Second law assessment of di methyl ether and its mixtures in domestic refrigeration system.

Dimethyl ether (DME) and its blend of refrigerants (R429A, R435A, and R510A) are considered in this study's second law analysis as potential replacements for R134a. The performance of various refrigerants in a vapour compression refrigeration system is examined using the Design package CYCLE D. The software REFPROP 9.0 is used to extract all of the thermal and physical parameters of DME and its blend of refrigerants. The Second law performance parameters such as Efficiency Defects, Entropy generation and ExergyEfficiency are discussed. The refrigerants R429A and R510A are more energy efficient than R134a across a condensing temperature range of 30 to 55 °C at - 10 °C evaporation temperature. R134a was exceeded by R429A and R510A in terms of exergetic efficiency by 2.08 and 0.43%, respectively. In comparison to other losses in different components, the compressor's exergy loss is larger at 37-40% of the total exergy loss. By employing RE170 and its blends, the Vapour Compression Refrigeration System often performs better under the second law than R134a.The result shows that the efficiency defects in the compressor are the largest, followed by the condenser and evaporator. Thus, the design improvement of a compressor is of at most importance to improve the system performance by lowering the overall irreversibility.

Influence of capillary tube length on the performance of domestic refrigerator with eco-friendly refrigerant R152a.

The household heating and cooling system often use the capillary device. The use of the helical capillary eliminates the need for lightweight refrigeration devices in the system. Capillary pressure is noticeably affected by the capillary geometric parameters, such as length, mean diameter, and pitch. This paper is concerned with the effects of the capillary length on the performance of the system. Three separate length capillary tubes were used in the experiment. The data on R152a were studied under various conditions to assess the impact of varying the length. Maximum COP is obtained at an evaporator temperature of - 12 °C and capillary length of 3.65 m. The result is drawn that the system performance enhances when the capillary length is improved to 3.65 m when compared to 3.35 m and 3.96 m. As a result, as the capillary length increases up to a specific amount, the system's performance improves. The findings from the experiment were compared with those from the computational fluid dynamics (CFD) analysis.

Complex Membrane Remodeling during Virion Assembly of the 30,000-Year-Old Mollivirus Sibericum.

Cellular membranes ensure functional compartmentalization by dynamic fusion-fission remodeling and are often targeted by viruses during entry, replication, assembly, and egress. Nucleocytoplasmic large DNA viruses (NCLDVs) can recruit host-derived open membrane precursors to form their inner viral membrane. Using complementary three-dimensional (3D)-electron microscopy techniques, including focused-ion beam scanning electron microscopy and electron tomography, we show that the giant Mollivirus sibericum utilizes the same strategy but also displays unique features. Indeed, assembly is specifically triggered by an open cisterna with a flat pole in its center and open curling ends that grow by recruitment of vesicles never reported for NCLDVs. These vesicles, abundant in the viral factory (VF), are initially closed but open once in close proximity to the open curling ends of the growing viral membrane. The flat pole appears to play a central role during the entire virus assembly process. While additional capsid layers are assembled from it, it also shapes the growing cisterna into immature crescent-like virions and is located opposite to the membrane elongation and closure sites, thereby providing virions with a polarity. In the VF, DNA-associated filaments are abundant, and DNA is packed within virions prior to particle closure. Altogether, our results highlight the complexity of the interaction between giant viruses and their host. Mollivirus assembly relies on the general strategy of vesicle recruitment, opening, and shaping by capsid layers similar to all NCLDVs studied until now. However, the specific features of its assembly suggest that the molecular mechanisms for cellular membrane remodeling and persistence are unique.IMPORTANCE Since the first giant virus Mimivirus was identified, other giant representatives are isolated regularly around the world and appear to be unique in several aspects. They belong to at least four viral families, and the ways they interact with their hosts remain poorly understood. We focused on Mollivirus sibericum, the sole representative of "Molliviridae," which was isolated from a 30,000-year-old permafrost sample and exhibits spherical virions of complex composition. In particular, we show that (i) assembly is initiated by a unique structure containing a flat pole positioned at the center of an open cisterna, (ii) core packing involves another cisterna-like element seemingly pushing core proteins into particles being assembled, and (iii) specific filamentous structures contain the viral genome before packaging. Altogether, our findings increase our understanding of how complex giant viruses interact with their host and provide the foundation for future studies to elucidate the molecular mechanisms of Mollivirus assembly.

Crystal structure of bis-(thio-cyanato-κS)bis-(thio-urea-κS)mercury(II).

In the title complex, [Hg(NCS)2(CH4N2S)2], the Hg(II) atom is four-coordinated having an irregular four-coordinate geometry composed of four thione S atoms of two thio-cyanate groups and two thio-urea groups. The S-Hg-S angles are 172.02 (9)° for the trans-thio-cyanate S atoms and 90.14 (5)° for the cis-thio-urea S atoms. The mol-ecular structure is stabilized by an intra-molecular N-H⋯S hydrogen bond, which forms an S(6) ring motif. In the crystal, mol-ecules are linked by a number of N-H⋯N and N-H⋯S hydrogen bonds, forming a three-dimensional framework. The first report of the crystal structure of this compound appeared in 1966 [Korczynski (1966 ▶). Rocz. Chem. 40, 547-569] with an extremely high R factor of 17.2%, and no mention of how the data were collected.

Self-regulation in self-propelled nematic fluids.

We consider the hydrodynamic theory of an active fluid of self-propelled particles with nematic aligning interactions. This class of materials has polar symmetry at the microscopic level, but forms macrostates of nematic symmetry. We highlight three key features of the dynamics. First, as in polar active fluids, the control parameter for the order-disorder transition, namely the density, is dynamically convected by the order parameter via active currents. The resulting dynamical self-regulation of the order parameter is a generic property of active fluids and destabilizes the uniform nematic state near the mean-field transition. Secondly, curvature-driven currents render the system unstable deep in the nematic state, as found previously. Finally, and unique to self-propelled nematics, nematic order induces local polar order that in turn leads to the growth of density fluctuations. We propose this as a possible mechanism for the smectic order of polar clusters seen in numerical simulations.

Anti-MRSA activity of aldehyde Schiff base N-aryl thiosemicarbazones.

Eight different newly synthesised aldehyde Schiff base N-aryl thiosemicarbazones, differing in R, R' groups, are tested on 25 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and a standard strain. Antibacterial activity was carried out by a well-diffusion method in concentrations of 15-500 microg/well. Compounds 1, 2, 3, 4 and 6 showed good inhibition of MRSA. Increasing concentration of the test compounds enlarged the inhibition zone. Determination of minimum inhibitory concentration (MIC) was carried out using a dilution susceptibility test in concentrations of 4-512 microg/mL of the medium. The lowest MIC value (16 microg/mL) was produced by compound 4.

[The evaluative cycle of the process of an overall geriatric evaluation program at a health center]. / Ciclo evaluativo del proceso de un programa de valoración geriátrica global en un centro de salud.

OBJECTIVE: To improve the procedures in an Elderly Persons' Care programme. DESIGN: A complete evaluative cycle of the care process, with an analysis phase and a phase to implement corrective measures. SETTING: Primary care. Ortuella (Bizkaia) Health Centre. PATIENTS AND PARTICIPANTS: Data on the first 50% on the list of residents over 75 in Ortuella were analysed in this evaluation (n = 249). Residents in elderly people's homes, people passing through and who had recently moved were excluded. In the re-evaluation all those still to be evaluated were analysed once corrective measures had been implemented (n = 81). INTERVENTIONS: After analysis of the first phase, corrective measures were applied, and both the coverage and the correct performance of activities generated in the development of the programme were re-evaluated. MEASUREMENTS AND MAIN RESULTS: There was similar coverage (72.3 to 66.7%). There was improvement in registration (76.9 to 90.7%), long-treatment card (60 to 85.7%), medicines (42.9 to 75%) and nutritional habits (46.1 to 57.1%). Action taken on visual (93.1 to 75%) and hearing (76 to 71.4%) pathologies deteriorated. CONCLUSIONS: The programme's procedures improved with simple corrective measures (a session concerning proper recording of the history and how to follow the protocol; professionals who controlled registration and coverage). A proper record was important.

Conjoined twins in a triplet pregnancy.

Conjoined twins in a triplet pregnancy is an extremely rare occurrence. We present here, a 27-year-old multigravida with gestational diabetes and a conjoined twins in a triplet pregnancy.

Fetal heart sound analysis: a preliminary evaluation.

The aim of this study, is to determine whether the fine characteristics of the fetal heart sounds could be used to identify intrauterine growth retarded fetuses. A preliminary evaluation, was conducted to compare these characteristics between intrauterine growth retarded fetuses and normal fetuses in the antenatal period after 36 weeks of gestation. Altogether, 7 IUGR fetuses were compared with 12 normal fetuses. An instrument named the Fetal Frequency Phonocardiogram was designed for this purpose. When connected to a personal computer and with a software programme specially written, the fetal heart sound characteristics were analysed. After detailed analysis, there were 3 significant differences between IUGR and normal fetuses, all of which gave a p-value of < 0.01. The frequency of the first heart sound was significantly higher in the IUGR fetuses compared to normal fetuses. The ratio of the amplitude of the first heart sound over the second heart sound was higher in the IUGR group. Finally, the ratio of the time between the first and second heart sound over the cardiac cycle was shorter in the IUGR fetuses. Fetal heart sound analysis, may provide a simple non-invasive method of detecting and monitoring fetuses at risk in the antenatal period.