Advances in experimental medicine and biology最新文献

The rapid advancement of digital technologies has reshaped education, yet significant barriers persist in ensuring equitable access for students with disabilities. Digital accessibility in education extends beyond technological solutions, requiring institutional commitment, policy reform, and faculty preparedness. This study examines the challenges and opportunities associated with digital accessibility in higher education and workplace inclusion, emphasizing systemic barriers such as inadequate assistive technologies, inaccessible Learning Management Systems (LMSs), and insufficient faculty training. The findings highlight the transformative potential of adaptive learning strategies, including artificial intelligence (AI), extended reality (XR), and human-computer interaction (HCI), in fostering personalized and inclusive learning environments. However, ethical concerns, algorithmic biases, and inconsistent implementation pose substantial obstacles to their effectiveness. The COVID-19 pandemic further exposed critical shortcomings in digital accessibility policies, disproportionately affecting students and employees with disabilities and underscoring the need for inclusive digital literacy initiatives. Addressing these challenges necessitates a holistic approach that integrates universal design principles, strengthens faculty training programs, and fosters interdisciplinary collaboration between educators, policymakers, and technologists. Through this review, sustained investment in assistive technologies is advocated, along with regulatory frameworks mandating digital inclusivity, and the development of digital learning ecosystems. By embedding accessibility as a fundamental component of educational and employment policies, institutions can mitigate the digital divide and advance equitable opportunities for all learners.

Caffeine, a habit-forming substance of no nutritional value, is consumed daily by most pregnant women. This focused narrative review examines evidence of association between maternal caffeine consumption and negative pregnancy outcomes, and assesses whether current advice guidelines are consistent with the available evidence. The majority finding from original empirical studies, systematic reviews, and meta-analyses is that maternal consumption of caffeine is reliably associated with serious negative pregnancy outcomes and negative outcomes in offspring. Evidence of harm is strong for miscarriage, stillbirth, and low birth weight and/or small for gestational age, while being less strong for childhood acute leukemia, childhood overweight and obesity, and childhood behavioural and neurocognitive development. In contrast, preterm birth appears not to be at increased risk. Many studies report significant dose-response associations indicative of causation and the absence of a threshold of consumption below which associations are absent. In general, findings are robust to threats from potential confounding and misclassification. Notwithstanding compelling grounds to the contrary, national and international authorities continue to suggest that "moderate" caffeine consumption during pregnancy is safe. Rather, pregnant women and women contemplating pregnancy should be advised not to consume coffee, tea, sodas, or energy drinks that contain caffeine.

Prenatal alcohol exposure (PAE) is recognized as a teratogenic factor that affects neural development, resulting in a range of structural, functional, and cognitive/behavioral abnormalities contributing to the pathogenesis of fetal alcohol spectrum disorder (FASD). FASD is a major preventable cause of developmental delay in humans. There are many molecular and cellular mechanisms by which PAE could contribute to abnormalities seen in individuals with FASD. Understanding these mechanisms will be critical for the development of therapeutic approaches that could benefit not only the developing fetus, but the newborn as they mature into adolescence and adulthood. The goal of this review is to discuss the impact of PAE on neural and vascular development/function and define potential cellular/molecular mechanisms that contribute to the effects of PAE. We believe that an understanding regarding the influence of PAE on cerebral vascular function may provide insights into the pathogenesis of symptoms related to FASD.

Tissue engineering in pediatric dentistry focuses on regenerating damaged dental tissues in children, aiming to restore their natural functions and address challenges associated with immature teeth. This field applies interdisciplinary biological principles to repair and regenerate tissues, using biomaterials, stem cells, and growth factors. Current advancements emphasize the regeneration of the dentin-pulp complex and tooth development through the use of biomaterials such as collagen, which offers structural support for cell growth and favorable interactions in tissue engineering. Additionally, various growth factors like FGF, TGF-β, BMP, and VEGF play vital roles in tissue regeneration by regulating signaling mechanisms in the dentin-pulp complex. Stem cells, particularly dental-derived ones such as DPSCs, SHEDs, and PDLSCs, have shown great potential in regenerating dental tissues in pediatric patients. These multipotent cells are capable of differentiating into various lineages, including odontoblasts, and are essential for the regeneration of both soft and hard dental tissues. While gene therapy, scaffolding techniques, and advanced technologies like three-dimensional (3D) bioprinting hold promise for tissue engineering, challenges remain in clinical implementation due to high costs and the need for further research. However, tissue engineering has already begun revolutionizing pediatric dental treatments, particularly in regenerative endodontics, and offers a minimally invasive alternative to traditional procedures like root canal treatments for young immature teeth. The future of regenerative dentistry in pediatric care lies in improving the application of stem cell-based therapies and bioactive materials to achieve complete tissue regeneration and provide more effective, personalized care for young patients.

Bone implants and stents are medical devices that are commonly used to treat bone and cardiovascular diseases, respectively. Both require successful integration with the surrounding tissue to achieve long-term success. Osteointegration, the process by which the implant becomes integrated with the surrounding bone, is critical to the success of bone implants, while the stent healing process involves endothelialization, re-endothelialization, and neointimal formation. The healing process of bone is complex and influenced by various factors, including the properties of the implant material, the surgical technique, and patient factors such as age and overall health. Several materials have been developed for bone implants, including metals, ceramics, and polymers. The choice of material depends on the specific application, as each material has unique properties that affect its suitability for a particular use. For example, titanium is commonly used in orthopedic implants due to its biocompatibility, strength, and ability to promote osteointegration. The healing process of stents is influenced by the materials used and the stent design. Drug-eluting stents, which release drugs to reduce restenosis, have been developed to improve the healing process. Endothelialization, the formation of a layer of endothelial cells over the stent, is critical to the prevention of restenosis. Neointimal formation, the formation of new tissue over the stent, can cause restenosis and has been a major concern with bare-metal stents. Factors that affect osteointegration and stent healing process include implant surface properties, such as roughness and topography, as well as the size, shape, and placement of the implant. In addition, patient factors such as age, overall health, and medication use can also affect the healing process. In conclusion, successful integration with the surrounding tissue is critical to the long-term success of bone implants and stents. The choice of implant material, surgical technique, and patient factors all play a role in the healing process, and ongoing research is needed to improve the design and performance of these medical devices.

This study aimed to determine the changes in the time to nadir of mean arterial pressure (MAP) and oxygenated hemoglobin (O₂Hb) in the right and left prefrontal cortices (R-PFC and L-PFC, respectively) during repeated episodes of rapid hypotension. Four cycles of blood pressure reduction were induced via bilateral thigh occlusion at 250 mmHg followed by rapid deflation. Sixteen healthy male university students participated. MAP was recorded beat by beat, and O₂Hb was continuously monitored using near-infrared spectroscopy. The time from deflation to nadir was measured and compared across each deflation cycle. MAP and O₂Hb in the R-PFC and L-PFC reached their nadir values approximately 7 to 8 s post-deflation, with no significant changes observed across repetitions. These findings indicate that the time to nadir of MAP and O₂Hb in the R-PFC and L-PFC remains stable during repeated rapid hypotension.

In continuous-wave electron paramagnetic resonance (CW-EPR) imaging, many spectral projections are required to accurately reconstruct four-dimensional (4D) spectral-spatial data, which are used for oxygen mapping in tumors. The ability to obtain fewer spectral projections with less degradation of the resultant image quality is desirable because acquiring many spectral projections leads to a longer time for EPR imaging acquisition. The algebraic reconstruction technique (ART) is one of the most powerful image-reconstruction techniques for 4D spectral-spatial imaging. ART can be applied to incomplete sets of spectral projections. However, data sets of many spectral projections can provide reconstructed images of higher quality. In this study, we aimed to enhance acquisition speed by randomly collecting spectral projections and subsequently synthesizing those that had not been recorded. We applied this strategy to a numerical phantom and a mouse Hs766T xenograft model to confirm the feasibility of our concept. Random acquisition can prevent image degradation in linewidth mapping, which is the foundation for oxygen mapping with CW-EPR.

Background: The diaphragm muscle is the primary muscle involved in inspiration and is unique to mammals. Because the diaphragm is a constantly active muscle, its contraction may depend on oxidative phosphorylation and O₂ supply to create adenosine triphosphate. This study aimed to evaluate the role of intrinsic vasodilator nitric oxide (NO) in diaphragm O₂ dynamics.

Methods: Wistar male rats (n = 6, 10 wks old, 311 ± 14 g) were mechanically ventilated under isoflurane anesthesia. The diaphragm was exposed to measure microvascular partial O₂ pressure (PO₂mv) by phosphorescence quenching technique during electrical stimulation-induced diaphragm contractions (6 V, 2 ms, 2 Hz, 180 s). The 180 s of muscle contractions and PO₂mv measurement were repeated 10 min after endothelial NO synthase inhibition by the intra-arterial infusion of nitro-l-arginine methyl ester (L-NAME; eNOS inhibitor). The PO₂mv change during the transition from rest to contraction was fitted to a nonlinear regression model. Time delay, time constant (tau), rate constant (K), and nadir in PO₂mv were calculated and compared before and after eNOS inhibition. [Results] Diaphragm PO₂mv decreased during contractions both before and after eNOS inhibition. The time delay and K were not different before and after L-NAME. However, the L-NAME administration decreased the tau and nadir in PO₂mv (tau, 7.61 [5.18-13.41] vs. 3.36 [1.81-5.57] s; nadir, 7.45 [1.41-14.85] vs. 3.93 [0.89-9.47] mmHg; before vs. after eNOS inhibition, median [25-75 percentiles], P < 0.05, respectively).

Discussion: The time constant in PO₂mv is determined by oxygen supply to the capillaries and oxygen utilization. The faster time constant and lower nadir in PO₂mv possibly indicate the slower and lower oxygen supply to diaphragm capillaries after eNOS inhibition.

Conclusion: The NO has a crucial role in the diaphragm oxygen dynamics of intact rats.

Mobilization of critically ill patients within 72 hours of admission is associated with improved outcomes. Recently, the predictive value of regional cerebral oxygen saturation (rSO₂) measured via near-infrared spectroscopy (NIRS) has been emphasized. This study aimed to evaluate the differences in rSO₂ values depending on the availability of mobilization within 72 hours in the ICU. Eighty patients admitted to the emergency center between June 2020 and December 2022 were analyzed. Patients were assessed based on whether they could be mobilized within 72 hours (early mobilization group, EM) or later (non-early mobilization group, non-EM). During mobilization, prefrontal rSO₂ values were monitored. Regarding patient background, significant differences were noted between the groups, including delayed release in non-EM patients. rSO₂ values varied significantly, with the lowest values in the first half of end-sitting in both groups (non-EM 56.5 ± 4.8%, EM 58.6 ± 4.3%, p < 0.05). The rSO₂ value was also lower in the non-EM group than in the EM group (P < 0.014). A weak correlation was observed between rSO₂ and the number of days to first mobilization (r = -0.251, p = 0.025). The rSO₂ value may serve as a potential marker to guide the timing of mobilization in ICU patients.

A theoretical framework is presented to clarify the role of architectural and structural forces in ion selectivity. It expresses the relative free energy of bound ions in terms of a reduced subsystem corresponding to the local degrees of freedom coupled to the rest of the protein. The latter is separated into a first contribution that includes all the forces keeping the ion and the coordinating ligands confined to a microscopic sub-volume but do not prevent the ligands from adapting to a smaller ion, while the second contribution regroups the remaining forces that serve to dictate the precise geometry of the coordinating ligands best adapted to a given ion. The theoretical framework makes it possible to delineate two important limiting cases. In the limit where the geometric forces are dominant (rigid binding site), selectivity is controlled via the cavity size according to the familiar "snug-fit" mechanism of host-guest chemistry. In the limit where the geometric forces are negligible, the ion and ligands behave as a dynamical "confined droplet" that is free and adapt to the ion's size. In this case, selectivity is controlled by the number and the chemical type of ion-coordinating ligands.