetuate chondrocyte apoptosis and highlight the prominent role of autophagy in modulating these events to mitigate OA progression.

6.
Tissue Cell ; 84: 102162, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37487256

RESUMO

Peripheral nerve injury is one of the common disabling clinical conditions and around 50% of the cases end up in permanent impairment. Due to the lack of effective treatment options regenerative medicine employing stem cells is being evaluated. The presented study evaluated and compared regeneration potential of mesenchymal stem cells (MSCs) derived from bone marrow (BM) and adipose tissue (AD) in acute rabbit sciatic nerve injury (axonotmesis) model. A total of n = 54 grey giant rabbits were made subject of the study and divided equally into 3 groups: Control, BM-MSCs in Collagen I and AD-MSCs in Collagen I as per the treatment given. Iliac crest BM and omental AD was harvested from the same donor for isolation and culture of MSCs. The repair of sciatic nerve injury was evaluated on days 60 and 90. The clinical and histopathological scores and SEM morphology was better in cell treated groups as compared to the control. Morphology and histological studies revealed injured nerve in different levels of regenerative process. Gene expression was more than double for N-Cadherin in cell treated groups as compared to the control, especially at day 60. Between cell treated groups, BM-MSCs group showed better response as compared to the AD-MSCs, although statistically non-significant (p > 0.05). Incomplete nerve regeneration observed under various diagnostic parameters was in compliance to the incomplete clinical recovery at day 90. It was concluded that MSCs may improve sciatic nerve healing but fall short of complete regeneration at day 90, although BM-MSCs may have an edge over AD-MSCs.


Assuntos
Células-Tronco Mesenquimais , Traumatismos dos Nervos Periféricos , Animais , Coelhos , Traumatismos dos Nervos Periféricos/terapia , Medula Óssea , Tecido Adiposo , Nervo Isquiático , Colágeno Tipo I
7.
Cluster Comput ; : 1-26, 2023 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-37359060

RESUMO

The year 2020 has witnessed the emergence of coronavirus (COVID-19) that has rapidly spread and adversely affected the global economy, health, and human lives. The COVID-19 pandemic has exposed the limitations of existing healthcare systems regarding their inadequacy to timely and efficiently handle public health emergencies. A large portion of today's healthcare systems are centralized and fall short in providing necessary information security and privacy, data immutability, transparency, and traceability features to detect fraud related to COVID-19 vaccination certification, and anti-body testing. Blockchain technology can assist in combating the COVID-19 pandemic by ensuring safe and reliable medical supplies, accurate identification of virus hot spots, and establishing data provenance to verify the genuineness of personal protective equipment. This paper discusses the potential blockchain applications for the COVID-19 pandemic. It presents the high-level design of three blockchain-based systems to enable governments and medical professionals to efficiently handle health emergencies caused by COVID-19. It discusses the important ongoing blockchain-based research projects, use cases, and case studies to demonstrate the adoption of blockchain technology for COVID-19. Finally, it identifies and discusses future research challenges, along with their key causes and guidelines.

8.
Insects ; 14(5)2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37233110

RESUMO

The red palm weevil (RPW), Rhynchophorus ferrugineus, poses a severe threat to agro-industrial crops, particularly major cultivated palm species. Infestations result in economic losses due to reduced fruit quality and yield. The entomopathogenic fungus, Metarhizium anisopliae, has shown promise as a potential biocontrol agent against the RPW. However, the use of an emulsion formulation of M. anisopliae for managing this serious insect pest has yet to be fully explored. The oil-emulsion formulation containing this entomopathogen may enhance the conidia's stability, prolong its lifetime, and reduce the impact of heat stress or UV irradiation on the fungus. Therefore, this study aimed to investigate the bioefficacy of a new oil-in-glycerol emulsion formulation on mycoinsecticidal activity against RPW adults by direct and indirect bioassays. Results showed that conidia concentration was directly proportional to the RPW mortality percentage. The LT50 of 8.183 days was achieved by the conidial formulation against RPW, with a significantly lower LC50 (1.910 × 105 conidia mL-1) compared to the aqueous conidia suspension (LT50 = 8.716 days; LC50 = 7.671 × 105 conidia mL-1). Indirect bioassays revealed that the oil-in-glycerol emulsion had a disease-spreading ability that resulted in up to 56.67% RPW mortality. A zero E-value reading indicates that the DNA sequence being studied is highly similar to that of the fungal species M. anisopliae, which has been identified in the NCBI database. Although the new emulsion formulation has improved the efficacy and pathogenicity of M. anisopliae in vitro, it is important to also consider the fungal pathogen's compatibility with other agricultural practices to prevent any loss of control efficiency in the actual usage environment.

9.
Tissue Cell ; 82: 102075, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37004269

RESUMO

Tendon injuries account up to 50% of all musculoskeletal problems and remains a challenge to treat owing to the poor intrinsic reparative ability of tendon tissues. The natural course of tendon healing is very slow and often leads to fibrosis and disorganized tissues with inferior biomechanical properties. Mesenchymal stem cells (MSC) therapy is a promising alternative strategy to augment tendon repair due to its proliferative and multilineage differentiation potential. Hypoxic conditioning of MSC have been shown to enhance their tenogenic differentiation capacity. However, the mechanistic pathway by which this is achieved is yet to be fully defined. A key factor involved in this pathway is hypoxia-inducible factor-1-alpha (HIF-1α). This review aims to discuss the principal mechanism underlying the enhancement of MSC tenogenic differentiation by hypoxic conditioning, particularly the central role of HIF-1α in mediating activation of tenogenic pathways in the MSC. We focus on the interaction between HIF-1α with fibroblast growth factor-2 (FGF-2) and transforming growth factor-beta 1 (TGF-ß1) in regulating MSC tenogenic differentiation pathways in hypoxic conditions. Strategies to promote stabilization of HIF-1α either through direct manipulation of oxygen tension or the use of hypoxia mimicking agents are therefore beneficial in increasing the efficacy of MSC therapy for tendon repair.


Assuntos
Células-Tronco Mesenquimais , Traumatismos dos Tendões , Humanos , Tendões/metabolismo , Diferenciação Celular , Traumatismos dos Tendões/terapia , Traumatismos dos Tendões/metabolismo , Hipóxia/metabolismo
10.
Cluster Comput ; 26(1): 197-221, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35309043

RESUMO

Deep learning has gained huge traction in recent years because of its potential to make informed decisions. A large portion of today's deep learning systems are based on centralized servers and fall short in providing operational transparency, traceability, reliability, security, and trusted data provenance features. Also, training deep learning models by utilizing centralized data is vulnerable to the single point of failure problem. In this paper, we explore the importance of integrating blockchain technology with deep learning. We review the existing literature focused on the integration of blockchain with deep learning. We classify and categorize the literature by devising a thematic taxonomy based on seven parameters; namely, blockchain type, deep learning models, deep learning specific consensus protocols, application area, services, data types, and deployment goals. We provide insightful discussions on the state-of-the-art blockchain-based deep learning frameworks by highlighting their strengths and weaknesses. Furthermore, we compare the existing blockchain-based deep learning frameworks based on four parameters such as blockchain type, consensus protocol, deep learning method, and dataset. Finally, we present important research challenges which need to be addressed to develop highly trustworthy deep learning frameworks.

11.
Opt Lett ; 47(8): 2105-2108, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35427348

RESUMO

Multiresonant metasurfaces could enable many applications in filtering, sensing, and nonlinear optics. However, developing a metasurface with more than one high-quality-factor or high-Q resonance at designated resonant wavelengths is challenging. Here, we experimentally demonstrate a plasmonic metasurface exhibiting different, narrow surface lattice resonances by exploiting the polarization degree of freedom where different lattice modes propagate along different dimensions of the lattice. The surface consists of aluminum nanostructures in a rectangular periodic lattice. The resulting surface lattice resonances were measured around 640 nm and 1160 nm with Q factors of ∼50 and ∼800, respectively. The latter is a record-high plasmonic Q factor within the near-infrared type-II window. Such metasurfaces could benefit such applications as frequency conversion and all-optical switching.

12.
IEEE Access ; 9: 44905-44927, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34812386

RESUMO

The year 2020 has witnessed unprecedented levels of demand for COVID-19 medical equipment and supplies. However, most of today's systems, methods, and technologies leveraged for handling the forward supply chain of COVID-19 medical equipment and the waste that results from them after usage are inefficient. They fall short in providing traceability, reliability, operational transparency, security, and trust features. Also, they are centralized that can cause a single point of failure problem. In this paper, we propose a decentralized blockchain-based solution to automate forward supply chain processes for the COVID-19 medical equipment and enable information exchange among all the stakeholders involved in their waste management in a manner that is fully secure, transparent, traceable, and trustworthy. We integrate the Ethereum blockchain with decentralized storage of interplanetary file systems (IPFS) to securely fetch, store, and share the data related to the forward supply chain of COVID-19 medical equipment and their waste management. We develop algorithms to define interaction rules regarding COVID-19 waste handling and penalties to be imposed on the stakeholders in case of violations. We present system design along with its full implementation details. We evaluate the performance of the proposed solution using cost analysis to show its affordability. We present the security analysis to verify the reliability of the smart contracts, and discuss our solution from the generalization and applicability point of view. Furthermore, we outline the limitations of our solution in form of open challenges that can act as future research directions. We make our smart contracts code publicly available on GitHub.

13.
Arch Med Sci Atheroscler Dis ; 6: e85-e94, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34027217

RESUMO

INTRODUCTION: Despite the common occurrence of streptokinase-induced hypotension among patients with acute myocardial infarction, the underlying pathophysiology remains obscure and poorly understood. Our study aimed to pool clinical evidence on the potential mechanism of streptokinase-induced hypotension through a systematic review of the literature. MATERIAL AND METHODS: We conducted literature search from Medline, Scopus and Web of Science on clinical studies related to streptokinase-induced hypotension. RESULTS: Our search yielded 972 citations. After removal of duplicates, 878 articles were screened for eligibility, of which 856 papers were excluded due to various reasons. Of the remaining 22 articles retrieved with full texts, eight relevant articles were selected for final analysis. Three themes emerged as the proposed mechanisms of streptokinase-induced hypotension, including (i) reduction in total peripheral resistance, (ii) complement activation, and (iii) dismissal of hypotheses involving other intermediaries. CONCLUSIONS: Our findings suggest that the underlying mechanism of streptokinase-induced hypotension lies primarily in the reduction in total peripheral resistance.

14.
Sci Rep ; 11(1): 5439, 2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33686116

RESUMO

In this paper, Jr.NiFe2O4 nanoparticles (NPs) were synthesized first time using the leaves extract of Juglans regia via a straightforward process. The physio and phytochemical analysis of plant confirm the presence of macromolecules which function as bio-reductant and stabilize the nanoparticles. The Jr.NiFe2O4 NPs were characterized by UV-visible, FTIR spectroscopy, PXRD pattern, SEM and TGA/DTA analysis. The nanoparticles proved to be optically active having a value of indirect bandgap of energy in the range of 1.53 eV. The Jr.NiFe2O4 NPs have the ability in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) free radicals and showed 58.01% ± 1.2% scavenging activity at 100 µg/mL concentrations. The photocatalytic degradation study of ciprofloxacin (CIP) and Congo red (CR) reveals that the highest degradation rate was acquired for CIP using pH = 3, at 254 nm, while 85% of removal rate was analysed for CR. The kinetic studies in case of CR removal followed pseudo-first-order model with thermodynamic parameters (∆G° = - 5.87 kJ mol-1 K, ΔH° = 1393.50 kJ mol-1 and ΔS° = 22.537 kJ mol-1 K) with error analysis. Overall, these data recommend an innovative inspiring application of a plant-mediated synthesis of Jr.NiFe2O4 NPs.

15.
Int J Med Inform ; 148: 104399, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33540131

RESUMO

OBJECTIVE: Telehealth and telemedicine systems aim to deliver remote healthcare services to mitigate the spread of COVID-9. Also, they can help to manage scarce healthcare resources to control the massive burden of COVID-19 patients in hospitals. However, a large portion of today's telehealth and telemedicine systems are centralized and fall short of providing necessary information security and privacy, operational transparency, health records immutability, and traceability to detect frauds related to patients' insurance claims and physician credentials. METHODS: The current study has explored the potential opportunities and adaptability challenges for blockchain technology in telehealth and telemedicine sector. It has explored the key role that blockchain technology can play to provide necessary information security and privacy, operational transparency, health records immutability, and traceability to detect frauds related to patients' insurance claims and physician credentials. RESULTS: Blockchain technology can improve telehealth and telemedicine services by offering remote healthcare services in a manner that is decentralized, tamper-proof, transparent, traceable, reliable, trustful, and secure. It enables health professionals to accurately identify frauds related to physician educational credentials and medical testing kits commonly used for home-based diagnosis. CONCLUSIONS: Wide deployment of blockchain in telehealth and telemedicine technology is still in its infancy. Several challenges and research problems need to be resolved to enable the widespread adoption of blockchain technology in telehealth and telemedicine systems.


Assuntos
Blockchain , COVID-19 , Telemedicina , Registros Eletrônicos de Saúde , Humanos , SARS-CoV-2 , Tecnologia
16.
Vet Surg ; 50(2): 444-454, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33325099

RESUMO

OBJECTIVE: Quantitation of mechanical properties of a novel locking compression plate (LCP) for bovine tibia. STUDY DESIGN: Prospective in vitro study. SAMPLE POPULATION: Adult Murrah buffalo (250-350 kg) tibiae. METHODS: Forty tibiae were randomly assigned to five treatment groups (n = 8/group): intact bone and bone constructs with a standard nonlocking plate, single LCP, double LCP, and novel LCP. During implant application, a mid-diaphyseal, oblique osteotomy was performed in all constructs, which were subsequently tested in axial compression (n = 4 each) or three-point craniocaudal bending (n = 4 each). Novel LCP alone (n = 4) was tested only in bending. Stiffness, yield load, ultimate failure load, and bending moment were determined from the load deformation curves and compared among different treatment groups (P < .05). RESULTS: Under compression, yield load of the novel LCP (24.07 ± 3.45 kN) was greater than that of the nonlocking plate (11.10 ± 2.46 kN) and the single LCP (18.01 ± 2.07 kN) but less than that of the double LCP (30.61 ± 1.95 kN), and ultimate failure load of the novel LCP (25.85 ± 4.32 kN) was greater than that of the nonlocking plate (13.18 ± 2.91 kN) but similar to that of the single LCP (21.17 ± 2.33 kN) and the double LCP (32.40 ± 1.46 kN). Bending moment, yield load, and ultimate failure load of the novel LCP were 565.37 ± 79.30 Nm, 7.90 ± 1.14 kN, 9.83 ± 1.38 kN, respectively, which were greater than those of the nonlocking plate and the single LCP but comparable to those of the double LCP. CONCLUSION: The novel LCP developed for bovine tibia was mechanically superior to the standard nonlocking plate or the single LCP and comparable to the double LCP. CLINICAL SIGNIFICANCE: The novel LCP may provide rigid fixation of tibial diaphyseal fractures in buffaloes and cattle weighing 250 to 350 kg.


Assuntos
Placas Ósseas/veterinária , Búfalos/cirurgia , Osteotomia/veterinária , Tíbia/cirurgia , Fraturas da Tíbia/veterinária , Animais , Fenômenos Biomecânicos , Osteotomia/instrumentação , Estudos Prospectivos , Estresse Mecânico , Fraturas da Tíbia/cirurgia
17.
Opt Lett ; 45(18): 5189-5192, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32932485

RESUMO

We report on the distributed shape measurement of small deformations produced along the length of an optical fiber. The fiber contains multiple waveguiding cores, each inscribed with weak continuous Bragg gratings. The distributed Bragg-reflectivity data for the fiber cores, obtained from the optical backscatter reflectometry, are used to estimate the local curvature and the position of the fiber. We successfully demonstrate the sensing of periodic microdeformations-approximately 1 µm or less in amplitude and a few hundred µm in length. Such microbends are known to cause attenuation in optical fibers, and the approach presented here can enable a detailed measurement of these microbends in applications ranging from telecommunications cable design to biotechnology, robotics, manufacturing, aerospace, and security.

18.
Stem Cells Int ; 2020: 5385960, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32908542

RESUMO

It has been suggested that mechanical strain may elicit cell differentiation in adult somatic cells through activation of epithelial sodium channels (ENaC). However, such phenomenon has not been previously demonstrated in mesenchymal stromal cells (MSCs). The present study was thus conducted to investigate the role of ENaC in human bone marrow-derived MSCs (hMSCs) tenogenic differentiation during uniaxial tensile loading. Passaged-2 hMSCs were seeded onto silicone chambers coated with collagen I and subjected to stretching at 1 Hz frequency and 8% strain for 6, 24, 48, and 72 hours. Analyses at these time points included cell morphology and alignment observation, immunocytochemistry and immunofluorescence staining (collagen I, collagen III, fibronectin, and N-cadherin), and gene expression (ENaC subunits, and tenogenic markers). Unstrained cells at similar time points served as the control group. To demonstrate the involvement of ENaC in the differentiation process, an ENaC blocker (benzamil) was used and the results were compared to the noninhibited hMSCs. ENaC subunits' (α, ß, γ, and δ) expression was observed in hMSCs, although only α subunit was significantly increased during stretching. An increase in tenogenic genes' (collagen1, collagen3, decorin, tenascin-c, scleraxis, and tenomodulin) and proteins' (collagen I, collagen III, fibronectin, and N-cadherin) expression suggests that hMSCs underwent tenogenic differentiation when subjected to uniaxial loading. Inhibition of ENaC function resulted in decreased expression of these markers, thereby suggesting that ENaC plays a vital role in tenogenic differentiation of hMSCs during mechanical loading.

19.
Opt Express ; 28(6): 8400-8406, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32225466

RESUMO

We report on the excitation and polarization preserved propagation of a very large effective-area (Aeff ∼ 2240 µm2) higher-order-mode in an optical fiber. A laser signal operating in the 1 µm wavelength region is transported in a Bessel-like LP0,4 mode over a 10 m long section of the polarization-maintaining higher-order-mode fiber. We observe that the light propagates through the fiber with >10 dB polarization-extinction-ratio as the fiber is coiled into circular loops of 40 cm diameter.

20.
Vet Q ; 39(1): 95-120, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31291836

RESUMO

Healing of articular cartilage is a major clinical challenge as it also lacks a direct vasculature and nerves, and carries a limited number of resident chondrocytes that do not proliferate easily. Damaged articular cartilages are usually replaced by fibrocartilages, which are mechanically and structurally weaker and less resilient. Regenerative medicine involving stem cells is considered to have a definitive potential to overcome the limitations associated with the currently available surgical methods of cartilage repair. Among various stem cell types, mesenchymal stem cells (MSCs) are preferred for clinical applications. These cells can be readily derived from various sources and have the ability to trans-differentiate into various tissue-specific cells, including those of the cartilage by the process of chondrogenesis. Compared to embryonic or induced pluripotent stem cells (iPSCs), no ethical or teratogenic issues are associated with MSCs. These stem cells are being extensively evaluated for the treatment of joint affections and the results appear promising. Unlike human medicine, in veterinary medicine, the literature on stem cell research for cartilage regeneration is limited. This review, therefore, aims to comprehensively discuss the available literature and pinpoint the achievements and limitations associated with the use of MSCs for articular cartilage repair in animal species.


Assuntos
Cartilagem Articular/cirurgia , Cães/cirurgia , Cabras/cirurgia , Cavalos/cirurgia , Transplante de Células-Tronco Mesenquimais/veterinária , Animais , Cães/lesões , Cabras/lesões , Cavalos/lesões , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais , Medicina Regenerativa/métodos , Fatores de Risco , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...