A Novel Probe-to-Probe Method for Measuring Thermal Conductivity of Individual Electrospun Nanofibers

Polymer nanofibers have the ability to replace expensive materials, such as metals, ceramics and composites, in specific areas, such as heat exchangers, energy storage and biomedical applications. These properties have caused polymer nanofibers to be explored as solutions to a growing list of thermal management problems, driving an even greater need to better measure and understand the thermal properties of these nanofibers. This study intends to further the understanding of the thermal properties of polymer nanofibers through the use of a novel Probe-to-Probe measurement method. Polycaprolactone nanofibers fabricated using the electrospinning method can be easily collected and loaded into a traditional atomic force microscope through a mechanical design for thermal measurement. This Probe-to-Probe method demonstrates the ability to accurately measure the thermal boundary conditions about a polymer nanofiber with a heating prong temperature up to 400 ∘C and assists in characterizing its thermal properties.     

Gap junction alterations in human cardiac disease

Gap junctions, assembled from connexins, form the cell-to-cell pathways for propagation of the precisely orchestrated patterns of current flow that govern the regular rhythm of the healthy heart. As in most tissues and organs, multiple connexin types are expressed in the heart; connexin43, connexin40 and connexin45 are found in distinctive combinations and relative quantities in different, functionally specialized subsets of cardiomyocyte. Alterations of gap junction organization and connexin expression are now well established as a consistent feature of human heart disease in which there is an arrhythmic tendency. These alterations may take the form of structural remodelling, involving disturbances in the distribution of gap junctions and/or alteration of the amount or type of connexin(s) expressed. In the diseased ventricles, the most consistent quantitative alteration involves heterogeneous reduction in connexin43 expression. In the atria, features of gap organization and connexin expression have been implicated in the initiation of atrial fibrillation and, once the condition becomes chronic, gap junction alterations associated with remodelling may contribute to persistence of the condition. By correlating data from studies on the human patient with those from animal and cell models, alterations in gap junctions and connexins have emerged as important factors to be considered in understanding the pro-arrhythmic substrate found in a variety of forms of heart disease.     

Large-scale mapping of live corals to guide reef conservation

Coral is the life-form that underpins the habitat of most tropical reef ecosystems, thereby supporting biological diversity throughout the marine realm. Coral reefs are undergoing rapid change from ocean warming and nearshore human activities, compromising a myriad of services provided to societies including coastal protection, fishing, and cultural practices. In the face of these challenges, large-scale operational mapping of live coral cover within and across reef ecosystems could provide more opportunities to address reef protection, resilience, and restoration at broad management- and policy-relevant scales. We developed an airborne mapping approach combining laser-guided imaging spectroscopy and deep learning models to quantify, at a large archipelago scale, the geographic distribution of live corals to 16-m water depth throughout the main Hawaiian islands. Airborne estimates of live coral cover were highly correlated with field-based estimates of live coral cover (R² = 0.94). Our maps were used to assess the relative condition of reefs based on live coral, and to identify potential coral refugia in the face of human-driven stressors, including marine heat waves. Geospatial modeling revealed that water depth, wave power, and nearshore development accounted for the majority (>60%) of live coral cover variation, but other human-driven factors were also important. Mapped interisland and intraisland variation in live coral location improves our understanding of reef geography and its human impacts, thereby guiding environmental management for reef resiliency.

Coral is the foundational, habitat-generating life-form of most tropical reefs, but coral is under increasing pressure from marine heat waves, coastal development, and resource extraction (1). Coral change is occurring at multiple ecological scales ranging from genotypic- and species-level responses to broad reef- and regional-level reorganization (2). However, the spatially continuous distribution of live coral cover remains unknown, owing to a scale gap between field and drone-based surveys that sample portions of any given reef and satellite-based approaches that fail to resolve live coral cover from space (3). This gap makes it difficult to map very large regions, such as island archipelagos, at the spatial and biological resolution of the habitat-forming organisms inhabiting these regions.Operational mapping of live coral cover within and across reef ecosystems could provide opportunities for science and management to better address reef protection, resilience, and restoration. For example, reef areas with live coral cover persisting after repeated stressors, such as marine heat waves, may indicate coral refugia (4). Spatial information on refugia may then drive innovations in marine protection as well as scientific investigation of underlying drivers of coral survival (5). In turn, new understanding of survivorship may alter predictions of reef change in the current and forthcoming ocean climate (6, 7). Large-scale information on live coral cover can also inform restoration efforts. Reefs that have lost coral cover from activities such as coastal development could be targeted for restoration if these activities are curtailed. However, low coral cover reefs previously exposed to repeated marine heat waves and severe degradation may represent intractable restoration possibilities (8).The eight main Hawaiian islands (MHIs) are an iconic case in point of regional variability in the face of multiple stressors. Human pressure on Hawaiian reefs is wide-ranging, from relatively low impact on Kahoʻolawe to high impact on Oʻahu (9). Coastal development has resulted in hot spots of sedimentation, waterborne pollutants, and reef removal, while fishing and other resource uses have generated declines in reef resilience (10). In parallel, a series of marine heat waves has nonuniformly engulfed the MHIs, with the 2014, 2015, and 2019 bleaching events being the most recent. The 2015 event generated live coral losses reaching more than 50% in some areas, but the geographic extent of loss or resistance remains unknown (11).The MHIs span a latitude and longitude range of 4° and 6°, respectively, and vary in geologic age, from less than a few years old on parts of Hawaiʻi Island to more than six million years old on Niʻihau (12). Island age is accompanied by stage of accretion and subsidence, processes that generate enormous interisland and intraisland variation in reef extent associated with benthic substrate availability. Combined geophysical and anthropogenic variability across the MHIs has generated ecological complexity in reef composition common to reef systems worldwide.To assess land–sea controls over live coral cover, and to expand options for coral conservation and management, we undertook the first large-scale, high-resolution mapping study of live coral cover across an island archipelago. While there have been extensive in-water surveys of coral reefs in the MHIs, these have been constrained by site access and benthic variability, making the use of field information a challenge to the development of comprehensive regional maps of where live coral exists. Moreover, most airborne or satellite-based approaches derive benthic composition as aggregate classes such as coral combined with algal cover (e.g., refs. 13 and 14), and no programs have operationalized a method to cover large areas (e.g., >1,000 ha) with highly automated mapping of live coral location. We developed an airborne mapping approach that combines laser-guided imaging spectroscopy and computational deep learning to quantify the geographic distribution of live corals to a depth of 16 m. The resulting map was used to assess the relative condition of reefs from a coral perspective, and to identify areas of high live coral cover, deemed potential refugia. Following geospatial analyses of live corals, we used computational machine learning to quantify multiple land–sea drivers affecting live coral cover, as a means to inform mitigation and restoration efforts throughout the MHIs.     

Endocrine pancreatic insufficiency in chronic pancreatitis.

Chronic pancreatitis (CP) is considered to be a rare cause of diabetes mellitus. However, in both the developed and developing world, there is an increasing number of patients suffering from pancreatitis probably due to lifestyle changes, which is partially associated with both social factors and the poor health status of immigrants. Owing to these circumstances, CP has evolved with one of the possible causes of diabetes in a selected group of patients and should be included in the differential diagnosis of diabetes. Several studies have shown that the long-term rate of diabetic complications in patients with CP and insulin-dependent diabetes is similar to that in patients with type 1 diabetes of equal duration. The hypothesis that early diagnosis of CP should result in better prognosis is not validated and may complicate the issue, since the risk of diabetes has been shown to increase significantly only once pancreatic calcification has developed. Accumulative evidence suggests that the risk of diabetes is not influenced by elective pancreatic surgical procedures other than distal pancreatectomy. The lack of contemporary data points to the urgent need for large prospective studies in order to accurately evaluate the special characteristics of disorders in glucose homeostasis in patients with CP.     

High prevalence of gastroesophageal reflux symptoms and esophagitis with or without symptoms in the general adult Swedish population: a Kalixanda study report

OBJECTIVE: Gastroesophageal reflux disease has been reported to be a common burden on health-care resources in the Western world, but its manifestations in the general population are as yet unclear. The aim of this study was to estimate the prevalence of, and to identify the risk factors for gastroesophageal reflux symptoms (GERS) and erosive esophagitis (EE) in the adult population of two Swedish municipalities. MATERIAL AND METHODS: A random sample (n =3000) of the adult population (20-81 years of age) of two Swedish municipalities (n =21,610) was surveyed using a validated postal questionnaire assessing gastrointestinal symptoms. The response rate was 74%. A subsample (n = 1000) of the responders was subsequently invited, in random order, for esophago-gastro-duodenoscopy with evaluation of GERS, risk factors and tests for Helicobacter pylori. RESULTS: GERS were reported by 40.0% and EE was found in 15.5% of the population that had undergone endoscopy. Of those with GERS, 24.5% had EE while 36.8% of those with EE reported no GERS. Hiatus hernia and obesity remained significant risk factors for GERS and/or EE, with or without symptoms in a main effect model (OR up to 14 at EE). Those with active H. pylori infection had a higher risk of GERS without EE than those without H. pylori infection (OR = 1.71 (1.23 2.38)). CONCLUSIONS: GERS and EE (of which one-third is asymptomatic) are highly prevalent in the Swedish adult population. H. pylori infection seems to play a role in the manifestations of gastroesophageal reflux.     

Detection of circulating crosslinked fibrin derivatives by a heat extraction-SDS gradient gel electrophoretic technique

A technique has been developed to identify and quantitate unique plasmic degradation products of crosslinked fibrin in plasma. In this method, fibrin derivatives are extracted by heat precipitation and dissolved with disulfide bond reduction, after which the crosslinked gamma-gamma chain remnants are identified by SDS-polyacrylamide gradient gel electrophoresis and quantitated by densitometric analysis. A heterogenous group of gamma-gamma chains with molecular weights between 100,000 and 76,000 daltons was identified in lysates of crosslinked fibrin during plasmic degradation in vitro. Three stages of crosslinked fibrin degradation have been arbitrarily defined based primarily on the extent of degradation of these gamma-gamma polypeptide chains. As little as 20 microgram of crosslinked fibrin digests added to 1 ml of normal plasma could be detected by the heat-extraction--gel- electrophoresis technique, identifying the gamma-gamma derivatives with molecular weights of 96,000, 86,000, 82,000, and 76,000 daltons. Plasmic derivatives of gamma-gamma chains were not found in normal plasma, but they were identified in the plasma of patients with disseminated intravascular coagulation and deep-vein thrombosis, both before and in increased quantity during successful thrombolytic therapy.     

A clinical trial to evaluate the worth of preoperative multimodality therapy in patients with operable carcinoma of the rectum

PURPOSE: National Surgical Adjuvant Breast and Bowel Project Protocol R-03 was designed to determine the worth of preoperative chemotherapy and radiation therapy in the management of operable rectal cancer. METHODS: Thus far, 116 patients of an eventual 900 with primary operable rectal cancer have been randomized to receive multimodality therapy to begin preoperatively (59 patients) or identical therapy beginning after curative surgery (57). All patients received seven cycles of 5-fluorouracil (FU)/leucovorin (LV) chemotherapy. Cycles 1 and 4 through 7 used a high-dose weekly FU regimen. In Cycles 2 and 3, FU and low-dose LV chemotherapy was given during the first and fifth week of radiation therapy (5,040 cGy). The preoperative arm (Group 1) received the first three cycles of chemotherapy and all radiation therapy before surgery. The postoperative arm (Group 2) received all radiation and chemotherapy after surgery. Primary study end points included disease-free survival and survival. Secondary end points included local recurrence, primary tumor response to combination therapy, tumor downstaging, and sphincter preservation. RESULTS: Overall treatment-related toxicity was similar in both groups. Although seven preoperative patients had events after randomization that precluded surgery, eight events occurred during an equivalent follow-up period in the postoperative group. No patient was deemed inoperable because of progressive local disease. Sphincter-saving surgery was intended in 31 percent of Group 1 patients and 33 percent of Group 2 patients at the time of randomization. Such surgery was actually performed in 50 percent of the preoperatively treated patients and 33 percent of the postoperatively treated patients. The use of protective colostomy in patients undergoing sphincter-sparing surgery and the development of perioperative complications in all surgical patients were similar in both groups. There was evidence of tumor downstaging in evaluable patients under-going preoperative therapy, with 8 percent of Group 1 patients having had a pathologic complete response. CONCLUSION: These data do suggest that the preoperative chemotherapy and radiation therapy regimen used are, at least, as safe and tolerable as standard postoperative treatment. There is presently a trend to tumor downstaging and sphincter preservation in the preoperative arm. Whether this arm will have greater or lesser survival and long-term toxicity awaits the completion of this relevant study.Supported by National Cancer Institute Grants U10-CA-12027 and U10-CA-37377 and American Cancer Society Grant R-13.Read at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 9 to 14, 1996.     

Clinical features and outcome in childhood T-cell leukemia-lymphoma according to stage of thymocyte differentiation: a Pediatric Oncology Group Study

The immunophenotypes of lymphoblasts from children with newly diagnosed T-cell acute lymphoid leukemia (T-ALL, n = 101) or T-cell non-Hodgkin lymphoma (T-NHL, n = 31) were analyzed to correlate stage of thymocyte differentiation with clinical features and outcome. The 67 boys and 34 girls with T-ALL were 1 month to 18 years old (median, 8 years) with leukocyte counts ranging from 2 to 810 x 10(9)/L (median, 55 x 10(9)/L). Eighteen of these patients were black, and 70 had a mediastinal mass. Twenty-six boys and five girls with a median age of 9 years (range, 1 to 20 years) had T-NHL. Seven of these patients were black, and 24 had a mediastinal mass. The distributions of thymocyte developmental stages (early [CD7+], intermediate [CD1+ and/or CD4+ and/or CD8+], and mature [CD3+]) in cases of T-ALL and T-NHL were significantly different: 34%, 43%, and 23% v 6%, 62%, and 32% (P = .02). A comparison of the patients' clinical features according to the maturational stage of thymocytes failed to disclose significant differences in the majority of characteristics studied. However, patients with mature-stage T-NHL, with or without the addition of subjects with mature-stage T-ALL, were less likely to have a mediastinal mass (P = .02 for both comparisons). Those with intermediate-stage T-cell malignancy (T-ALL and T-NHL combined) were the subgroup most likely to have a mediastinal mass (P = .01). Response to remission induction therapy was significantly worse in the T-ALL subgroup with an early-stage phenotype: a failure rate of 21% v 0% and 6% for the two more differentiated phenotypic subgroups (P = .007). Event-free survival was not affected by thymocyte maturational stage in cases of either T-ALL or T-NHL. Despite evidence of clinical heterogeneity among the maturational stages of T-cell malignancies in children, these developmental subdivisions do not appear to be critical determinants of outcome once remission is achieved. We conclude that such phenotypes need not be included in the stratification plans for clinical trials using common induction treatment.