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1.
Proc Natl Acad Sci U S A ; 121(42): e2408119121, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39383004

RESUMO

Strong steels are primarily fabricated by introducing spatial obstacles (e.g., stacking faults and precipitates) that inhibit dislocation slips under stress to achieve high strength. However, for most low-carbon steels, such obstacles are difficult to form mainly because the martensitic transition is kinetically unfavorable by conventional methods, which precludes the attainment of high-strength materials in these steels with low solute contents. Here, we report an innovative high-pressure preparation of martensitic pure Fe with involving nano-effect, which leads to the formation of ultrastrong bulk iron with exceptionally high yield strength, ultimate strength, and hardness of 2.9 GPa, 3.7 GPa, and 9.0 GPa, respectively, exceeding those of high-speed steels. Such extraordinary mechanical properties are closely attributed to its high-density martensites with unique multiscale hierarchical structures formed due to complex phase transitions under pressure.

2.
Proc Natl Acad Sci U S A ; 120(12): e2209188120, 2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36913568

RESUMO

Local chemical short-range ordering (SRO) and spatial fluctuations of planar fault energy are important features of multi-element and metastable complex concentrated alloys (CCAs). Arising from them, dislocations in such alloys are distinctively wavy in both static and migrating conditions; yet, such effects on strength have remained unknown. In this work, molecular dynamics simulations are used to show that the wavy configurations of dislocations and their jumpy motion in a prototypic CCA of NiCoCr are due to the local fluctuations of the energy of SRO shear-faulting that accompanies dislocation motion, with the dislocation getting pinned at sites of hard atomic motifs (HAMs) associated with high local shear-fault energies. Unlike the global averaged shear-fault energy which in general will subdue on successive dislocation passes, the local fluctuations in the fault energy always remain in a CCA, thus offering a strength contribution that is unique in such alloys. Analysis of the magnitude of this form of dislocation resistance shows that this is dominating over contributions due to elastic misfit of alloying elements and is in good agreement with strengths predicted from molecular dynamics simulations and experiments. This work has unfolded the physical basis of strength in CCAs, which is important for the development of these alloys into useful structural materials.

3.
Proc Natl Acad Sci U S A ; 119(3)2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-35012985

RESUMO

Materials containing heterogeneous nanostructures hold great promise for achieving superior mechanical properties. However, the strengthening effect due to plastically inhomogeneous deformation in heterogeneous nanostructures has not been clearly understood. Here, we investigate a prototypical heterogeneous nanostructured material of gradient nanotwinned (GNT) Cu to unravel the origin of its extra strength arising from gradient nanotwin structures relative to uniform nanotwin counterparts. We measure the back and effective stresses of GNT Cu with different nanotwin thickness gradients and compare them with those of homogeneous nanotwinned Cu with different uniform nanotwin thicknesses. We find that the extra strength of GNT Cu is caused predominantly by the extra back stress resulting from nanotwin thickness gradient, while the effective stress is almost independent of the gradient structures. The combined experiment and strain gradient plasticity modeling show that an increasing structural gradient in GNT Cu produces an increasing plastic strain gradient, thereby raising the extra back stress. The plastic strain gradient is accommodated by the accumulation of geometrically necessary dislocations inside an unusual type of heterogeneous dislocation structure in the form of bundles of concentrated dislocations. Such a heterogeneous dislocation structure produces microscale internal stresses leading to the extra back stress in GNT Cu. Altogether, this work establishes a fundamental connection between the gradient structure and extra strength in GNT Cu through the mechanistic linkages of plastic strain gradient, heterogeneous dislocation structure, microscale internal stress, and extra back stress. Broadly, this work exemplifies a general approach to unraveling the strengthening mechanisms in heterogeneous nanostructured materials.

4.
Proc Natl Acad Sci U S A ; 119(25): e2200607119, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35696570

RESUMO

Multi-principal element alloys (MPEAs) exhibit outstanding mechanical properties because the core effect of severe atomic lattice distortion is distinctly different from that of traditional alloys. However, at the mesoscopic scale the underlying physics for the abundant dislocation activities responsible for strength-ductility synergy has not been uncovered. While the Eshelby mean-field approaches become insufficient to tackle yielding and plasticity in severely distorted crystalline solids, here we develop a three-dimensional discrete dislocation dynamics simulation approach by taking into account the experimentally measured lattice strain field from a model FeCoCrNiMn MPEA to explore the heterogeneous strain-induced strengthening mechanisms. Our results reveal that the heterogeneous lattice strain causes unusual dislocation behaviors (i.e., multiple kinks/jogs and bidirectional cross slips), resulting in the strengthening mechanisms that underpin the strength-ductility synergy. The outcome of our research sheds important insights into the design of strong yet ductile distorted crystalline solids, such as high-entropy alloys and high-entropy ceramics.

5.
Nano Lett ; 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39298740

RESUMO

The pursuit of harnessing superior mechanical properties achieved through the size effect on a macroscopic scale has been a prominent focus in engineering, as size-induced strengthening is enabled only in the nanoscale regime. This study presents a metal/ceramic/metal (MCM) nanocomposite reinforced by ceramic nanoarchitectures. Through proximity-field nanopatterning, the inch-scale production of nanoarchitecture films is enabled in a single fabrication step. The developed three-dimensional (3D) Ni/Al2O3/Ni nanocomposite film exhibits significantly high compressive strength, corresponding to an increase of approximately 30% compared with that calculated using the upper limits of the conventional rule of mixtures. The exceptional strength of the 3D MCM nanocomposite can be attributed to the extrinsic size effect of the ceramic nanoarchitectures. By combining size-induced strengthening of ceramics with the strengthening law for composites, a new type of strengthening model is derived and experimentally validated using the 3D MCM nanocomposite.

6.
BMC Med ; 22(1): 231, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38853263

RESUMO

BACKGROUND: Global progress on malaria control has stalled recently, partly due to challenges in universal access to malaria diagnosis and treatment. Community health workers (CHWs) can play a key role in improving access to malaria care for children under 5 years (CU5), but national policies rarely permit them to treat older individuals. We conducted a two-arm cluster randomized trial in rural Madagascar to assess the impact of expanding malaria community case management (mCCM) to all ages on health care access and use. METHODS: Thirty health centers and their associated CHWs in Farafangana District were randomized 1:1 to mCCM for all ages (intervention) or mCCM for CU5 only (control). Both arms were supported with CHW trainings on malaria case management, community sensitization on free malaria care, monthly supervision of CHWs, and reinforcement of the malaria supply chain. Cross-sectional household surveys in approximately 1600 households were conducted at baseline (Nov-Dec 2019) and endline (Nov-Dec 2021). Monthly data were collected from health center and CHW registers for 36 months (2019-2021). Intervention impact was assessed via difference-in-differences analyses for survey data and interrupted time-series analyses for health system data. RESULTS: Rates of care-seeking for fever and malaria diagnosis nearly tripled in both arms (from less than 25% to over 60%), driven mostly by increases in CHW care. Age-expanded mCCM yielded additional improvements for individuals over 5 years in the intervention arm (rate ratio for RDTs done in 6-13-year-olds, RRRDT6-13 years = 1.65; 95% CIs 1.45-1.87), but increases were significant only in health system data analyses. Age-expanded mCCM was associated with larger increases for populations living further from health centers (RRRDT6-13 years = 1.21 per km; 95% CIs 1.19-1.23). CONCLUSIONS: Expanding mCCM to all ages can improve universal access to malaria diagnosis and treatment. In addition, strengthening supply chain systems can achieve significant improvements even in the absence of age-expanded mCCM. TRIAL REGISTRATION: The trial was registered at the Pan-African Clinical Trials Registry (#PACTR202001907367187).


Assuntos
Administração de Caso , Agentes Comunitários de Saúde , Acessibilidade aos Serviços de Saúde , Malária , Humanos , Malária/diagnóstico , Malária/tratamento farmacológico , Madagáscar , Masculino , Criança , Adolescente , Pré-Escolar , Feminino , Lactente , Adulto , Adulto Jovem , Pessoa de Meia-Idade , Estudos Transversais , Serviços de Saúde Comunitária , População Rural , Idoso
7.
Small ; 20(27): e2310692, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38243875

RESUMO

Multiscale defects engineering offers a promising strategy for synergistically enhancing the thermoelectric and mechanical properties of thermoelectric semiconductors. However, the specific impact of individual defects, in particular precipitation, on mechanical properties remains ambiguous. In this work, the mechanical and thermoelectric properties of Sn1.03- xMnxTe (x = 0-0.30) semiconductors are systematically studied. Mn-alloying induces dense dislocations and Mn nano-precipitates, resulting in an enhanced compressive strength with x increased to 0.15. Quantitative calculations are performed to assess the strengthening contributions including grain boundary, solid solution, dislocation, and precipitation strengthening. Due to the dominant contribution of precipitation strengthening, the yield strength of the x = 0.10 sample is improved by ≈74.5% in comparison to the Mn-free Sn1.03Te. For x ≥ 0.15, numerous MnTe precipitates lead to a synergistic enhancement of strength-ductility. In addition, multiscale defects induced by Mn alloying can scatter phonons over a wide frequency spectrum. The peak figure of merit ZT of ≈1.3 and an ultralow lattice thermal conductivity of ≈0.35 Wm-1 K-1 are obtained at 873 K for x = 0.10 and x = 0.30 samples respectively. This work reveals tha precipitation evolution optimizes the mechanical and thermoelectric properties of Sn1.03- xMnxTe semiconductors, which may hold potential implications for other thermoelectric systems.

8.
Small ; 20(30): e2310072, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38470190

RESUMO

Flexible wearable sensors recently have made significant progress in human motion detection and health monitoring. However, most sensors still face challenges in terms of single detection targets, single application environments, and non-recyclability. Lipoic acid (LA) shows a great application prospect in soft materials due to its unique properties. Herein, ionic conducting elastomers (ICEs) based on polymerizable deep eutectic solvents consisting of LA and choline chloride are prepared. In addition to the good mechanical strength, high transparency, ionic conductivity, and self-healing efficiency, the ICEs exhibit swelling-strengthening behavior and enhanced adhesion strength in underwater environments due to the moisture-induced association of poly(LA) hydrophobic chains, thus making it possible for underwater sensing applications, such as underwater communication. As a strain sensor, it exhibits highly sensitive strain response with repeatability and durability, enabling the monitoring of both large and fine human motions, including joint movements, facial expressions, and pulse waves. Furthermore, due to the enhancement of ion mobility at higher temperatures, it also possesses excellent temperature-sensing performance. Notably, the ICEs can be fully recycled and reused as a new strain/temperature sensor through heating. This study provides a novel strategy for enhancing the mechanical strength of poly(LA) and the fabrication of multifunctional sensors.


Assuntos
Ácido Tióctico , Água , Dispositivos Eletrônicos Vestíveis , Ácido Tióctico/química , Água/química , Humanos , Temperatura , Elastômeros/química
9.
Cancer Causes Control ; 35(4): 611-622, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37979072

RESUMO

PURPOSE: Be Well Communities™ is MD Anderson's signature place-based approach for cancer prevention and control, working with communities to promote wellness and address modifiable risk factors for cancer. The purpose of this paper is to describe implementation of the planning phase of the Be Well Communities model in Acres Homes which began in 2019. METHODS: A community advisory group (Steering Committee) including residents, non-profit organizations, health care partners, city and county agencies, plus other stakeholders, was convened and aligned through a structured process to develop shared goals, foster multisector collaboration, as measured by a stakeholder survey administered twice, and enhance community capacity to improve health outcomes through development of a Community Action Plan. RESULTS: Clear, achievable goals were developed, multisector collaboration was enhanced, and more than 400 h of capacity building support led to a Community Action Plan initially focused on healthy eating and active living, including 15 evidence-based interventions led by 18 organizations. The majority (93%) of the Steering Committee reports that this plan reflects community priorities and will reach the residents most in need. CONCLUSION: By listening and developing trust, the Be Well Communities team successfully worked with Acres Homes residents and organizations to enhance community capacity to address health inequities in one of Houston's most diverse and historic communities.


Assuntos
Desigualdades de Saúde , Neoplasias , Humanos
10.
J Pediatr ; 269: 113983, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38401789

RESUMO

OBJECTIVE: To examine the preliminary impact of group cognitive behavioral therapy and multiple family group-based family strengthening to address HIV stigma and improve the mental health functioning of adolescents living with HIV in Uganda. STUDY DESIGN: We analyzed data from the Suubi4Stigma study, a 2-year pilot randomized clinical trial that recruited adolescents living with HIV (10-14 years) and their caregivers (n = 89 dyads), from 9 health clinics. We fitted separate three-level mixed-effects linear regression models to test the effect of the interventions on adolescent outcomes at 3 and 6 months post intervention initiation. RESULTS: The average age was 12.2 years and 56% of participants were females. Participants in the multiple family group-based family strengthening intervention reported lower levels of internalized stigma (mean difference = -0.008, 95% CI = -0.015, -0.001, P = .025) and depressive symptoms at 3 months (mean difference = -0.34, 95% CI = -0.53, -0.14, P < .001), compared with usual care. On the other hand, participants in the group cognitive behavioral therapy intervention reported lower levels of anticipated stigma at 3 months (mean difference = -0.039, 95% CI = -0.072, -0.006), P = .013) and improved self-concept at 6 months follow-up (mean difference = 0.04, 95% CI = 0.01, 0.01, P = .025). CONCLUSION: Outcome trends from this pilot study provide compelling evidence to support testing the efficacy of these group-based interventions on a larger scale. TRIAL REGISTRATION: The study is registered in the Clinical trials.gov database (Identifier #: NCT04528732).


Assuntos
Terapia Cognitivo-Comportamental , Infecções por HIV , Psicoterapia de Grupo , Estigma Social , Humanos , Feminino , Masculino , Adolescente , Uganda , Infecções por HIV/psicologia , Infecções por HIV/terapia , Criança , Projetos Piloto , Terapia Cognitivo-Comportamental/métodos , Psicoterapia de Grupo/métodos , Saúde Mental , Cooperação e Adesão ao Tratamento/psicologia , Cuidadores/psicologia
11.
Chemistry ; 30(9): e202303092, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38057492

RESUMO

While great achievements have been made in the development of mechanically robust nanocomposite hydrogels, incorporating multiple interactions on the bases of two demensional inorganic cross-linkers to construct self-strengthening hydrogels has rarely been investigated. To this end, we propose here a new method for the coupling the dynamic covalent bonds and non-covalent interactions within a pseudo double-network system. The pseudo first network, formed through the Schiff Base reation between Tris-modified layered double hydroxides (Tris-LDHs) and oxidized dextran (ODex), is linked to the second network built upon non-covalent interactions between Tris-LDHs and poly(acrylamide-co-2-acrylamido-2-methyl-propanesulfonate) (p-(AM-co-AMPS). The swelling and mechanical properties of the resulting hydrogels have been investigated as a function of the ODex and AMPS contents. The as-prepared hydrogel can swell to 420 times of its original size and retain more than 99.9 wt.% of water. Mechanical tests show that the hydrogel can bear 90 % of compression and is able to be stretched to near 30 times of its original length. Cyclic tensile tests reveal that the hydrogels are capable of self-strengthening after mechanical training. The unique energy dissipation mechanism based on the dynamic covalent and non-covalent interactions is considered to be responsible for the outstanding swelling and mechanical performances.

12.
AIDS Behav ; 28(5): 1630-1641, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38308772

RESUMO

This study examined the feasibility and acceptability of two group-based interventions: group-cognitive behavioral therapy (G-CBT) and a family-strengthening intervention delivered via multiple family group (MFG-FS), to address HIV stigma among adolescents living with HIV (ALHIV) and their caregivers. A total of 147 adolescent -caregiver dyads from 9 health clinics situated within 7 political districts in Uganda were screened for eligibility. Of these, 89 dyads met the inclusion criteria and provided consent to participate in the study. Participants were randomized, at the clinic level, to one of three study conditions: Usual care, G-CBT or MFG-FS. The interventions were delivered over a 3-month period. While both adolescents and their caregivers attended the MFG-FS sessions, G-CBT sessions were only attended by adolescents. Data were collected at baseline, 3 and 6-months post intervention initiation. The retention rate was 94% over the study period. Across groups, intervention session attendance ranged between 85 and 92%, for all sessions. Fidelity of the intervention was between 85 and 100%, and both children and caregivers rated highly their satisfaction with the intervention sessions. ALHIV in Uganda, and most of sub-Saharan Africa, are still underrepresented in stigma reduction interventions. The Suubi4Stigma study was feasible and acceptable to adolescents and their caregivers -supporting testing the efficacy of the interventions in a larger trial.


Assuntos
Cuidadores , Terapia Cognitivo-Comportamental , Estudos de Viabilidade , Infecções por HIV , Estigma Social , Humanos , Adolescente , Cuidadores/psicologia , Feminino , Masculino , Infecções por HIV/psicologia , Uganda , Terapia Cognitivo-Comportamental/métodos , Adulto , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Psicoterapia de Grupo/métodos , Adulto Jovem
13.
AIDS Behav ; 28(5): 1570-1580, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38231361

RESUMO

We examined the impact of an economic empowerment intervention on ART adherence among ALHIV. We used data from 455 ALHIV, randomized into intervention, n = 111, and control n = 344. ALHIV were aged 12-16 and recruited from 39 clinics in Uganda between January 2013 and December 2015. The intervention comprised a long-term child development account (CDA), micro-enterprise workshops, and educational sessions. Adherence was measured using unannounced pill counts. We used mixed-effects logistic regression analysis to examine the effect of the intervention on ART adherence. The mean age was 12.6 years. Despite observing non-significant group main effects, we found significant group-by-time interaction effects χ2(5) = 45.41, p < 0.001. Pairwise comparisons showed that compared to the control group, participants who received the intervention had significantly higher adherence at visit four, OR = 1.52 (95% CI: 1.07-2.18), p = 0.020; visit five, OR = 1.59 (95% CI: 1.06-2.38), p = 0.026; and visit six, OR = 1.94 (95% CI: 1.24-3.04), p = 0.004. Efforts to support ALHIV to live longer and healthier lives should incorporate components addressing poverty. However, declining adherence raises concerns over ALHIV's long-term well-being. The trial was registered at ClinicalTrials.gov, registration number NCT01790373, with a primary outcome of adherence to HIV treatment.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Adesão à Medicação , Humanos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/psicologia , Adolescente , Adesão à Medicação/estatística & dados numéricos , Adesão à Medicação/psicologia , Masculino , Feminino , Uganda/epidemiologia , Criança , Fármacos Anti-HIV/uso terapêutico , Empoderamento
14.
Macromol Rapid Commun ; 45(17): e2400277, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38771626

RESUMO

Addressing the demand for integrating strength and durability reinforcement in shape memory polyurethane (SMPU) for diverse applications remains a significant challenge. Here a series of SMPUs with ultra-high strength, self-healing and recyclability, and excellent shape memory properties through introducing dynamic boron-urethane bonds are synthesized. The introducing of boric acid (BA) to polyurethane leading to the formation of dynamic covalent bonds (DCB) boron-urethane, that confer a robust cross-linking structure on the SMPUs led to the formation of ordered stable hydrogen-bonding network within the SMPUs. The flexible crosslinking with DCB represents a novel strategy for balancing the trade-off between strength and durability, with their strengths reaching up to 82.2 MPa while also addressing the issue of durability in prolonged usage through the provision of self-healing and recyclability. The self-healing and recyclability of SMPU are demonstrated through rapid dynamic exchange reaction of boron-urethane bonds, systematically investigated by dynamic mechanical analysis (DMA). This study sheds light on the essential role of such PU with self-healing and recyclability, contributing to the extension of the PU's service life. The findings of this work provide a general strategy for overcoming traditional trade-offs in preparing SMPUs with both high strength and good durability.


Assuntos
Boro , Poliuretanos , Poliuretanos/química , Poliuretanos/síntese química , Boro/química , Uretana/química , Ligação de Hidrogênio , Estrutura Molecular , Ácidos Bóricos/química
15.
Cost Eff Resour Alloc ; 22(1): 46, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38790050

RESUMO

BACKGROUND: There is some evidence that differentiated service delivery (DSD) models, which use a client-centered approach to simplify and increase access to care, improve clinical outcomes among people living with HIV (PLHIV) in high HIV prevalence countries. Integrating economic strengthening tools (e.g., microcredit, cash transfers, food assistance) within DSD models can help address the poverty-related barriers to HIV antiretroviral therapy (ART). Yet there is minimal evidence of the cost-effectiveness of these types of multilevel care delivery models, which potentially prohibits their wider implementation. METHODS: Using a qualitative systematic review, this article synthesizes the literature surrounding the cost-effectiveness of differentiated service delivery models that employ economic strengthening initiatives to improve HIV treatment adherence in low- and middle-income countries. We searched three academic databases for randomized controlled trials and observational studies published from January 2000 through March 2024 in Sub-Saharan Africa. The quality of each study was scored using a validated appraisal system. RESULTS: Eighty-nine full texts were reviewed and 3 met all eligibility criteria. Two of the three included articles were specific to adolescents living with HIV. Economic strengthening opportunities varied by care model, and included developmental savings accounts, microenterprise workshops, and cash and non-cash conditional incentives. The main drivers of programmatic and per-patient costs were ART medications, CD4 cell count testing, and economic strengthening activities. CONCLUSION: All economic evaluations in this review found that including economic strengthening as part of comprehensive differentiated service delivery was cost-effective at a willingness to pay threshold of at least 2 times the national per capita gross domestic product. Two of the three studies in this review focused on adolescents, suggesting that these types of care models may be especially cost-effective for youth entering adulthood. All studies were from the provider perspective, indicating that additional evidence is needed to inform the potential cost-savings of DSD and economic strengthening interventions to patients and society. Randomized trials testing the effectiveness of DSD models that integrate economic strengthening should place greater emphasis on costing these types of programs to inform the potential for bringing these types of multilevel interventions to scale.

16.
World J Surg ; 48(5): 1056-1065, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38491816

RESUMO

BACKGROUND: Most low- and middle-income countries do not have a mature prehospital system limiting access to definitive care. This study sought to describe the current state of the prehospital system in Senegal and offer recommendations aimed at improving system capacity and population access to definitive care. METHODS: Structured interviews were conducted with key informants in various regions throughout the country using qualitative and quantitative techniques. A standardized questionnaire was generated using needs assessment forms and system frameworks. Descriptive statistics were performed for quantitative data analysis, and qualitative data was consolidated and presented using ATLAS.ti. RESULTS: Two (20%) of the studied regions, Dakar and Saint-Louis, had a mature prehospital system in place, including dispatch centers and teams of trained personnel utilizing equipped ambulances. 80% of the studied regions lacked an established prehospital system. The vast majority of the population relied on the fire department for transport to a healthcare facility. The ambulances in rural regions were not part of a formal prehospital system, were not equipped with life-support supplies, and were limited to inter-facility transfers. CONCLUSIONS: While Dakar and Saint-Louis have mature prehospital systems, the rest of the country is served by the fire department. There are significant opportunities to further strengthen the prehospital system in rural Senegal by training the fire department in basic life support and first aid, maintaining cost efficiency, and building on existing national resources. This has the potential to significantly improve access to definitive care and outcomes of emergent illness in the Senegalese community.


Assuntos
Serviços Médicos de Emergência , Acessibilidade aos Serviços de Saúde , Senegal , Acessibilidade aos Serviços de Saúde/organização & administração , Humanos , Serviços Médicos de Emergência/organização & administração , Inquéritos e Questionários
17.
BMC Pregnancy Childbirth ; 24(1): 224, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38539129

RESUMO

BACKGROUND: Early attendance at antenatal care (ANC), coupled with good-quality care, is essential for improving maternal and child health outcomes. However, achieving these outcomes in sub-Saharan Africa remains a challenge. This study examines the effects of a community-facility health system strengthening model (known as 4byFour) on early ANC attendance, testing for four conditions by four months of pregnancy, and four ANC clinic visits in Migori county, western Kenya. METHODS: We conducted a mixed methods quasi-experimental study with a before-after interventional design to assess the impact of the 4byFour model on ANC attendance. Data were collected between August 2019 and December 2020 from two ANC hospitals. Using quantitative data obtained from facility ANC registers, we analysed 707 baseline and 894 endline unique ANC numbers (attendances) based on negative binomial regression. Logistic regression models were used to determine the impact of patient factors on outcomes with Akaike Information Criterion (AIC) and likelihood ratio testing used to compare models. Regular facility stock checks were undertaken at the study sites to assess the availability of ANC profile tests. Analysis of the quantitative data was conducted in R v4.1.1 software. Additionally, qualitative in-depth interviews were conducted with 37 purposively sampled participants, including pregnant mothers, community health volunteers, facility staff, and senior county health officials to explore outcomes of the intervention. The interview data were audio-recorded, transcribed, and coded; and thematic analysis was conducted in NVivo. RESULTS: There was a significant 26% increase in overall ANC uptake in both facilities following the intervention. Early ANC attendance improved for all age groups, including adolescents, from 22% (baseline) to 33% (endline, p = 0.002). Logistic regression models predicting early booking were a better fit to data when patient factors were included (age, parity, and distance to clinic, p = 0.004 on likelihood ratio testing), suggesting that patient factors were associated with early booking.The proportion of women receiving all four tests by four months increased to 3% (27/894), with haemoglobin and malaria testing rates rising to 8% and 4%, respectively. Despite statistical significance (p < 0.001), the rates of testing remained low. Testing uptake in ANC was hampered by frequent shortage of profile commodities not covered by buffer stock and low ANC attendance during the first trimester. Qualitative data highlighted how community health volunteer-enhanced health education improved understanding and motivated early ANC-seeking. Community pregnancy testing facilitated early detection and referral, particularly for adolescent mothers. Challenges to optimal ANC attendance included insufficient knowledge about the ideal timing for ANC initiation, financial constraints, and long distances to facilities. CONCLUSION: The 4byFour model of community-facility health system strengthening has the potential to improve early uptake of ANC and testing in pregnancy. Sustained improvement in ANC attendance requires concerted efforts to improve care quality, consistent availability of ANC commodities, understand motivating factors, and addressing barriers to ANC. Research involving randomised control trials is needed to strengthen the evidence on the model's effectiveness and inform potential scale up.


Assuntos
Mães , Cuidado Pré-Natal , Feminino , Humanos , Gravidez , Quênia , Aceitação pelo Paciente de Cuidados de Saúde , Primeiro Trimestre da Gravidez , Cuidado Pré-Natal/métodos
18.
BMC Pregnancy Childbirth ; 24(1): 478, 2024 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-39003482

RESUMO

Guinea-Bissau has among the world's highest maternal and perinatal mortality rates. To improve access to quality maternal and child health (MCH) services and thereby reduce mortality, a national health system strengthening initiative has been implemented. However, despite improved coverage of MCH services, perinatal mortality remained high. Using a systems-thinking lens, we conducted a situation analysis to explore factors shaping timeliness and quality of facility-based care during labour, childbirth, and the immediate postpartum period in rural Guinea-Bissau. We implemented in-depth interviews with eight peripartum care providers and participant observations at two health facilities (192 h) in 2021-22, and analysed interview transcripts and field notes using thematic network analysis. While providers considered health facilities as the only reasonable place of birth and promoted facility birth uptake, timeliness and quality of care were severely compromised by geographical, material and human-resource constraints. Providers especially experienced a lack of human resources and materials (e.g., essential medicines, consumables, appropriate equipment), and explained material constraints by discontinued donor supplies. In response, providers applied several adaptation strategies including prescribing materials for private purchase, omitting tests, and delegating tasks to birth companions. Consequences included financial barriers to care, compromised patient and occupational safety, delays, and diffusion of health worker responsibilities. Further, providers explained that in response to persisting access barriers, women conditioned care seeking on their perceived risk of developing birthing complications. Our findings highlight the need for continuous monitoring of factors constraining timeliness and quality of essential MCH services during the implementation of health system strengthening initiatives.


Assuntos
Pesquisa Qualitativa , Qualidade da Assistência à Saúde , Humanos , Feminino , Gravidez , Guiné-Bissau , População Rural , Período Periparto , Serviços de Saúde Materna/normas , Acessibilidade aos Serviços de Saúde , Fatores de Tempo , Serviços de Saúde Rural/normas , Serviços de Saúde Rural/organização & administração , Adulto , Assistência Perinatal/normas
19.
BMC Public Health ; 24(1): 2592, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39334131

RESUMO

Digital technology offers scalable, real-time interventions for mental health promotion and treatment. This systematic review explores the opportunities and challenges associated with the use of digital technology in mental health, with a focus on informing mental health system strengthening interventions in the United Arab Emirates (UAE). Following PRISMA guidelines, a systematic search of databases was conducted up to August 2023 and identified a total of 8479 citations of which 114 studies were included in the qualitative analysis. The included studies encompass diverse digital interventions, platforms, and modalities used across various mental health conditions. The review identifies feasible, acceptable, and efficacious interventions, ranging from telehealth and mobile apps to virtual reality and machine learning models. Opportunities for improving access to care, reducing patients' transfers, and utilizing real-world interaction data for symptom monitoring are highlighted. However, challenges such as digital exclusion, privacy concerns, and potential service replacement caution policymakers. This study serves as a valuable evidence base for policymakers and mental health stakeholders in the UAE to navigate the integration of digital technology in mental health services effectively.


Assuntos
Tecnologia Digital , Serviços de Saúde Mental , Telemedicina , Emirados Árabes Unidos , Humanos , Serviços de Saúde Mental/organização & administração , Transtornos Mentais/terapia
20.
Eur J Appl Physiol ; 2024 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-39307853

RESUMO

BACKGROUND: Although brief skin cooling (BSC) is widely used in sports medicine and rehabilitation for its positive effects on motor performance, the mechanism underlying this motor facilitation effect remains unclear. OBJECTIVES: To explore the hypothesis that BSC enhances muscle force generation, with cold-induced sympathetic activation leading to heightened muscle spindle sensitivity, thereby contributing to this effect. METHODS: The study involved two experiments. Experiment 1 included 14 healthy volunteers. Participants submerged their hand in ice water for 3 min. Sympathetic activity was measured via heart rate (HR), muscle force generation was assessed through plantar flexor strength during maximum voluntary contraction (MVC), and cortical contribution to force generation via the volitional wave (V-wave) with and without the cold pressor test (CPT). Experiment-2 involved 11 healthy volunteers and focused on muscle spindle sensitivity and Ia synapse efficacy, assessed using soleus T-reflex and H-reflex recordings before, during, and after CPT. RESULTS: Experiment 1 showed significant increases in HR (7.8%), MVC force (14.1%), and V-wave amplitude (93.4%) during CPT compared to pre-CPT values (p = 0.001, p = 0.03, and p = 0.001, respectively). In Experiment-2, hand skin temperature significantly decreased during CPT and remained lower than pre-CPT after 15 min (p < 0.001). While H-reflex and background EMG amplitudes remained unchanged, T-reflex amplitude (113.7%) increased significantly during CPT and returned to pre-CPT values immediately afterward (p < 0.001). A strong correlation was also observed between HR and T-reflex amplitude (r = 0.916, p = 0.001). CONCLUSION: BSC enhances muscle spindle sensitivity via the sympathetic nervous system, promoting more significant muscle force generation. The method used in this study can be safely applied in clinical practice.

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