Silane influence on bonding to CAD-CAM composites: An interfacial fracture toughness study

ObjectivesTo evaluate silane influence on the interfacial fracture toughness (IFT) of composite cement, with the two sub-classes of CAD-CAM composites, polymer-infiltrated ceramic networks (PICN) and dispersed fillers (DF), after hydrofluoric acid etching (HF) or airborne-particle abrasion (AB). A secondary objective was to correlate results with developed interfacial area ratio (Sdr) and surface wettability.MethodsExperimental PICN and DF blocks were cut into equilateral half-prisms, which were treated with HF or AB, then treated with an experimental silane or not and bonded to their counterparts with an experimental light-cure resin cement. After thermocycling, samples (n = 30 per group) were tested for IFT using the notchless triangular prism test in a water bath at 36 °C. Moreover, profilometry and contact angle measurement were performed on rectangular samples of each group. Finally, bonding interface was analysed by SEM.ResultsPICN-HF treated with silane showed the highest IFT significantly. Three-way ANOVA revealed the influence of silane, material class and surface pre-treatment (HF or AB) on IFT (p < 0.05). When silane was used, IFT was correlated with Sdr, while surface wettability was increased. Silane application significantly increased IFT for PICN but not for DF, while PICN performed better with HF and DF with AB.SignificanceSilane increases IFT of composite cement with PICNs, but not with DF materials. Results suggest that silane increases the micromechanical bond by promoting resin cement spreading and penetration in surface roughness. This roughness is significantly higher for pre-treated PICNs than for DF due to their specific honeycomb microstructure when etched, which explains their better bonding properties.     

Stigma predicts residential treatment length for substance use disorder

Background: Stigma has been suggested as a possible contributor to the high rates of treatment attrition in substance-dependent individuals, but no published empirical studies have examined this association. Objectives: The present paper assessed the relationship between baseline stigma variables and length of treatment stay in a sample of patients in a residential addictions treatment unit. Methods: The relationship between baseline stigma variables (self-stigma, enacted stigma, and shame) and length of stay for participants (n?=?103) in a residential addictions treatment unit was examined. Results: Higher self-stigma predicted longer stay in residential addictions treatment, even after controlling for age, marital status, race, overall mental health, social support, enacted stigma, and internalized shame. However, other stigma variables (i.e. internalized shame, stigma-related rejection) did not reliably predict length of treatment stay. Conclusion: These results are consistent with other findings suggesting that people with higher self-stigma may have a lowered sense of self-efficacy and heightened fear of being stigmatized and therefore retreat into more protected settings such as residential treatment, potentially resulting in higher treatment costs. Specialized clinical interventions may be necessary to help participants cope with reduced self-efficacy and fear of being stigmatized.     

胶囊内镜滞留临床特征及处置策略

目的探讨胶囊内镜滞留的临床特征及处理。方法回顾性分析2008年9月-2013年9月行胶囊内镜检查中出现胶囊滞留的病例特征。结果 559例胶囊内镜检查中,共发生胶囊滞留11例,发生率为2.0%,9例为克罗恩病,2例为小肠肿瘤;其中2例因并发肠梗阻、1例并发消化道穿孔行手术治疗,1例小肠镜下取出胶囊,1例4个月后自行排出,4例仍在继续随访中,无胶囊滞留相关的死亡病例。结论胶囊滞留是胶囊内镜检查中较严重并发症,应尽可能在内镜下取出胶囊或行手术治疗。     

Pathways of hepatic and renal damage through non‐classical activation of the renin‐angiotensin system in chronic liver disease

In liver cirrhosis, renin‐angiotensin system (RAS) activation sustains renal sodium retention and hepatic fibrogenesis. New information has recently enlivened the traditional concept of RAS. For instance, renin and prorenin bind their ubiquitous receptors, resulting in the local production of angiotensin (Ang) II; increased serum calcium and calcimimetic agents, through stimulation of extracellular calcium‐sensing receptors (CaSR), blunt renin production and lead to natriuretic effects in human and experimental cirrhosis. Alongside systemic production, there is Ang II tissue production within various organs through RAS enzymes different from angiotensin‐converting enzyme (ACE), that is chymase, tissue plasminogen activator and several cathepsins. In experimental cirrhosis, inhibition of chymase leads to natriuretic and hepatic antifibrotic effects, without changes in systemic haemodynamics. In the kidney, local RAS coordinates proximal and distal tubular sodium reabsorption. However, renalase, whose plasma and tissue levels are severely altered in experimental cirrhosis, degrades systemic and renal tubule catecholamines, antagonizing the effects of renal RAS. Angiotensinogen‐derived natriuretic and vasodilating peptides (Ang1‐9, Ang1‐7, Ang3‐8) and their receptors have been described. Receptor agonists or antagonists are available to affect portal hypertension and sodium retention in cirrhosis. ACE2‐dependent generation of Ang1‐7 may inhibit experimental liver fibrosis. inhibition of Ang1‐7 clearance by means of neprilysin blockade has portal hypotensive and natriuretic effects. Ang1‐12, whose production renin does not regulate, is converted to several different angiotensin peptides via chymase. Finally, Ang II behaves as either an antinatriuretic or a natriuretic agent, based on the tissue content of AT₁R and AT₂R receptors, their ratio being prone to pharmacological modulation.     

Suppression of Complex Visual Hallucinatory Experiences by Occipital Transcranial Magnetic Stimulation: A Case Report

We report a patient with visual hallucinations and illusions along with an associated visual field defect after bilateral ischemic damage to his occipital visual cortex. These hallucinations were long-standing and of both simple and complex (well-formed) type. Application of low frequency (1 Hz) repetitive Transcranial Magnetic Stimulation (rTMS) to the occipital cortex led to a complete cessation of visual hallucinatory symptoms. The use of TMS to probe the neurophysiology, and possibly alleviate, visual hallucinatory experiences is discussed.     

Glycosaminoglycan entrapment by fibrin in engineered heart valve tissues

Tissue engineered heart valves (TEHVs) may provide a permanent solution to congenital heart valve disease by permitting somatic valve growth in the pediatric patient. However, to date, TEHV studies have focused primarily on collagen, the dominant component of valve extracellular matrix (ECM). Temporal decreases in other ECM components, such as the glycosaminoglycans (GAGs), generally decrease as cells produce more collagen under mechanically loaded states; nevertheless, GAGs represent a key component of the valve ECM, providing structural stability and hydration to the leaflets. In an effort to retain GAGs within the engineered constructs, here we investigated the utility of the protein fibrin in combination with a valve-like, cyclic flexure and steady flow (flex–flow) mechanical conditioning culture process using adult human periodontal ligament cells (PLCs). We found both fibrin and flex–flow mechanical components to be independently significant (p < 0.05), and hence important in influencing the DNA, GAG and collagen contents of the engineered tissues. In addition, the interaction of fibrin with flex–flow was found to be significant in the case of collagen; specifically, the combination of these environments promoted PLC collagen production resulting in a significant difference compared to dynamic and statically cultured specimens without fibrin. Histological examination revealed that the GAGs were retained by fibrin entrapment and adhesion, which were subsequently confirmed by additional experiments on native valve tissues. We conclude that fibrin in the flex–flow culture of engineered heart valve tissues: (i) augments PLC-derived collagen production; and (ii) enhances retention of GAGs within the developing ECM.     

The general surgery workforce shortage is worse when assessed at county level

Background

Multiple studies have documented a significant decrease in the general surgery workforce in the United States, both rural and urban, for the past 3 decades. This 11-year study evaluates the Texas general surgery workforce at both the state and local level in 2002 and 2012.

Methods

Data were obtained from the Texas Medical Board, the United States Census Bureau/Texas State Library and Archives Commission, and the Texas Department of State Health Services for 2002 and 2012. A benchmark target of 7 general surgeons per 100,000 population was used.

Results

During the study period, the Texas population increased 21%, and actively practicing physicians increased 44%. All surgical specialists increased by 26%. General surgeons increased 4%; however, the number of general surgeons per 100,000 population decreased 14% (from 6.7 to 5.8/10⁵). Using the total Texas population for 2012, an additional 329 general surgeons are needed by benchmark standards. However, when analyzed by individual county population, 449 additional general surgeons are needed in the individual counties. These effects were greater in the nonmetropolitan areas of Texas where per capita general surgeons decreased by 21%.

Conclusions

The absolute increase in Texas general surgeons over the past decade has not kept pace with an increase in the Texas population. The general surgery workforce deficit based on the Texas state population underestimates the local workforce shortage, particularly in the nonmetropolitan areas of Texas.