Advancements in Subchondral Bone Biomechanics: Insights from Computed Tomography and Micro-Computed Tomography Imaging in Equine Models.

PURPOSE OF REVIEW: This review synthesizes recent advancements in understanding subchondral bone (SCB) biomechanics using computed tomography (CT) and micro-computed tomography (micro-CT) imaging in large animal models, particularly horses. RECENT FINDINGS: Recent studies highlight the complexity of SCB biomechanics, revealing variability in density, microstructure, and biomechanical properties across the depth of SCB from the joint surface, as well as at different joint locations. Early SCB abnormalities have been identified as predictive markers for both osteoarthritis (OA) and stress fractures. The development of standing CT systems has improved the practicality and accuracy of live animal imaging, aiding early diagnosis of SCB pathologies. While imaging advancements have enhanced our understanding of SCB, further research is required to elucidate the underlying mechanisms of joint disease and articular surface failure. Combining imaging with mechanical testing, computational modelling, and artificial intelligence (AI) promises earlier detection and better management of joint disease. Future research should refine these modalities and integrate them into clinical practice to enhance joint health outcomes in veterinary and human medicine.

Mechanism of flavonols on detoxification, migration and transformation of indium in rhizosphere system.

Soil contamination by toxic heavy metal induces serious environmental hazards. In recent years, the use of indium (In) in semiconductor products has increased considerably and the release of In is inevitable, which will pose great risk to the ecosystem. The interaction between metal and plants which are the fundamental components of all ecosystems are an indispensable aspect of indium assessment and remediation. The role of flavonols, which is essential to plant resistance to In stress, remains largely unknown. FLS1 related lines of A. thaliana (Col, fls1-3 and OE) were exposed to In stress in soil and flavonols as root exudates were analyzed in exogenous application test. The accumulation and release of flavonols could be induced by In stress. However, flavonols exhibited different function in vivo and in vitro of plant. The basic function of flavonols was to affect root morphology via regulating auxin, but being intervened by In stress. The synthesis and accumulation of flavonols in vivo could activate the antioxidant system and the metal detoxification system to alleviate the toxic effects of In on plant. In addition, plants could make phone calls to rhizosphere microbes for help when exposed to In. Flavonols in vitro might act as the information transmission. Combination of endogenous and exogenous flavonols could affect the migration and transformation of In in soil-plant system via metal complexation and transportation pathway.

Numerical Study on the Impact of Locked-In Stress on Rock Failure Processes and Energy Evolutions.

Locked-in stress refers to internal stress present within rock formations that can influence the failure process of rocks under specific conditions. A simplified mechanical model is applied, drawing on elasticity and the hypothesis of locked-in stress, to explore the influence of locked-in stress on the mechanical properties of loaded rocks. An analytical solution is obtained for the stress distribution in a failure model of rocks that include locked-in stress. The findings demonstrate that the geometry and orientation of stress inclusions within the rock influence the initiation and propagation of cracks under the combined influence of locked-in stress and high-stress conditions. Moreover, the presence of locked-in stress substantially reduces the rock's capacity to withstand maximum stress, thereby increasing its susceptibility to reaching a state of failure. The increase in closure stress leads to a significant increase in the magnitude of the maximum stress drop and radial strain variation within the rock, resulting in reduced strength and a shortened life of the ageing failure of the rock. In addition, the influence of stress inclusions on energy dissipation is investigated, and a novel relationship is established between the roughness coefficient of the rock structure surface and the angle of the rock failure surface. This relationship serves to characterize the linear dynamic strength properties of rock materials containing locked-in stress. This investigation not only advances the comprehension of stress distribution patterns and the effects of locked-in stress on rock failure patterns but also facilitates a more precise portrayal of the nonlinear features of alterations in the rock stress-strain curve under the influence of confined stress. These findings provide a solid theoretical foundation for ensuring the safety of excavations in various deep engineering projects.

Malignant Hypertension Without End-Organ Damage Secondary to Stressful Condition in a Female.

Malignant hypertension (hypertensive emergency), is an extreme elevation of blood pressure under certain conditions that can lead to organ damage and other serious consequences. It is a common condition that affects about one in three Americans, according to the Centers for Disease Control and Prevention. An elevation of systolic blood pressure above 180 mmHg and diastolic blood pressure above 120 mmHg is considered a hypertensive emergency. This article addresses the case of a 61-year-old female patient who presented to the ER with a semicomatose and gasping condition and response to painful stimuli with an unclear voice. She also had unstable vital signs, with a blood pressure of 370/200 mmHg, a pulse rate of 115, a respiratory rate of 22, and a pulse oximetry of 96%, but no fever. Her son provided a brief history and reported that a stressful condition had occurred at home one hour before; she had begun to scream and been brought to the ER by ambulance in the condition described above. Cardiac monitoring and an electrocardiograph were performed and indicated a normal condition besides the unstable vital signs. Oxygen was administered via a nasal cannula with 20 mg of intravenous hydralazine, and the patient's blood pressure improved progressively. Moreover, she regained consciousness with no end-organ damage. A hypertensive emergency is usually associated with end-organ damage, such as heart, kidney, eye, or brain damage. However, in this case, despite the extreme elevation of her blood pressure, the patient suffered no organ damage. It is essential to manage the extreme elevation of blood pressure as soon as possible and monitor the patient for consequences.

A standardized method to determine the effect of polymerization shrinkage on the cusp deflection and shrinkage induced built-in stress of class II tooth models.

OBJECTIVES: Using standardized aluminum tooth models, this study: 1) measured the deflection along the cusp wall of models with a Class II cavity restored using either bulk filling or horizontal incremental filling techniques, and 2) calculated the cusp deflection and built-in stress within the restored tooth models for both filling techniques using a finite element (FE) model. METHODS: Standardized tooth models with Class II cavities 4 mm deep, 4 mm high and 6 mm wide were machined out of aluminum. The models were restored using Filtek Posterior Restorative A2 shade resin-based composite (RBC). Both bulk filling and horizontal incremental filling techniques were used to restore the tooth models. After photocuring for 20 s from a single peak wavelength light-curing unit (LCU) with a radiant exitance of 1.25 W/cm2, the deflection of the cusp wall surface was measured using a profilometer. A FE model was used to predict the cuspal deflection and built-in stress of the restored tooth models. RESULTS: The elastic modulus within the FE model was parameterized using cusp deflection data obtained on a bulk filled tooth model. An agreement was found between the measured and predicted cusp deflection only when considering partial stress relaxation within the first incremental layer for the two-layer incremental filling technique. The calculated built-in stress was significantly reduced within the RBC and along the cavity walls when the cavity was filled incrementally in a horizontal direction compared to when it was bulk filled, resulting in a significantly smaller cusp deflection. SIGNIFICANCE: The FE model was first calibrated and then validated using measured cusp deflection data. Partial stress relaxation may play a significant role in the horizontal incremental filling technique. The model can be used to predict where the built-in stress within the tooth model occurs. This study explains why for a given RBC, a horizontal incremental filling and curing technique results in lower built-in stress within the restored tooth and lower cusp deflection compared to the bulk curing technique.

Bacterial Compound N,N-Dimethylhexadecylamine Modulates Expression of Iron Deficiency and Defense Response Genes in Medicago truncatula Independently of the Jasmonic Acid Pathway.

Plants face a variety of biotic and abiotic stresses including attack by microbial phytopathogens and nutrient deficiencies. Some bacterial volatile organic compounds (VOCs) activate defense and iron-deficiency responses in plants. To establish a relationship between defense and iron deficiency through VOCs, we identified key genes in the defense and iron-deprivation responses of the legume model Medicago truncatula and evaluated the effect of the rhizobacterial VOC N,N-dimethylhexadecylamine (DMHDA) on the gene expression in these pathways by RT-qPCR. DMHDA increased M. truncatula growth 1.5-fold under both iron-sufficient and iron-deficient conditions compared with untreated plants, whereas salicylic acid and jasmonic acid decreased growth. Iron-deficiency induced iron uptake and defense gene expression. Moreover, the effect was greater in combination with DMHDA. Salicylic acid, Pseudomonas syringae, jasmonic acid, and Botrytis cinerea had inhibitory effects on growth and iron response gene expression but activated defense genes. Taken together, our results showed that the VOC DMHDA activates defense and iron-deprivation pathways while inducing a growth promoting effect unlike conventional phytohormones, highlighting that DMHDA does not mimic jasmonic acid but induces an alternative pathway. This is a novel aspect in the complex interactions between biotic and abiotic stresses.

In-Fiber Production of Laser-Structured Stress-Mediated Semiconductor Particles.

The ability to generate stressed semiconductor particles is of great importance in the development of tunable semiconductor and photonic devices. However, existing methods including both bottom-up synthesis and top-down fabrication for producing semiconductor particles are inherently free of stress effects. Here, we report a simple approach to generate controllable stress effects on both encapsulated and free-standing semiconductor particles using laser-structured in-fiber materials engineering. The physical mechanism of thermally induced in-fiber built-in stress is investigated, and the feasibility of precisely tuning the stress state during the particle formation is experimentally demonstrated by controlling the laser treatment. Gigapascal-level built-in stress, which is a sufficiently strong stimulus to enable inelastic deformations on the fabricated semiconductor particles, has been achieved via this approach. Both encapsulated and free-standing stressed semiconductor particles are generated for a wide range of in-fiber and out-fiber optoelectronic and biomedical applications.

Specificity in mediated pathways by anxiety symptoms linking adolescent stress profiles to depressive symptoms: Results of a moderated mediation approach.

BACKGROUND: We investigated the specificity in mediated pathways that separately link specific stress dimensions through anxiety to depressive symptoms and the protective utility of resilience. Thus, this study goes beyond lumping together potential mediating and moderating processes that can explain the relations between stress and (symptoms of) psychopathology and the buffering effect of resilience. METHODS: Ghanaian adolescents between 13 and 17 years (female = 285; male = 244) completed the Adolescent Stress Questionnaire (ASQ), Spielberger State Anxiety Inventory (STAI), Short Mood Feeling Questionnaire (SMFQ) and the Resilience Scale for Adolescents (READ). Independent samples t-test, multivariate analysis of covariance with follow-up tests and moderated mediation analyses were performed. RESULTS: Evidences were found for specificity in the associations between dimensions of adolescent stressors and depressive symptoms independent of transient anxiety. Transient anxiety partly accounted for the indirect effects of eight stress dimensions on depressive symptoms. Except stress of school attendance and school/leisure conflict, resilience moderated the indirect effects of specific stress dimensions on depressive symptoms. Results suggested differences in how Ghanaian adolescents view the various stress dimensions, and mediated pathways associated with anxiety and depressive symptoms. LIMITATIONS: Use of cross-sectional data does not show causal process and temporal changes over time. CONCLUSIONS: Findings support and clarify the specificity in the interrelations and mediated pathways among dimensions of adolescent stress, transient anxiety, and depressive symptoms. Conditional process analyses shows that resilience does not only buffer direct, but also indirect psychological adversities. Interventions for good mental health may focus on low resilience subgroups in specific stress dimensions while minimizing transient anxiety.

Role of urodynamics in stress urinary incontinence: A critical appraisal.

INTRODUCTION: Role of urodynamics prior to surgery of stress urinary incontinence (SUI) is under constant debate. Demonstration of the presence of detrusor overactivity is the only aspect that has been emphasized in the literature so far. We believe that there are number of other factors which may influence the evaluation and in turn the choice of surgical management and prediction of outcome of treatment. They are as follows: (1) Presence of voiding inefficiency, (2) asymptomatic detrusor overactivity, (3) and severity of SUI. These features may complicate the precise evaluation of patients of SUI. The main objective of this study is to analyze the dynamics of leakage and voiding using urodynamics. This study also aims at correlating these findings with clinical information. MATERIALS AND METHODS: One hundred consecutive cases referred to our center for preoperative evaluation of SUI were recruited in the study prospectively. All patients were interrogated using International Consultation on Incontinence Questionnaire. All patients underwent complete urodynamic evaluation including uroflowmetry, filling cystometry, leak point pressure measurement, and pressure flow studies, according to Good Urodynamic Practice guidelines. Patients' symptoms were correlated with urodynamic findings, with special emphasis on the presence of detrusor overactivity, severity of SUI, voiding efficiency, and presence of bladder outlet obstruction. Clinical information and urodynamic findings were correlated using Chi-square test. RESULTS: There is a statistically significant correlation between the presence of symptoms of urge urinary incontinence and urodynamic findings of detrusor overactivity at P < 0.05. There is a statistically significant correlation between the symptoms of urge incontinence (in addition to SUI) and urodynamic findings of intrinsic sphincter deficiency at P < 0.05. Fifteen of 51 patients who did not have associated storage symptoms were found to have some degree of detrusor overactivity on urodynamic evaluation. There was no statistically significant correlation between asymptomatic cases of urge incontinence and incidental finding of detrusor overactivity at P < 0.05. There is no statistically significant correlation between the urodynamic findings of symptoms of voiding dysfunction and urodynamic findings, suggestive of the same value at P < 0.05. CONCLUSIONS: Urodynamic study in SUI has a potential of giving much more information than demonstration of Detrusor Overactivity alone. The predominant symptom of urge urinary incontinence can predictably diagnose detrusor overactivity in these cases. However, the incidence of asymptomatic detrusor overactivity remains as high as 15% and may have implication in postoperative results. This study clearly shows that there is a definite incidence of significant voiding dysfunction, which cannot be reliably evaluated without properly conducted pressure flow study. This factor may govern the choice of correct treatment which also predicts the outcome more reliably. Preoperative urodynamic study thus adds a dimension of precision to evaluation of the patients of SUI and may also influence technique and outcome measures in this group of patients.

CaPUB1, a Hot Pepper U-box E3 Ubiquitin Ligase, Confers Enhanced Cold Stress Tolerance and Decreased Drought Stress Tolerance in Transgenic Rice (Oryza sativa L.).

Abiotic stresses such as drought and low temperature critically restrict plant growth, reproduction, and productivity. Higher plants have developed various defense strategies against these unfavorable conditions. CaPUB1 (Capsicum annuum Putative U-box protein 1) is a hot pepper U-box E3 Ub ligase. Transgenic Arabidopsis plants that constitutively expressed CaPUB1 exhibited drought-sensitive phenotypes, suggesting that it functions as a negative regulator of the drought stress response. In this study, CaPUB1 was over-expressed in rice (Oryza sativa L.), and the phenotypic properties of transgenic rice plants were examined in terms of their drought and cold stress tolerance. Ubi:CaPUB1 T3 transgenic rice plants displayed phenotypes hypersensitive to dehydration, suggesting that its role in the negative regulation of drought stress response is conserved in dicot Arabidopsis and monocot rice plants. In contrast, Ubi:CaPUB1 progeny exhibited phenotypes markedly tolerant to prolonged low temperature (4°C) treatment, compared to those of wild-type plants, as determined by survival rates, electrolyte leakage, and total chlorophyll content. Cold stress-induced marker genes, including DREB1A, DREB1B, DREB1C, and Cytochrome P450, were more up-regulated by cold treatment in Ubi:CaPUB1 plants than in wild-type plants. These results suggest that CaPUB1 serves as both a negative regulator of the drought stress response and a positive regulator of the cold stress response in transgenic rice plants. This raises the possibility that CaPUB1 participates in the cross-talk between drought and low-temperature signaling pathways.

Measurement of nonlinear property of artery wall using remote cyclic actuation.

PURPOSE: For tissue characterization of the arterial wall, we developed a "phased tracking" method to measure the strain (change in wall thickness) and elasticity of the arterial wall. To improve the accuracy of tissue characterization, we are now attempting to measure other mechanical properties in addition to elasticity. METHODS: In this study, the change in elasticity during the cardiac diastole was measured with ultrasound by generating a change in internal pressure using remote cyclic actuation. RESULTS: From the measured change in elasticity during cardiac diastole, the nonlinear property in the stress-strain relationship of the artery wall was estimated. In basic experiments using a silicone rubber tube and in vivo experiments in human carotid arteries. CONCLUSION: The proposal method enables the noninvasive measurement of the nonlinear mechanical property in addition to the elasticity of the arterial wall.