Mass Loss Research Articles

Investigation of the degradation behaviour of poly-L-lactic acid braided stents under real-time and accelerated conditions

Degradation tests are a key step in the development of a bioresorbable stent. The present study focused on the degradation of bioresorbable stents made from PLLA filaments, and examined the variation of the physical, thermal, and mechanical properties of the material and the devices under both real-time and accelerated degradation conditions. Results showed that the undegraded filaments were highly crystalline and composed by both α and α′ crystalline phases, induced by both the melt spinning and heat treatment processes. The latter was shown to have an important influence on the further formation of α crystalline phase and therefore crystalline structure perfectioning. Real-time degradation tests showed that the devices maintained structural stability for up to a year, meeting the required 6-month degradation period for vascular stents. Degradation was shown to primarily affect the crystalline regions, and to cause a gradual loss of material ductility before any mass loss or decrease in crystallinity. In turn, a constant decrease of molecular weight was observed, with stent failure occurring around day 389 due to a drop in molecular weight below 10,000 g/mol. Accelerated degradation tests mirrored real-time results until mass loss began. Subsequently a slower molecular weight decrease was observed, with an increase and subsequent decrease of material crystallinity. The consistency of the data obtained between real-time and accelerated degradation before mass loss confirmed the possibility to gain insights into real-time degradation through an accelerated protocol. However, attention must be paid to the initial molecular weight of the material, which has been shown to highly influence the acceleration rate. This study provides a wide range of experimental data both on the real-time and thermally accelerated degradation behaviour of PLLA braided stents that can be used as benchmark for further studies in the field.

From the Surface to the Stratosphere: Large‐Scale Atmospheric Response to Antarctic Meltwater

AbstractThe ocean response to Antarctic Ice Sheet (AIS) mass loss has been extensively studied using numerical models, but less attention has been given to the atmosphere. We examine the global atmospheric response to AIS meltwater in an ensemble of experiments performed using two fully coupled climate models under a pre‐industrial climate. In response to AIS meltwater, the experiments yield cooling from the surface to the tropopause over the subpolar Southern Ocean, warming in the Southern Hemisphere polar stratosphere, and cooling in the upper tropical troposphere. Positive feedbacks, initiated by disrupted ocean‐atmosphere heat exchange, result in a change in the top‐of‐atmosphere radiative balance caused primarily through surface and near‐surface albedo changes. Changes in the atmospheric thermal structure alter the jet streams aloft. The results highlight the global influence of AIS melting on the climate system and the potential for impacts on mid‐latitude climate patterns and delayed regional warming signals.

Study of coarse and fine natural aggregates at high temperature in Algeria

Under high temperature, concrete undergoes changes which occurred in the hardened cement past and aggregates. These changes modified the mechanical and physical properties of concrete. The main objective of this study is to observe and identify the influence of high temperature on the physical properties of different nature of aggregates used to cast concrete. Four types of aggregates were studied in this research, siliceous sand (SS), calcareous sand (CS), white calcareous aggregates (WCA) and gray calcareous aggregates (GCA). These aggregates were subjected to different temperatures, from 100°C to 900°C. The mass loss, absorption coefficient, water porosity and density were determined before and after the exposure to the high temperatures. The results show that gray calcareous aggregates (GCA) suffered more deterioration than the other types of aggregates after the high temperature exposures. The results presented in this paper allow improving the knowledge of aggregate’s deterioration phenomena and the evolutions of physical properties of these different aggregates can be used to explain the evolution of physical and mechanical properties of concretes.

Accumulation of advanced oxidation protein products promotes age-related decline of type H vessels in bone.

Type H vessels have been proven to couple angiogenesis and osteogenesis. The decline of type H vessels contributes to bone loss in the aging process. Aging is accompanied by the accumulation of advanced oxidation protein products (AOPPs). However, whether AOPP accumulation is involved in age-related decline of type H vessels is unclear. Here, we show that the increase of AOPP levels in plasma and bone were correlated with the decline of type H vessels and loss of bone mass in old mice. Exposure of microvascular endothelial cells to AOPPs significantly inhibited cell proliferation, migration, and tube formation, increased NADPH oxidase activity and excessive reactive oxygen species generation, upregulated the expression of vascular cell adhesion molecule-1 and intercellular cell adhesion molecule-1, and eventually impaired angiogenesis, which was alleviated by redox modulator N-acetylcysteine and NADPH oxidase inhibitor apocynin. Furthermore, reduced AOPP accumulation by NAC treatment was able to alleviate significantly the decline of type H vessels, bone mass loss and deterioration of bone microstructure in old mice. Collectively, these findings suggest that AOPPs accumulation contributes to the decline of type H vessels in the aging process, and illuminate a novel potential mechanism underlying age-related bone loss.

Calcium plus vitamin D supplementation during pregnancy has no impact on postpartum transient longitudinal changes in hip geometry in adolescent mothers: a secondary analysis of a randomised controlled trial.

We have previously demonstrated that calcium plus vitamin D supplementation during adolescent pregnancy reduces the magnitude of transient postpartum bone mass loss. In the present post hoc analysis, we further investigated the effect of calcium plus vitamin D supplementation during pregnancy in hip geometry throughout one year postpartum in Brazilian adolescents with low daily calcium intake (∼600 mg/d). Pregnant adolescents (14-19 years) were randomly assigned to receive calcium (600 mg/d) plus vitamin D3 (200 μg/d) or a placebo from 26 weeks of gestation until parturition. Dual-energy X-ray absorptiometry images were obtained at 5 (n 30 and 26 for calcium plus vitamin D and placebo, respectively), 20 (n 26 and 21) and 56 (n 18 and 12) weeks postpartum, and hip geometry parameters were analysed by Advanced Hip Assessment software. The effects of the intervention, time point and their interaction were assessed using repeated-measures mixed-effects models. No significant intervention effects or intervention × time interactions were observed on hip geometry parameters (P > 0·05). Time effects were observed in cross-sectional area, cross-sectional moment of inertia and section modulus parameters with decreases from the 5th to the 20th week postpartum followed by recovery from the 20th to the 56th week (P < 0·05). Our findings indicate that the postpartum period is associated with transient changes in the hip geometry of lactating adolescent mothers, regardless of the low calcium intake and the supplementation offered during pregnancy, suggesting that a physiological adaptation of these adolescents to low calcium intake is at play.

Formation of requirements for impact resistance and wear resistance of grinding balls

The article presents the results of a study of the operation processes of steel grinding balls in semi-autogenous grinding mills (SAG). It was determined that the balls experience both abrasive and impact loads. The properties of steel grinding balls with the same production technology are determined by the chemical composition and the formed microstructure over the entire cross-section of the ball. Balls made using 3 different technologies were studied. The balls of sets 1 and 2 show high hardness values at the surface, sufficient to ensure good resistance to wear during operation, and a sharp decrease in hardness at a distance of ~(15–20) mm from the surface as the volume of pearlite structures increases. At the same time, the balls of the 1st and 2nd sets showed low values of impact strength and insufficient resistance to impact. The lowest hardness values from the surface to the center were observed for set 3. Also, the highest mass loss during the abrasive wear test was recorded for set 3, which is explained by the lowest hardness values. The balls of set 3 showed higher values of impact strength and no splitting during the ball-on-ball test, which is explained by the soft ferrite-pearlite structure both on the surface and across the cross section of the ball, due to the reduced carbon content and the presence of nickel in the chemical composition. At the same time, the balls from set 3 showed the worst result in terms of abrasive wear. In the course of the conducted research, it was established that for successful operation in SAG, steel grinding balls must have a surface with high hardness due to the martensitic structure and a viscous core with a ferrite-pearlite structure. A promising direction in the development of technology for the production of steel grinding balls will be to obtain a steel ball microstructure that decreases uniformly from the surface to the center, which will allow maintaining high wear resistance and increasing the resistance to ball splitting

X-Shooting ULLYSES: Massive stars at low metallicity. VI. Atmosphere and mass-loss properties of O-type giants in the Small Magellanic Cloud

Mass loss through a stellar wind is an important physical process that steers the evolution of massive stars and controls the properties of their end-of-life products, such as the supernova type and the mass of compact remnants. To probe its role in stellar evolution over cosmic time, mass loss needs to be studied as function of metallicity. For mass loss to be accurately quantified, the wind structure needs to be established jointly with the characteristics of small-scale inhomogeneities in the outflow, which are known as wind clumping. We aim to improve empirical estimates of mass loss and wind clumping for hot main-sequence massive stars, study the dependence of both properties on the metal content, and compare the theoretical predictions of mass loss as a function of metallicity to our findings. Using the model atmosphere code Fastwind and the genetic algorithm fitting method Kiwi-GA we analyzed the optical and ultraviolet spectra of 13 O-type giant to supergiant stars in the Small Magellanic Cloud galaxy, which has a metallicity of approximately one-fifth of that of the Sun. We quantified the stellar global outflow properties, such as the mass-loss rate and terminal wind velocity, and the wind clumping properties. To probe the role of metallicity, our findings were compared to studies of Galactic and Large Magellanic Cloud samples that were analyzed with similar methods, including the description of clumping. We find significant variations in the wind clumping properties of the target stars, with clumping starting at flow velocities $0.01 - 0.23$ of the terminal wind velocity and reaching clumping factors $f_ cl = 2 - 30$. In the luminosity ($ L / odot = 5.0 - 6.0$) and metallicity ($Z/Z_ odot = 0.2 - 1$) range we considered, we find that the scaling of the mass loss $ M $ with metallicity $Z$ varies with luminosity. At $ odot = 5.75$, we find $ M Z^m$ with $m = 1.02 0.30$, in agreement with pioneering work in the field within the uncertainties. For lower luminosities, however, we obtain a significantly steeper scaling of $m &gt; 2$. The monotonically decreasing $m(L)$ behavior adds a complexity to the functional description of the mass-loss rate of hot massive stars. Although the trend is present in the predictions, it is much weaker than we found here. However, the luminosity range for which $m$ is significantly larger than previously assumed (at $ odot 5.4$) is still poorly explored, and more studies are needed to thoroughly map the empirical behavior, in particular, at Galactic metallicity.

From Burst to Sustained Release: The Effect of Antibiotic Structure Incorporated into Chitosan-Based Films

Background/Objectives: Medical devices are susceptible to bacterial colonization and biofilm formation, which can result in severe infections, leading to prolonged hospital stays and increased burden on society. Antibacterial films have the potential to assist in preventing biofilm formation, thereby reducing administration of antibiotics and the emergence of antibiotic-resistant strains. In a previous study, a chitosan-based matrix crosslinked with tannic acid and loaded with gentamicin was reported. In this study, five different antibiotics (moxifloxacin, ciprofloxacin, trimethoprim, sulfamethoxazole or linezolid) were loaded into these chitosan-based films, and their impact on the release behavior carefully assessed. Methods: The samples were characterized according to their thickness, swelling, and mass loss in phosphate-buffered saline (PBS), as well as by morphology using scanning electron microscopy (SEM) and optical phase contrast microscopy. Antibiotic release over time was quantified in PBS by high-performance liquid chromatography (HPLC). Antibacterial activity was investigated by disk diffusion test and antibiotic release over time. Finally, the cytotoxicity of the samples was assessed with human dermal fibroblasts. Results: The obtained results differed significantly, especially regarding the antibiotic release time and antibacterial activity, which varied from one day to six months, enabling classification of the films from burst/transient to prolonged release. The films also showed antibacterial features against bacteria mostly present in medical devices and displayed to be non-cytotoxic. Conclusions: In conclusion, it was demonstrated that the antibiotics structure significantly alters the release kinetics, and that by carefully selecting the antibiotic, the consequent release can be tuned. This approach yielded films that could be used for potentially-scalable release in antimicrobial coatings specific to medical devices, aiming to reduce biomaterial associated infections (BAIs).

Advances in sarcopenia and urologic disorders

Sarcopenia is a loss of muscle strength, muscle mass, and function that can increase a patient’s risk of injury, illness, and can even severely impair quality of life and increase a patient’s risk of death. A growing body of research suggests that sarcopenia and urinary tract disorders are closely related. In this review, we aimed to emphasize the definition of skeletal sarcopenia, summarize the methods used to diagnose skeletal sarcopenia, discuss the advances in the study of sarcopenia in benign diseases of the urinary system, discuss the advances in the study of sarcopenia in malignant diseases of the urinary system. Sarcopenia and urologic diseases interact with each other; urologic diseases cause sarcopenia, and sarcopenia aggravates the condition of the original disease, thus falling into a vicious circle. This review provides a comprehensive understanding of sarcopenia in urologic diseases, which is very important for the management and prognosis of urologic diseases.

Protein requirement in obesity.

The combined obesity and ageing pandemic require action to avoid a total health system infarct. Obesity is largely challenged with caloric restriction and endurance exercise, likely to be assisted by drugs. The older adults with the highest obesity levels may face extreme loss of muscle mass and increased risk of sarcopenic obesity.Within this context the question of what is the protein requirement is extremely urgent. While the topic is essential, no trials have directly assessed protein requirements for obesity. Therefore, we will have to deal with more indirect evidence. Several systematic reviews have appeared for obesity treatment involving protein and a few randomized controlled trials during weight loss are worth mentioning considering the amount of protein needed, especially with increasing age. Protein requirements are hard to derive for obesity defined by BMI over 30 perse. During weight loss the rebuilding of the body is likely to need at least 1.2 g/kg body weight/d with a maximum weight of BMI 30, especially in the aged. Obesity might increase protein requirements, however being obese with a healthy and active lifestyle might result in normal protein requirements.

Energy and protein nutrition adequacy in general wards among intensive care unit survivors: A systematic review and meta-analysis.

Adequate energy and protein provision is mandatory to optimize survival chances in critical illness, prevent loss of muscle mass, and reduce length of stay. Data are available concerning feeding adequacy in intensive care unit (ICU) participants, but little is known about the adequacy in post-ICU participants. This systematic review aimed to evaluate feeding adequacy in post-ICU participants and addressed causes of feeding interruption leading to suboptimal adequacy. For this systematic review, a bibliographic search was performed in PubMed, Scopus, and Web of Science. Randomized controlled studies, non-randomized controlled studies, and observational studies conducted between January 1990 and November 2023 fulfilling the inclusion criteria were withheld. Eight studies were included. Outcomes reported were energy and protein adequacy, barriers, and feeding routes. Energy and protein requirements were determined in various ways, including indirect calorimetry and standardized and weight-based formulas. Energy adequacy ranged from 52% to 102% and protein adequacy between 63% and 86%. Participants were mainly fed with enteral nutrition (EN) or a combination of oral nutrition and EN. The main barrier reported for inadequate nutrition intake was feeding tube removal. Next to different ways in calculating targets and reporting results, a wide range in energy and protein adequacy was observed, but with constant protein underfeeding. Participants fed with EN or a combination of EN and oral nutrition had the best adequacy; inappropriate tube removal is a common barrier leading to inadequate therapy. Standardized reporting and larger studies are needed to guide nutrition care for post-ICU participants.

Thwaites Glacier thins and retreats fastest where ice-shelf channels intersect its grounding zone

Abstract. Antarctic ice shelves buttress the flow of the ice sheet but are vulnerable to increased basal melting from contact with a warming ocean and increased mass loss from calving due to changing flow patterns. Channels and similar features at the bases of ice shelves have been linked to enhanced basal melting and observed to intersect the grounding zone, where the greatest melt rates are often observed. The ice shelf of Thwaites Glacier is especially vulnerable to basal melt and grounding zone retreat because the glacier has a retrograde bed leading to a deep trough below the grounded ice sheet. We use digital surface models from 2010–2022 to investigate the evolution of its ice-shelf channels, grounding zone position, and the interactions between them. We find that the highest sustained rates of grounding zone retreat (up to 0.7 km yr−1) are associated with high basal melt rates (up to ∼250 m yr−1) and are found where ice-shelf channels intersect the grounding zone, especially atop steep local retrograde slopes where subglacial channel discharge is expected. We find no areas with sustained grounding zone advance, although some secular retreat was distal from ice-shelf channels. Pinpointing other locations with similar risk factors could focus assessments of vulnerability to grounding zone retreat.

Electrochemical dissolution of titanium under alternating current polarization to obtain its dioxide

Abstract The titanium electrode was polarized under the influence of alternating current (AC) at 50 Hz. The current density was varied between 100 and 5,000 A m−2. Initially, the titanium electrode oxidized, and then, titanium oxides were reduced during the cathodic half-cycle of the AC. When the cathodic half-cycle changes to the anodic half-cycle, titanium is oxidized to the trivalent state: Ti − 3 e ̄ → Ti 3 + {{\rm{Ti}}-3{\rm{e}}{\rm{&amp;#x0304;}}\to {\rm{Ti}}}^{3+} . The direction of the AC changes depending on its frequency, causing the processes occurring on the electrodes to be periodically repeated. The current efficiency of the titanium electrode dissolution depends on the sulfuric acid concentration and electrolyte concentration, reaching up to 63.4% under optimal conditions. Bipolar electrodes were used during AC electrolysis. It was found that the decrease in the mass of titanium electrodes increases almost linearly at first, from 400 to 1,600 A m−2, and then more intensively within the current densities from 1,800 to 2,500 A m−2. It was shown that when using a bipolar electrode, the total mass loss of the electrodes is 1.38 times greater than the total mass loss during polarization without a bipolar electrode. The composition of the titanium dioxide obtained as a result of electrolysis was identified using physico-chemical analysis methods.

Fire parameters of recycled plastic pellets

AbstractDuring the recycling process, waste plastic undergoes various processes that change its geometry. The thermal properties and fire behaviour of plastic in different geometries has not been widely studied. This paper aims to determine critical thermal properties of plastic pellets made of recycled plastic. For this paper, cone calorimeter tests of various volumes of recycled plastic pellets of low‐ and high‐density polyethylene and polypropylene were conducted. During these tests, the heat release rate (HRR), mass loss rate and time‐to‐ignition were measured, thereafter the heat of combustion (HOC) was calculated. A calibration of suitable time‐to‐ignition equations is carried out. The average HRR is between 353 and 581 kW/m2 with an external heat flux of 50 kW/m2. The measured time‐to‐ignition values ranged between 27 s at 50 kW/m2 and just more than 90 s at 25 kW/m2. Values obtained analytically from the thermally thin time‐to‐ignition equations for these materials describe ignition well, which appears to be due to the particulate nature of the samples. The HOC (40–41 MJ/kg) shows good agreement with the HOC for virgin plastic found in literature. These properties can be used as a basis for material characterisation, and further testing will be done before using this as simulation inputs to determine how bulk stored plastic pellets will behave in the event of a fire.

Advanced nano-composite coatings of ZrB₂/ZrC/SiC on carbon fibers via eco-friendly precursor synthesis

This study presents a comprehensive investigation into the synthesis and characterization of ZrB2/ZrC/SiC composite coatings on carbon fiber substrates via a solution-based process followed by high-temperature pyrolysis. The precursor solution was prepared using Gum Ghatti (GG), zirconyl chloride, tetraethyl orthosilicate, and boric acid. Optimization of precursor concentration and molar ratios was performed to achieve suitable viscosity and composition. The pyrolysis process was conducted in an argon atmosphere, resulting in the formation of well-defined ZrB2, ZrC, and SiC phases. XRD analysis confirmed the phase composition, while SEM imaging revealed spheroidal particle aggregates with a uniform distribution of composite phases. TG-DTA analysis reveals the thermal decomposition behavior, highlighting distinct stages of mass loss and phase transformations. Coated carbon fibers exhibited enhanced oxidation resistance, as evidenced by TGA analysis. SEM analysis confirmed the uniform distribution and adhesion of the composite matrix on the carbon fiber substrate. This study demonstrates the successful synthesis of ZrB2/ZrC/SiC composite coatings with promising thermal properties for advanced applications.

Outcomes of Sub-Neptune Collisions

Observed high multiplicity planetary systems are often tightly packed. Numerical studies indicate that such systems are susceptible to dynamical instabilities. Dynamical instabilities in close-in tightly packed systems, similar to those found in abundance by Kepler, often lead to planet–planet collisions. For sub-Neptunes, the dominant type of observed exoplanets, the planetary mass is concentrated in a rocky core, but the volume is dominated by a low-density gaseous envelope. For these, using the traditional perfect merger assumption (also known as the “sticky-sphere” approximation) to resolve collisions is questionable. Using both N-body integration and smoothed-particle hydrodynamics, we have simulated sub-Neptune collisions for a wide range in realistic kinematic properties such as impact parameters ( b′ ) and impact velocities ( vim ) to study the possible outcomes in detail. We find that the majority of the collisions with kinematic properties similar to what is expected from dynamical instabilities in multiplanet systems may not lead to mergers of sub-Neptunes. Instead, both sub-Neptunes survive the encounter, often with significant atmosphere loss. When mergers do occur, they can involve significant mass loss and can sometimes lead to complete disruption of one or both planets. Sub-Neptunes merge or disrupt if b′<bc′ , a critical value dependent on vim /v esc, where v esc is the escape velocity from the surface of the hypothetical merged planet assuming perfect merger. For vim/vesc≲2.5 , bc′∝(vim/vesc)−2 , and collisions with b′<bc′ typically leads to mergers. On the other hand, for vim/vesc≳2.5 , bc′ ∝ vim /v esc, and the collisions with b′<bc′ can result in complete destruction of one or both sub-Neptunes.

Synthesis, Characterization, Density Functional Theory Study, Antibacterial Activity and Molecular Docking of Zeolitic Imidazolate Framework‐8

ABSTRACTIn this study, Zeolitic Imidazolate Framework‐8 (ZIF‐8) nanomaterials were synthesized using a co‐precipitation one‐pot method that uses ethanol, methanol, and water as solvents for the precursors (2‐methylimidazole and Zinc nitrate hexahydrate), resulting in yields of 66.77%, 73.14%, and 68.12%, respectively. The as‐synthesized ZIF‐8 nanomaterials were thoroughly characterized by X‐ray diffraction analysis, transmission electron microscopy, ultraviolet–visible spectroscopy, and Fourier‐transform infrared spectroscopy. The X‐ray diffraction analysis showed that the crystallite size of ethanol‐based ZIF‐8 (24.76 ± 1.67 nm) was smaller than those synthesized in water (26.92 ± 1.89 nm) and methanol (31.39 ± 1.03 nm). However, methanol‐based ZIF‐8 exhibited lower crystallinity (85.93%) than water‐based ZIF‐8 (91.48%) and ethanol‐based ZIF‐8 (92.71%). Zeta potential studies revealed that ethanol‐based ZIF‐8 had a larger surface charge (+37 mV) than water‐based ZIF‐8 (+35 mV) or methanol‐based ZIF‐8 (+24 mV). Transmission electron microscopy analysis confirmed particle sizes of 54.35 ± 2.11 nm for ethanol‐based ZIF‐8, 57.91 ± 2.26 nm for water‐based ZIF‐8, and 63.25 ± 4.12 nm for methanol‐based ZIF‐8. Thermogravimetric analysis indicated thermal stability up to 800 °C, with mass losses of 55.98% for ethanol‐ZIF‐8, 50.12% for water‐based ZIF‐8, and 65.36% for methanol‐based ZIF‐8 by 600 °C. In antibacterial studies, water‐based ZIF‐8 exhibited the largest zone of growth inhibition (17.30 ± 0.26 mm) against Escherichia coli compared to ethanol‐based ZIF‐8 (15.57 ± 0.32 mm) and methanol‐based ZIF‐8 (14.70 ± 0.20 mm). Pearson's correlation study revealed that zeta potential, crystallinity, and antibacterial activity are positively related. Furthermore, water‐based ZIF‐8, with a minimum inhibitory concentration of 50 μg/100 μL, confirmed evident cell membrane disruption. Molecular docking experiments revealed ZIF‐8's significant binding affinity for the E. coli protein 5AZC, supporting its robust antibacterial activity.

Precipitation drives western Patagonian glacier variability and may curb future ice mass loss.

Two-thirds of all glaciers worldwide are projected to disappear by 2100 CE. Large uncertainties however remain in maritime settings, where some glaciers have recently gained mass in response to increased snowfall. One of these regions is southern Patagonia, where increased precipitation since the 1980s seems to have attenuated glacier retreat. Whether this exceptional behavior will continue in a warmer future is unclear. Here, we use a numerical ice-flow model constrained by paleoglaciological data to simulate how climate variability influenced the evolution of three maritime outlet glaciers of the Southern Patagonian Icefield during the last 6000 years. Our experiments suggest that precipitation drove 67% of the centennial-scale fluctuations in the volume of the modeled glaciers. When applied to the temperature projected by 2100 CE, our simulations show that precipitation needs to increase by 10-50% to maintain present-day glacier volumes, depending on the climate scenario (SSP1-2.6 to SSP5-8.5). This implies that if greenhouse-gas emission cuts fail, these glaciers will enter a warmer regime unseen over the last 6000 years, where precipitation cannot offset glacier mass loss. Conversely, if emissions are curtailed, increased precipitation could halt mass loss of some of Patagonia's largest glaciers, and potentially of other maritime glaciers worldwide.

Clinical mechanism of muscle mass loss during neoadjuvant chemotherapy in older patients with esophageal cancer: a prospective cohort study.

In older patients with locally advanced esophageal cancer (LAEC), loss of skeletal muscle mass during neoadjuvant chemotherapy (NAC) is associated with poor clinical outcomes. This study aimed to investigate factors associated with loss of skeletal muscle mass during NAC in older patients with LAEC. This was a single-center exploratory prospective cohort study. Consecutive patients aged ≥65years with LAEC scheduled for curative esophagectomy after NAC were enrolled between October 2021 and December 2023. As a primary endpoint, loss of skeletal muscle mass index (ΔSMI: pre-NAC minus post-NAC value) was calculated from computed tomography images before and after NAC. Significant pre-NAC and during-NAC factors with ΔSMI were detected with a multivariate regression model. Statistical significance was considered as two-tailed P <0.05. A total of 69 patients were analyzed. The mean age was 72.9years, and 53 (77%) were male. Mean SMI before and after NAC was 43.1 and 40.9cm2/m2, and mean ΔSMI was 2.2cm2/m2. In multivariate analysis, ΔSMI was associated with increased sitting time during NAC (per 1min/day, adjusted coefficient 0.007, 95% confidence interval [CI] 0.001 to 0.013, P = 0.016), decreased Geriatric Nutritional Risk Index during NAC (per 1 score, adjusted coefficient -0.146, 95% CI -0.213 to -0.013, P = 0.002), and worsening decreased appetite during NAC (vs. no worsening, adjusted coefficient 1.571, 95% CI 0.279 to 2.862, P = 0.018). It was hypothesized that the inactivity-related mechanism and malnutrition-related mechanism are important for skeletal muscle mass loss during NAC in older patients with LAEC.

Enhanced BMP Signaling Alters Human β-Cell Identity and Function.

Inflammation contributes to the pathophysiology of diabetes. Identifying signaling pathways involved in pancreatic β-cell failure and identity loss can give insight into novel potential treatment strategies to prevent the loss of functional β-cell mass in diabetes. It is reported earlier that the immunosuppressive drug tacrolimus has a detrimental effect on human β-cell identity and function by activating bone morphogenetic protein (BMP) signaling. Here it is hypothesized that enhanced BMP signaling plays a role in inflammation-induced β-cell failure. Single-cell transcriptomics analyses of primary human islets reveal that IL-1β+IFNγ and IFNα treatment activated BMP signaling in β-cells. These findings are validated by qPCR. Furthermore, enhanced BMP signaling with recombinant BMP2 or 4 triggers a reduced expression of key β-cell maturity genes, associated with increased ER stress, and impaired β-cell function. Altogether, these results indicate that inflammation-activated BMP signaling is detrimental to pancreatic β-cells and that BMP-signaling can be a target to preserve β-cell identity and function in a pro-inflammatory environment.