Changes In Poly Research Articles

Reversible mesophase in stress-annealed poly(3-hydroxybutyrate) fibers: A synchrotron x-ray and polarized ATR-FTIR study

Structural changes in poly(3-hydroxybutyrate) (P3HB) monofilaments (diameter ~90 μm), induced by annealing under tensile stress (1 h with 1.6–40 MPa loading at 80–130 °C) have been investigated with synchrotron wide-angle x-ray diffraction (WAXD) and polarized attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Melt-spun P3HB fibers consist of an amorphous phase, a crystalline α-phase and a mesophase. Specific IR bands in s-polarized (electric field vector along the fiber axis) spectra have been identified to arise from the mesophase. For fibers annealed at low stress (1.6 MPa), the mesophase content practically disappears but can be recovered with tensile drawing. In-situ WAXD and polarized ATR-FTIR studies, performed during cyclic tensile loading/unloading, have revealed that the mesophase formation/dissolution is highly reversible in fibers annealed at low stress. This reversibility behavior, and the lack of off-axis reflections in WAXD patterns, support the theory that the mesophase is made of conformationally disordered and stretched chains, which are mainly located in-between α-crystals.

The effects of charmonium on the properties of the 1++ hidden charm poles in effective field theory

In this study, the properties of the JPC=1++ hidden charm poles are analyzed under the variation of the bare 2P charmonium mass within the effective field theory proposed in Ref. [1]. The main focus of the current work is on the pole trajectory of the χc1(2P) charmonium dressed by the DD¯⁎ meson loops. It is shown that the trajectories of the pole change radically for values of the bare charmonium mass above a certain value and also depending on how close the pole is to the threshold.

Development of dynamic pH and temperature-responsive smart membranes via immobilization of chitosan-graft-poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels on microfiltration membrane-support

Ultrafiltration is a pressure-driven membrane process which is widely used for water treatment and separations in biotechnology, chemical, pharmaceutical and food industries. The study deals with the development of novel smart membranes for ultrafiltration which reversibly change flux and human serum albumin (HSA) rejection as a response to the change of the pH and temperature of the feed solution. Smart membranes were prepared via immobilization of cross-linked dual-responsive chitosan-graft-poly(N-isopropylacrylamide (NIPAM)-co-methacrylic acid) hydrogels on the surface of the microfiltration membrane via filtration in dead-end mode. It was shown that pure water flux (PWF) increases by 1.8–4.7 times upon the temperature increase from 25 °C to 50 °C due to the conformational changes of poly(NIPAM) chains grafted to chitosan at temperature higher than lower critical solution temperature. It was shown that PWF increases by 8.7 times at T = 25 °C and 16.5 times at T = 50 °C when pH of the feed water decreases from 10 to 3. The developed smart membranes demonstrate extremely high cleaning efficiency and can be simply washed by distilled water at T = 50 °C after ultrafiltration of HSA solution (pH = 3). It was shown that PWF of smart membrane is restored by 1154% compared to 67% for reference microfiltration membrane.

Reverse transcription priming methods affect normalisation choices for gene expression levels in oocytes and early embryos.

Mammalian oocytes and embryos rely exclusively on maternal mRNAs to accomplish early developmental processes. Since oocytes and early embryos are transcriptionally silent after meiotic resumption, most of the synthesised maternal mRNA does not undergo immediate translation but is instead stored in the oocyte. Quantitative RT-PCR is commonly used to quantify mRNA levels, and correct quantification relies on reverse transcription and the choice of reference genes. Different methods for reverse transcription may affect gene expression determination in oocytes. In this study, we examined the suitability of either random or oligo(dT) primers for reverse transcription to be used for quantitative RT-PCR. We further looked for changes in poly(A) length of the maternal mRNAs during oocyte maturation. Our data indicate that depending on the method of reverse transcription, the optimal combination of reference genes for normalisation differed. Surprisingly, we observed a shortening of the poly(A) tail lengths of maternal mRNA as oocytes progressed from germinal vesicle to metaphase II. Overall, our findings suggest dynamic maternal regulation of mRNA structure and gene expression during oocyte maturation and early embryo development.

Impact of COVID-19 on Household’s Financial Situation in Poland

Purpose: The main purpose of the article was to assess the impact of the COVID-19 pandemic on the financial situation of households in Poland. This goal was supplemented with the main hypothesis, auxiliary hypotheses and research questions. Design/Methodology/Approach: The research was conducted in February 2021 by means of an questionnaire survey on a group of 1000 randomly selected Polish residents. The questionnaire was developed in the form of 19 record and substantive single or multiple choice questions. Another method that was used for the research was the review and analysis of bibliographic resources. Findings: The empirical results show that due to the COVID-19 pandemic, the financial situation of households in Poland has slightly deteriorated. Nearly 2/3 of the respondents were negatively affected by the financial effects of the pandemic to a small or medium degree. In 1/4 of the respondents, there was a marked reduction in income related to the pandemic crisis. It is worth noting the change in Poles' attitude to saving. The unpredictability of the pandemic crisis resulted in a significant reduction in purchasing expenses in more than half of the respondents, and nearly three quarters of them began to carefully plan their expenses. Two-thirds of respondents believe that one of the ways to protect themselves against another crisis caused by a pandemic, or another genesis of a phenomenon, is to save money. Practical Implications: With the pandemic, the approach of Polish households to collecting savings and spending money has changed. This informs potential entities and institutions offering their goods that they should remodel their offers and adapt them to the prevailing conditions on the Polish market. Originality/Value: Unique, authorial survey conducted on a representative research sample, dealing with current issues, concerning not only Poland, but also the entire world. The effects of the COVID-19 pandemic are described and the impact of respondent characteristics on the financial extent impact of the economic downturn is analyzed.

Electromagnetic Torque Characteristics Analysis of Nuclear Half-Speed Turbine Generator with Stator Winding Inter-Turn Short Circuit Fault

To research the variation characteristics and influence factors of air gap magnetic field and electromagnetic torque of nuclear power half-speed turbine generator with stator winding inter-turn short circuit, the two-dimensional transient electromagnetic field of generator-external circuit-grid coupling mathematical model is established by field-circuit-network coupling method. Taking the national laboratory’s generator as an example, and comparing the simulation results of the inter-turn short circuit of the armature winding with experimental data, the correctness of the model is validated. On this basis, the simulation model of a 1407MVA nuclear power half-speed turbine generator is built. Then the stator winding inter-turn short circuit fault is simulated when the generator is connected to the grid with rated load. The characteristics of air gap flux density and electromagnetic torque are obtained before and after fault, as well as, the relationship between their each component and the fault degree is obtained. At the same time, the variation law of air gap flux density and electromagnetic torque is obtained when the relative position between fault winding and magnetic pole changes. The theoretical reference for fault diagnosis and localization using harmonic electromagnetic torque after fault is provided.

Improvement of Anode of Prebaked Cell in Aluminum Electrolysis

Compared with the previous self-cultivation anode electrolyzer, the current prebaked anode electrolyzer has advanced technical and economic indexes, high degree of mechanization and automation, and relatively little environmental pollution, which has achieved great development. However, the continuity of aluminum electrolysis production and the limited economic height of anode constitute two contradictory opposites. In order to solve this contradiction, the processes of replacing anode periodically, cleaning the residual electrode and electrolyte, pressing off the residual electrode and phosphorus-iron ring, crushing and grinding the residual electrode have been produced, which has increased the investment and labor cost per ton of aluminum. Moreover, when the anode is replaced, the operator can say that the working environment is harsh and dangerous directly in front of the high-temperature electrolyte, and a large amount of fluorine-containing flue gas is discharged out of order and pollutes the environment due to the opening of the slot cover plate and the placement of the high-temperature residual electrode during the anode replacement. At the same time, pole change has great interference on electrolytic production. At present, inert anodes can't be put into industrial production, and the continuous preparation anodes in Germany have high power consumption, so it is of great practical significance to perfect or improve the existing anode structure. This paper discusses how to solve this problem.

Effect of hot water extract of Korean ginseng on neuroblastoma cell parthanatos

To explore the effect of pretreatment of neuroblastoma cells with hot water extract of Korean ginseng on MNNG-induced parthanatos and its mechanism. Neuroblastoma SH-SY5Y cells were pretreated with 1 mg/L hot water extract of Korean ginseng before induction with 250 μmol/L MNNG for 1 h or 4 h. CCK-8 and cell flow cytometry were used to detect cell survival rate. Western blotting was used to detect the changes in poly(ADP-ribose) (PAR) expression in the treated cells. Immunofluorescence assay was used to detect nuclear distribution of apoptosis-inducing factor (AIF), and flow cytometry was used to detect the level of reactive oxygen species (ROS) in the cells. Compared with the blank control cells, MNNG-treated SH-SY5Y cells showed significantly decreased survival rate as the concentration of MNNG and the stimulation time increased (P < 0.05). Stimulation with MNNG also resulted in significantly increased expression of PAR protein in the cells (P < 0.05). Pretreatment of the cells with hot water extract of Korean ginseng obviously inhibited MNNG-induced cell death and significantly reduced AIF expression and nucleation in the cells (P < 0.05). MNNG stimulation significantly increased ROS level in the cells, which was decreased significantly by pretreatment of the cells with the extract (P < 0.05). Pretreatment with hot water extract of Korean ginseng reduces MNNG-induced parthanatos and ROS production in SH-SY5Y cells.

Spectroscopic and insilico Studies of Ab (1-16) on Copper induced conformational changes in Poly (dG-dC). Poly ( dG-dC) [Poly(GC)] DNA sequence: Implications in Alzheimer’s disease

DNA molecules are dynamic and play a crucial role in life processes. DNA is polymorphic and flexible having the ability to undergo structural changes depending on the environment. The structural property and stability of DNA are very important for cellular functions, and are involved in normal functioning of processes like replication, repair of DNA and protein synthesis processes. Metals like Fe and Cu are known to play a crucial role in brain functioning and deviations in concentration from the normal are often recognized as symptoms of malfunctions or disease. The effect of copper(Cu) and amyloid peptide (Ab ) on DNA in the brain has been considered very important due to their role in oxidative DNA damage, structural changes of the Amyloid peptide and are the etiological factors for neurodegenerative diseases. In the current investigation, changes in conformation of Poly (GC) sequence DNA induced by copper and Ab 1-16 is studied using Circular Dichroism (CD). CD studies have shown the shift in conformation of DNA, from B form to an altered B-, and C-DNA conformation. The CD studies were substantiated by Molecular docking confirms that the Ab -copper complexes with DNA via hydrogen bond formed between Guanine-Cytosine (GC) pairs. This work gives clues as to how copper Ab complex modulates DNA conformations which attributes to the stability. Keywords: Alzheimer’s disease, DNA, Copper, Circular Dichroism, Molecular Docking.

Spatio-Temporal Characteristics for Moon-Based Earth Observations

Spatio-temporal characteristics are the crucial conditions for Moon-based Earth observations. In this study, we established a Moon-based Earth observation geometric model by considering the intervisibility condition between a Moon-based platform and observed points on the Earth, which can analyze the spatio-temporal characteristics of the observations of Earth’s hemisphere. Furthermore, a formula for the spherical cap of the Earth visibility region on the Moon is analytically derived. The results show that: (1) the observed Earth spherical cap has a diurnal period and varies with the nadir point. (2) All the annual global observation durations in different years show two lines that almost coincide with the Arctic circle and the Antarctic circle. Regions between the two lines remain stable, but the observation duration of the South pole and North pole changes every 18.6 years. (3) With the increase of the line-of-sight minimum observation elevation angle, the area of an intervisible spherical cap on the lunar surface is obviously decreased, and this cap also varies with the distance between the barycenter of the Earth and the barycenter of the Moon. In general, this study reveals the effects of the elevation angle on the spatio-temporal characteristics and additionally determines the change of area where the Earth’s hemisphere can be observed on the lunar surface; this information can provide support for the accurate calculation of Moon-based Earth hemisphere observation times.

Reducing the pathogenicity of wastewater with killer vapor-induced phase separation membranes

While smart antibacterial surfaces with bacteria-killing/bacteria-releasing properties have been reported, no strategy existed up to date to prepare phase-inversion membranes having these capabilities in one single step, without any surface-modification. We addressed this challenge by synthesizing two copolymers made of butyl methacrylate (BMA) units and of 2-(dimethylamino)ethyl methacrylate (DMAEMA), poly(BMA-r-DMAEMA), or (trimethylamino)ethyl methacrylate chloride (TMAEMA), poly(BMA-r-TMAEMA), both miscible with poly(vinylidene fluoride) (PVDF), and prepared membranes by the vapor-induced phase separation process. Results showed that all membranes were able to kill almost 100% of bacteria that came into contact with the surface. A washing procedure with a saline solution of sodium hexametaphosphate permitted to regenerate the membrane modified with poly(BMA-r-TMAEMA). Strong hydration of the interface between positively-charged brushes and dead bacteria after docking with hexametaphosphate anions, combined to the excess of negative charges, results in bacteria release following conformational changes of poly(BMA-r-TMAEMA) polyelectrolyte brushes. However, the membrane modified with poly(BMA-r-DMAEMA) could not be regenerated, likely because poly(BMA-r-DMAEMA) does not behave as a polyelectrolyte. Results also reveal that poly(BMA-r-TMAEMA)-modified PVDF membranes were able to kill various species of bacteria, and that multiple cycles could be successively run. The prepared MF membranes are able to kill the majority of microorganisms once they contact the membrane during filtration. Domains of applications are numerous from wastewater-treatment to healthcare applications, wherever bacteria are wanted dead after separation.

Dynamic RNA 3' Uridylation and Guanylation during Mitosis.

SummarySuccessful cell division involves highly regulated transcriptional and post-transcriptional control. The RNA poly(A) tail represents an important layer of RNA post-transcriptional regulation. Previous TAIL-seq analysis of S phase and M phase poly(A) tail information showed that only a small number of genes showed more than 2-fold change in their poly(A) tail length between the two cell cycle stages. In addition, the changes in poly(A) tail length between these two stages showed minimal impact on the translation of the genes as long as the poly(A) tails were longer than 20 nt. Therefore, the significance of poly(A) tail dynamics during the cell cycle remains largely unknown. Here, by re-analyzing the S phase and M phase TAIL-seq data, we uncovered an interesting global dynamics of RNA poly(A) tails in terms of their terminal modifications, implying global RNA regulation between mitotic cell cycles through poly(A) tail terminal modifications.

Ablation thresholds and morphological changes of poly‐l‐lactic acid for pulse durations in the femtosecond‐to‐picosecond regime

Biodegradable polymers such as poly‐l‐lactic acid (PLLA) are essential tools for a wide range of medical applications because of their mechanical robustness and bio‐affinity. Laser processing is commonly used to construct various structures from biodegradable polymers. However, in general, polymers deteriorate rapidly owing to laser‐induced heating effects. In this study, we investigate the optimum irradiation conditions for PLLA processing, using an ultrafast laser and finely controlling the pulse duration over the femtosecond‐to‐picosecond range. We report on the morphological characteristics of the craters generated by single‐shot and multiple‐shot laser irradiation under pulse duration control. Our results show that crater morphology and damage threshold in the single‐shot regime depend on pulse duration and that the degree of crater unevenness is insensitive to pulse duration in the multishot regime.

Rapid Screening of Blood Mitochondrial D310 and D315 Mutations in Breast Cancer Patients

Aims: 'Poly C' stretch extending from 303 to 315 nucleotide positions known as (D310) by GeneBank within the non-coding region HVR-II of mitochondrial DNA (mtDNA) has been identified as a mutational hotspot of primary cancer. We aimed to find this mutation in Bangladeshi breast cancer patients and control samples for screening the changes in poly C stretches. Materials and Methods: We have analyzed a total of 98 breast cancer blood samples and 98 healthy control blood samples and extracted DNA from blood samples for direct sequencing using ABI®3130 Genetic Analyzer. Results: We observed 70.41% C insertion at 310 regions (P<0.001, OR = 16.30 and 95% CI=7.83-33.93) in breast cancer patient whereas it is present only in 12.24% healthy individuals. No alterations were observed in 29.59% breast cancer samples. We also check the mutation pattern at D315 regions, but no significant observation was found (P=1.00). Conclusions: This is the first study from Bangladeshi breast cancer (BC) patients indicating a relatively high frequency of D310 mutations, which suggests that mtDNA instability at D310 may be a common characteristic of BC, study also supports the hypothesis that mtDNA D310 screening may represent additional blood based biomarker for breast cancer prognosis.

Cyclic variations in the main components of the solar large-scale magnetic field

ABSTRACT We consider variations of the dipole and quadrupole components of the solar large-scale magnetic field. Both axial and equatorial dipoles exhibit a systematic decrease during the past four cycles, in accordance with the general decrease of solar activity. The transition of the pole of a dipole from the polar region to the midlatitudes occurs rather quickly, so that the longitude of the pole changes little. With time, however, this inclined dipole region shifts to larger longitudes, which suggests an acceleration of dipole rotation. The mean rotation rate exceeds the Carrington velocity by 0.6 per cent. The behaviour of a quadrupole differs dramatically. Its decrease over the last four cycles was much smaller than that of the dipole moment. The ratio of the quadrupole and dipole moments has increased for four cycles more than twice, in contrast to sunspot numbers, which displayed a twofold decrease for the same time interval. Regarding quadrupole rotation, the mean longitude of the poles of one sign decreased by 600° over four cycles, which suggests that the mean rotation rate was lower than the Carrington velocity by 0.28 per cent. We do not, however, see any conclusive evidence that, in the period under discussion, a mode of quadrupole symmetry was excited in the Sun along with the dipole mode.

Wide-ranging transcriptome remodelling mediated by alternative polyadenylation in response to abiotic stresses in Sorghum.

Alternative polyadenylation (APA) regulates diverse developmental and physiological processes through its effects on gene expression, mRNA stability, translatability, and transport. Sorghum is a major cereal crop in the world and, despite its importance, not much is known about the role of post-transcriptional regulation in mediating responses to abiotic stresses in Sorghum. A genome-wide APA analysis unveiled widespread occurrence of APA in Sorghum in response to drought, heat, and salt stress. Abiotic stress treatments incited changes in poly(A) site choice in a large number of genes. Interestingly, abiotic stresses led to the re-directing of transcriptional output into non-productive pathways defined by the class of poly(A) site utilized. This result revealed APA to be part of a larger global response of Sorghum to abiotic stresses that involves the re-direction of transcriptional output into non-productive transcriptional and translational pathways. Large numbers of stress-inducible poly(A) sites could not be linked with known, annotated genes, suggestive of the existence of numerous unidentified genes whose expression is strongly regulated by abiotic stresses. Furthermore, we uncovered a novel stress-specific cis-element in intronic poly(A) sites used in drought- and heat-stressed plants that might play an important role in non-canonical poly(A) site choice in response to abiotic stresses.

Microstructural features affecting mechanical properties: Effect of processing on dispersion of carbon black (N220) nanoparticles reinforcement in poly (lactic acid)

The interrelation between microstructure and macroscopic behavior is important information, which is used to characterize generally inhomogeneity, orientations, distributions; ultimately its structure relationship with specific properties. Carbon black (N220) filled poly (lactic acid) composites were processed by using melt mixing (i.e. MMCM – Melt Mixing followed by Compression Molding) and solution mixing technique (i.e. DDCS – Dissolution Dispersion followed by Casting Sheet. Carbon black filled poly (lactic acid) composites were characterized for microscopic – structural analysis and compared with mechanical properties. Microstructural analysis on tensile fractured specimens by optical microscope and scanning electron microscope was done in order to determine the microstructural features affecting mechanical properties; transmission electron microscopy and atomic force microscopy were performed to evaluate the effect of processing techniques on the dispersion of carbon black nanoparticles reinforcement in poly (lactic acid). The analysis of the mechanical properties showed an increase up to the loading of 2–3 wt% of carbon black followed by a decrease in mechanical properties at 5 wt% and above due to microstructural changes induced by low structure carbon black in the poly (lactic acid) matrix. The dominance of filler-filler interaction beyond 2.5 wt% was clearly visible in optical, electron and atomic force microscopic studies. The appearance of smooth and rough surfaces in optical and scanning electron microscopic images, presence of agglomerated carbon black in transmission electron microscopic images and the decrease in average roughness analyzed via atomic force microscopic images indicates microstructural changes in poly (lactic acid) after addition of carbon black. The filler-filler interaction as imaged and recorded from the transmission electron images and atomic force microscopic roughness values was the cause for a decrease in mechanical properties of carbon black filled poly (lactic acid) composites at 5.0wt% and beyond.

Altered topological organization of functional brain networks in drug-naive patients with paroxysmal kinesigenic dyskinesia

BackgroundPrevious neuroimaging studies have revealed aberrant basal ganglia-thalamocortical circuit in patients with paroxysmal kinesigenic dyskinesia (PKD) with drug treatment. This study aims to investigate the topological organization of functional networks in drug-naive PKD. MethodsResting-state functional magnetic resonance imaging (rs-fMRI) was performed in 24 drug-naive PKD patients and 24 age, gender and mean framewise displacement (FD)-matched healthy controls (HCs). The network topological properties (including global and nodal measures) were analyzed between two groups by using graph-based theoretical approaches. Pearson's correlation analysis was performed between significant metrics and duration of disease and the age of onset of patients with PKD. ResultsCompare to HCs, the drug-naïve PKD patients showed increased nodal centralities mainly in left precentral gyrus, basal ganglia and limbic regions and decreased nodal centralities in the temporal pole. Our results showed that drug-naïve PKD patients presented the small-world topology and at the global level no significant differences were found between PKD and HCs. In the correlation analysis, the increased nodal efficiency in the left pallidum was positively correlated with the onset of age. ConclusionsOur findings supported the previous observation of the disruptive cortical-basal ganglia circuitry in PKD patients, but difference in that the prominent change of precentral area and temporal pole were also observed in our study when the potential impact of drug was excluded. These findings may provide a novel insight into further delineation of the pathophysiological genesis and possible target for PKD.

Analysis of the Synchronization Process and the Synchronization Capability for a Novel 6/8-Pole Changing LSPMSM

This article presents a novel 6/8-pole changing line-start permanent-magnet synchronous motor (LSPMSM) for improving the starting and synchronization capabilities. A 6/8-pole changing stator winding with simple structure, convenient switching, and speed detection capability is designed and studied. The synchronization process, which follows the 6/8-pole winding switching process, is analyzed. The effects of the switching speed, switching phase difference, and the rotor resistance on the synchronization process, respectively, are studied. Moreover, on the basis of the improvement of the starting capability utilizing the pole changing starting strategy, the rotor resistance is appropriately designed smaller to simultaneously balance the synchronization capability. The larger maximum moment of inertia that the motor can pull into synchronization validates the analysis. Through processing, both starting and synchronization capabilities have been improved for the proposed 6/8-pole changing LSPMSM compared with the conventional 8-pole LSPMSM.

A Wound-Field Pole-Changing Vernier Machine for Electric Vehicles

This paper proposes a wound field pole changing vernier machine with fractional slot concentrated winding for electric vehicles application. The main aim of the paper is to utilize the advantages of a vernier machine and a wound field synchronous machine in a single topology using a fractional slot concentrated armature winding. The proposed machine operates in a vernier mode at low speeds and a wound-field synchronous mode at high speeds to utilize the merits of both a vernier machine and a wound-field synchronous machine. The topology, operating principle and pole-changing method of the proposed machine are explained initially. Then, finite element analysis (FEA) is utilized to study the electromagnetic characteristics such as back EMF, torque, wide speed range operation and efficiency of the proposed topology in two modes. Further, a prototype of the machine is manufactured and the FEA results are validated through experiments. The FEA and experiment results show that the proposed machine is a promising candidate for electric vehicles application.