A variety of industrial applications such as power generation, water distillation, and high-density cooling rely on heat transfer processes involving boiling. Enhancements to the boiling process can ...improve the energy efficiency and performance across multiple industries. Highly wetting textured surfaces have shown promise in boiling applications since capillary wicking increases the maximum heat flux that can be dissipated. Conversely, highly nonwetting textured (superhydrophobic) surfaces have been largely dismissed for these applications as they have been shown to promote formation of an insulating vapor film that greatly diminishes heat transfer efficiency. The current Letter shows that boiling from a superhydrophobic surface in an initial Wenzel state, in which the surface texture is infiltrated with liquid, results in remarkably low surface superheat with nucleate boiling sustained up to a critical heat flux typical of hydrophilic wetting surfaces, and thus upends this conventional wisdom. Two distinct boiling behaviors are demonstrated on both micro- and nanostructured superhydrophobic surfaces based on the initial wetting state. For an initial surface condition in which vapor occupies the interstices of the surface texture (Cassie-Baxter state), premature film boiling occurs, as has been commonly observed in the literature. However, if the surface texture is infiltrated with liquid (Wenzel state) prior to boiling, drastically improved thermal performance is observed; in this wetting state, the three-phase contact line is pinned during vapor bubble growth, which prevents the development of a vapor film over the surface and maintains efficient nucleate boiling behavior.
•Simulation of diabatic bubble growth for hygrophilic, hygrophobic, and ambiphilic surfaces.•Unique heat transfer behavior and promising performance of ambiphilic surfaces revealed.•Minimizing ...receding contact angle mitigates vapor spreading, reduces departure time.•Increasing advancing contact angle maximizes nucleation site density.•Decreasing advancing contact angle maximizes microlayer heat transfer.
Decades of prior study has yet to fully disentangle the complex transport mechanisms that are attributed to highly effective heat transfer during boiling. Rational design of enhanced surfaces to maintain lower surface temperatures during boiling requires improved insight into the individual heat transfer processes and their dependence on surface characteristics. This study seeks to advance the understanding of the fundamental role that surface wettability plays in determining the relative contributions of different heat transfer mechanisms and on the overall heat transfer efficacy during bubble growth. Two-phase, diabatic simulations of single bubble growth considering interfacial phase change and a custom dynamic contact angle framework are employed to investigate how the distinct contact-line and bubble dynamics that are experienced on hygrophilic, hygrophobic, and ambiphilic surfaces impact heat transfer. The local surface temperature and heat flux profiles underneath the bubble are examined during the receding, pinning, and advancing stages of bubble growth to explore the dominant heat transfer modes at each stage. The results indicate that both hygrophilic and ambiphilic surfaces are promising candidates for the development of enhanced surfaces, but for different reasons related to microlayer heat transfer versus nucleation characteristics, respectively. Target ranges for the dynamic receding and advancing contact angles within each wettability regime are suggested to inform design of surfaces with tailored wettability that maximize performance. These findings indicate that the contact line dynamics play an important role in determining the heat transfer efficacy of a surface and provide a framework for the development of enhanced boiling surfaces.
Multiple myeloma (MM) is a blood cancer in which monoclonal plasma cells cause end organ damage resulting in hypercalcemia, renal failure, anemia, and bone lesions. MM is considered incurable, ...however, recent advances in treatment have improved survival. Historically, MM has been treated with immunomodulatory drugs (IMiDs), proteosome inhibitors (PIs), and corticosteroids. While newer therapeutic approaches such as monoclonal antibodies and cellular therapies have broadened the treatment horizon, the selection and sequencing of these therapies has become more complex. This review aims to help advanced practice providers navigate through the diagnosis, staging, treatment, and supportive care considerations in the MM space.
Multiple myeloma; Immunomodulators; Proteosome inhibitors; Anti-CD38-targeting antibodies.
The process of brain remodeling after stroke is time- and neural activity-dependent, and the latter makes it inherently sensitive to behavioral experiences. This generally supports targeting early ...dynamic periods of post-stroke neural remodeling with rehabilitative training (RT). However, the specific neural events that optimize RT effects are unclear and, as such, cannot be precisely targeted. Here we review evidence for, potential mechanisms of, and ongoing knowledge gaps surrounding time-sensitivities in RT efficacy, with a focus on findings from animal models of upper extremity RT. The reorganization of neural connectivity after stroke is a complex multiphasic process interacting with glial and vascular changes. Behavioral manipulations can impact numerous elements of this process to affect function. RT efficacy varies both with onset time and its timing relative to the development of compensatory strategies with the less-affected (nonparetic) hand. Earlier RT may not only capitalize on a dynamic period of brain remodeling but also counter a tendency for compensatory strategies to stamp-in suboptimal reorganization patterns. However, there is considerable variability across injuries and individuals in brain remodeling responses, and some early behavioral manipulations worsen function. The optimal timing of RT may remain unpredictable without clarification of the cellular events underlying time-sensitivities in its effects.
To identify the gene responsible for 14q32-linked dominant spinal muscular atrophy with lower extremity predominance (SMA-LED, OMIM 158600).
Target exon capture and next generation sequencing was ...used to analyze the 73 genes in the 14q32 linkage interval in 3 SMA-LED family members. Candidate gene sequencing in additional dominant SMA families used PCR and pooled target capture methods. Patient fibroblasts were biochemically analyzed.
Regional exome sequencing of all candidate genes in the 14q32 interval in the original SMA-LED family identified only one missense mutation that segregated with disease state-a mutation in the tail domain of DYNC1H1 (I584L). Sequencing of DYNC1H1 in 32 additional probands with lower extremity predominant SMA found 2 additional heterozygous tail domain mutations (K671E and Y970C), confirming that multiple different mutations in the same domain can cause a similar phenotype. Biochemical analysis of dynein purified from patient-derived fibroblasts demonstrated that the I584L mutation dominantly disrupted dynein complex stability and function.
We demonstrate that mutations in the tail domain of the heavy chain of cytoplasmic dynein (DYNC1H1) cause spinal muscular atrophy and provide experimental evidence that a human DYNC1H1 mutation disrupts dynein complex assembly and function. DYNC1H1 mutations were recently found in a family with Charcot-Marie-Tooth disease (type 2O) and in a child with mental retardation. Both of these phenotypes show partial overlap with the spinal muscular atrophy patients described here, indicating that dynein dysfunction is associated with a range of phenotypes in humans involving neuronal development and maintenance.
The "Good" Limb Makes the "Bad" Limb Worse Allred, Rachel P; Cappellini, Colleen H; Jones, Theresa A
Behavioral neuroscience,
02/2010, Letnik:
124, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Following stroke-like lesions to the sensorimotor cortex in rats, experience with the ipsi-to-lesion (ipsilesional), "nonparetic", forelimb worsens deficits in the contralesional, "paretic", ...forelimb. We tested whether the maladaptive effects of experience with the nonparetic limb are mediated through callosal connections and the contralesional sensorimotor cortex. Adult male rats with proficiency in skilled reaching with their dominant (for reaching) forelimb received ischemic bilateral sensorimotor cortex lesions, or unilateral lesions, with or without callosal transections. After assessing dominant forelimb function (the paretic forelimb in rats with unilateral lesions), animals were trained with their nonparetic/nondominant forelimb or underwent control procedures for 15 days. Animals were then tested with their paretic/dominant forelimb. In animals with unilateral lesions only, nonparetic forelimb training worsened subsequent performance with the paretic forelimb, as found previously. This effect was not found in animals with both callosal transections and unilateral lesions. After bilateral lesions, training the nondominant limb did not worsen function of the dominant limb compared with controls. Thus, the maladaptive effects of training the nonparetic limb on paretic forelimb function depend upon the contralesional cortex and transcallosal projections. This suggests that this experience-dependent disruption of functional recovery is mediated through interhemispheric connections of the sensorimotor cortex.
Penoscrotal transposition (PST) is an uncommon urogenital malformation in which the penis is mal-positioned to be inferior to the scrotum. The purpose of this study was to explore PST risk by ...maternal characteristics and to describe co-occurring congenital abnormalities in the Texas Birth Defects Registry (TBDR).
We conducted a population-based descriptive study examining occurrence of PST in the TBDR between 1999 and 2019. The primary outcome variable was PST diagnosis during infancy. Descriptive variables included maternal age, education, and race/ethnicity. Prevalence ratios (PRs) were calculated within each maternal variable category using Poisson regression. Counts and percentages of cases with select co-occurring congenital abnormalities were also calculated.
Overall, 251 infants had PST, providing a prevalence of 0.61/10,000 live male births (95% CI: 0.53-0.68). PST prevalence was significantly lower among infants of mothers who had lower educational attainment (<high school vs. >high school), who were younger (<25 vs. 25-34), and who were Hispanic (vs. non-Hispanic White) and was significantly higher among older mothers (35+ vs. 25-39). Hypospadias was the most common co-occurring genitourinary anomaly, affecting close to 70% of cases.
To our knowledge, this is the first investigation exploring the prevalence of PST in a population-based birth defects registry. Our findings help to understand the risk for PST among select maternal demographic characteristics and may assist in generating hypotheses about the underlying etiology of this condition for future work.
•Investigation of boiling on hydrophobic surfaces with differing dynamic wetting behaviors.•The receding contact angle governs the occurrence of critical heat flux.•Visualizations show that bubble ...dynamics depend strongly on dynamic wetting behavior.•Bubble dynamics agree with a bubble growth model based on the receding contact angle.•Demonstrates the potential of parahydrophobic surfaces for use in boiling applications.
Despite extensive study of boiling processes and their widespread use in industry, critical interactions between the fluid and surface during boiling remain poorly understood. Simplistic, static descriptions of the contact angle are still relied upon to describe the effects of surface wettability on dynamic interfacial processes that govern boiling. This work demonstrates the critical role of the dynamic wettability characteristics of a surface on bubble growth dynamics and boiling performance. In spite of their superior nucleation behavior, hydrophobic surfaces have received little attention for boiling applications due to their typically premature transition from efficient nucleate boiling to inefficient film boiling. Evaluation of hydrophobic surfaces with high contact angle hysteresis reveals that the heat transfer efficacy of these surfaces can be exploited in boiling, so long as the receding contact angle of the surface is sufficiently small to mitigate vapor spreading and thereby extend the nucleate boiling regime. A new paradigm of textured boiling surfaces – parahydrophobic surfaces that exhibit the “petal effect” and mimic the wetting behavior of a rose petal – are shown to have untapped potential in boiling applications resulting from highly hydrophobic behavior coupled with low receding contact angles.
Food insecurity affects close to half the population of Senegal, West Africa, a country simultaneously affected by the ongoing global diabetes pandemic. Diabetes and food insecurity are associated ...with adverse mental health, yet research exploring the relationship between chronic physical illness, food insecurity, and mental illness in Senegal is currently lacking. The objective of this study was to investigate the association between food insecurity and depression and anxiety, separately, in Senegalese women living with diabetes and hypertension. Food insecurity was measured using the Household Food Insecurity Access Scale. Occurrence of depression and anxiety symptoms was assessed using the Modified Hopkins Symptoms Checklist Survey (HSCL‑25). A sensitivity analysis examining the relationship between food insecurity and depression and anxiety was performed by comparing two previously validated cutoff values (1.75 and 2.25) on the HSCL‑25. Most participants (83%) had some level of food insecurity. More than 80% of the sample were depressed or anxious using 1.75 as the cutoff, while 42 and 60% were depressed or anxious, respectively, using 2.25 as the cutoff. Food insecurity increased relative risk for depression (RRR: 1.40, 95% CI: 1.05‑1.31, 1.75 as cutoff; RRR: 1.06, 95% CI: 0.99‑1.14, 2.25 as cutoff) and anxiety (RRR: 1.17, 95% CI: 1.05‑1.31, 1.75 as cutoff; RRR: 1.11, 95% CI: 1.04‑1.19, 2.25 as cutoff). These findings demonstrate that among populations suffering from diabetes and hypertension, food insecurity is a modifiable risk factor for depression and anxiety and a potential intervention target in this setting.
•Adiabatic bubble growth and departure simulations are performed considering the dynamic wetting characteristics of the surface•The receding contact angle is shown to be the dominant wetting ...characteristic governing maximum contact diameter and departure diameter•The advancing contact angle governs the departure mechanism and has a modest influence on the departure diameter•Correlations are established for the maximum contact diameter and departure diameter based on the advancing and receding contact angles•Boiling surface wetting classifications of hygrophilic, hygrophobic and ambiphilic are defined based on characteristic bubble dynamics
Surface wettability is known to have a major influence on the ebullition characteristics of a bubble growing from a solid surface. Yet, simplistic static characterization of the wetting behavior is still relied upon to indicate performance characteristics during boiling. In this study, a theoretical framework is developed for the wetting and dewetting processes occurring during bubble growth based upon the dynamic contact angles. This framework is incorporated into adiabatic volume-of-fluid simulations to capture the influence of the surface wettability on contact line and contact angle dynamics during bubble growth and departure. The simulations span a large range of dynamic wetting behaviors and fluid properties. The receding contact angle is shown to govern the early stages of bubble growth as the contact line recedes outward from the bubble center and is the dominant wetting characteristic that determines the maximum contact diameter and departure size. The advancing contact angle dictates the departure morphology as the contact line retracts inward and has a secondary role in determining the departure size. Following, improved reduced-order models are developed that establish fluid-property-independent correlations for the maximum contact diameter and departure diameter as a function of the dynamic contact angles. The results call for the need to redefine wettability classifications based on dynamic contact angles rather than static contact angle in the context of boiling. Hygrophilicity and hygrophobicity are redefined in this context, and an additional classification, ambiphilicity, is introduced for boiling surfaces exhibiting low receding contact angles and high advancing contact angles.
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