Structure evolution of a magnetite iron ore/carbon composite pellet during solid-state reduction under microwave heating

In the present study, the structure evolution under direct reduction of a Minh-Son magnetite iron ore/carbon composite pellets in a microwave-heating kiln under different microwave wattage of 60 and 90 % (with the firing time from 15 to 120 min.) was investigated. The microstructure of the pellets was characterized by scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction (XRD). The phase formation was indexed using MDI Jade from the peaks matching the reference sample. At the microwave’s wattage of 60 %: the wustite (FeO) has appeared after firing time of 60 min., the metallic iron and fayalite have appeared in the reduced samples after firing time of 90 min. to 120 min. with retained phases of Fe203, Fe304, FeO and Si02– While at the microwave’s wattage of 90 %, the metallic iron has appeared in the reduced samples after firing time of 30 min. to 120 min and fayalite has appeared in the reduced samples after firing time of 60 min. to 120 min. The final reduced pellet, under microwave’s wattage of 90 % and firing time of 120 min., shows the only phases of metallic iron and fayalite according to the XRD resolution. The present work could provide a scientific understanding to illustrate iron ore/carbon composite pellet behavior during solid-state carbothermic reduction under a microwave-heating.

An Investigation of Dopamine’s Role in Six Psychiatric Illnesses

This paper aims to investigate the neurotransmitter dopamine’s role in six prevalent psychiatric disorders: attention-deficit disorder, autism spectrum disorder, bipolar disorder, major depression, post-traumatic stress disorder, and schizophrenia. Although dopamine’s contribution to schizophrenia is the most understood, dopamine’s role in other disorders is also an increasing area of research. Dopamine affects reward-motivated behavior, motor control, cognition, and possesses many other sub-functions as well. Dysfunction in dopamine firing rate, firing time, tonic and phasic levels, and receptor and transporter density can lead to numerous diseases and symptoms. Having a better understanding of how dopamine affects these illnesses specifically can lead to the development of more effective treatment and medication. Thus, the analysis of the studies and proposals for how dopamine is involved in various mental disorders are discussed in this review.

TECHNOLOGY AND EQUIPMENT FOR PROCESSING OF LARGE-SIZED VERMICULITE MICAS OF THE KOVDOR DEPOSIT

The development of technology and equipment for the processing of large-sized vermiculite mica obtained from mining waste from the Kovdorsky deposit allows the large-scale vermiculite to be returned to processing industry. This article reviews the aspects of the technology for processing of large-sized mica with dimensions of 20 mm or more. The aim of the research is to study the grinding technology of large-sized vermiculite raw materials by the chopping overall particles, to develop the technological equipment and to study of its operating processes. The object of the research is the operating process of the chopping unit for grinding the large-sized vermiculite raw materials and its design. The methods are based on study of simulated movement of chopped large-sized particles and the determination of the main characteristics of the chipping unit operating process. It was found that the firing of large particles without grinding in chopping units requires a significant increase in firing time, which reduces the productivity of electric furnaces. The time of dropping particles out in the slot of the receiving drums of the chopping unit is determined, based on which the rotation speed of the receiving drums and its operational efficiency are calculated.

Behavior of a Model for Feedback-Controlled Reverberating Circuit and Immediate Memory Function

In this work we implement a mathematical model of synaptic transmission connecting neurons in a circuit of reverberating discharges in order to investigate its behavior in front of parametric variations. Using a program developed in C language, we verified if this model would behave as short-term memory circuit. In the simulation, we used neural parametric values from experimental measures in animal. Our model was able to reproduce polysynaptic activity of a neuronal group of rat brain (looping time of about 102 ms). On the other hand, we verified that the inhibitory feedback synapses in circuit with weight varying with presynaptic firing time and frequency is capable to change the circuit characteristic to reproduce the typical behavior of neural circuits. The results suggest that, differently from some recent considerations, the reverberating circuit model has great potential to reproduce the typical behavior of neural circuits and could be seen as a possible model for immediate memory.

Genome-Wide Mapping of Human DNA Replication by Optical Replication Mapping Supports a Stochastic Model of Eukaryotic Replication

DNA replication is regulated by the location and timing of replication initiation. Therefore, much effort has been invested in identifying and analyzing the sites of human replication initiation. However, the heterogeneous nature of eukaryotic replication kinetics and the low efficiency of individual initiation site utilization in metazoans has made mapping the location and timing of replication initiation in human cells difficult. A potential solution to the problem of human replication mapping is single-molecule analysis. However, current approaches do not provide the throughput required for genome-wide experiments. To address this challenge, we have developed Optical Replication Mapping (ORM), a high-throughput single-molecule approach to map newly replicated DNA, and used it to map early initiation events in human cells. The single-molecule nature of our data, and a total of more than 2000-fold coverage of the human genome on 27 million fibers averaging ~300 kb in length, allow us to identify initiation sites and their firing probability with high confidence. In particular, for the first time, we are able to measure genome-wide the absolute efficiency of human replication initiation. We find that the distribution of human replication initiation is consistent with inefficient, stochastic initiation of heterogeneously distributed potential initiation complexes enriched in accessible chromatin. In particular, we find sites of human replication initiation are not confined to well-defined replication origins but are instead distributed across broad initiation zones consisting of many initiation sites. Furthermore, we find no correlation of initiation events between neighboring initiation zones. Although most early initiation events occur in early-replicating regions of the genome, a significant number occur in late-replicating regions. The fact that initiation sites in typically late-replicating regions have some probability of firing in early S phase suggests that the major difference between initiation events in early and late replicating regions is their intrinsic probability of firing, as opposed to a qualitative difference in their firing-time distributions. Moreover, modeling of replication kinetics demonstrates that measuring the efficiency of initiation-zone firing in early S phase suffices to predict the average firing time of such initiation zones throughout S phase, further suggesting that the differences between the firing times of early and late initiation zones are quantitative, rather than qualitative. These observations are consistent with stochastic models of initiation-timing regulation and suggest that stochastic regulation of replication kinetics is a fundamental feature of eukaryotic replication, conserved from yeast to humans.

Thermal effect of holmium laser during ureteroscopic lithotripsy

Background: Holmium laser lithotripsy is the most common technique for the management of ureteral stone. Studies founded that holmium laser firing can produce lethal heating which will cause thermal injury towards ureter. The aim of our current study is to explore factors affecting thermal effect of holmium laser during ureteroscopic lithotripsy.Materials and Methods: An in vitro experimental model is design to simulate the ureteroscopic lithotripsy procedure. Different laser power settings (10w (0.5JX20Hz, 1.0JX10Hz), 20w (1.0JX20Hz, 2.0JX10Hz), 30w (1.5JX20Hz, 3.0JX10Hz)) with various firing time (3s, 5s, 10s) and irrigation flow rates（10ml/min, 15ml/min, 20ml/min and 30ml/min）were employed in the experiment. The temperature around the laser tip was recorded by thermometer.Results: The temperature in the “ureter” rises significantly with the increasing laser power, prolonging firing time and reducing irrigation flow. The highest regional temperature is 78.0℃ at the experimental set-up, and the lowest temperature is 23.5℃. Higher frequency setting produces more heat at the same power. Laser power<=10w, irrigation flow>=30ml/ml and “high-energy with low-frequency” can permit a safe working temperature.Conclusion: We clarify that the thermal effect of holmium laser is related with both laser working parameters and irrigation flow. The proper setting is the key factor to ensure the safety during ureteroscopic holmium laser lithotripsy.

Investigation of PTCR characteristics in Nb2O5-doped BaTiO3-based chip-type ceramics prepared by reduction sintering-reoxidation method

This study investigates the influence of sintering conditions on electrical properties and positive temperature coefficient of resistance (PTCR) of [Formula: see text] (BTNO) ceramics, fired at [Formula: see text]C for different times from 1 to 6 h in a reducing atmosphere and reoxidised within the temperature range of [Formula: see text]–[Formula: see text]C for 1 h. The results showed that the room-temperature (RT) resistance and the resistance jump of the multilayer BTNO ceramics decreased with an increase in the firing time. Furthermore, the RT resistance of the BTNO samples gradually increased at first and then rapidly increased with increasing reoxidation temperature. In addition, the influence of sintering times on the microstructure of ceramics was also investigated.

Multi-Scale Investigation of Body-Glaze Interface in Ancient Ceramics

Bernard Palissy is a French Renaissance ceramist renowned for his masterpieces called Rustiques Figulines on which dozens of glazes of different chemistries (and thus firing behaviors) coexist harmoniously. This study aims at gathering information on the master procedure -never revealed- by investigating the body-glaze interface region (focusing on iron-colored honey transparent glaze-white body system). Optical and electron microscopies including transmission electron microscopy (TEM) are used to characterize the micro and nanostructure of both archaeological and replicas interfaces elaborated in controlled conditions (firing time, cooling rate, addition of Al in the glazing mixture). Both types of interfaces are comparable: a modified paste area from which are growing a relatively continuous layer of interfacial crystals identified as lead feldspars (K,Ca)PbAl2Si2O8 micro-sized single-crystals incorporating mullite 3Al2O3.2SiO2 nano-sized single-crystals. Modification of the firing parameters and removal of Al from the glazing mixture change essentially the interface extension and the micro-crystals morphology. By comparing archaeological and replica interfaces and considering previous studies, we can now state that Palissy was very likely adding clay (Al) in his frit. Moreover, he was probably working with a firing time of more than 1 h followed by slow cooling in the oven.

Ceramsite production from sediment in Beian River: characterization and parameter optimization

In order to realize pollution control and resource recovery, sediment from Beian River in Mudanjiang City China was used for ceramsite production. The maximum content of total nitrogen (TN), total phosphorus (TP) and organic matter (OM) in sediments of Beian River were 2975 mg kg −1 , 2947 mg kg −1 and 29.6%, respectively. So, it should be treated properly for resource utilization. The orthogonal experiment of L 16 (4 5 ) was adopted to determine the best conditions for ceramsite production and the result demonstrated that the sewage sludge ratio of 15%, binder ratio of 5%, pre-heating temperature of 450°C, sintering temperature of 1150°C and firing time of 23 min were the optimum conditions. The corresponding product met with the standard of CJ/T 299-2008 and the heavy metal leaching experiment showed it was lower than the threshold of China's industrial standard. Thus, it demonstrated that ceramsite production was a feasible way for utilization of sediment.

Origin Firing Regulations to Control Genome Replication Timing

Complete genome duplication is essential for genetic homeostasis over successive cell generations. Higher eukaryotes possess a complex genome replication program that involves replicating the genome in units of individual chromatin domains with a reproducible order or timing. Two types of replication origin firing regulations ensure complete and well-timed domain-wise genome replication: (1) the timing of origin firing within a domain must be determined and (2) enough origins must fire with appropriate positioning in a short time window to avoid inter-origin gaps too large to be fully copied. Fundamental principles of eukaryotic origin firing are known. We here discuss advances in understanding the regulation of origin firing to control firing time. Work with yeasts suggests that eukaryotes utilise distinct molecular pathways to determine firing time of distinct sets of origins, depending on the specific requirements of the genomic regions to be replicated. Although the exact nature of the timing control processes varies between eukaryotes, conserved aspects exist: (1) the first step of origin firing, pre-initiation complex (pre-IC formation), is the regulated step, (2) many regulation pathways control the firing kinase Dbf4-dependent kinase, (3) Rif1 is a conserved mediator of late origin firing and (4) competition between origins for limiting firing factors contributes to firing timing. Characterization of the molecular timing control pathways will enable us to manipulate them to address the biological role of replication timing, for example, in cell differentiation and genome instability.