Ring Area Research Articles

X-ray structure of the Rhodobacter sphaeroides reaction center with an M197 Phe→His substitution clarifies the properties of the mutant complex.

The first steps of the global process of photosynthesis take place in specialized membrane pigment-protein complexes called photosynthetic reaction centers (RCs). The RC of the photosynthetic purple bacterium Rhodobacter sphaeroides, a relatively simple analog of the more complexly organized photosystem II in plants, algae and cyanobacteria, serves as a convenient model for studying pigment-protein interactions that affect photochemical processes. In bacterial RCs the bacteriochlorophyll (BChl) dimer P serves as the primary electron donor, and its redox potential is a critical factor in the efficient functioning of the RC. It has previously been shown that the replacement of Phe M197 by His strongly affects the oxidation potential of P (E m P/P+), increasing its value by 125 mV, as well as increasing the thermal stability of RC and its stability in response to external pressure. The crystal structures of F(M197)H RC at high resolution obtained using various techniques presented in this report clarify the optical and electrochemical properties of the primary electron donor and the increased resistance of the mutant complex to denaturation. The electron-density maps are consistent with the donation of a hydrogen bond from the imidazole group of His M197 to the C2-acetyl carbonyl group of BChl PB. The formation of this hydrogen bond leads to a considerable out-of-plane rotation of the acetyl carbonyl group and results in a 1.2 Å shift of the O atom of this group relative to the wild-type structure. Besides, the distance between BChl PA and PB in the area of pyrrole ring I was found to be increased by up to 0.17 Å. These structural changes are discussed in association with the spectral properties of BChl dimer P. The electron-density maps strongly suggest that the imidazole group of His M197 accepts another hydrogen bond from the nearest water molecule, which in turn appears to form two more hydrogen bonds to Asn M195 and Asp L155. As a result of the F(M197)H mutation, BChl PB finds itself connected to the extensive hydrogen-bonding network that pre-existed in wild-type RC. Dissimilarities in the two hydrogen-bonding networks near the M197 and L168 sites may account for the different changes of the E m P/P+ in F(M197)H and H(L168)F RCs. The involvement of His M197 in the hydrogen-bonding network also appears to be related to stabilization of the F(M197)H RC structure. Analysis of the experimental data presented here and of the data available in the literature points to the fact that the hydrogen-bonding networks in the vicinity of BChl dimer P may play an important role in fine-tuning the redox properties of the primary electron donor.

VIRIAL THEOREM LIMITATIONS FOR THE TOROIDAL MAGNETIC ENERGY STORAGE CAUSED BY THE LOCATION OF SUPPORT STRUCTURE ELEMENTS AND THEIR MECHANICAL PROPERTIES

Based on the virial theorem, the influence of the following factors to characteristics of mechanical support systems of toroidal magnetic energy storage is considered: the configuration of the coils, the support system elements location under compressive forces, the mechanical properties of the material, the distribution of the cross-sectional areas of the support rings and the corresponding distribution of radial forces. It is established that the volume of structure requirement depends only on the radii from which the coils transmit forces to the support rings. The found general relation, in contrast to the existing ones, establishes a relationship between all the parameters that determine the volume of the support structures. The characteristics of support systems are analyzed both for identical mechanical stresses and for identical mechanical properties of all support elements. The characteristics for specific examples of toroidal systems with circular coils are found. It is shown that systems with support elements in compression located on the side of the vertical axis of the torus have a significantly smaller volume of structure compared to other locations. The influence of the relative radial size of the torus cross-section and the distribution of the cross-sectional areas of the support rings on the structure requirement is analyzed. The relationship between dimensionless characteristics that determine the volume of elements subjected to mechanical stresses of compression and tension is noted. References 37, figures 8, table 1.

Study of the influence laws of the flow and cavitation characteristics in an injector control valve

AbstractFuel cavitation can cause damage to the structure of an injector control valve, which can further affect the service life of the injector. Therefore, it is of great importance to carry out research on the mechanism of cavitation in injector control valves. In this study, the dynamic evolution of the cavitation and fuel flow characteristics during the opening of a ball valve in a high‐pressure common rail injector control valve were studied. First, a transient CFD simulation of the cavitation during the opening of the control valve was performed using dynamic mesh technology to analyze the evolution and formation mechanism of the cavitation. The cavitation was influenced by the fuel flow velocity, which was affected by the sealing cone angle and the ball valve movement. Additionally, the fuel reflux could effectively inhibit the development of cavitation. By comparing with the pressure, velocity, and mass flow rate of the fuel under conditions without cavitation, it was found that the cavitation had a remarkable effect on reducing the hydraulic shock to the ball valve and sealing cone as well as stabilizing the fluctuation of the fuel velocity in the control chamber. In addition, the cavitation noticeably decreased the fuel mass flow rate (by up to 32% at 0.015 ms) and increased the average pressure in the chamber (by up to 29.1% at 0.01 ms), ultimately leading to a slower response of the control valve. The analysis of different inlet pressures of the control valve indicated that the increase in the inlet pressure caused the cavitation to extend upward along the sealing cone, and that the cavitation ring area and the cavitation strength increased.

Diversity and determinants of the sigmoid septum and its impact on morphology of the outflow tract as revealed using cardiac computed tomography.

The sigmoid septum has been generally evaluated subjectively and qualitatively, without detailed examination of its diversity, impact on the morphology of the left ventricular outflow tract (LVOT), and anatomical background. We enrolled 100 patients without any background cardiac diseases (67.5 ± 12.8 years old; 43% women) who underwent cardiac computed tomography. Basal septal morphology was evaluated using antero-superior and medial bulging angles (bidirectional angulation of the basal septum relative to the LVOT). The eccentricity index of the LVOT, area narrowing ratio (LVOT/virtual basal ring area), aortic-to-left ventricular axial angle (angulation of the aortic root relative to the left ventricle), and wedged height (non-coronary aortic sinus to inferior epicardium distance) were also quantified. The antero-superior bulging, medial bulging, aortic-to-left ventricular axial angles, LVOT eccentricity index, area narrowing ratio, and wedged height were 76° ± 17°, 166° ± 27°, 127° ± 9°, 1.8 ± 0.5, 1.0 ± 0.2, and 41.2 ± 9.1mm, respectively. Both bulging angles were correlated with each other and contributed to the narrowing and deformation of the LVOT. Angulated aortic root was not correlated with either bidirectional septal bulge or LVOT narrowing. Clockwise rotation of the aortic root rotation was an independent predictor of prominent antero-superior septal bulge. Deeper aortic wedging was a common independent predictor of bidirectional septal bulge. The extent of septal bulge varies in normal hearts. Along with deep aortic wedging, the bidirectional bulge of the basal septum deforms and narrows the LVOT without affecting the virtual basal ring morphology.

METHOD FOR INGUINAL HERNIA TREATMENT WITH XENOPERICARDIUM

— Our experimental study shows the possibility of using a xenopericardial plate as a prosthesis in patients with inguinal hernias. The method of hernioplasty proposed by us is tension-free prosthetic technique. The advantage of the proposed method is the low probability of recurrence of a hernia in the area of the inner inguinal ring by strengthening both the posterior and anterior walls of the inguinal canal. Due to the fact that the spermatic cord, m. transversus abdominis and m. obliquus internus abdominis are in contact with the smooth antiadhesive surface of the xenopericardial plate, there is no formation of rough cicatricial fusion and no dysfunction of these structures. As an experiment, this method was tested on thirty Wistar rats with implantation of a prosthesis in the tissue of the anterior abdominal wall. Morphological and morphometric assessment of the tissue in the area of implantation shows that the formation of connective tissue around the implanted hernioprosthesis is very active. The final stage of the experiment (after 3 months) has revealed that the rough side of xenopericardial plate is tightly fixed to the underlying tissues. The xenopericardial plate contacting the tissues with the smooth side does not cause the formation of connective tissue, which protects this area from adhesions in the postoperative period.

Twelve-year follow up of a case of autosomal recessive bestrophinopathy with transient resolution of retinal edema in one eye.

To report 12-year follow-up of a patient with ARB. A 25-year-old man presented with blurred vision in his both eyes (OU). Best-corrected visual acuity (BCVA) was 20/63 Snellen equivalent in the right eye (OD) and 20/32 Snellen equivalent in the left eye. The intraocular pressures and anterior segment examination were unrevealing in OU. Posterior segment examination revealed multiple yellowish flecks and dots in the posterior pole in OU. Optical coherence tomography (OCT) showed subretinal fluid (SRF), intraretinal hyporeflective spaces, elongated and shaggy photoreceptors and outer retinal defects. Fundus autofluorescence demonstrated mottling hyperautofluorescence and hypoautofluorescence in the posterior pole in OU. Fluorescein angiography illustrated hyperfluorescence in the posterior pole and surrounding the arcades in OU. Multifocal electroretinography objectified mild to markedly abnormal responses in all ring areas in OU. Molecular genetic testing confirmed two heterozygous sequence variations in the BEST1 gene. At 4 years of follow-up, OCT revealed a complete resolution of SRF and a partial resolution of intraretinal hyporeflective spaces in the OD with corresponding improvement in the BCVA to 20/23 Snellen equivalent in the OD, even though outer retinal defects persisted. Our patient denied recent changes in his alimentary habits and medical history at that time. Posteriorly, SRF and intraretinal hyporeflective spaces reappeared in the OD. To the best of our knowledge, this is the first case report of ARB with a transient resolution of retinal edema in one eye without medical treatment and dietary therapy.

Reference Database of Inner Retinal Layer Thickness and Thickness Asymmetry in Healthy Thai Adults as Measured by the Spectralis Spectral-Domain Optical Coherence Tomography

Introduction: The study aimed to determine a reference database of the thickness and intraocular thickness asymmetry of total retina, retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) in healthy Thai subjects measured by the Spectralis spectral-domain optical coherence tomography. Methods: This cross-sectional study recruited the healthy subjects age ≥18 years, having spherical refraction within ±6 diopters and cylindrical refraction ±3 diopters, from a hospital’s personnel and the people visiting the ophthalmology department. Only 1 eye of each subject was randomly selected for an analysis. Macular images were obtained using posterior pole thickness scan protocol over a 24° × 24° area at the center of the fovea. The automated retinal thickness segmentation values of total retina and three inner retinal layers were calculated for the mean and the mean intraocular thickness difference between superior and inferior retinal hemispheres. The influence of age, gender, and axial length on thickness and thickness asymmetry of individualized retinal layer was evaluated. Results: 252 subjects were included in study with a mean (SD) age of 46.7 (15.8) years, and 120 (47.6%) were males. According to the Early Treatment Diabetic Retinopathy Study map, the inner ring area was the thickest location of the total retina (range; 326.0–341.5 µm), GCL (range; 47.7–52.7 µm), and IPL (range; 39.9–42.1 µm), whereas the thickest location of RNFL was at the outer ring area (range; 18.8–47.5 µm). For posterior pole intraocular thickness asymmetry, the greatest mean ± SD difference was observed for total retina (9.0 ± 2.2 µm), followed by RNFL (9.9 ± 3.2 µm) and GCL (2.7 ± 0.6 µm), and the lowest mean difference was noted for IPL (2.4 ± 0.5 µm). The thickness and thickness asymmetry of each retinal layer were variably influenced by age, gender, and axial length; however, these factors had a minimal influence on the thickness asymmetry maps of GCL and RNFL. Conclusion: The reference database of the macular thickness and thickness asymmetry from this study would be beneficial in determining physiologic variations of the OCT parameters in the healthy Thai population.

РАНЕВЫЕ ГНОЙНО-ВОСПАЛИТЕЛЬНЫЕ ОСЛОЖНЕНИЯ ПОСЛЕ НЕНАТЯЖНОЙ ГЕРНИОПЛАСТИКИ

Objective: Analysis of surgical site suppurative complications after correction of large and giant ventral hernias. Methods: Various types of hernioplasty were performed on 220 patients with large and giant ventral hernias. Among the total number of patients, tension-free hernioplasty was performed in 123 patients, which accounted for 56% of the total number of patients. Various types of mesh implants were used, as well as different techniques of mesh placement in the area of the hernia ring. Results: Surgical site suppuration in the postoperative period occurred in 7 patients, which amounted to 5.6%. Partial removal of the mesh polymer implant was carried out only in one case. Timely diagnosis of the complications and adequate sanitation of the surgical site in 6 cases showed a good effect, and the implants did not necessitate removal. In one observation with necrosis of the edges of the wound and suppuration of the surgical site, after partial removal of the implant, a hernia recurrence was noted in the area of the removed mesh. In 6 other cases, there was no recurrence of the pathology during the long-term follow-up. Conclusion: Surgical site suppurative inflammation in the postoperative period, negatively affecting the outcome of the operation, can contribute to hernia recurrence. Timely diagnosis of complications and adequate sanitation of surgical site in most cases give satisfactory results. Keywords: Large and giant ventral hernias, hernia recurrence, tension-free hernioplasty, suppurative inflammation.

Progression of Primary Open Angle Glaucoma on Optical Coherence Tomography of the Optic Nerve Head

Aims: To describe the progression of Primary open angle glaucoma (POAG) on Optical Coherence Tomography (OCT) of the optic nerve head and retinal nerve fiber layers (RNFL). Method: We conducted a descriptive retrospective study from January 1, 2015 to December 31, 2019, a period of 5 years from the files of patients followed for POAG and having carried out at least two OCT examinations of the optic nerve head (ONH), one automated visual field and Intraocular pression (IOP). The variables studied were: age, sex, mean IOP, glaucoma stage, progression of ONH parameters, and progression of RNFL parameters. Results: During the period, 112 eyes of 56 patients were included. The mean age was 48.96 ± 16.57 [12 - 83] years with a sex-ratio of 1.33 (32 M/27 F). The mean IOP was 21 ± 4.54 [10 - 36] mm Hg. According to the mean deviation (MD) of the visual field, 98 eyes or 87.5% were stage 1 of POAG, 10 eyes or 8.9% at stage 2 and 4 eyes or 3.6% at stage 3. The mean time between the 1st and 2nd OCT examination was 28.91 ± 11.07 [6 - 56] months, corresponding to an average of 2.18 OCT per patient in 5 years of follow-up. There was an average increase of 6.2% of the Cup area and an increase in the vertical Cup/Disc ratio of 1.79% per year. The thinning average of neuro-retinal ring area was 1.64% per year. The RNFL thickness had decreased on average by 4.28 μ or 0.93% per year. The lower quadrant had the highest fiber loss with 1.08% per year followed by the upper quadrant with a loss of 1.05% per year. Conclusion: OCT of the ONH and RNFL proves to be an essential tool in the follow-up of POAG. A subsequent study taking into account the OCT of the macular ganglion complex will enable to study its contribution in the follow-up of glaucomatous patients in the same population.

The temperature distribution of the wet cylinder liner of v-12 engine according to calculation and experiment

In order to serve the design, improvement, and manufacture of engine cylinder liners, it is necessary to accurately determine its temperature distribution. This paper presents the calculation of the cylinder liner temperature distribution in a V-12 engine by the finite element method (FEM) written in ANSYS Parametric Design Language (APDL) and verified with experimental results. In this model, the process of heat transfer from the ring group and area of the piston skirt to the cylinder liner wall is considered by using the thermal circuit method. In the study, at engine speeds of 2000 [rev/min] and 1200 [rev/min], the thermal distribution of the cylinder liner is carried out at 50%, 60%, 75%, and 100% of an entire load. The results of the tests show that the theoretical model is highly reliable, with the largest relative error of 5.49%.

Study of rheological properties of carbon nanotube-reinforced ultrafine cement grouting materials

In this study, three different diameters of multi-walled carbon nanotubes (MWCNTs) dispersed by polyvinyl pyrrolidone (PVP) were used to reinforce superfine cement grouting materials. The effect of MWCNTs and PVP on the rheological properties of grouting material were accordingly studied. It was found that the yield stress (τ0) and plastic viscosity (η) decreased slightly when PVP content was low and increased when PVP content increased. The effect of MWCNT diameter on τ0was not found to be clear but was more significant on η. The smaller the MWCNT diameter, the quicker η increased. It was also found that the thixotropic ring area increased as the MWCNT content increased. The addition of PVP and MWCNTs caused an increase in the number of entanglement points in different scales, which was the main reason for the viscosity and thixotropy increase. Therefore, the rheological properties of superfine cement grouting material should be adjusted when MWCNTs are added as a reinforcing component. Owing to the wrapping of PVP on cement particles, which isolates the contacting part between water and cement particles, it slows down the hydration rate of cement and thus slows down the fluidity loss of the slurry.

701 ECMO assistance during TAVI in high-risk patient with recent COVID-19 pneumonia

Methods and resultsA 87 years old woman, with history of dyslipidemia and permanent Atrial Fibrillation, already undergone full SARS-CoV2 vaccination few months before, referred to our E.R. with complain of dyspnoea and chest pain. COVID-19 molecular test resulted positive and CT Scan of the chest confirmed the presence of several areas of ground-glass opacity and consolidation together with bilateral pleural effusion (right 6 cm with pulmonary atelectasis; left 2 cm), not requiring drainage. Moreover, it showed severe calcification of both the aortic valve and root. Transthoracic echocardiogram showed eccentric LV hypertrophy with diffuse hypokinesia (EF 20–25%), ectatic ascending aorta (45 mm) with severe LF-LG aortic stenosis (AVAi 0.19 cm2) and moderate regurgitation, moderate-severe mitral regurgitation. During hospitalization in the COVID-19 Unit, despite O2 therapy she experienced worsening of the respiratory status with concomitant pulmonary oedema, hypotension and acute kidney injury, requiring administration of i.v. dobutamine and high dose diuretics. After gradual stabilization and COVID-19 negativization on 10th molecular test, she was transferred to our Coronary Care Unit. Coronary angiography showed absence of significant stenoses in the main vessels. In the following days the patient underwent a new clinical deterioration with dyspnoea, hypotension (BP 85/50 mmHg), oliguria and ankle swelling, requiring Ventimask O2 therapy and Dobutamine infusion. Transtoracic echocardiogram confirmed EF of 25% with PASP 30 mmHg. We decided to perform a ‘Rescue’ TAVI procedure, facilitated by extra-corporeal cardiac and respiratory support. CT Angiography of the chest, performed with low-dose contrast injection under amines infusion, showed severly calcific aortic valve with large sizes of the ring (Virtual Basal Ring area 620 mm2, perimeter 91 mm), measures compatible with the largest sizes of TAVI prostheses. After Veno-Arterial Extracorporeal Membrane Oxygenation (ECMO) cannulation, we performed the implantation of a 34 mm Evolut R (Medtronic) TAVI prosthesis, post-dilated with 24 mm balloon for under-expansion due to massive calcification. During both self-expandable TAVI delivery and balloon inflation the patient underwent two phases of cardiac arrest, during which the ECMO flow provided a proper circulatory support.ConclusionsSince percutaneous valve replacement the patient’s recovery was fast with rapid ECMO removal and discontinuation of inotropic therapy. Few weeks after discharge, at first follow-up examination, the patient appeared asymptomatic, in excellent clinical conditions. 701 Figure

Изменчивость элементного состава годичных колец хвойных пород

Distribution of chemical elements in tree rings bears important information on various biogeochemical processes. In order to achieve a reliable interpretation of the information, it is necessary to know the degree of variation in the content of chemical elements both at the level of the entire species and at the level of individual trees. The research aims to determine which chemical elements have a stable distribution in the trunks of a number of conifers: Siberian spruce (Picea obovata Ledeb.), Scots pine (Pinus sylvestris L.), Siberian larch (Larix sibirica Ledeb.), and Siberian pine (Pinus sibirica Du Tour). The data for the analysis were obtained on the basis of the long-term experiment in forest growing. The experimental site was laid out in 1971–1972 in the vicinity of Krasnoyarsk by the staff of the Sukachev Institute of Forest of the Siberian Branch of the Russian Academy of Sciences. Before planting the seedlings, the soil ground was mechanically levelled, and thus, sufficiently equal growth conditions were created for all plantings. Cores with a diameter of 12 mm were sampled from three normally developing trees of each species and analyzed using modern X-ray fluorescence methods. Content relative values of elements (counts) were obtained with the Itrax Multiscanner (COX Analytical Systems). The content of elements in the tree rings was characterized by the concentration and reserve of elements. Concentration was calculated as the number of counts per 1 mm2 of the ring area; reserve was calculated as the number of counts over the entire ring area. Each of these variables was defined by the parameters of linear slope in the calendar year series and the standard deviation. The cluster analysis was performed in the 4-dimensional space of the obtained parameters. This allowed determining whether the series of element distributions from different trees and species are grouped. Three elements (Ca, Co, and P) show high stability of distribution parameters in tree rings with no regard to tree species. A number of other elements (Mn, Pb, Cl, Cr, Ni, Sr, and W) are stably grouped depending on the species. The results of the research enable to focus on the study of the elements stably distributed in the conifer trunks. For citation: Gavrikov V.L., Fertikov A.I., Sharafutdinov R.A., Vaganov E.A. Variability in Elemental Composition of Conifer Tree Rings. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 24–37. DOI: 10.37482/0536-1036-2021-6-24-37

Effect of central and peripheral cone- and rod-specific stimulation on the pupillary light reflex

PurposeTo assess the effect of central and peripheral stimulation on the pupillary light reflex. The aim was to detect possible differences between cone- and rod-driven reactions.MethodsRelative maximal pupil constriction amplitude (relMCA) and latency to constriction onset (latency) to cone- and rod-specific stimuli of 30 healthy participants (24 ± 5 years (standard deviation)) were measured using chromatic pupil campimetry. Cone- and rod-specific stimuli had different intensities and wavelengths according to the Standards in Pupillography. Five filled circles with radii of 3°, 5°, 10°, 20° and 40° and four rings with a constant outer radius of 40° and inner radii of 3°, 5°, 10° and 20° were used as stimuli.ResultsFor cone-and rod-specific stimuli, relMCA increased with the stimulus area for both, circles and rings. However, increasing the area of a cone-specific ring by minimizing its inner radius with constant outer radius increased relMCA significantly stronger than the same did for a rod-specific ring. For cones and rods, a circle stimulus with a radius of 40° created a lower relMCA than the summation of the relMCAs to the corresponding ring and circle stimuli which combined create a 40° circle-stimulus. Latency was longer for rods than for cones. It decreased with increasing stimulus area for circle stimuli while it stayed nearly constant with increasing ring stimulus area for cone- and rod-specific stimuli.ConclusionThe effect of central stimulation on relMCA is more dominant for cone-specific stimuli than for rod-specific stimuli while latency dynamics are similar for both conditions.

Lutein and Zeaxanthin Distribution in the Healthy Macula and Its Association with Various Demographic Factors Examined in Pseudophakic Eyes.

The macular pigment consisting of lutein (L) and zeaxanthin (Z) protects photoreceptors via its antioxidative and barrier activities. This study aimed to determine L and Z distribution in the healthy macula and their association with various demographic factors. Macular pigment optical density (MPOD) was measured using fundus autofluorescence spectroscopy in 352 pseudophakic eyes with no fundus diseases. Pseudophakia was chosen to avoid the influence of cataract in the measurement of fundus autofluorescence. The mean patient age was 72.3 ± 8.6 years. MPOD was analyzed separately in three zones, i.e., A: a central area within a radius of 0.5°, mainly containing Z; B: a ring area with radii from 0.5° to 1.3°, containing Z and L; C: a ring area with radii from 1.3° to 9°, containing L. Multivariate analyses were performed with MPOD as the dependent variable and sex, supplement intake, smoking habits, glaucoma, diabetes, age, body mass index (BMI), skin carotenoid levels, retinal thickness, retinal volume, axial length as the independent variables. The mean total MPOD volume within 9° eccentricity was 20,121 ± 6293. Age was positively associated with MPOD in all zones. Supplement and BMI were positively and negatively associated with MPOD in zones B and C. Smoking was negatively associated with MPOD in zone A. This study revealed the standard MP values of aged Japanese, which resulted to be higher than the previously reported values in other races. Age was found to have a positive association with MP values. L in the outer foveola was affected by BMI and supplements, but Z in the foveola was not. The amount of Z in the Müller cell cone may not be changed easily by factors such as hunger and satiety in the context of preservation of homeostasis in the human body, but tobacco had a negative effect on Z.

Host facial features and Airbnb listing prices: a spatial hedonic pricing approach

ABSTRACT This study aims to examine the relationship between hosts’ facial features and Airbnb listing prices alongside other house attributes. We use a spatial hedonic pricing model to analyze 1,411 Airbnb listings in Shanghai, China. The results show that intrinsic functional attributes of listings are the dominant factors of price, followed by host attributes (especially host facial features such as facial width-to-height ratio). Specifically, the lower a host’s facial width-to-height ratio is, the higher the listing price. In addition, the results from concentric ring areas vary within the same city. This study contributes new insights into pricing in shared accommodations.

An automatic decision algorithm and simulation performance analysis for public safety

As the current society is increasingly facing major challenges from extremism and terrorism, protecting key urban public facilities and important targets from destruction is an important challenge facing the security departments of all countries. Based on real scene, this paper conducts researches on anti-terrorism security game algorithms and emergency response models in response to the three key links of before, during and after terrorist attacks. First of all, this paper constructs a multi-round joint attack game and emergency response model based on cooperation, establishes the optimization problem of solving the defender’s optimal strategy in mathematical form, and then obtains the optimal defense strategy. Secondly, in response to the fact that terrorists are not completely rational, a new hybrid model is constructed to propose an efficient allocation and scheduling algorithm for safe resources in response to terrorist attacks. Thirdly, a model of crowd evacuation strategy after a terrorist attack is built based on the problem of crowd evacuation in multiple rounds of premeditated cooperative attacks. Finally, taking the area of the first ring of a certain city as a real scene, a complete game system of the whole process is constructed, and the game effectiveness evaluation of the existing security resource allocation scheme in the first ring area is carried out. Through the research of this thesis, the author puts forward some new technical ideas for the current society’s anti-terrorism governance, and hopes to provide some technical references for the decision-making of security agencies.

A Novel Multi-Layer Structure for Axial Flux Machines

In an axial flux machine (AFM), an effective air-gap area is a ring form of which the size is decided by the outer and inner diameter of the stator. The inner diameter is usually not small, which leaves a relatively large inner space unused because the slot size has to keep uniform radially for current density. This article proposes a multi-layer structure that adopts concentric rings consisting of multiple layers instead of the conventional single layer. A conventional single-sided axial flux permanent magnet synchronous machine (AFPMSM) is introduced as a baseline design with 110 kW output power and 350 mm outer diameter. Through transforming this baseline design, the benefit of this new structure has been revealed with three different investigations in this article: 1) the output power per mass can be improved; 2) the compactness (output power in a limited space) can be increased; and 3) the constant power speed range could be significantly extended with a new type inverter (only design specification of the new inverter given), in which no additional technique of flux modulation required. The proposed multi-layer structure bypasses the issue that the area of a single ring cannot be enlarged due to the limitation of inner diameter. The air-gap area can be extended to the complete inner radial space for generating electromagnetic force. Besides, two factors, i.e., the number of layers and the coordination between multiple layers, make the performance of AFM highly customizable for different design objectives.

ANALISA TIPE FLUIDA MANIFESTASI PANASBUMI MENGGUNAKAN DIAGRAM TRILINIER CL-SO4-HCO3 DI DESA BAKAN KECAMATAN LOLAYAN KABUPATEN BOLAANG MONGONDOW

Indonesia is an area that could potentially be the source of the power of nature, including the source of power geothermal (geothermal). This is because Indonesia is a country located in the area of the world's ring of fire, where the tectonic plate stretches from the tip of the island of Sumatra, Java, to the Bandang Maluku area. Wrong one area in North Sulawesi, which has manifestations of geothermal, namely the village Bakan, the District Lolayan, District Bolaang Mongondow. In areas that are manifestations of geothermal eyes water hot. With the presence of one of the manifestations that the area that there is a potential for geothermal. Methods have used that method of geochemical and retrieval of data physical and samples of water hot in the field and then do the analysis laboratory on samples that. Based on the results of the research content of ions Cl, SO4 and HCO3 in a sample of water in the village Bakan which has been analyzed and the results of the calculation of the percentage of each ion that has been plotted into the diagram ternary showed that samples of water in the village Bakan is water sulfate (SO4), with the temperature manifestations 78 and the air temperature of 26 and pH showed value between 5 and 6 which means that the nature of the manifestations that are acidic due to having a pH less than 7.

Effect of interventional edge-to-edge repair in tricuspid regurgitation on ring dimensions

Abstract Background The concept of percutaneous tricuspid valve edge-to-edge repair (pTVR) is based on the connection of leaflets in the area of insufficiency using a coaptation device. By closing the coaptation device a considerable tractive force is applied on the leaflets, which might have an effect on the valve ring. Aim of the study was to examine the impact of device implantation on tricuspid ring dimensions. Methods During pTVR 3D zoom loops of tricuspid valve were acquired before and after clip placement using transoesophageal echocardiography. Measurements of TV ring dimensions included the following parameters: ring area (TV area), maximal diameter, minimal diameter, eccentricity index (Figure 1). Tenting area was derived from a four-chamber view of the valve. In addition, regurgitation severity was graded from 1+ to 5+ by measuring vena contracta area (VCA3D) in 3D full volume colour Doppler loop using multiplanar reconstruction. Right atrial (RA) and ventricular volumes (RVVd3D, RVVs3D) and function (RVEF3D) were assessed in a 3D full volume loop. Results The study population comprised 97 patients (age 78±6 years, 47 male), who underwent pTVR at our hospital. As expected cavity dimension correlated with TV area size (for RVVd3D r=0.51, p<0.001 and for RA volume r=0.71, p<0.001). The mean TV ring area was significantly reduced (ring area 8.53±2.23 cm2/m2BSA vs. 7.55±2.18 cm2/m2BSA, p<0.001) and the ring shape became more oval (Eccentricity index 1.2±0.15 vs. 1.29±0.17, p<0.001) after pTVR. The reduction of ring area (12±7%, range 0.7–28%) showed an only modest correlation to the number of implanted coaptation devices (r=0.30, p<0.001) and percentage reduction of VCA3D (r=0.36, p<0.001). In the patient group with a ring area change ≥12% a reduction to TR grade ≤2+ by pTVR was achieved in 83% of cases, whereas only 62% of patients reached moderate TR when area change was below 12%. Conclusion pTVR using coaptation devices reduces the ring area. This effect is related to the number of devices implanted. Funding Acknowledgement Type of funding sources: None.