Science Progress最新文献

A voltage mode capacitance multiplier for ultra-low frequency physiological signal processing is designed with a circuit model. With the proposed multiplier, a filter can achieve a cutoff frequency of 12 mHz with a 1 pF basic capacitance and a 10 kΩ resistor. The corresponding multiplication factor will be 1.35 × 10⁹. By changing the controlling terminal, the multiplication factor can be widely tuned from 1950 to 1.35 × 10⁹ and the corresponding filter cutoff frequency will be from 12 mHz to 8.15 kHz. According to the circuit model, to further increase the multiplication factor to decrease the chip area, more multiplication stages can be added to the feedback loop.

Among the components of high-tech ships, the structural complexity of the propeller profile requires a high degree of flexibility in the CNC polishing machine. In addressing this requirement, the study formulates the flexible optimization problem pertaining to research on the propeller CNC polishing machine. A comprehensive analysis is undertaken to scrutinize the geometric features of the propeller and the phenomenon of polished contact. The propeller profile-polishing head dynamic contact mechanism is revealed, and the contact force characteristics of propeller polishing are obtained. It is suggested that the propeller configuration-process-polishing machine structure coupling mechanism be explored under the influence of polishing contact force. Subsequently, a dynamic model of the propeller CNC polishing process is formulated. Based on the above model, a simulation of the motion personification and structural flexibility of the propeller CNC polishing machine is proposed to obtain dynamic personification and flexibility rules. Integrating polishing contact force characteristics with dynamic personification and flexibility rules, the dynamic flexible collaborative optimization principle of the propeller CNC polishing machine is revealed. On this basis, multi-objective optimization modeling and solving are carried out, forming a new method for the flexible optimization design of propeller CNC polishing machines.

Objectives: Basilar artery atherosclerotic plaque is the predominant cause of stroke in the posterior circulation. İscheamic stroke caused basilar artery atherosclerosis faces a high risk of recurrence despite optimal medical treatment, which might lie in the less than ideal recognition of underlying stroke mechanism and lack of individualized treatment for strokes of different mechanisms. We aim in this study to investigate the effect on stroke mechanism, stroke recurrence and clinical outcome in stroke patients with basilar artery atherosclerosis.

Methods: In this study, 107 ischaemic stroke patients with atherosclerotic stenosis in the BA who were followed up in Uludag University Faculty of Medicine between 1 January 2019 and 1 January 2022. The study was conducted retrospectively and observationally.

Results: According to the results of our study, the degree of stenosis in atherosclerotic stenosis of the symptomatic basilar artery was found to be an independent risk factor for stroke recurrence. Independent risk factors for unfavourable clinical outcomes in these patients were determined as female gender, stenosis being in the proximal segment, stroke mechanism being from artery to artery embolism, and congestive heart failure.

Conclusion: The most striking result of our study is that clinical outcome was found to be closely related to the female gender, the stroke mechanism being artery-to-artery embolism, and the stenosis is in the proximal segment. If stroke mechanisms were evaluated more clearly, it would likely help provide individualised treatments.

Melatonin, N-acetyl-5-methoxytryptamine, is a neuroendocrine hormone secreted by the pineal gland. This pleiotropic indoleamine possesses amphiphilic properties, allowing it to penetrate most biological barriers and exert its effects at the subcellular level. Importantly, melatonin also plays a crucial role in regulating the body's response to circadian rhythms, adapting to internal and external environmental cues. Melatonin functions as a powerful antioxidant and free radical scavenger, protecting cells from oxidative damage. Its diverse physiological roles include maintaining the functional integrity of endothelial cells, thereby preventing atherosclerosis, a major contributor to cardiovascular disease. Additionally, melatonin exhibits antioxidant and free radical scavenging properties, potentially improving metabolic disorders. These combined effects suggest a unique adjunctive therapeutic potential for melatonin in treating cardiovascular diseases. This review aims to explore the mechanisms by which melatonin interacts with the cardiovascular system and investigates its potential use as an adjunctive therapeutic agent in managing cardiovascular disease.

With the continuous improvement in the efficiency of the heavy-haul railway freight transportation, the pressure on on-site maintenance is increasing. In-depth research on fault characteristics carries significant importance for fault scientific judgment and fault prevention. This study proposes an efficient association rule mining (ARM) algorithm, HM-RDHP, for analyzing fault data from heavy-haul railway freight trains. The algorithm introduces distributed parallel computing technology, integrating the MapReduce framework and HBase on the Hadoop platform to process large volumes of complex fault data efficiently. Experimental results show that the HM-RDHP algorithm can efficiently uncover hidden patterns and associations within the fault data of heavy-haul railway freight trains. The mined association rules provide a valuable reference model to aid in predictive maintenance and fault prevention strategies for freight train maintenance departments.

As sessile photoautotrophs, plants constantly encounter diverse environmental stresses. Recent research has focused on elucidating sugar and energy signaling mediated by hexokinase (HXK), sucrose non-fermenting 1-related protein kinase 1 (SnRK1), and the target of rapamycin (TOR) and assessing its intricate interplay with hormones and secondary metabolism. HXK serves as a pivotal regulator of glucose sensing and metabolism. It affects plant growth and development in response to nutrient availability. SnRK1 acts as a vital energy sensor that regulates metabolic adjustments during stress to bolster plant resilience. Moreover, TOR integrates nutrient signals to finely modulate growth and development, balancing cellular metabolism and resource allocation. Understanding the functions of HXK, SnRK1, and TOR can provide profound insights into plant adaptation mechanisms and open promising avenues for leveraging biotechnological strategies to enhance the stress tolerance and nutritional value of crops. This narrative review focuses on recent advancements in the molecular mechanisms of HXK, SnRK1, and TOR and explores their potential applications in agricultural biotechnology.

In modern cryptography, Substitution Boxes (S-boxes) are critical in introducing confusion into ciphertext, significantly enhancing encryption security. With the rising sophistication of hacking techniques, there is a growing need to develop stronger and more dynamic S-boxes. This paper proposes a novel method for constructing cryptographically secure S-boxes using graph theory, specifically based on the Minimum Spanning Tree (MST) of cycle graphs. The process begins by converting plaintext into vertices, forming a cycle graph. Special characters are incorporated, and ASCII-based values are assigned to vertices. The distance between vertices is calculated using their intersections, leading to the creation of an MST graph. The final step involves obtaining the adjacency matrix, which is further processed to generate the S-box. The S-box's unpredictability is enhanced by employing the S₂₅₆ permutation from the symmetric group. Various cryptographic tests are conducted to evaluate the proposed S-box's performance, with results demonstrating its robustness when compared to existing S-box designs. Furthermore, this S-box is applied to an image encryption scheme, and its efficacy is thoroughly assessed. The findings highlight the potential of the proposed method to contribute significantly to cryptographic security.

The corrosion of metals, particularly rust on iron and its alloys, poses significant challenges across industries, with notable economic and environmental consequences. Traditional rust prevention methods, reliant on chemical inhibitors and coatings, often raise concerns regarding their environmental and health impacts. In response, advancements in corrosion science have emphasized the potential of o-phenylenediamine (OPD) derivatives and vaseline-based mixtures as innovative, eco-friendly solutions. This article reviews the efficacy of OPD derivatives in mitigating anodic and cathodic reactions, thereby preventing rust formation by creating robust protective layers on metal surfaces. These derivatives act as physical barriers, impeding corrosive agents and offering versatile applications, including integration into protective coatings for new and existing metal structures. The synergistic combination of OPD with other inhibitors enhances protection, supporting sustainable practices by reducing resource consumption and environmental impact. Vaseline-based layers, while providing satisfactory initial hydrophobicity and ease of application, face challenges such as achieving uniform coverage on polar metal surfaces and preventing pore formation. Integrating Fe(III)(BTA)₃ into vaseline coatings represents a paradigm shift in sustainable corrosion prevention, with a 30% concentration identified as optimal for maximum protection. This development marks a pivotal advancement in materials science, offering robust corrosion protection aligned with sustainability principles. The use of OPD derivatives introduces a novel, environmentally benign approach, leveraging their ability to adsorb onto metal surfaces and create protective layers against moisture and oxygen. This innovation aligns with global initiatives to reduce industrial environmental footprints, promoting sustainable, effective corrosion prevention strategies.

Objective: This retrospective study aimed to investigate the correlation between neutrophil gelatinase-associated lipocalin (NGAL) levels and the clinical progression and severity of diabetes-related acute kidney injury (AKI). The quantitative determination of NGAL in plasma on the Beckman Coulter AU480 analyzer was measured using the Bioporto NGAL Test^TM, a particle-enhanced turbidimetric immunoassay with hospitalized patients at an East Central Georgia Medical Center.

Methods: The clinical determination of plasma NGAL included a retrospective cohort study where 45 adult patients were selectively recruited. The selective criteria were patients with and without diabetes mellitus (DM) at risk for developing AKI admitted to the Medical Center between January and November 2023. All patients included in the study had pNGAL levels measured upon admission and up to 96 h post-admission. Receiver operating characteristics and likelihood ratio methods were used to determine optimal sensitivity, specificity, and cutoff value of pNGAL in AKI patients associated with and without DM.

Results: The intra-assay and interassay imprecision percent relative standard deviation was between 2.7% and 4.2%. pNGAL levels were higher for patients with AKI compared to non-AKI patients, regardless of DM status. The optimal cutoff value for pNGAL to predict AKI for patients with DM was 293 ng/mL, with a sensitivity of 80% and specificity of 87%. In a multivariate logistic regression model, pNGAL levels at 48 h post-admission were determined to be associated with diabetes-related AKI patients.

Conclusion: Plasma NGAL levels at 48 h are associated with patients with diabetes-related AKI. The specific cutoff values for AKI for early diagnosis and risk stratification and its association with comorbidities must be determined to improve patient outcomes.

Aims: Patients with epistaxis typically visit the emergency department for initial treatment. According to recent studies, tranexamic acid (TXA) is effective in the treatment of epistaxis. This study compared the therapeutic superiority of saline to that of 500 and 1000 mg doses of topical TXA for the treatment of anterior epistaxis. Materials and methods: This phase 4 clinical trial was a randomized, controlled, and double-blind trial. A total of 152 patients were divided into three groups. Group 1 was treated with 1000 mg TXA, Group 2 with 500 mg TXA, and Group 3 with saline. Results: Based on multinomial logistic regression analysis, the bleeding frequency at the 5th minute was 2.9 times and rebleeding status was 4.3 times less in Group 1 (1000 mg TXA) than in Group 3 (saline). There were no differences between the three groups in terms of side effects or salvage therapy. Conclusion: In addition to its superiority in treatment, 1000 mg of TXA is recommended because of the decreased rate of recurrent bleeding and low incidence of side effects.