Weston Solutions (United States)

Abstract This study investigates the performance and molecular stability of ultra-high molecular weight polyethylene (UHMWPE) fiber-reinforced hydrogen-rich polybenzoxazine composites exposed to the space environment on the International Space Station (ISS). The composite is designed specifically for spacecraft applications requiring lightweight radiation shielding against galactic cosmic rays and solar particle events. Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), dynamic mechanical analysis (DMA), and short beam shear testing were used to evaluate both surface degradation and bulk property retention. Chemical degradation due to direct sunlight exposure is limited to the uppermost 30 nm of the composite surface, with formation of hydroxyl and carbonyl groups. No significant changes in the glass transition temperature (T g), short beam shear strength, or density are observed between space-exposed and control samples. Thermoluminescence dosimetry data indicated significant attenuation of incident radiation. This study confirms the potential of the UHMWPE composite material for use as a multifunctional structure and radiation shield for extended space missions. Graphical Abstract

Based on the latest molecular phylogenies of Gonyosoma sensu lato, which recovered five clades with robust support, we utilize morphological characters to demonstrate the distinctiveness of each clade, resulting in the resurrection of three genera (Gonyophis Boulenger, 1891; Rhynchophis Mocquard, 1897; and Rhadinophis Vogt, 1922) and a proposal of a new genus and a new tribe. A synopsis of the group, with descriptions and diagnoses, is provided for the five genera and eight species in addition to distribution maps and illustrations of the head of each taxon. An artificial key to the species and genera in the new tribe is presented in addition to the estimated origin times for each clade.

Researchers repeatedly reported that factors besides a student's academic intelligence, such as socioeconomic background and ethnicity, are significantly associated with students' SAT scores. This study employed aggregated school-level data from Massachusetts and New York City (NYC) to assess the quantitative relationships between average SAT scores and school-level demographics and interventions. The assessment aims to help regional and national education policymakers identify factors related to school academic merits and devise inclusive and effective ways to promote educational equality. Three analytical methods - multiple linear regression, relaxed Least Absolute Shrinkage and Selection Operator (LASSO), and decision trees - were conducted sequentially to decipher complex relationships among variables. The analysis showed schools with high percentages of Black, Hispanic, and low-income students tend to have lower average scores than schools with high percentages of White, Asian, and well-off students. Moreover, these schools with lower SAT performance are closely tied to their funding levels, such as low school expenditure per student. The results indicate that more SAT preparation resources are needed at schools with higher percentages of Black, Hispanic, and low-income students to level the playing field in SAT testing.

Background: The enactment of the Philippine Universal Health Care (UHC) Act mandates the formation of Integrated Health Care Provider Networks (IHCPN), linking hospitals and health facilities, which includes government and privately-owned primary care providers. While hospitals and some health facilities are already under government regulation, primary care providers have not been subjected to formal licensing requirements. In this changing service delivery model, the possible impact of three regulatory policy options being considered need to be assessed according to the goal of ensuring that health services remain affordable and are of high quality. Methodology: A multi-method approach to regulatory impact analysis (RIA) systematically assessed three regulatory options: 1) one Department of Health (DOH) license per hospital and health facility (status quo); 2) one DOH license for all public hospitals and health facilities within an IHCPN and another for individual private hospitals and health facilities; and 3) one DOH license per individual hospital and health facility, and one DOH certification issued to individual hospitals and health facilities as part of an IHCPN. Information from literature, documents, focus group discussions, and cost analyses were triangulated. Results: Regulators are faced with two main risks : there is no standard for networked health care delivery that could provide a foundation for regulation, and provider participation is voluntary, which could lower the interest of private providers to integrate. The three regulatory options considered these risks. Option 1 requires the least change in regulatory policy, but is expected to increase costs to regulators due to the expansion of licensing and enforcement work covering primary care providers. Option 2 requires the most change in regulatory policy, but may be the least expensive to enforce, especially if all facilities join a network. This can also be preferred in a setting with existing interlocal health zones, and participation in the network by private providers poses the most challenge. Option 3 is a tiered regulatory set up that projects the highest cost to regulators as a result of both establishing new certification standards and guidelines on top of a wider scope for enforcement. Conclusion: This is the first RIA conducted for the Philippine health system, with challenges similar to those experienced in developing countries. Across the three pre-determined regulatory models, the least costly option may not be the easiest to mount and enforce. Implementability appears to be a stronger consideration which seems to be hinged to the option requiring incremental rather than large form of changes.

Background: Cardiac sarcoidosis (CS) is a rare disease that can present with a variety of clinical scenarios including, heart failure and sudden death. We present a case of isolated CS presenting as recurrent transient ischemic attacks (TIA) in a previously asymptomatic patient. Description of Case. A 54-year-old female with a history of two previous TIAs presented 30 minutes after the onset of left-sided facial droop and incomprehensible speech. CT and MRI brain did not show acute infarction. ECG showed a right bundle branch block pattern. Transthoracic echocardiogram (TTE) showed an abnormal global longitudinal strain of 12.8%, a left ventricular ejection fraction of 40%, segmental wall motion abnormalities involving the apex and basal inferior walls, and swirling of contrast at the apex. She had no previous history of cardiomyopathy. CTA was unrevealing for coronary artery disease but a cardiac MRI showed areas of late gadolinium enhancement and a RV wall aneurysm. PET scan revealed multifocal patchy nodular areas of FDG uptake within the myocardium. A diagnosis of isolated CS was made. At a three-month follow-up, TTE showed a new apical thrombus measuring 0.8cm x 0.6 cm. The patient was started on anticoagulation with the eventual resolution of the thrombus. She had no further ischemic events. Discussion. TIAs and ischemic stroke are extremely rare complications of CS and are largely attributed to cardioembolic phenomena, in the absence of systemic disease. Cardiac structural changes that lead to arrhythmias, hypokinesis, and stasis with clot formation largely explain embolic events in these patients. In addition, evidence suggests that the inflammatory cytokines, such as IFN gamma and IL-12, released by the sarcoid granuloma may also have an independent role in clot formation. The combination of stagnant flow in akinetic areas and a strong inflammatory bed of cytokines led to recurrent TIAs in this patient and the apical thrombus that was later identified.

Case Presentation: 75-year-old female with history of conservatively managed ascending aortic aneurysm with mild Aortic Insufficiency (AI) and a chronic Type B aortic dissection. Due to rapid aneurysmal expansion she underwent surgical ascending aortic aneurysm repair with a 32-mm Gelweave graft, aortic valve commissuroplasty, and 1-vessel aorta-to-right coronary artery bypass graft. She was discharged 15 days post-op in stable condition. However presented 2 weeks later with new onset dyspnea with minimal exertion, orthopnea, peripheral edema, wide arterial pulse pressure (150/50 mmHg), jugular venous distention. Transthoracic and transesophageal echocardiography showed a new and severe AI, with preserved left ventricular ejection fraction. A computed tomography angiogram (CTA) of the chest showed an acute aortic dissection at the proximal and distal segments of the aortic graft (Figure 1). She underwent a transcatheter aortic valve implantation (TAVI) with a self-expanding bioprosthesis: 27 mm Portico TM valve (St. Jude Medical, St. Paul, MN, USA) anchored at the annular level (annular area 370 mm 2 , perimeter 69 mm with calculated over sizing of 30%) and at the 32 mm Gelweave graft level (42 mm bioprosthesis aortic outflow dimension) without acute complications (Figure 2). She was discharged and remained clinically well without recent readmission for CHF exacerbation. Conclusions: Patient was deemed a poor surgical candidate due to frailty and recent sternotomy. This case demonstrates TAVI as off-label treatment option for severe AI due to aortic root dissection in poor surgical candidates.

We read with great interest the article entitled “A Prospective, Randomized Study Comparing Closed-Incision Negative-Pressure Wound Therapy with Standard Care in Immediate Breast Reconstruction” by Pieszko et al.1 in Plastic and Reconstructive Surgery. The authors assessed the impact of closed-incision negative-pressure wound therapy versus standard dressings after immediate breast reconstruction on surgical-site complications, superficial skin temperature, skin elasticity, and subjective scar quality, to determine the potential benefit of prophylactic closed-incision negative-pressure wound application. There is growing evidence that negative-pressure therapy on closed wounds can reduce complication rates following surgery. The authors showed that application of closed-incision negative-pressure on the wound correlated with a significant decrease in surgical-site complications within 1 year of immediate breast reconstruction. Active smoking status was not significant between the two groups, yet the actual number of smokers in the standard dressing group was over twice the size. Radiotherapy was the most important risk factor for developing surgical-site complications, as previously reported in the literature.2 There is some heterogenicity between the cohorts that is not represented by sufficient statistical significance but raises questions and may be a potential source of bias. In direct conjunction with the above-mentioned factors, the small sample size in this study may potentially compromise the validity of the conclusions that can be drawn and makes it prone to bias. However, these findings correlate with previous studies focused on bilateral breast reduction mammaplasty showing fewer complications in favor of the negative-pressure wound therapy–treated sites.3,4 The authors performed scar assessment based on the average coefficient of elasticity, and superficial skin temperature. The authors found more elastic scar tissue and superficial skin temperature to be significantly higher in the closed-incision negative-pressure wound therapy group. Tanaydin et al. measured scar viscoelasticity in 32 women undergoing bilateral breast reduction mammaplasty. They reported that skin viscoelasticity measurements did not show significant improvement in negative-pressure therapy compared with fixation strips.3 In contrast, Nagata et al. reported that scars treated with negative-pressure therapy are softer as measured with a scanning acoustic microscope (a technique used to measure tissue elasticity), which correlates with the results found by the authors.5 The effect of negative-pressure therapy on scar elasticity in breast reconstruction remains controversial, and further studies are needed to better define how negative-pressure wound therapy affects scar elasticity in breast reconstruction. It is well known that lower temperatures improve angiogenesis and wound healing.6 In contrast, Muenchow et al. demonstrated a significant increase in skin microcirculation parameters when a negative-pressure dressing was applied. The authors assessed local blood flow, capillary-venous oxygen saturation, blood flow velocity, and the relative amount of hemoglobin using a combined tissue laser/photospectrometry technique. However, no mention of superficial skin temperature was made.7 Further studies are needed to assess whether higher skin temperatures benefit scar formation during negative-pressure wound therapy. We would appreciate it if the authors would perform some noninvasive quantitative measurements of scar properties, such as digital photography with image analysis.8 According to the Patient and Observer Scar Assessment Scale v2.0, subjective scar outcomes in both groups were comparable in this study. This represents a reliable and valid scar assessment scale that measures scar quality from two perspectives; however, one of the major limitations of this particular outcome is that neither patients nor assessing physicians were blinded to the type of dressing used in this study. We would appreciate it if the authors would record the postoperative satisfaction of patients, which should be combined with the surgeon’s professional evaluation. Breast reconstruction is an expensive procedure that is usually paid for by the patient’s insurance. Using a disposable device adds an extra cost to the operation. We would appreciate a cost analysis assessment of vacuum-assisted closure therapy versus standard wound care.9 This analysis would determine the real cost-effectiveness of single-use vacuum-assisted closure therapy in this patient population. In conclusion, and despite some minor methodologic limitations inherent in clinical research, the authors provided useful data that add to the current body of scholarly literature on vacuum-assisted closure therapy and breast reconstruction, and the results are promising. We expect further long-term, large-sample studies that support the authors’ findings in the near future. DISCLOSURE The authors have no financial interest to declare in relation to the content of this Discussion or of the associated article.