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A 650-V/84-m normally-off GaN/SiC cascode device is demonstrated with systematic static and dynamic characterizations. The cascode device features a low voltage enhancement-mode (E-mode) GaN-HEMT to enable normally-off gate control, and a 650 V normally-on SiC JFET provides the high-voltage blocking capability. The GaN/SiC cascode device exhibits many application-desired behaviors, including reverse conduction capability, avalanche breakdown capability, thermally stable threshold voltage, low input/output capacitances, no dynamic RON degradation, and negligible dynamic VTH shift. In addition, a customized double-pulse test board is built to evaluate the switching performance of this cascode device and other 650-V SiC-based power devices. This cascode device adopting low-voltage GaN HEMT has low QGRON and exhibits excellent switching performance. The switching losses (EON and EOFF) are much smaller than that of 650-V Si/SiC cascode device and comparable to that of the state-of-the-art 650-V SiC MOSFETs.

In order to address the issue of wireless communication signal blocking in the traditional cavity resonance wireless power transfer (CR WPT), a wall-meshed cavity resonator constructed of the meshed metallic walls is proposed together with an analytical design method. This cavity resonator can not only generate and confine the electromagnetic waves of natural resonant modes inside the cavity resonator, but also support wireless communications with outside. The wall-meshed cavity resonator is analytically designed by the known theoretical equations without time-consuming optimizations and verified by electromagnetic simulations and experiments. The results show that the proposed CR WPT system can achieve simultaneous wireless power transfer in the cavity and wireless communications with outside. The maximum power transfer efficiency is higher than 85%. The power transfer efficiency exceeds 60% within about 70% areas inside the wall-meshed cavity. For wireless communication signals passing through the wall-meshed cavity, the attenuation at 2.1 GHz (4G), 2.45 GHz (Wi-Fi), and 3.5 GHz (5G) is about 6.0 dB, 5.1 dB, and 3.8 dB, respectively. Additionally, the safety performance of the proposed CR WPT system is numerically investigated by the specific absorption rate analysis of a human torso model.

The full-bridge submodules (FB-SMs) in hybrid modular multilevel converters need to absorb the enormous energy stored in dc side and arm inductors during dc fault blocking, which may lead to severe overvoltage. An energy absorbing branch (EAB) composed of metal oxide varistor (MOV) and thyristors is proposed in this letter. No extra power loss is produced by the EAB during normal operation. The EAB can absorb a part of the energy and reduce the energy absorbed by FB-SMs suffering from severe overvoltage by clamping the dc voltage. Thus, the maximum FB-SM overvoltage is reduced. Turning off the EAB several milliseconds after the blocking of the converter can accelerate the decaying of the dc fault in the transmission line and reduce the required energy volume of MOV with minimal effect on the maximum FB-SM overvoltage. The proposed EAB shows better technical and economic performance than existing methods. The proposed EAB is validated by simulations and experiments.

A displaced surgical neck fracture can be a good indication for antegrade intramedullary nailing. However, nail insertion may result in malreduction and translational displacement of the humeral head fragment because of muscle traction and size discrepancies between the diameters of the medullary canal and the intramedullary nail. We used blocking screw augmentation in 20 fractures with residual medial displacement of the distal fragment after nail insertion to anatomically reduce displacement of the fracture and to maintain the reduced position before bone union. A blocking screw was placed percutaneously at the lateral side of the canal. Next, a straight intramedullary nail was reinserted medial to the blocking screw. Finally, the nail was locked both proximally and distally. All cases showed bone union without fixation failure at the time of the final follow-up. Blocking screw augmentation with intramedullary nailing is feasible for the treatment of humeral surgical neck fractures and is thought to be helpful for fracture reduction during surgery and stable fixation after surgery.

The insulated gate bipolar transistor (IGBT) can be configured to provide forward and reverse blocking voltage capability using the symmetric structure or only forward blocking voltage capability using the asymmetric structure. The control of current flow through the IGBT can be obtained by using either a planar D-MOS gate structure or a trench U-MOS gate structure. The collector region doping profile can be adjusted to reduce the injected carrier density with the transparent emitter concept. Complementary n-channel and p-channel IGBT structures are useful for AC power control. Lateral IGBTs are of interest for integration with control circuits. Novel IGBT structures that allow enhanced performance are described.

Background Autophagy is a conserved catabolic process, which plays an important role in regulating tumor cell motility and degrading protein aggregates. Chemotherapy-induced autophagy may lead to tumor distant metastasis and even chemo-insensitivity in the therapy of hepatocellular carcinoma (HCC). Therefore, a vast majority of HCC cases do not produce a significant response to monotherapy with autophagy inhibitors. Results In this work, we developed a biomimetic nanoformulation (TH-NP) co-encapsulating Oxaliplatin (OXA)/hydroxychloroquine (HCQ, an autophagy inhibitor) to execute targeted autophagy inhibition, reduce tumor cell migration and invasion in vitro and attenuate metastasis in vivo. The tumor cell-specific ligand TRAIL was bioengineered to be stably expressed on HUVECs and the resultant membrane vesicles were wrapped on OXA/HCQ-loaded PLGA nanocores. Especially, TH-NPs could significantly improve OXA and HCQ effective concentration by approximately 21 and 13 times in tumor tissues compared to the free mixture of HCQ/OXA. Moreover, the tumor-targeting TH-NPs released HCQ alkalized the acidic lysosomes and inhibited the fusion of autophagosomes and lysosomes, leading to effective blockade of autophagic flux. In short, the system largely improved chemotherapeutic performance of OXA on subcutaneous and orthotopic HCC mice models. Importantly, TH-NPs also exhibited the most effective inhibition of tumor metastasis in orthotopic HCCLM3 models, and in the HepG2, Huh-7 or HCCLM3 metastatic mice models. Finally, we illustrated the enhanced metastasis inhibition was attributed to the blockade or reverse of the autophagy-mediated degradation of focal adhesions (FAs) including E-cadherin and paxillin. Conclusions TH-NPs can perform an enhanced chemotherapy and antimetastatic effect, and may represent a promising strategy for HCC therapy in clinics. Graphical Abstract

Degradation caused by humidity affects the blocking characteristic of an insulated gate bipolar transistor (IGBT) module, leading to an increased leakage current and/or a reduced voltage blocking capability. The proposed measurement system enables the in situ detection of decreased breakdown voltage and increased leakage current. Thus, it can assess the degradation level of power modules when installed in a converter. This test is intended primarily for wind power converters and can be part of the start-up procedure of the system. The working principle has been validated on predamaged power modules arranged in half-bridge configuration, using a demonstrator implementation of the proposed approach in laboratory experiments. Due to the simplicity of the circuit, this concept is easy to integrate in existing inverter systems at a comparatively low cost.

The trade-off relationship between specific on-resistance and short-circuit withstand time in 1.2 kV 4H-SiC MOSFETs was drastically increased using a novel device structure. MOSFETs with deep P-well formed using channeling implantation were firstly demonstrated to improve short-circuit ruggedness (~4 times longer than conventional MOSFET) with no negative impact on specific on-resistance. Proposed MOSFETs achieved short-circuit withstand time of 8 μs. Channeling implant with low energy was conducted to form deep P-well junctions. Fabrication of a deep P-well using channeling implantation is demonstrated using no additional nor complicated processes when compared to the conventional MOSFET fabrication process. A comparison between the conventional and novel designs was performed in terms of the output characteristics, blocking behaviors, and short-circuit ruggedness.

Blocking over Greenland is known to lead to strong surface impacts, such as ice sheet melting, and a change in its future frequency can have important consequences. However, as previous studies demonstrated, climate models underestimate the blocking frequency for the historical period. Even though some improvements have recently been made, the reasons for the model biases are still unclear. This study investigates whether models with realistic Greenland blocking frequency have a correct representation of its dynamical drivers, most importantly, cyclonic wave breaking (CWB). Because blocking is a rare event and its representation is model-dependent, we here use a multi-model large ensemble. All of the models underestimate CWB frequency and four out of five models underestimate the frequency of Greenland blocking. Nevertheless, they all show the typical Greenland blocking features, namely a ridge with anticyclonic anomaly over Greenland and an equatorward-shifted jet over the North Atlantic. However, we find that the model with the most realistic Greenland blocking frequency, MIROC5, has the most negative CWB frequency bias. While in reanalysis CWB is an important mechanism leading to blocking formation, the link between blocking and CWB is much weaker in MIROC5, suggesting that another mechanism leads to blocking in this model. Composites over Greenland blocking days show that the present and future experiments of each model are very similar to each other in both amplitude and pattern and that there is no significant change of Greenland blocking frequency in the future. However, this result must be taken with caution since the Greenland blocking driver is not well represented in all models. This highlights the need to accurately understand and represent the mechanisms leading to blocking formation and maintenance in models to get more reliable future projections.

Photons not welcomeTwo identical fermions cannot occupy the same quantum state, or so says the Pauli principle. For a cold gas of fermionic atoms, this means that all states up to the Fermi energy will be occupied, with only the atoms with the highest energy able to change their state. Such conditions have long been predicted to suppress light scattering off gases because the atoms receiving a kick from collisions with photons would have no state to move to. Debet al., Margalitet al., and Sanneret al. now describe this so-called Pauli blocking of light scattering. —JS

The Pauli exclusion principle forbids indistinguishable fermions to occupy the same quantum mechanical state. Its implications are profound and it for example accounts for the electronic shell structure of atoms. Here we perform measurements on the scattering of off-resonant light from ultracold gasses of fermionic atoms. For Fermi gases in the quantum degenerate regime, we observe a marked suppression in light scattering as compared to a similarly prepared thermal Bose gas. We attribute the observed increased transmission of light through the quantum degenerate Fermi gas to Pauli blocking, where Fermi-Dirac statistics causes atoms to occupy a large region of the momentum space limiting the number of accessible states for the scattered atom. Our work confirms a longstanding fundamental result in the theory of the optical response of quantum gases and is an important step towards novel cooling and thermometry mechanisms for degenerate Fermi gases.

PURPOSE In the case of a nuclear incident, the release of radioiodine must be expected. Radioiodine accumulates in the thyroid and by irradiation enhances the risk of cancer. Large doses of stable (non-radioactive) iodine may inhibit radioiodine accumulation and protect the thyroid ('thyroid blocking'). Protection is based on a competition at the active carrier site in the cellular membrane and an additional temporary inhibition of the organification of iodide (Wolff-Chaikoff effect). Alternatively, other agents like e.g. perchlorate that compete with iodide for the uptake into the thyrocytes may also confer thyroidal protection against radioiodine exposure.Biokinetic models for radioiodine mostly describe exchanges between compartments by first order kinetics. This leads to correct predictions only for low (radio)iodide concentrations. These models are not suited to describe the kinetics of iodine if administered at the dosages recommended for thyroid blocking and moreover does not permit to simulate either the protective competition mechanism at the membrane or the Wolff-Chaikoff effect. Models adapted for this purpose must be used. Such models may use a mathematical relation between the serum iodide concentration and a relative uptake suppression or a dependent rate constant determining total thyroidal radioiodine accumulation. Alternatively, the thyroidal uptake rate constant may be modeled as a function of the total iodine content of the gland relative to a saturation amount. Newer models integrate a carrier-mechanism described by Michalis-Menten kinetics in the membrane and in analogy to enzyme kinetics apply the rate law for monomolecular irreversible enzyme reactions with competing substrates to model the competition mechanism. An additional total iodide uptake block, independent on competition but limited in time, is used to simulate the Wolff-Chaikoff effect. CONCLUSION The selection of the best model depends on the issue to be studied. Most models cannot quantify the relative contributions of the competition mechanism at the membrane and the Wolff-Chaikoff effect. This makes it impossible or exceedingly difficult to simulate prolonged radioiodine exposure and the effect of repetitive administrations of stable iodine. The newer thyroid blocking models with a separate modeling of competition and Wolff-Chaikoff effect allow better quantitative mechanistic insights and offer the possibility to simulate complex radioiodine exposure scenarios and various protective dosage schemes of stable iodine relatively easily. Moreover, they permit to study the protective effects of other competitors at the membrane carrier site, like e.g. perchlorate, and to draw conclusions on their protective efficacy in comparison to stable iodine.

This paper presents a computational account of nonderived environment blocking (NDEB) that indicates the challenges it has posed for phonological theory do not stem from any inherent complexity of the patterns themselves. Specifically, it makes use of input strictly local (ISL) functions, which are among the most restrictive (i.e., lowest computational complexity) classes of functions in the subregular hierarchy (Heinz 2018) and shows that NDEB is ISL provided the derived and nonderived environments correspond to unique substrings in the input structure. Using three classic examples of NDEB from Finnish, Polish, and Turkish, it is shown that the distinction between derived and nonderived sequences is fully determined by the input structure and can be achieved without serial derivation or intermediate representations. This result reveals that such cases of NDEB are computationally unexceptional and lends support to proposals in rule- and constraint-based theories that make use of its input-oriented nature.

In order to effectively suppress the intractable high-frequency conducted common-mode (CM) electromagnetic interference (EMI) and reduce the dependence on the high-frequency performance of the EMI filter, this article proposes a separate floating heatsink based suppression method (SFHBSM). SFHBSM suppresses high-frequency CM EMI by improving both the CM EMI source and the propagation path. On the one hand, SFHBSM achieves the nonringing CM EMI source without introducing additional resistive loss, by properly designing the parameters of the SFHBSM, the ringing effect in the CM EMI source can be pushed into a narrow bandwidth in the very high-frequency domain, where the ringing effect can be naturally killed by the skin effect. On the other hand, the CM EMI propagation path of the SFHBSM-based power converter is mathematically deduced, verifying that the SFHBSM can provide effective blocking for the CM EMI propagation in the high-frequency domain. Experiments show that under the combined effect of the ringing suppression and propagation blocking, SFHBSM achieves EMI reduction in almost the whole high-frequency domain, and provides up to 35 dB attenuation in a two-level three-phase power converter. Besides, ablation experiments have been conducted to evaluate the individual and combined effectiveness of each part of the SFHBSM.

Distributed Denial-Of-Service (DDoS) attacks are one of the all the more difficult security issues on the Internet today. They can without much of a stretch, fumes the assets of the potential Victims. The issue is much more extreme since the aggressors regularly produce their IP delivers to shroud their character. The current guard mechanism against DDoS attacks, the attack traffic will be filtered at the victim’s side. For this situa- tion, regardless of whether the attacking traffic is filtered by the victim, the attacker may achieve the objective of blocking access to the victim’s bandwidth. IP-Trace back ap- proaches enable the victim to trace back to the wellspring of an attack and they will not be able to minimize the attack when the attack is in progress. Hence is to minimize the quan- tity of malicious packets entering into the network we put forth a quantum annealing technique to identify and alleviate the DDoS attack. The attack messages are minimized by utilizing client puzzle as a part of the ingress router; the path fingerprint is used at the egress side. Simulation studies prove that the proposed mechanism is optimally successful in recognizing and mitigating the DDoS attacks.

The thermal safety of pouch lithium-ion batteries (LIBs) with a nominal capacity of 2000 mA h is improved by adding nanoscale Mg(OH)2 into the LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode, and the thermal ...

Study Design This is a basic science research. Introduction Isolating excursion of the flexor digitorum profundus (FDP) in zones I and II is common practice in the current management after flexor tendon repair. During this procedure, the proximal interphalangeal joint is sometimes fully extended with unmeasured external forces at the middle phalanx when the distal interphalangeal joint is actively flexed. Purpose of the Study The purpose of the study was to investigate the incremental effect of external force with palmar blocking versus lateral blocking and increased angles of flexion on internal tendon forces at the repair site for a safer application of force by the treating therapist. Methods Eight human cadaveric fingers were studied. To simulate palmar or lateral finger blocking, a compression force of blocking was applied from 5N (510 grams) to 25N (2,550 grams) on the skin surface of the palmar or the lateral aspect of each of these middle phalanges in 5N increments. The tensile load on the FDP tendon during distal interphalangeal joint flexion from 0° to 60° was measured in 10° increments. Results During palmar blocking, the tensile load was significantly increased with increases in palmar blocking force. However, no significant increase in the tensile load on the FDP tendon was observed at any lateral blocking. Discussion Lateral blocking exercise can be performed with less tensile force on the FDP tendon when performing blocking exercise after flexor tendon injury repair. Conclusions This study supports the concept that lateral blocking with incremental joint angles allows a safer application of force for the healing tendon.

Psoriasis is one of the most common autoimmune dermatoses with a chronic relapsing course. Biologic therapy should be initiated for patients with moderate to severe psoriasis when conventional systemic therapy and phototherapy are ineffective, or their use is limited due to comorbidities. In Latvia, adalimumab is the first choice of biologic drugs for treatment of psoriasis. The correlation between changes in cellular and humoral immunological parameters and clinical signs based on immunological data from psoriasis patients are evaluated in the publication.

Periodontitis is a chronic inflammation of periodontal tissue, and programmed cell death plays an important role in chronic periodontitis induced by P. gingivalis. Studies have shown that the increased expression of pyroptosis-related NLRP3 inflammasome and the pro-inflammatory cytokines IL-1β and IL-18 in gingivitis, invasive periodontitis, and chronic periodontitis patients. The present study aimed to investigate whether the inhibition of pyroptosis could protect porphyromonas gingival lipopolysaccharide (pg-LPS)-induced human periodontal ligament stem cells (hPDLSCs) injury and inflammation. The hPDLSCs were treated with pg-LPS and ATP in the presence of caspase1/4 inhibitor VX765. The cell proliferation and survival were assessed by CCK-8, the osteogenic differentiation capacity was evaluated by Alkaline Phosphatase (ALP) assay and alizarin red staining. Then, cell apoptosis, cleavage of gasdermin D (GSDMD) and generation of inflammatory cytokines were estimated. Lastly, western blotting was used to detect the expression of potential target proteins. Results showed that the treatment of pg-LPS plus ATP significantly inhibited the proliferation, survival and osteogenic differentiation of hPDLSCs, while inducing cell apoptosis, pyroptosis and inflammation. However, the presence of VX765 partially recovered the cell proliferation, survival and osteogenic differentiation. At the same time, VX765 inhibited cell apoptosis, cleavage of GSDMD and generation of inflammatory cytokines. Besides, the expression of related proteins including Bax, Bcl-2, cleaved (c)-caspase3, c-caspase4, c-caspase1, Toll Like Receptor 4, High Mobility Group Box 1 (HMGB1) and NLRP3 was all rescued by VX765. In conclusion, our results revealed that the blocking of cell pyroptosis could protect hPDLSCs from pg-LPS-induced injury. Therefore, the application of pyroptosis inhibitor may be a valuable therapeutic approach for treating periodontitis.

This paper examines the impact of the meridional and vertical structures of a preexisting upstream storm track (PUST) organized by preexisting synoptic-scale eddies on eddy-driven blocking in a nonlinear multiscale interaction model. In this model, the blocking is assumed, based on observations, to be comprised of barotropic and first baroclinic modes, whereas the PUST consists of barotropic, first baroclinic, and second baroclinic modes. It is found that the nonlinearity (dispersion) of blocking is intensified (weakened) with increasing amplitude of the first baroclinic mode of the blocking itself. The blocking tends to be long lived in this case. The lifetime and strength of blocking are significantly influenced by the amplitude of the first baroclinic mode of blocking for given basic westerly winds (BWWs), whereas its spatial pattern and evolution are also affected by the meridional and vertical structures of the PUST. It is shown that the blocking mainly results from the transient eddy forcing induced by the barotropic and first baroclinic modes of PUST, whereas its second baroclinic mode contributes little to the transient eddy forcing. When the PUST shifts northward, eddy-driven blocking shows an asymmetric dipole structure with a strong anticyclone–weak cyclone in a uniform BWW, which induces northward-intensified westerly jet and storm-track anomalies mainly on the north side of blocking. However, when the PUST has no meridional shift and is mainly located in the upper troposphere, a north–south antisymmetric dipole blocking and an intensified split jet with maximum amplitude in the upper troposphere form easily for vertically varying BWWs without meridional shear.

Beach volleyball is spectacular with many rapid actions, agility moves, and high jumping. One of the key elements present in high-performance beach volleyball, having a decisive role in the defensive apparatus, is the blocking movements. This action is done mainly by the tallest player or with the most considerable jumping ability. A high blocking ability can facilitate the defensive movement of the player that is positioned in the back of the court. Blocking ability is facilitated by anticipation capacity, good sight, agility movement, and high jumping ability generated by solid legs. This paper analyses the fundamentals of blocking actions in beach volleyball, giving critical elements in executing a good and efficient block.

The optical analysis of Linear Fresnel Reflectors solar concentrators deals with the calculation of the absorbed flux at the receiver. Due to concentrator discrete and complex geometry ray tracing numerical simulations is the main used method, in parallel with some analytical approaches that have been developed for specific cases. This paper presents an analytical method for Linear Fresnel Reflectors with a flat receiver. It is based on Zhu’s vector-based method and Rabl’s concepts of acceptance and effective source, although new shading (including receiver shading), blocking, and cosine losses analyzes are presented, with the inclusion of end-losses effect. As shown, the problem is better described by the concept of intercept factor, the effective aperture area used to collect the incident sunlight. Comparison tests with ray tracing simulations performed in SolTrace for three different effective sources were carried out to validate the analytical model for both factorized and biaxial models of the intercept factor, including energetic evaluations for Evora, Portugal. In general, analytical results do agree very well with ray tracing, better for the factorized model than the biaxial. Errors in the analytical estimative of intercept factor can be high up to 132% for the biaxial model at high longitudinal incidence angles; on the other hand, errors in the amount of annual absorbed energy were high up to only 3%.

To monitor infection by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and successful vaccination against coronavirus disease 2019 (COVID‐19), the kinetics of neutralizing or blocking anti‐SARS‐CoV‐2 antibody titers need to be assessed. Here, we report the development of a quick and inexpensive surrogate SARS‐CoV‐2 blocking assay (SUBA) using immobilized recombinant human angiotensin‐converting enzyme 2 (hACE2) and human cells expressing the native form of surface SARS‐CoV‐2 spike protein. Spike protein‐expressing cells bound to hACE2 in the absence or presence of blocking antibodies were quantified by measuring the optical density of cell‐associated crystal violet in a spectrophotometer. The advantages are that SUBA is a fast and inexpensive assay, which does not require biosafety level 2‐ or 3‐approved laboratories. Most importantly, SUBA detects blocking antibodies against the native trimeric cell‐bound SARS‐CoV‐2 spike protein and can be rapidly adjusted to quickly pre‐screen already approved therapeutic antibodies or sera from vaccinated individuals for their ACE2 blocking activities against any emerging SARS‐CoV‐2 variants., A simple, inexpensive surrogate SARS‐CoV‐2 neutralization assay is introduced. Ectopic expression of the SARS‐CoV‐2 spike protein confers binding of Ramos‐Ig ‐ or HEK293 cells to plate‐bound recombinant human angiotensin‐converting‐enzyme‐2. This interaction can be blocked with reconvalescent or immune serum or with anti‐receptor‐binding domain antibodies. Bound spike‐expressing cells are quantitated with crystal violet.

BACKGROUND Fractures of both proximal and distal metaphyses with small distal fragment of tibia are not uncommon. Internal fixation using intramedullary nails alone could lead to misalignment. Using blocking screws (Poller screws) in addition to intramedullary nails would help in narrowing the medullary cavity and decreases the degree of misalignment and chances of displacement. The present study was conducted to evaluate functional and radiological outcome of blocking screws with intramedullary nail in the treatment of proximal and distal metaphyses fractures of tibia with short distal fragment. METHODS A prospective observational study of 34 patients with proximal and distal tibial metaphyses fractures was treated with statically locked intramedullary nailing with supplementary blocking screws. The study was conducted from January 2018 to December 2020 with a maximum follow up of 18 months. Medullary canal diameter was measured at the levels of fracture and isthmus. RESULTS Among the 34 patients, 29 (85.29 %) were males and 05 (14.70 %) were females with a male to female ratio of 5.8 : 1. The mean age was 34.97 ± 3.10 years. The mean healing period was 20 ± 1.45 weeks. 25/34 (73.52 %) of the patients showed Karlstrom and Olerud functional grading score of excellent. The fracture varus/valgus alignment was 1.9 ± 0.3 degrees. The mean antecurvatum/recurvatum alignment was 0.3 degrees. CONCLUSIONS Blocking screws act as reduction tools, help in reducing the medullary lumen of distal metaphyses and prevent failures in initial reduction. They extend the indication of intramedullary nailing to the distal segment of tibia and minimize the misalignment in terms of varus /valgus and/or antecurvatum/recurvatum. KEYWORDS Tibia, Intramedullary, Blocking Screws, Internal Fixation and Misalignment

Cognitive radio is an emerging technology, aimed at efficient use of the scarce radio spectrum. In cognitive radio networks (CRNs), spectrum licensed to the primary users (PUs) is shared by the secondary users (SUs) which affects the performance of the network. This paper proposes a novel spectrum management scheme for CRNs, where heterogeneous secondary real-time and non-real time users compete for the available channels with primary users and utilize two types of buffers under the probability retrial policy. To enhance the quality of service (QoS) for the secondary users (SUs), spectrum handoff and call buffering strategies with retrial policy are employed jointly so that SUs that would otherwise be blocked or forcibly dropped could be queued and possibly served later. The whole system is modeled using a multi-dimensional continuous-time Markov chain (CTMC) and accordingly, the QoS performance metrics are derived. Numerical results are presented which illustrate that the provision of queues under the proposed retrial policy increases overall network resource utilization and throughput while decreasing blocking and dropping probabilities.

We introduce and study weighted bipartite matching problems under strict preferences where blocking edges can be paid for, thus imposing costs rather than constraints as in classical models. We focus on the setting in which the weight of an edge represents the benefit from including it in the matching and/or the cost if it is a blocking edge. We show that this setting encompasses interesting special cases that remain polynomially-solvable, although it becomes APX-hard even in a quite restricted case.

A monolithic bidirectional switch based on anti-paralleled two reverse blocking p-GaN HEMTs has been proposed and demonstrated in this work. The recessed Schottky drain technique is utilized to effectively reduce the on-state voltage and thus lowering the power loss of bidirectional switches. A significant reduction in parasitic elements and switch area is obtained by monolithic integration. The fabricated bidirectional switch exhibits a threshold voltage of ~1.85 V, on-state voltage of ~0.63 V, and the forward and reverse off-state breakdown voltages of ~650 V at ${I}_{{\text {S1}-\text {S2}}} = 1\,\,\mu \text{A}$ /mm. In addition, the function of proposed bidirectional switch as an AC power chopper has been successfully verified.

Analysis of satellite and reanalysis data indicates a relationship between pyrogenic NO2 emissions and atmospheric blocking events. According to the estimates obtained for the period of 2001–2019, total NO2 emissions into the atmosphere during wildfires in Russia increase by 0.7 Mt with an increase in the integral blocking index by 10%. Against the background of the general decrease in pyrogenic NO2 emission in 2001–2019, a statistically significant increase in the NO2 emission density per unit area by 23% has been revealed. At the same time, a decrease in the total NO2 emission during wildfires is noted in relation to the corresponding emissions of carbon monoxide and fine aerosol.

Using satellite data and reanalysis data, the characteristics and mechanisms of the formation of an ozone “mini-hole” in the atmosphere over Siberia in the winter of 2015–2016 have been investigated. The relationship between the regional negative anomaly of the total ozone content (TOC), reaching –140 Dobson units, with atmospheric blocking was established. The TOC anomaly was mainly due to a decrease in the ozone content in the lower stratosphere, reaching 50% near the 70 hPa level. With the key contribution of atmospheric dynamic processes to the formation of the ozone “mini-hole,” the possibility of the contribution of ozone destruction in heterogeneous reactions on the surface of polar stratospheric clouds, due to a strong decrease in temperature in the stratosphere above the blocking region, was noted.

A CoPc/CNT system has been only recently reported to transform CO2 to methanol via electrochemical reductions, despite the fact that catalyst has been studied extensively since the 1980s. The expla ...

In this paper, we consider a bistable monotone reaction–diffusion system in cylindrical domains. We first prove the existence of the entire solution emanating from a planar front. Then, it is proved that the entire solution converges to a planar front if the propagation is complete and the domain is bilaterally straight. Finally, we give some geometrical conditions on the domain such that the propagation of the entire solution is complete or incomplete, respectively.

We consider a situation, when braking is the only way to avoid obstruction of an automotive vehicle or a railroad train with a suddenly detected steadfast obstacle blocking the path. The velocity a...

Blocking the tunnel portal is one strategy in railway tunnel firefighting. In order to evaluate the effect of tunnel portal sealing ratio on fire behaviour, Fire Dynamics Simulator (FDS) was used to simulate tilted tunnel fire with different slope angles varying from 0% to 5%, heat release rate varying from 10 to 50 MW and sealing ratios varying from 0% to 75%. Results show that the experimental data of the temperature distribution inside the tilted tunnel were in good agreement with the simulation results. Moreover, the ceiling temperature rise decreases along the tunnel with the increase of the tunnel portal sealing ratio at initial stage and then tends to stabilize because of less oxygen supply when the heat release rate is relatively large. The maximum temperature rise decays exponentially along the tunnel ceiling with distance. The current model for temperature decay beneath the tunnel ceiling was proposed to be modified by taking the tunnel entrance sealing ratio into account. The predictions by the modified model agree well with the experimental measurement. The results could provide practical information and knowledge in ventilation system design and emergency evacuation for inclined railway tunnels.

Proline utilization A (PutA) from Bradyrhizobium japonicum (BjPutA) is a bifunctional avoenzyme that catalyzes the oxidation of proline to glutamate using fused proline dehydrogenase (PRODH) and ∆1-pyrroline-5-carboxylate dehydrogenase (P5CDH) domains. Recent crystal structures and kinetic data suggest an intramolecular channel connects the two active sites, promoting substrate channeling of the intermediate P5C from the PRODH domain to the P5CDH domain. In this work several mutations were made along the channel in an effort to block passage of P5C to the second active site. Analysis of several site-specic mutants in the substrate channel of BjPutA revealed an important role for D779 in the channeling path. BjPutA mutants D779Y and D779W signicantly decreased the overall PRODH-P5CDH channeling reaction indicating that bulky mutations at residue D779 impede travel of P5C through the channel. Interestingly, D779Y and D779W also exhibited lower P5CDH activity, suggesting that exogenous P5C must enter the channel upstream of D779. Replacing D779 with a smaller residue (D779A) had no effect on the catalytic and channeling properties of BjPutA showing that the carboxylate group of D779 is not essential for channeling. An identical mutation at D778 (D778Y) did not impact BjPutA channeling activity. Thus, D779 is optimally orientated so that replacement with the larger side chains of Tyr/Trp blocks P5C movment through the channel. The kinetic data reveal not only that bulky mutations at residue D779 hinder passage of P5C to the second active site, but also P5C must use the channel to efciently access the P5CDH domain. Moreover, these mutants may be used to learn more about the hydrolysis event that is thought to take place within the channel