Liquid Guayule Natural Rubber,a Sustainable Processing Aid,Enhances the Processability,Durability and Dynamic Mechanical Properties of Rubber Composites

Petroleum-based oils are widely used as processing aids in rubber composites to improve processability but can adversely affect rubber composite performance and increase carbon footprint. In this research, liquid guayule natural rubber (LGNR), produced from guayule natural rubber, was used as a renewable processing aid to replace naphthenic oil (NO) in Hevea natural rubber, styrene-butadiene rubber (SBR) and guayule natural rubber (GNR) composites. The rheological properties, thermal stability, glass transition temperature, dynamic mechanical properties, aging, and ozone resistance of rubber composites with and without NO or LGNR were compared. Natural and synthetic rubber composites made with LGNR had similar processability to those made with NO, but had improved thermal stability, mechanical properties after aging, and ozone resistance. This was due to the strong LGNR–filler interaction and additional crosslinks formed between LGNR and the rubber matrices. The glass transition temperature of SBR composites was reduced by LGNR because of its increased molecular mobility. Thus, unlike NO, LGNR processing aid can simultaneously improve rubber composite durability, dynamic performance and renewability. The commercialization of LGNR has the potential to open a new sustainable processing-aid market.     

Effects on physiologic measures of appetite from intragastric balloon and endoscopic sleeve gastroplasty: results of a prospective study

Background:Endoscopic bariatric therapies can help address widening management gaps in obesity. Their ability to facilitate weight loss is largely tied to influences on appetite through perturbations of gastric emptying and accommodation. As these tools gain traction in obesity therapy, their physiologic underpinnings require exploration, which may enhance efficacy, tolerance, and patient-tailored care.Methods:We prospectively assessed consecutive subjects with fluid-filled intragastric balloons (IGBs) (n = 18) placed between October 2016 and June 2017 or underwent endoscopic sleeve gastroplasty (ESG) (n = 23) from March 2018 to June 2018. Patients underwent physiologic appraisal at 3 months with ¹³C-spirulina-based gastric emptying breath test to determine time to half emptying (T50), as well as maximum tolerated volume (MTV) of a standard nutrient drink test. Changes in T50 and MTV at 3 months were compared with percent total body weight loss (%TBWL) at 3 and 6 months using best-fit linear regression.Results:The change in T50 at 3 months correlated with %TBWL at 3 months for IGB (P = 0.01) and ESG (P = 0.01) but with greater impact on %TBWL in IGB compared to ESG (R² = 0.42 vs. 0.26). Change in T50 at 3 months was predictive of weight loss at 6 months for IGB (P = 0.01) but not ESG (P = 0.11). ESG was associated with greater decrease in MTV compared to IGB (340.25 ± 297.97 mL vs. 183.00 ± 217.13 mL, P = 0.08), indicting an enhanced effect on satiation through decreased gastric accommodation. Changes in MTV at 3 months did not correlate with %TBWL for either IGB (P = 0.26) or ESG (P = 0.49) but trended toward significance for predicting %TBWL at 6 months for ESG (P = 0.06) but not IGB (P = 0.19).Conclusion:IGB and ESG both induce weight loss but likely through distinct gastric motor function phenotypes, and gastric emptying may predict future weight loss in patients with IGB.     

Opportunities for Earlier Diagnosis and Treatment of Cardiac Amyloidosis

Despite the rapid expansion of noninvasive (nonbiopsy) diagnosis, contemporary patients with cardiac amyloidosis too often present with advanced features of disease, such as diminished quality of life, elevated natriuretic peptides, and advanced heart failure. Therapeutics for transthyretin cardiomyopathy (ATTR-CM) are most effective when administered before significant symptoms of cardiac dysfunction manifest, making early identification of affected individuals of paramount importance. Community engagement and ensuring that a broad range of clinicians have working knowledge of how to screen for ATTR-CM in everyday practice will be an important step in moving disease identification further upstream. However, reliance on the appropriate and timely diagnosis by individual clinicians may continue to underperform. This review highlights how targeted screening of special populations may facilitate earlier diagnosis. Systems of care that operationalize screening of high-risk subpopulations and prospective validation of novel approaches to ATTR-CM identification are needed.     

Eisen-Resorption an isolierten Dünndarmpräparaten von normalen und anämischen Ratten

Zusammenfassung 1. Am isoliert durchströmten Darmpräparat der Ratte wurde die Eisen-Resorption mit Hilfe von radioaktiv markiertem Eisen (⁵⁹Fe) untersucht. Hierzu wurden von jeder Ratte, an der Flexura duodenojejunalis beginnend, 4 Jejunumstücke präpariert, die im Mittel 8 cm lang waren. Die Fe-Konzentration in der Durchströmungsflüssigkeit war 10^–5 m.2. Die Fe-Konzentration im Resorbat der beiden proximalen Darmabschnitte betrug etwa 3%, die der beiden distalen Darmabschnitte etwa 1% der Fe-Konzentration in der angebotenen Flüssigkeit, wenn das Fe zu Versuchsbeginn als Fe²⁺ zugesetzt wurde. 16–20 cm unterhalb der Flexura duodenojejunalis nahm die Fähigkeit der Darmpräparate, Eisen zu resorbieren, steil ab.3. Wurde der Durchströmungsflüssigkeit zu Versuchsbeginn Fe³⁺ zugegeben, so war die Fe-Konzentration im Resorbat der beiden proximalen Darmsegmente nur 0,7% der Fe-Konzentration der angebotenen Flüssigkeit, die Fe-Aufnahme in die Mucosa der Darmabschnitte nur ein Viertel derjenigen, die man nach Zugabe von Fe²⁺ zur Durchströmungsflüssigkeit messen konnte.4. Der zeitliche Verlauf der Eisen-Resorption zeigte, daß der Penetration des Fe durch die Darmwand offenbar die Bindung des Eisens in der Mucosa vorangeht.5. Bei Angebot einer niedrigen Fe-Konzentration (2,5 · 10^–7) wird prozentual mehr Eisen resorbiert als bei Angebot einer höheren Fe-Konzentration (10^–4 m).6. Durch eine vorhergehende Fe-Beladung der Darmsegmente in vivo kann der Anteil des angebotenen Eisens, der in vitro resorbiert wird, vermindert werden. Umgekehrt ist die Eisen-Resorption bei Darmpräparaten von Tieren mit Eisenmangel-Anämie gegenüber derjenigen von gesunden Tieren mehr als doppelt so hoch. Beim anämischen Tier kann die gesteigerte Eisen-Resorption in vitro durch eine vorhergehende Fe-Beladung des Darmes in vivo wieder gesenkt werden. Die Befunde sprechen dafür, daß die Mucosa des Darmes ein System mit begrenzter Kapazität besitzt, das für die Eisen-Resorption und deren Regulation verantwortlich ist.

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Summary 1. The absorption of iron was studied in the isolated gut preparation of the rat using ⁵⁹Fe as a tracer. Gut segments of a mean length of 8 cm were prepared starting from the duodenojejunal flexur. The iron concentration of the perfusing medium was 10^–5 molar.2. When iron was presented in the ferrous state the iron concentration of the fluid absorbed by the two proximal gut segments was 3% and of two more distal segments was 1% of the inital concentration of the perfusing medium. At a distance of 16–20 cm distal to the duodenojejunal flexure the ability of gut to absorb iron decline steeply.3. When iron was presented in the ferric state the iron concentration on fluid absorbed by the proximal segments of the gut was only 0.7% of the concentration of the perfusing medium. The uptake of iron into the wall of the gut reached only 1/4 the value obtained with iron in the ferrous state.4. The time course of absorption suggests that the penetration of iron through the wall of the gut is preceded by the binding of iron to the mucosa cells.5. The percentage of iron absorbed from a perfusing medium of low iron concentration (2,5 × 10^–7 molar) was greater than that absorbed from a higher one (10^–4 molar).6. A single administration of iron in vivo 2 hours prior to the preparation diminished the percentage of iron in vitro. The iron absorption was, however, increased, if gut segments were taken from animals made anemic by bleeding and by feeding a diet low in iron content. This enhancement of iron absorption could be abolished if the anemic animals were treated in vivo with a single iron dose 2 hours before the gut segments were isolated.These findings are in favour with the assumption that the mucosa cells are provided with an iron binding system of limited capacity, which seems to adjust iron utilization to iron demand.

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Mit 4 Textabbildungen

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Herrn Professor Georg von Hevesy zum 80. Geburtstag in Verehrung gewidmet.

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Über einen Teil der Ergebnisse wurde bereits auf dem 1. Internationalen Symposion über Radioisotope in der Hämatologie (1.—3. 3. 1962) in Freiburg berichtet.     

Immunogenicity of Helicobacter pylori urease B protein and DNA vaccines in a mouse model

A vaccine could alleviate major morbidity and mortality associated with Helicobacter pylori infection. We immunized BALB/c mice with 3 doses of a protein or DNA vaccine based on H pylori urease B. Protein alone was immunogenic even after the first dose, whereas DNA did not elicit antibodies after 3 doses. DNA preceding protein (D-P-P) appeared to blunt the response to protein, whereas DNA following protein (P-D-D) shifted from a predominantly T helper 2 (Th2) profile to a balanced Th1:Th2 profile. These preliminary findings may have important implications for the development of an H pylori vaccine.     

Congenital pancreatic hypoplasia: a syndrome of exocrine and endocrine pancreatic insufficiency

We describe two brothers with small size at birth, early-onset insulin-dependent diabetes, and pancreatic exocrine insufficiency. In contrast to the findings in pancreatic aplasia, their serum C-peptide and glucagon levels were measurable. These findings, in concert with their clinical courses, are consistent with the diagnosis of congenital pancreatic hypoplasia.     

Lack of efficacy of thickened feeding as treatment for gastroesophageal reflux

The efficacy of thickened feedings for the treatment of gastroesophageal reflux in infancy was evaluated. Fifty-two infants were examined with prolonged pH monitoring of the distal esophagus after feedings of apple juice or apple juice thickened with rice cereal. All infants had a minimum of three feedings of both thickened and unthickened juice. The recordings of distal esophageal pH were analyzed for the percent of time the pH was less than 4 in the first 2 hours after each feeding. The infants were maintained in the following positions after feeding: prone (n = 29), prone-board with the head elevated 30 degrees from horizontal (n = 29), supine (n = 7), and unrestricted (n = 21). We found no significant difference in the percent of time with reflux with thickened versus unthickened feedings except in those infants maintained in the 30-degree prone position. In the first 2 hours after eating thickened juice, infants maintained in this position had increased esophageal reflux time (P less than 0.006). Further analysis revealed that 33% of the infants had a greater than 30% increase in esophageal reflux time after thickened feedings. Our study suggests that the immediate effect of thickened feedings on gastroesophageal reflux in infants is unpredictable.     

MRI prostate contouring is not impaired by the use of a radiotherapy image acquisition set-up. An intra- and inter-observer paired comparative analysis with diagnostic set-up images

PurposeThe use of MRI for radiotherapy planning purposes is growing but image acquisition using radiotherapy set-ups has impaired image quality. Whether differences in image acquisition set-up could modify organ contouring has not been evaluated. Therefore, we aimed to evaluate differences in contouring between paired of image sets that were acquired in the same scanning session using different parameters.Material and methodsTen patients underwent RT treatment planning with MRI co-registration. MRI was carried out using two different set-ups during the same session, MRI radiotherapy set-ups and MRI diagnostic set-ups. Prostates and rectums were retrospectively contoured in both image sets by 5 radiation oncologists and 4 radiologists. Intra-observer analysis was carried out comparing organ volumes, the Dice coefficient and hausdorff distance values between two contouring rounds. Inter-observer analysis was carried out by comparing individual contours to a generated STAPLE consensus contour, which is considered the gold standard reference.ResultsNo significant differences were observed between MRI acquisition set-ups. Significant differences were observed for the dice and hausdorff parameters, comparing individual contours to the STAPLE consensus contour, when analysing diagnostic images between rounds, although raw values were similar.ConclusionProstate and rectum contours did not differ significantly when using diagnostic or radiotherapy MRI acquisition set-ups.