Rapid Decrease Research Articles

Sleeve-gastrectomy results in improved metabolism and a massive stress response of the liver proteome in a mouse model of metabolic dysfunction-associated steatohepatitis

BackgroundBariatric surgery has been shown to improve the histopathological findings in patients with obesity and metabolic dysfunction-associated steatohepatitis, but there are also reports about non-responders or progressive disease after bariatric interventions. Therefore, it is of utmost importance to understand the pathophysiological processes in the liver after bariatric surgery. Materials and methodsIn the present study, 4 weeks old male C57/Bl6 mice were fed a Western Diet to induce metabolic dysfunction-associated steatohepatitis and sleeve-gastrectomy (SG), or sham operation in the pair-fed and ad libitum control group were performed. Mice were observed for two or eight weeks after surgery and metabolic assessment was performed throughout the experiment. Histopathology, flow cytometry and proteomic analyses were conducted to evaluate hepatic inflammation, liver metabolism and affected signaling pathways. ResultsWeight loss was higher, and metabolism significantly improved after SG. Two weeks after SG major inflammatory and regulatory disturbances in the liver were observed. The proportion of hepatic CD3+NK1.1+ cells were decreased, and proteins involved in apoptosis like Fas, Casp1 and Casp9 or in the acute phase response were upregulated in SG mice. These disturbances decreased in the long-term and we observed an increase of many proteins involved in lipid metabolism eight weeks following SG. ConclusionsThe rapid weight loss and decrease of hepatic fat after SG lead to a proinflammatory response in the liver in the early phase after surgery, which changes to a more moderate immune response in the long-term. We suggest a preoperative risk stratification and postoperative surveillance depending on the histopathological findings.

Pain outcomes of outside-the-cage robotic thoracic surgery: a prospective matched-cohort study

Management of acute and chronic pain after thoracic surgery for pulmonary resection or thymectomy remains a challenge for both thoracic surgeons and anesthesiologists. Advances in minimally invasive robotic procedures have made subcostal outside-the-cage (OTC) resections possible, but the procedure’s pain benefits have not been previously measured. A single-center cohort was consented to undergo robotic-assisted thoracoscopic surgery (RATS) with an OTC or transthoracic (TT) approach. On every post-operative day (POD), patients were asked to complete the visual analog scale (VAS) of pain, assigning a score of 0–10 with higher scores equaling higher pain intensity. Additionally, patients’ opioid consumption was recorded and classified using morphine equivalent dose (MED). Descriptive statistics of demographics, Mann–Whitney, and Chi-squared tests were performed in a matched analysis. Altogether, 50 OTC patients and 50 TT patients were included. For each group, 1 pneumonectomy, 19 lobectomies, 10 segmentectomies, and 20 thymectomies were performed. Between groups, most were male (n = 54; p = 0.42) and there were no differences in American Society of Anesthesiologists scores (p = 0.51), or tobacco consumption (p = 0.45). Patients who received an OTC approach experienced significantly lower pain scores on POD-0 (p = 0.001), POD-1 (p < 0.001), and POD-2 (p < 0.001). POD-3 OTC VAS scores were not different from those of the TT group (p = 0.09). Similarly, MED was lower for the OTC group on POD-0 (p < 0.001), POD-1 (p = 0.03), and POD-3 (p = 0.03). The RATS-OTC approach results in a more rapid decrease in self-reported pain by the patient as well as significantly lower levels of MED.

Impact of glucagon-like peptide-1 receptor agonists on diabetic retinopathy: A meta-analysis of clinical studies emphasising retinal changes as a primary outcome.

To determine if glucagon-like peptide-1 receptor agonists (GLP-1RA) are associated with the development and progression of diabetic retinopathy (DR). A systematic search was conducted on PubMed, Cochrane Library, and Embase from inception to February 2024 to identify clinical studies reporting the development of and changes in DR as the primary outcome in patients with type 2 diabetes taking GLP-1RA, insulin, or oral antidiabetic medication (OAD). Two researchers independently completed the search and referred to a third as necessary. Data for meta-analysis was pooled using a random-effects model. Analysis of seven studies representing 242 537 patients showed a significantly decreased risk of incidence of DR between GLP-1RA and insulin use (RR = 0.66, 95% CI (0.48, 0.91), p = 0.01). There was no difference in the risk of DR complications (e.g., vitreous haemorrhage, retinal detachment, or requiring treatment with intravitreal injections, lasers, vitrectomy). Between GLP-1RA and OAD use, there was no difference in the risk of incidence of DR, while there was a significantly increased risk of DR complications (RR = 1.39, 95% CI (1.07, 1.80), p = 0.01). Our findings indicate no elevated risk of incidence of DR linked to GLP-1RA compared to insulin. In fact, GLP-1RA may offer potential advantages over insulin regarding the overall incidence of DR. The increased risk of DR requiring treatment and associated complications in the GLP-1RA group compared to OAD may be due to the transient progression of DR associated with a rapid decrease in HbA1c - a phenomenon not specific to GLP-1RA and warrants further investigation.

Lung function decline in people with serious mental illness: A call to action

This prospective observational study aimed to evaluate the rate of change in forced expiratory volume in the first second (FEV1) and to explore the factors associated with changes in FEV1 in people with serious mental illness (SMI). Sixty subjects diagnosed with schizophrenia or bipolar disorder who were smokers and without history of respiratory illness agreed to participate. The mean (range) follow-up period was 3.54 (3.00–4.98) years. The mean (standard deviation) annual rate of change in FEV1 decreased by 39.1 (105.2) mL/year. Thirty-one (51.7 %) patients experienced a decrease in the FEV1 ≥40 mL/year (i.e. a rapid decline). The factors associated with the absolute change in FEV1 were the baseline International Physical Activity Questionnaire activity score in metabolic equivalents of tasks (β 0.145, 95 % confidence interval [CI] 0.043 to 0.246; p = 0.005), baseline FEV1 (β -0.025, 95 % CI -0.076 to 0.027; p = 0.352), and the interaction term of both variables (β -3.172e-05, 95 % CI -6.025e-05 to -0.319e-05; p = 0.029). The factors associated with rapid FEV1 decline were income (odds ratio [OR] 0.999, 95 % CI 0.995 to 1.003; p = 0.572), the rate of change in abdominal circumference (OR 0.000, 95 % CI 0.000 to 0.890; p = 0.081), and the interaction term of both variables (OR 1.038, 95 % CI 1.010 to 1.082; p = 0.026). In conclusion, a substantial proportion of people with SMI experienced a rapid decrease in FEV1. If our results are confirmed in larger samples, the routine evaluation of lung function in people with SMI would be an opportunity to identify individuals at greater risk of morbidity and mortality.

Finger-specific effects of age on tapping speed and motor fatigability.

Increased motor fatigability is a symptom of many neuromuscular and neurodegenerative disorders. However, it is difficult to pinpoint pathological motor fatigability, since the phenomena has not yet been fully characterized in the healthy population. In this study, we investigate how motor fatigability differs across age. Given that many disorders involve supraspinal components, we characterize motor fatigability with a paradigm that has previously been associated with supraspinal mechanisms. Finger tapping at maximal speed results in a rapid decrease in movement speed, which is a measure of motor fatigability. We collected finger tapping data in a field experiment from the general population with a smartphone app, and we investigated age differences in maximal tapping speed, as well as the decrease in tapping speed for the index, middle, and little fingers. We found that the maximal tapping speed differed significantly between young (18-30 years, n = 194) and aged (50-70 years, n = 176), whereas the fatigability-induced relative decrease in movement speed did not differ between the age groups (average decrease: 17.0% ± 6.9% (young) vs. 16.5% ± 7.5% (aged) decrease). Furthermore, tapping speed and motor fatigability depended on which finger was used. These findings might relate to dexterity, with more dexterous movements being more resistant to fatigue. In this study, we provide a characterization of motor fatigability in the general population which can be used as a comparison for clinical populations in the future.

Evaluation of Seed Quality of Grain Corn Varieties through Accelerated Ageing

In an accelerated ageing test carried out to evaluate seed quality two hybrid grain corn varieties, 4546 and 888, were subjected to ageing conditions to assess their tolerance. The objective was to identify any differences between the varieties in their ability to maintain seed quality under accelerated ageing conditions. These tests simulate and hasten the natural ageing process of seeds, providing insight into their performance during storage over time and under adverse conditions. Following the ageing process, factors such as germination rate, vigour, and overall seed quality were assessed. The seeds of hybrid grain corn varieties 4546 and 888 were exposed to accelerated ageing by maintaining them at 40°C and 100% relative humidity in a growth chamber. Evaluations were conducted at intervals of 0, 48, 96, and 144 hours. The overall results indicated that seed quality in grain corn deteriorates following accelerated ageing treatment. Variety 4546 showed a rapid decrease in germination, germination rate, and seedling vigour throughout the testing period. Both varieties experienced an increase in moisture content from 11% to 20% during the ageing process. Additionally, the electrical conductivity of seed leachate increased for both varieties as the testing progressed. The experiment concluded that the 888 grain corn variety outperformed 4546 in all evaluated parameters. The 4546 variety was found to be highly sensitive to accelerated ageing.

Stochastic Schrödinger equation for hot-carrier dynamics in plasmonic systems

We present a multiscale method coupling the theory of open quantum systems with real-time ab initio treatment of electronic structure to study hot-carrier dynamics in photoexcited plasmonic systems. We combine the Markovian Stochastic Schrödinger equation with an ab initio GW coupled to the Bethe–Salpeter (BSE) equation description of the electronic degrees of freedom, interacting with a metallic nanoparticle modeled classically according to the polarizable continuum model. We apply this methodology to study the effect of relaxation (T1) and pure dephasing (T2) times on the hot-carrier dynamics in a system composed of a quantum portion described at GW/BSE level, i.e., a CHO fragment adsorbed on a vertex of a rhodium nanocube, and of the rest of the nanocube, treated classically, when irradiated with a 2.7 eV light pulse, inspired by the experimental results on plasmon-driven CO2 photoreduction. A net hole injection from rhodium to CHO is observed, with and without the classical portion of the nanocube. The nanocube effect is to enhance the generated charge population by two orders of magnitude. The nonradiative decay, via a relaxation time T1 based on the energy-gap law, produces a rapid decrease of the charge population. Results with T2 only show that a charge injection retarded with respect to the pulse, which is present in the coherent dynamics, disappears when coherence is erased.

A novel, centrally acting mammalian aminosterol, ENT-03, induces weight loss in obese and lean rodents.

ENT-03, a spermine bile acid we recently discovered in the brain of newborn mice acts centrally to regulate energy and metabolism. Obese, diabetic (ob/ob) mice treated with five doses of ENT-03 over 2 weeks, demonstrated a rapid decrease in blood glucose levels into the range seen in non-obese animals, prior to any significant weight loss. Weight fell substantially thereafter as food intake decreased, and serum biochemical parameters normalized compared with both vehicle and pair-fed controls. To determine whether ENT-03 could be acting centrally, we injected a single dose of ENT-03 intracerebroventricularly to Sprague-Dawley rats. Weight fell significantly and remained below vehicle injected controls for an extended period. By autoradiography, ENT-03 localized to the arcuate nucleus of the hypothalamus, the choroid plexus and cerebrospinal fluid. Significant cFosactivation occurred in multiple anatomical regions within the hypothalamus and brainstem involved in appetite suppression, food-entrained circadian rhythmicity, autonomic function, and growth. These data support a role for ENT-03 in the treatment of type 2 diabetes and obesity. Phase 1 studies in subjects with obesity and diabetes are currently in progress.

Overexpression of PRDM16 attenuates acute kidney injury progression: genetic and pharmacological approaches.

Acute kidney injury (AKI) presents as a condition marked by a sudden and rapid decrease in kidney function over a short timeframe, resulting from diverse causes. As a transcription factor, PR domain-containing 16 (PRDM16), has recently been implicated in brown fat biogenesis and heart diseases. Our recent works indicated that PRDM16 could suppress the occurrence of renal interstitial fibrosis in diabetic kidney disorder. Nonetheless, the effect and regulatory mechanism of PRDM16 in AKI remain elusive. Our study demonstrated that PRDM16 inhibited apoptosis induced by ischemic/reperfusion (I/R) in BUMPT (Boston University mouse kidney proximal tubular) cells and HK-2(Human Kidney-2)cells. Mechanistically, PRDM16 not only bound to the promoter region of S100 Calcium Binding Protein A6 (S100A6)and upregulated its expression but also interacted with its amino acids 945-949, 957-960, and 981-984 to suppress the p38MAPK and JNK axes via inhibition of PKC-η activity and mitochondrial reactive oxygen species (ROS) production. Furthermore, cisplatin- and I/R-stimulated AKI progression were ameliorated in PRDM16 proximal-tubule-specific knockin mice, whereas exacerbated in PRDM16 knockout proximal-tubule-specific mice). Moreover, we observed that formononetin ameliorated I/R- and cisplatin-triggered AKI progression in mice. Taken together, these findings reveal a novel self-protective mechanism in AKI, whereby PRDM16 regulates the S100A6/PKC-η/ROS/p38MAPK and JNK pathways to inhibit AKI progression.

The impact of basal cell carcinoma on the quality-of-life in older patients

Basal cell carcinoma (BCC) is the most frequent malignant tumour worldwide and incidences are rising rapidly. BCC grow locally, but can invade surrounding tissues. Little is known concerning their impact on the health-related quality of life (HrQoL), and limited available data reports contradicting results. Measuring HrQoL in BCC patients should be done using disease-specific questionnaires such as the Basal and Squamous cell carcinoma Quality of Life (BaSQoL) questionnaire. The aim of this study was to assess the BCC-related HrQoL by examining all relevant patient, tumour and treatment characteristics to identify the main factors for the BCC-related impact. Specific attention for older BCC patients wass brought forward because of the often complex decisions in this subgroup. Patients ≥ 18 years with a history of BCC were asked to fill in the BaSQoL questionnaire, consisting of 5 subdomains. Multivariable analyses were done using a generalized additive model (GAM) because of the need for incorporation of non-linear functions. The study obtained approval of the Ethics Committee of the Ghent University Hospital (EC/2019/1352). Informed consent was obtained from all subjects. All experiments were performed in accordance with relevant guidelines and regulations. Four hundred patients with a median age of 66 were enrolled. Mean BaSQoL subscores were 0.78 (SD 0.63) for ‘behaviour’, 1.01 (SD 0.73) for ‘diagnosis&treatment’, 0.90 (SD 0.73) for ‘worries’, 0.40 (SD 0.63) for ‘appearance’ and 1.20 (SD 0.75) for ‘other people’, illustrating the low to moderate impact of BCC on the HrQoL. A GAM with subsequent ANOVA testing was done for all relevant variables. In 4 out of 5 BaSQoL subdomains ‘age’ showed a significant correlation (‘behaviour’ p = 0.007; ‘diagnosis&treatment’ p = 0.026; ‘worries’ p = 0.003; ‘appearance’ p = 0.008). Lower BaSQoL scores were seen in older patients, meaning less BCC-impact on their HrQoL. There was a clear non-linear correlation between BaSQoL scores and age, illustrating that the impact of BCC on the HrQoL shows a rapid decrease starting around the age of 70. This study is the first to illustrate the relation between the BCC-related HrQoL and the age of patients with the use of a disease-specific HrQoL instrument. We found a lower BaSQoL score in older adults, with a specific age group of interest starting around the age of 70–75. This is an argument for a potential wait-and-see strategy for BCC in these patients.

Influence of Early Hydration Process on the Hydrostatic Pressure Change of Cement Pastes at Different Temperatures.

In cementing operations, a rapid decrease in the hydrostatic pressure of cement paste is one of the main causes of early gas channeling. In response to this issue, tests were conducted on the variation in the hydrostatic pressure of cement paste over time at different temperatures (30 °C-180 °C), and it was found that the curve of its rapid decrease time point with temperature change conforms to the Boltzmann function. The relationship between the early hydration process and the microstructure of paste at 90 and 150 °C, as well as the changes in hydrostatic pressure, was studied using X-ray powder diffraction, thermogravimetry, and scanning electron microscopy. The results show that the hydrostatic pressure curve of the paste shows a trend of first stabilization and then rapidly decreasing at medium and low temperatures (30 and 90 °C). At high temperatures (150 °C), the pressure curve initially increases until stabilization, enters a stable period, and finally rapidly decreases. In the early stage of hydration induction, there is a large amount of free water between hydration products, and the hydrostatic pressure of the paste remains stable. In the process of hydrostatic pressure reduction, the microstructure of the paste develops from the particle hydration products to a "gel framework", which isolates the pressure transfer of part of the free water. During the acceleration period of hydration, the hydration products enhance the "framework" and reduce the porosity of the paste, completely cutting off the transmission of water pressure, resulting in a rapid decrease in the hydrostatic pressure of the paste. A method for predicting the rapid decrease in hydrostatic pressure of the paste was proposed using the hydration reaction process.

Photoperiodism, testosterone and adult neurogenesis in canaries (Serinus canaria).

Domestic strains of canaries (Serinus canaria) variably respond to photoperiod changes and apparently stay in breeding state for extended periods. Fife Fancy canaries are supposed to be similar to the native species living at 27-39° north where photoperiod significantly changes across the year. Our birds showed reproductive cycles when exposed to light regimes mimicking the annual cycle of photoperiod. However after 6 months in short days (SD: 8L:16D), males developed large testes, as observed by X-ray tomography, and intense singing. Switching to long days (LD: 16L:8D) did not further increase song rate nor testes size but increased song duration, number of syllables per song, and trill occurrence frequency. No sign of regression was observed after 12 weeks in LD but return to SD produced a rapid decrease in testes size and singing activity below values in birds maintained throughout in SD. Fife Fancy thus does not seem to develop absolute but only relative refractoriness. The relatively high singing activity expressed by SD-photosensitive males does not seem to depend on high testosterone (T) concentrations. Singing did not correlate with plasma testosterone (T). Treatment with ATD + Flutamide only marginally decreased song rate and did not affect song quality nor song control nuclei volume. These birds are either supersensitive to low T levels or their reproductive physiology is activated by other mechanisms. Neurogenesis is increased by T and by LD but the function of new neurons incorporated in HVC is poorly understood. We developed a procedure based on X-ray focal irradiation to deplete neural progenitors adjacent to HVC and study the functional consequences. The decrease in neurogenesis increased the variability of T-induced songs in females and decreased their bandwidth. Neurogenesis in HVC thus plays a role in song production and X-ray focal irradiation represents an excellent tool to analyze adult neurogenesis.

New estimates of sulfate diffusion rates in the EPICA Dome C ice core

Abstract. To extract climatically relevant chemical signals from the deepest, oldest Antarctic ice, we must first investigate the degree to which chemical ions diffuse within solid ice. Volcanic sulfate peaks are an ideal target for such an investigation because they are high-amplitude, short-duration (∼3 years) events with a quasi-uniform structure. Here we present an analysis of the EPICA Dome C sulfate record over the last 450 kyr. We identify volcanic peaks and isolate them from the non-sea-salt sulfate background to reveal the effects of diffusion: amplitude damping and broadening of peaks in the time domain with increasing depth and age. Sulfate peak shape is also altered by the thinning of ice layers with depth that results from ice flow. Both processes must be simulated to derive effective diffusion rates. This is achieved by running a forward model to diffuse idealised sulfate peaks at different rates while also accounting for ice thinning. Our simulations suggest a median effective diffusion rate of sulfate ions of 2.4±1.7×10-7 m2 yr−1 in Holocene ice, slightly faster than suggested by previous work. The effective diffusion rate observed in deeper ice is significantly lower, and Holocene ice shows the highest rate of the last 450 kyr. Beyond the Holocene, there is no systematic difference between the effective diffusion rates of glacial and interglacial periods despite variations in soluble ion concentrations, dust loading, and ice grain radii. Effective diffusion rates for 40 to 200 ka are relatively constant and of the order 1×10-8 m2 yr−1. Our results suggest that the diffusion of sulfate ions within volcanic peaks is relatively fast initially, perhaps through an interconnected vein network, but slows significantly after 40 kyr. In the absence of clear evidence for a controlling influence of temperature on sulfate diffusivity with depth and age, we hypothesise that the rapid decrease in effective diffusion rate from the time of deposition to ice of 50 ka age may be due to a switch in the mechanism of diffusion resulting from the changing location of sulfate ions within the ice microstructure and/or interconnectedness of veins and grain boundaries.

Present Climate and Future Changes in the Annual Cycle of TC Activity in the WNP Investigated by HighResMIP GCMs

Abstract Atmospheric general circulation models (AGCMs) and coupled general circulation models (CGCMs) in the High Resolution Model Intercomparison Project (HighResMIP) were evaluated on their ability to simulate tropical cyclone (TC) activity in the western North Pacific (WNP) over its annual cycle. Specifically, we examined these models’ ability to simulate the south–north migration of the mean TC genesis location. The results revealed that both types of models realistically captured TC numbers and the south–north migration of TC genesis locations associated with the meridional migration of the WNP subtropical high ridge in response to the annual cycle. However, TC numbers decreased less rapidly in the AGCMs than in both the CGCMs and observed data during the monsoon retreat period (after September). This bias was probably attributed to a low-tropospheric cyclonic anomaly over the Philippine Sea in response to La Niña–like sea surface temperature (SST) differences between the AGCMs and the CGCMs. Because of these differences, the TC genesis frequency in the AGCMs over the Philippine Sea was overestimated. The cyclonic anomaly occurred when the northeasterly trade wind arose and was maintained through wind–evaporation–SST feedback. In future climate (2021–50), the main changes occurred during the monsoon retreat period. A more rapid decrease in TC numbers shown in AGCMs was likely attributed to the decrease (increase) of low-level vorticity (vertical wind shear) modulated by enhanced WNP subtropical high and subsidence anomalies. Conversely, a cyclonic circulation and ascending anomalies projected by CGCMs were identified off-equator, which favored TC genesis location shifting northward. Significance Statement Model performance and future changes in the annual cycle of tropical cyclone (TC) activity in the western North Pacific are investigated. We found that high-resolution uncoupled and coupled models realistically captured the TC numbers and meridional migration of TC genesis locations associated with the meridional migration of subtropical high ridge. However, TC numbers decreased more gradually in the uncoupled models than in the coupled models after September. This lower skill may stem from differences between the uncoupled and coupled models in simulating a cyclonic anomaly over the Philippine Sea in response to the La Niña–like sea surface temperature difference. In future climate (2021–50), TC numbers are significantly projected to decrease more rapidly during the monsoon retreat period in uncoupled models.

Impact of Regular and Irregular Pore Distributions on the Elasticity of Porous Materials: A Microstructure-Free Finite Element Study.

Conventional analytical formulas for predicting the effective Young's modulus of porous materials often rely on simplifying assumptions and do not explicitly incorporate microstructural information. This study investigates the impact of regular versus irregular pore distributions on the stiffness of porous materials using microstructure-free finite element modeling (MF-FEM). After conducting a convergence study, MF-FEM predictions were validated against experimental data and used to assess the accuracy of commonly employed analytical models. The results demonstrate that materials with irregular microstructures exhibit a rapid decrease in Young's modulus, approaching zero at porosities slightly greater than 50%. In contrast, regular microstructures show a more gradual decline, maintaining significant stiffness until the porosity exceeds 90%. Additionally, the study reveals that some analytical formulas align better with irregular microstructures while others are more suited to regular ones, attributable to the underlying assumptions of these models. These findings underscore the necessity of considering pore distribution patterns in modeling to accurately predict the mechanical behavior of porous materials.

Friction dependence on processing priority for graphitization/passivation coupled amorphous carbon films

In this study, amorphous carbon (a-C) films were modified using different process sequences—H passivation followed by graphitization (a-C@H@G2000K) and graphitization followed by H passivation (a-C@G2000K@H). The friction dependence on the surface H content and the processing priority was comparatively investigated at the atomic scale, with a focus on the coupling mechanism for achieving low friction. The results indicated that the friction properties closely depended on the H content of the contacted a-C surfaces. An appropriate H content significantly improved the friction property through the coupling effect of the lubrication between surface graphitized structures and the repulsion between H atoms, resulting in a rapid decrease in the friction coefficient; however, the graphitization mechanism remained dominant. Excessive H reduced the repulsion between the contacted graphitized structures and hindered the sliding of these structures (shear susceptible), resulting in a slow increase in the friction coefficient. Most importantly, compared with the a-C@H@G2000K systems, the a-C@G2000K@H system exhibited higher effectiveness in reducing the friction coefficient, achieving a lower friction coefficient under the same surface H content; this was attributed not only to the small surface roughness and the low fraction of unsaturated bonds but also to the well stress distribution of the surface H atoms.

Investigation on ejector design for CO2 heat pump applications us-ing Dymola

In this paper, the Dymola modelling tool is used to study the influence of ejector design onto the whole heat pump cycle working with carbon dioxide. The cycle is built using the components provided by the TIL Modelica library. It is found that the ejector models in TIL are quite limited, namely by their inability to properly capture the on-design plateau and rapid decrease in performance in off-design operation. Therefore, an in-house state-of-the-art ejector model, originally developed in Python, is implemented as a Dymola object. This model is then calibrated onto CO2 experimental data. The operation of a simple CO2 heat pump system is investigated, with focus on the ejector sizing at fixed geometry. It is found that there exists an ejector size that maximises the COP of the cycle. Furthermore, critical ejector pressure is not reached at this optimum COP point; the ejector is operating well under the on-design regime.

The Effect of the Season on the Time Dependent Changes in Colostrum Lactoferrin Level in Murciano-Granadina Goats in Intensive System Farming.

The aim of this research was to evaluate the effects of postpartum day and parity season on the lactoferrin (LF), immunoglobulin G (IgG), and chemical composition of Murciano-Granadina goat colostrum during the first 96 h after kidding, and the use of the Brix refractometer to estimate IgG content. A herd of 3500 intensively managed Murciano-Granadina dairy goats (45-50 kg body weight) was used. Colostrum samples were collected from days 1 to 4 postpartum in the winter, spring, summer, and autumn. The colostrum composition was assessed using an automated infrared method; the LF and IgG concentrations were measured using an ELISA, and for the Brix percentage, we used a digital refractometer. Colostrum taken on the first postpartum day showed the highest concentrations of LF, IgG, proteins and non-fat solids (NFSs). As the postpartum days progressed, a rapid decrease in the LF, IgG, protein, and NFS contents and the Brix value was observed. In contrast, the lactose content increased steadily until the fourth postpartum day (p < 0.001). The season influenced milk yield, LF, IgG, protein, fat, and somatic cell content (p < 0.05). LF contents were significantly higher in the spring season, IgG contents were higher in autumn colostrum, and fat components were higher in the winter season. The colostrum Brix value showed a positive correlation with the ELISA colostrum LF (r = 0.716, p < 0.001) and IgG (r = 0.894, p < 0.001) determination; a 20 mg IgG/mL colostrum concentration corresponded to 18 °Brix. Our results corroborate the importance of feeding colostrum to newborns on the first day after birth, not only because of its high level of IgG but also because of its greater presence of the other bioactive protein compounds such as lactoferrin.

SELECTION OF A MRP SYSTEM FOR OIL AND GAS DEPOSITS

A number of serious problems arise in the development of sub-gas zones of oil and gas deposits due to the joint occurrence of oil and gas. The key problem is gas breakthrough from the gas cap to oil wells. This entails an increase in the gas factor (GOR), a rapid and intense decrease in pressure in the gas cap. If there is a reservoir pressure maintenance system or an active aquifer as a result of a decrease in reservoir pressure in the gas cap, oil may be pushed back into it, which leads to a rise in gas-oil contact, jamming of mobile oil in the «dry sandstones» of the gas cap, which in turn leads to a decrease in reserves of mobile oil and a decrease in the oil recovery factor (ORF). All this together allows us to consider oil in the sub-gas zones as hard-to-recover reserves.Preventing and combating the negative consequences of gas breakthrough from the gas cap to oil wells is a complex task and consists of several areas, such as selection of rational drilling of production and injection wells, selection of optimal operating modes for them, use of inflow control devices or performance of repair and isolation work to limit inflow from intervals with gas breakthrough, periodic shutdown of wells to disband gas cones. The ultimate goal of solving these problems is to increase the oil recovery factor and economic efficiency indicators for the development of sub-gas zones.Due to the variety of ways to optimize the development of oil and gas reservoirs, it is not possible to cover them all in one work, therefore, the tasks associated with optimizing the reservoir pressure maintenance system are considered. It is worth noting that in comparison with the development of oil reservoirs, the presence of a gas cap significantly complicates this task due to the lack of analytical solutions for three-phase filtration. For this reason, the selection of the optimal parameters of the reservoir pressure maintenance system is usually carried out either by multivariate calculations in the hydrodynamic model (HDM), or by the method of analogies or the implementation of pilot tests of various approaches.In this study, an approach based on multivariate numerical calculations using the sector model of the development element of the gas zone was used. As a result of calculations, it was shown that when choosing the optimal parameters of the reservoir pressure maintenance system, it is advisable to use a differentiated approach, which consists in the fact that these parameters must be set individually for zones with different ratios of oil-saturated and gas-saturated thicknesses.

Hormonal profiles and biomarkers leading to parturition in cattle.

This study aimed to understand the physiological mechanisms regulating parturition and to identify potential biomarkers to predict onset of birth. Additionally, we compared hormone profiles between cows with shorter and longer gestation lengths. Twenty-eight days before due date until 3d postpartum, cows (n = 18) were blood sampled daily. Circulating concentrations were measured for progesterone (P4) and estradiol (E2) by RIA, testosterone, prostaglandin F2α metabolite (PGFM), cortisol, pregnancy-specific protein B (PSPB) by ELISA and lactate concentrations by colorimetric assay. At end of gestation, P4 decreased from d-14 to d-4 (from 3.6 to 1.4ng/mL), most likely from rapid loss of placental P4 production (64% of decline in 24h). A second rapid decrease in P4 to undetectable concentrations was observed from d-2 to parturition (from 1.4 to 0.1ng/ml; most likely luteal origin) corresponding to increase in PGFM from d-2 to parturition (249.7 to 2868.4pg/mL). Estradiol and PSPB increased ~8-fold from ~13d before parturition with acute rise in E2 but not PSPB (45% vs 13% in first 24h). Testosterone decreased slightly during the same period. Cortisol and lactate increased only at calving. Comparison of cows with shorter vs longer gestation, when data were normalized to parturition day, a difference was detected in circulating E2 and PGFM patterns, but not P4 and PSPB. Thus, the first significant hormonal changes associated with parturition begin at d-14 with E2 and PSPB as two clear biomarkers of impending parturition. Cows with shorter and longer gestation had hormonal differences indicative of identifiable earlier placental maturation.