bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on the Threading Dislocations Formed by Lattice Misfits during Initial Stage of Sublimation Growth of 4H-SiC
Authors: Eun Tai Hee , Yeo Im Gyu , Kim Jang Yul , Lee Seung Seok , Seo Han Suk , Chun Myong Chuel , Hong Soon Ku
Published: July 2020

We investigated the relation between the nucleation of dislocations and the lattice misfits by nitrogen concentration difference between seed and grown crystal during the initial stage of growth. 4H-SiC single crystals were grown with various nitrogen gas flow rates introduced into the crystal growing chamber under the same temperature and pressure to minimize the effect of thermal stress on the nucleation of dislocations. The nitrogen atomic concentrations of grown crystals depended on the introduced nitrogen gas ratios and they highly increased at the very early stage of growth. The generation of new threading dislocations at the interface also was affected by the nitrogen atomic concentrations differences between seed and grown crystals. Very few generated threading dislocations were observed in low nitrogen atomic concentration samples, however nucleation of threading dislocations at the interface were found in high nitrogen atomic concentrations samples. At initial stages of PVT growth process, the generation of threading dislocations induced by lattice misfits originated from nitrogen concentration difference between seed and grown crystals were investigated and found the appropriate nitrogen gas flow rates and profile at the heating and depressurized stage.
AFM Observation of Etch-Pit Shapes on β-Ga2O3 (001) Surface Formed by Molten Alkali Etching
Authors: Ogawa Kenichi , Ogawa Naoya , Kosaka Ryo , Isshiki Toshiyuki , Aiso Toru , Iyoki Masato , Yao Yong Zhao , Ishikawa Yukari
Published: July 2020

In order to understand the crystal defects of beta-gallium oxide (β-Ga2O3) in more detail, we classified the crystal defects of a 2-inch substrate of β-Ga2O3 (001) single crystal. As a result of observing the etch pits formed by molten alkali etching using scanning electron microscope (SEM) and atomic force microscope (AFM), we succeeded in observing six different etch pit shapes. These etch pit shapes are categorized into “Cicada I type”, “Cicada II type”, “Cannonball type”, “Trapezoid type”, “Bar type”, and “Shell type”. We consider that “Cicada I type” and “Cicada II type” are etch pit shapes caused by planar defects, and “Cannon ball type” is etch pit shapes due to dislocations. In addition, “Trapezoid type”, “Bar type”, and “Shell type” are deduced the result of surface morphology.
Graphene Quality Assessment Using an Entropy Approach of SEM Images
Authors: Hähnlein Bernd , Lebedev Sergey P. , Eliseyev Ilya A. , Davydov Valery Yu. , Lebedev Alexander A. , Pezoldt Joerg
Published: July 2020

In this work a new approach of analyzing epitaxial graphene layers on semi-insulating SiC through the gray-scale entropy of SEM images as a measure for the graphene inhomogeneity is demonstrated. Raman spectroscopy as a versatile and the standard tool for graphene characterization allows additionally the determination of the layer properties such as layer count, Fermi level, defect concentration and strain. It is shown that the gray-scale entropy correlates with the defect density derived from Raman measurements and thus can be used as an additional characterization technique with much higher resolution than the conventional Raman spectroscopy allows. As a consequence, the results are used to reflect the two-stepped growth itself and to conclude for advantageous growth conditions.
Pre-Deposition Interfacial Oxidation and Post-Deposition Interface Nitridation of LPCVD TEOS Used as Gate Dielectric on 4H-SiC
Authors: Lim Min Who , Sledziewski Tomasz , Rommel Mathias , Erlbacher Tobias , Kim Hong Ki , Kim Seongjun , Shin Hoon Kyu , Bauer Anton J.
Published: July 2020

In this work, the influence of pre-deposition interfacial oxidation or post-deposition interface nitridation on the performance of 4H-SiC MOS capacitors was investigated. The gate oxide was deposited by LPCVD using TEOS as a precursor. Interface breakdown strength was derived from leakage current and Time-Zero Dielectric Breakdown characteristics whereas interface quality was assessed by the determination of interface state density from the comparison of quasi-static and high frequency capacitance-voltage characteristics using high-low method. In the experimental results, it is demonstrated that the gate oxide deposited by LPCVD using TEOS which is post-deposition annealed in nitric oxide ambient is advantageous for trench-gate MOSFET due to its effectiveness for improving the interface quality and oxide reliability, whereas pre-deposition interfacial oxidation is deleterious to interface state density and breakdown strength.
Wafer-Level near Zero Field Spin Dependent Charge Pumping: Effects of Nitrogen on 4H-SiC MOSFETs
Authors: Anders Mark A. , Lenahan Patrick M. , Ryan Jason T.
Published: July 2020

In this work, we describe a new way to measure spin dependent charge capture events at MOSFET interfaces called near-zero-field spin dependent charge pumping (NZF SDCP) which yields similar information as conventional electron paramagnetic resonance. We find that NO anneals have a significant effect on the spectra obtained from 4H-SiC MOSFETs. We also likely resolve hyperfine interactions which are important for defect identification. Finally, we fully integrate a NZF SDCP measurement system into a wafer prober for high throughput applications.
Low-Energy Muons as a Tool for a Depth-Resolved Analysis of the SiO2/4H-SiC Interface
Authors: Woerle Judith , Prokscha Thomas , Grossner Ulrike
Published: July 2020

In this work, the potential of muon spin rotation (μSR) with low-energy muons (LE-μ) for the investigation of oxidation-induced defects at the SiO2/4H-SiC interface is explored. By using implantation energies for the muons in the keV range and comparing the fractions of muonium in different regions, the depth distribution of defects in the first 200 nm of the target material can be resolved. Defect profiles of interfaces with either deposited or thermally grown SiO2 layers on 4H-SiC are compared. The results show an increased number of defects in the case of a thermal oxide, both on the oxide and on the SiC side of the interface, with a spatial extension of a few tens of nm.
Monitoring on Creation and Annihilation of Interface Trap Levels with NO Oxidation, Re-Oxidation and N2 Annealing with Conductance Measurements
Authors: Zhou Xiang , Hitchcock Collin W. , Dahal Rajendra P. , Pandey Gyanesh , Kupernik Jacob , Bhat I. , Chow T. Paul
Published: July 2020

We have determined, using the Conductance-Frequency (G-ω) Technique, the creation and annihilation process of the 3 interface trap levels (OX, OX’ and NI levels) previously reported [1-3] and their possible correlation to inversion electron trapping and mobilities. The measurements were carried out on various 4H-SiC Metal Oxide Semiconductor (MOS) capacitors that have been processed using several gate oxide processes [2,5,6]. Our analysis focus on the correlation of the interface trap levels on the process conditions so as to first understand and then control their formation.
Evaluation of Interface Traps Type, Energy Level and Density of SiC MOSFETs by Means of C-V Curves TCAD Simulations
Authors: Matacena Ilaria , Maresca Luca , Riccio Michele , Irace Andrea , Breglio Giovanni , Daliento Santolo
Published: July 2020

SiC MOSFETs are promising devices for many power applications. They are replacing Si devices due to the higher performance of SiC material. However, there are some technological issues still unsolved. One of the main problems is the high density of traps at the SiC/SiO2 interface. Traps distribution at such interface is complex and it affects the overall performance of the device. Traps influence both current-voltage and capacitance-voltage characteristics of a SiC MOSFET. The aim of this work is the study of interface traps effects on C-V and I-V curves for a 1200 V SiC MOSFET. The numerical study is adopted to explain the shape of experimental C-V curves of commercial devices.
Reliability Study of MOS Capacitors Fabricated on 3C-SiC/Si Substrates
Authors: Li Fan , Qiu Song , Jennings Mike , Mawby Philip  Andrew
Published: July 2020

3C-SiC technology has advanced a lot in the last decade and the interests in making 3C-SiC power devices are growing again, in research and industry. Despite of that, there has been a lack of knowledge on the reliability of the 3C-SiC MOS structure. In this paper, we investigated the MOS capacitors fabricated on 3C-SiC/Si substrates at room temperature. From the simple I-V characterisation, an effective barrier height as high as 3.65-3.71 eV can be extracted for the fabricated 3C-SiC/SiO2 interface. Reliability test under elevated gate bias which lasts weeks demonstrates an acceptable failure rate (3450 PPM) for these state-of-the-art 3C-SiC MOS capacitors. The failure mechanism study suggests the intrinsic region is still not reached and there is still much room to improve the reliability. Minimising some obvious extrinsic defects which lead to early breakdown alone can reduce the failure rate by 100 times.
3× 1018 - 1 × 1019 cm -3 Al+ Ion Implanted 4H-SiC: Annealing Time Effect
Authors: Nipoti Roberta , Parisini Antonella , Boldrini Virginia , Vantaggio Salvatore , Canino Maria , Sanmartin Michele , Alfieri Giovanni
Published: July 2020

This work takes into account low Al implanted concentrations of 3 x 1018 cm-3 and 1 x 1019 cm-3 to compare the results of 1600°C and 1950°C post-implantation annealing treatments, done with two different annealing times per given implanted Al concentration and post implantation annealing temperature. Current-voltage and Hall effect measurements were performed to have the drift hole density and the drift hole mobility curves in the temperature range 100 - 650 K. The fitting of these curves in the frame of a carrier transport into the extended states of the valence band were performed to estimate the Al acceptor density, the donor compensator density, and the Al acceptor ionization energy. Peculiar feature of hole density and hole mobility curves is a contemporaneous increase of both carrier density and mobility values with increasing annealing time, which is congruent with the output parameters of the fitting procedure. The latter shows an almost stable Al electrical activation and a decrease of compensation with increasing annealing time for constant annealing temperature and given implanted Al concentration.
Development of SiC Etching by Chlorine Fluoride Gas
Authors: Takahashi Yoshinao , Kato Korehito , Habuka Hitoshi
Published: July 2020

Amorphous SiC and 4H-SiC were etched by chlorine fluoride (ClF), chlorine trifluoride (ClF3), fluorine (F2) and chlorine (Cl2) gases, in order to evaluate the etching capability of various reactive gases. The gaseous byproducts of SiC etching were observed by the quadrupole mass spectrometry. The ClF showed slow etching rate of amorphous SiC and 4H-SiC, while ClF3 and F2 quickly etched them. By the ClF gas, the etching rate of amorphous SiC was 120 nm/min at 400 °C. The ClF gas was expected to be suitable for a shallow etching, because of its moderate etching rate even at high temperatures.
Improvement of Repeatability on N-Type 4H-SiC Epitaxial Growth by High Speed Wafer Rotation Vertical CVD Tool
Authors: Daigo Yoshiaki , Ishiguro Akio , Ishii Shigeaki , Kobayashi Takehiko , Moriyama Yoshikazu
Published: July 2020

N-type 4H-SiC homo-epitaxial films were grown on 150 mm diameter wafers by high speed wafer rotation vertical CVD tool, and effect of surface C/Si ratio on short-term and long-term repeatability of the SiC films was investigated. By tuning of growth condition, high uniform SiC film with in-wafer thickness uniformity of ±2.8 % (1.6 % σ/mean) and carrier concentration uniformity of ±3.1 % (1.9 % σ/mean) was successfully grown at higher introduced C/Si ratio of about 1.80, which corresponds to surface C/Si ratio higher than 1.0 on the whole wafer. This result was comparable to the film grown at lower introduced C/Si ratio of about 1.35, which corresponds to surface C/Si ratio lower than 1.0 on the whole wafer. On the other hand, the films on 13 wafers successively grown at higher introduced C/Si ratio indicated low fluctuation from 1.85 to 3.09 % (σ/mean), and the short-term repeatability of the in-wafer carrier concentration uniformity of the films grown at higher introduced C/Si ratio was improved compared with the films grown at lower introduced C/Si ratio. Additionally, in-wafer carrier concentration uniformity of the films on 171 wafers grown at higher introduced C/Si ratio showed 75 % quartile of 4.26 % (σ/mean), and this result was greatly superior to that of 8.21 % (σ/mean) for the films on 130 wafers grown at lower introduced C/Si ratio.
Commercialization of Highly Rugged 4H-SiC 3300 V Schottky Diodes and Power MOSFETs
Authors: Gendron-Hansen Amaury , Hong Changsoo , Jiang Yi Fan , May John , Sdrulla Dumitru , Odekirk Bruce , Kashyap Avinash S.
Published: July 2020

In this paper, we present a new family of 3300 V silicon carbide (SiC) Schottky barrier diodes (SBDs) and power MOSFETs. The main design requirements are discussed with an emphasis on the design rules to improve the long-term reliability. Basic static and dynamic performance demonstrates low conduction and switching losses. Long-term tests such as high-temperature reverse bias (HTRB) and body diode forward bias stress were performed to evaluate the devices’ reliability. An emission microscopy (EMMI) study was conducted to assess the quality of the gate oxide. Outstanding surge and avalanche capabilities are reported with UIS ruggedness of 11.4 and 20.8 J.cm-2 for SBDs and MOSFETs, respectively.
Achievement of Low Carrier Concentration of High-Uniformity SiC Films Grown by High Speed Wafer Rotation Vertical CVD Tool
Authors: Daigo Yoshiaki , Ishiguro Akio , Ishii Shigeaki , Kobayashi Takehiko , Moriyama Yoshikazu
Published: July 2020

N-type 4H-SiC homo-epitaxial films were grown by high speed wafer rotation vertical CVD tool, and effect of surface C/Si ratios on in-wafer uniformity and lower limit of carrier concentration of the SiC films on 150 mm diameter wafers was investigated. From analysis of in-wafer distribution by mapping of whole wafers, it was found that high in-wafer thickness uniformity was obtained for the films grown both at lower introduced C/Si ratio of about 1.35, which corresponds to surface C/Si ratio is lower than 1.0, and at higher introduced C/Si ratio of about 1.80, which corresponds to surface C/Si ratio is higher than 1.0. However, larger fluctuation of the carrier concentration at wafer edge was observed for the film grown at lower introduced C/Si ratio, compared with the film grown at higher introduced C/Si ratio. Lower fluctuation of the carrier concentration for the film grown at higher introduced C/Si ratio is thought to be due to lower sensitivity of carrier concentration on growth temperature, which is observed for the film grown at surface C/Si ratio higher than 1.0. Also, the film grown at higher introduced C/Si ratio showed longer carrier lifetime with higher uniformity, although the film grown at lower introduced C/Si ratio indicated shorter carrier lifetime with lower uniformity. The mean carrier concentration of the films grown at higher introduced C/Si ratio was reduced by two digits compared with those grown at lower introduced C/Si ratio, and low carrier concentration of 1.7 x 1014 cm-3 with high in-wafer uniformity for intentionally doped SiC film grown at higher introduced C/Si ratio was achieved. Based on the results mentioned above, fabrication of thick and low-doped epi layer on 150 mm diameter wafer with high in-wafer uniformity was demonstrated.
SiC MOSFET with a Self-Aligned Channel Defined by Shallow Source-JFET Implantation: A Simulation Study
Authors: Sledziewski Tomasz , Erlbacher Tobias
Published: July 2020

A new concept for SiC MOSFET with a self-aligned channel is presented. The channel is defined by shallow source-JFET implantation into a counter-doped layer. This concept is verified by TCAD device simulations. It is shown that the method is applicable to fabrication of functional devices. The most critical parameter of the process is misalignment between channel and p-shield. Almost no change of electrical current in forward conduction state and the leakage current and electric field in the gate oxide in blocking state is observed for the misalignments below 400 nm.
20 kV-Class Ultra-High Voltage 4H-SiC n-IE-IGBTs
Authors: Koyama Akihiro , Kiuchi Yuji , Mizushima Tomonori , Takenaka Kensuke , Matsunaga Shinichiro , Sometani Mitsuru , Nakayama Koji , Ishimori Hitoshi , Kimoto Atsuko , Takei Manabu , Kato Tomohisa , Yonezawa Yoshiyuki , Okumura Hajime
Published: July 2020

We demonstrate 20 kV-class 4H-SiC n-channel implantation and epitaxial (IE)-IGBTs having both low on-state voltage and high blocking characteristics. We fabricated n-IE-IGBTs on a (0001) silicon face with free-standing epitaxial layers. Effective carrier lifetime increased significantly from 0.9 μs to 9.6 μs by a lifetime enhancement process. We used the IE structure to suppress an increase of the surface p+-well concentration, reduce implantation damage at the p+-well, and reduce junction field effect transistor (JFET) region resistance by ion implantation as a counter doping. The n-IE-IGBT at 100 A/cm2 on-state voltage and specific differential on-resistance was 8.2 V and 36.9 mΩcm2, respectively, at room temperature with a 30 V gate voltage. The blocking voltage was 26.8 kV at 45.7 μA.
Origin of Large Bumps Abnormally Grown on 4H-SiC Epitaxial Film by Adding HCl Gas with High Cl/Si Ratio in CVD Process
Authors: Daigo Yoshiaki , Ishiguro Akio
Published: July 2020

4H-SiC homo-epitaxial film was grown by adding HCl gas with a high Cl/Si ratio in CVD process, and defect formation and origin of the defect were investigated by confocal differential interference contrast (CDIC) microscope, PL imaging and normal differential interference contrast (DIC) microscope. It was found that a large number of large bumps are formed on the film grown at a high Cl/Si ratio of 30, and a large number of PL defects on bare substrate before the film growth are also observed. Coordinates where the bumps on the film are observed were good agreement with those where the PL defects on the bare substrate are observed. An etch pit sample on reproduced substrate from which epitaxial film was removed was fabricated by etching process using molten KOH+Na2O2, and some types of etch pits which might be originated from threading edge dislocations (TEDs), threading screw dislocations (TSDs) and basal plane dislocations (BPDs) in the substrate were observed. The coordinates where the etch pits on the reproduced substrate are observed were also good agreement with those where the bumps on the epitaxial film are observed. Therefore, it was clarified that a large number of the bumps abnormally grown on the epitaxial film are originated from the dislocations in the substrate.
Static and Switching Characteristics of 10 kV-Class Silicon Carbide Bipolar Junction Transistors and Darlingtons
Authors: Asllani Besar , Bevilacqua Pascal , Morel Hervé , Planson Dominique , Phung Luong Viet , Choucoutou Beverley , Lagier Thomas , Mermet-Guyennet Michel
Published: July 2020

This paper reports the device design, fabrication and characterisation of 10 kV-class Bipolar Junction Transistor (BJT). Manufactured devices have been packaged in single BJT, two paralleled BJTs and Darlington configurations. The static and switching characteristics of the resulting devices have been measured. The BJTs (2.4mm² active area) show a specific on-resistance as low as 198 mΩ·cm² at 100 A/cm² and room temperature for a βMax of 9.6, whereas the same active area Darlington beats the unipolar limit with a specific on-resistance of 102 mΩ·cm² at 200 A/cm² (β=11) for a βMax of 69. Double pulse tests reveal state of the art switching with very sharp dV/dt and di/dt. Turn-on is operated at less than 100 ns for an EON lower than 4mJ, whereas the turn-off takes longer times due to tail current resulting in EOFF of 17.2 mJ and 50 mJ for the single BJT and Darlington respectively when operated at high current density. Excellent parallelisation have been achieved.
A Subcircuit SPICE Model for SiC Charge-Balance Schottky Diodes
Authors: Hitchcock Collin W. , Zhou Xiang , Pandey Gyanesh , Ghandi Reza , Bolotnikov Alexander , Chow T. Paul
Published: July 2020

The electrical behavior of silicon carbide charge-balance (CB) Schottky/JBS diodes is examined. Based on the observed electrical characteristics, a subcircuit SPICE model for the experimental devices is proposed and validated against the data. The proposed model consists of a standard SPICE diode with custom parameters along with a network of discrete resistive and reactive subcircuit elements required to replicate the complex static and dynamic behavior of the experimental devices. With proper selection of component values, static, dynamic, and temperature-dependent device behavior are well modelled from room temperature to 150°C.
Analysis of Barrier Inhomogeneities of P-Type Al/4H-SiC Schottky Barrier Diodes
Authors: Ziko Mehadi Hasan , Koel Ants , Rang Toomas , Toompuu Jana
Published: July 2020

The diffusion welding (DW), known as direct bonding technique could be more used as an alternative approach to develop silicon carbide (SiC) Schottky rectifiers to existing mainstream metallization contact technologies. Measured results for p-type 4H-SiC Schottky barrier diodes (SBD) arepresented. And comprehensive numerical study to characterize the device has been performed. The simulations are carried out with ATLAS software (Silvaco). The measured and numerically simulated forward current-voltage (I–V) and capacitance-voltage (C–V) characteristics in a large temperaturerange are analyzed. Some of the measured p-type 4H-SiC Schottky diodes show deviation in specific ranges of their electrical characteristics. This deviation, especially due to excess current, dominates at low voltages (less than 1 V) and temperatures (less than room temperature). To verify the existence of electrically active defects under the Schottky contact, which influences the Schottky barrier height (SBH) and its inhomogeneity, the deep level transient spectroscopy (DLTS) technology was applied. DLTS measurements show the presence of a deep-level defect with activation energy corresponding typically for multilevel trap clusters.
Stress Test of Cascode Switch Using SiC Static Induction Transistor
Authors: Matsumoto Takashi , Tanaka Yasunori , Yano Koji
Published: July 2020

Stress tests were conducted for the cascode switch using the SiC buried gate static induction transistor (SiC-BGSIT). The stress of the reverse overshoot voltage was periodically applied to the pn junction between the gate terminal and source one in the BGSIT in the cascode with pulses of 40kHz for 202 hours. This simulates the stress which can be occurred in the channel region of the BGSIT during the turn-off and turn-on operation with a parasitic inductance in the interconnection of the cascode package. The result of the stress tests has revealed that there is no significant difference between the electrical characteristics of the BGSIT cascode sample before the stress and those after the stress. Thus, the BGSIT cascode can guarantee high reliability against the stress. The result from the drain current DLTS suggests that no deferent kind of defect is created in the channel region of the BGSIT by the stress.
Diminution in sperm quantity and quality in mouse models of Duchenne Muscular Dystrophy induced by a myostatin-based muscle growth-promoting intervention
Authors: Vaughan Danielle , Kretz Oliver , Alqallaf Ali , Mitchell Robert , Von der Heide Jennie L. , Vaiyapuri Sakthivel , Matsakas Antonios , Pasternack Arja , Collins-Hooper Henry , Ritvos Olli , Ballesteros Randy , Huber Tobias B. , Amthor Helge , Mukherjee Abir , Patel Ketan
Published: July 2020

Duchenne Muscular Dystrophy is a devastating disease caused by the absence of a functional rod-shaped cytoplasmic protein called dystrophin. Several avenues are being developed aimed to restore dystrophin expression in boys affected by this X-linked disease. However, its complete cure is likely to need combinational approaches which may include regimes aimed at restoring muscle mass. Augmenting muscle growth through the manipulation of the Myostatin/Activin signalling axis has received much attention. However, we have recently shown that while manipulation of this axis in wild type mice using the sActRIIB ligand trap indeed results in muscle growth, it also had a detrimental impact on the testis. Here we examined the impact of administering a powerful Myostatin/Activin antagonist in two mouse models of Duchenne Muscular Dystrophy. We report that whilst the impact on muscle growth was not always positive, both models showed attenuated testis development. Sperm number, motility and ultrastructure were significantly affected by the sActRIIB treatment. Our report suggests that interventions based on Myostatin/Activin should investigate off-target effects on tissues as well as muscle.
Percentile values of the standing broad jump in children and adolescence aged 6-18 years old
Authors: Thomas Ewan , Petrigna Luca , Tabacchi Garden , Teixeira Eduardo , Pajaujiene Simona , Sturm David J. , Sahin Fatma Nese , Gómez-López Manuel , Pausic Jelena , Paoli Antonio , Alesi Marianna , Bianco Antonino
Published: July 2020

The standing broad jump (SBJ) is a valid, reliable and feasible field-based test, which can evaluate explosive strength of the lower limbs and physical fitness. This study aimed to provide normative data for the SBJ for male and female children and adolescents and describe differences in performance between age groups and genders. A total number of 2140 children and adolescents, sampled in seven European nations have been included for analysis. The SBJ was performed to derive percentile values for gender and each age group. In general, males have greater jumping performance compared to females. Data demonstrate a linear increase in the jumping distance for both males and females until adolescence. However, such increase is evident in males up to 16-17 years old, whereas in females a plateau value is met at 12-13 years old, with a subsequent decrease in the jumping performance. No differences were present in jumping performance between male and female children, however differences between male and female adolescents were evinced. The study has provided percentile values useful to monitor the physical fitness status of children and adolescents.
A case report on expanding horizon of endobronchial ultrasound through esophagus
Authors: Tamburrini Mario , Thakare Parikshit , Zampieri Francesca , Scarda Angelo , Di Paolo Alessandra , De Leo Giancarlo , Gianfagna Enrico , Vietri Lucia , Zuccon Umberto
Published: July 2020

Endobronchial ultrasound has revolutionized the field of bronchoscopy and has become one of the most important tools for the diagnosis of intrathoracic lymphadenopathy and para-bronchial structures. The reach of this technique has not been limited to these structures and pleural lesions have been at times accessible. To our knowledge, pleural fluid collections have not been accessed with endobronchial ultrasound (EBUS) through oesophageal approach and rationale behind using this approach. We report a case of 70 years old man who has been referred from physician for the EBUS in view of hilar mass with mediastinal lymphadenopathy with pleural effusion. The endobronchial ultrasound through oesophagus (EUS-B) was done for thoracocentesis and lymph node cytology evaluation and ultimately endobronchial biopsy of hilar mass was done as rapid on-site (ROSE) analysis of lymph node was suggestive of necrotic tissue. The cytology report of lymph node and pleural effusion was positive for malignant cells. The final diagnosis was metastatic poorly differentiating adeno-squamous carcinoma.
Severe acute respiratory syndrome coronavirus-2 and pulmonary tuberculosis: convergence can be fatal
Authors: Singh Abhijeet , Prasad Rajendra , Gupta Ayush , Das Kamanasish , Gupta Nikhil
Published: July 2020

Disease associated with SARS-CoV-2 also termed as Coronavirus disease 2019 or COVID-19, has become a potential threat to public health by spreading across more than 200 countries worldwide within a short span of time. Tuberculosis (TB) is already existing as unprecedented pandemic worldwide over several years. Both diseases have many overlapping features but there are striking differences too. There is usually chronicity of symptoms in TB as compared to acute or rapid progression in COVID-19. Little evidence exists regarding TB and COVID-19 coinfection. It is anticipated that person with TB either in active, previously treated or latent forms are more at risk of poor outcomes with COVID-19. The relationship between the two diseases is still unclear at present, and more studies are needed to enable analyses of interactions and determinants of outcomes in patients affected by both the diseases. Most of the countries across the world imposed nationwide lockdown to promote social distancing, which is one important preventive measure to mitigate the spread of COVID-19 pandemic. However, it becomes quite challenging to ensure smooth functioning of programmatic services, leading to disruption of routine TB care, leading to transmission of infection. Health authorities should frame polices that can support TB patients by providing diagnostic, management and prevention services without any interruption during this era of ongoing COVID-19 pandemic. Effort should be made to control both the diseases simultaneously and avoid unfavourable outcome in near future.
Early trends of socio-economic and health indicators influencing case fatality rate of COVID-19 pandemic
Authors: Asfahan Shahir , Shahul Aneesa , Chawla Gopal , Dutt Naveen , Niwas Ram , Gupta Neeraj
Published: July 2020

Coronavirus disease 2019, i.e. COVID-19, started as an outbreak in a district of China and has engulfed the world in a matter of 3 months. It is posing a serious health and economic challenge worldwide. However, case fatality rates (CFRs) have varied amongst various countries ranging from 0 to 8.91%. We have evaluated the effect of selected socio-economic and health indicators to explain this variation in CFR. Countries reporting a minimum of 50 cases as on 14th March 2020, were selected for this analysis. Data about the socio-economic indicators of each country was accessed from the World bank database and data about the health indicators were accessed from the World Health Organisation (WHO) database. Various socioeconomic indicators and health indicators were selected for this analysis. After selecting from univariate analysis, the indicators with the maximum correlation were used to build a model using multiple variable linear regression with a forward selection of variables and using adjusted R-squared score as the metric. We found univariate regression results were significant for GDP (Gross Domestic Product) per capita, POD 30/70 (Probability Of Dying Between Age 30 And Exact Age 70 From Any of Cardiovascular Disease, Cancer, Diabetes or Chronic Respiratory Disease), HCI (Human Capital Index), GNI(Gross National Income) per capita, life expectancy, medical doctors per 10000 population, as these parameters negatively corelated with CFR (rho = -0.48 to -0.38 , p<0.05). Case fatality rate was regressed using ordinary least squares (OLS) against the socio-economic and health indicators. The indicators in the final model were GDP per capita, POD 30/70, HCI, life expectancy, medical doctors per 10,000, median age, current health expenditure per capita, number of confirmed cases and population in millions. The adjusted R-squared score was 0.306. Developing countries with a poor economy are especially vulnerable in terms of COVID-19 mortality and underscore the need to have a global policy to deal with this on-going pandemic. These trends largely confirm that the toll from COVID-19 will be worse in countries ill-equipped to deal with it. These analyses of epidemiological data are need of time as apart from increasing situational awareness, it guides us in taking informed interventions and helps policy-making to tackle this pandemic.
Severe bullous systemic lupus erythematosus successfully treated with low dose rituximab: a case report from sub-Saharan Africa
Authors: Akpabio A.A. , Otike-Odibi B.I.
Published: July 2020

Bullous systemic lupus erythematosus (BSLE) is a blistering skin condition occurring in lupus patients. Although cutaneous manifestations are common in lupus (59-85%), BSLE is rare, affecting <5% of lupus patients with very few reported cases among Africans. Dapsone is effective in mild to moderate cases, but off-label standard-dose rituximab (1,000 mg 2 weeks apart) has led to good outcomes in refractory cases. We report the case of a 39-yearold African lady with BSLE, who was successfully treated with low-dose rituximab (500 mg 2 weeks apart), healing her skin lesions at one year post-treatment. Low-dose rituximab may be as effective as standard dosing for the treatment of severe bullous SLE and is recommended in low resource settings.
The clinical manifestations at the onset of antisynthetase syndrome: A chameleon with multiple faces
Authors: Baccaro A.C.C.D. , Behrens Pinto G.L. , Carboni R.C.S. , Shinjo S.K.
Published: July 2020

The antisynthetase syndrome (ASS) is clinically characterized by fever, myositis, interstitial lung disease, joint involvement, mechanic’s hands, or Raynaud’s phenomenon, and the presence of antisynthetase autoantibodies. These clinical manifestations may not occur simultaneously. Therefore, the aim of this study was to analyze the sequence in which these clinical manifestations can develop at the onset of ASS. This retrospective, single-center cohort study enrolled 55 ASS patients. Their mean age at the onset of ASS symptoms was 42.3±11.8 years. There was a predominance of female patients (75.9%) and white patients (72.7%). At initial presentation, 41.8% of the patients had fever, 43.6% had joint symptoms, 38.2% had myositis, 36.4% had interstitial lung disease, 18.2% had Raynaud’s phenomenon, and 16.4% had mechanic’s hands. Subsequent clinical symptoms emerged at varying time points. In two out of 55 cases, joint, muscle, and lung manifestations developed simultaneously. The median time between the onset of symptoms and the complete ASS clinical manifestation was 19.9 (4.0-60.2) months; whereas, the timeframe between the onset of symptoms and the ASS diagnosis was 29.0 (11.0-63.0) months. The confounding misdiagnoses interfering with the initial diagnosis were polymyositis (52.7%), dermatomyositis (29.1%), nonspecific interstitial pneumopathy (23.6%), rheumatoid arthritis (18.2%), and others (10.9%). Clinical features at the onset of ASS are highly variable. Consequently, confounding factors can lead to significant delays for the final and definitive diagnosis of ASS. Therefore, ASS should be considered a differential diagnosis in patients with initial symptoms of joint, lung, and/or muscle involvements, as well as fever, mechanic’s hands, and/or Raynaud’s phenomenon manifestations.
Biaxial tests of some overcored samples from AECL's underground research laboratory, Lac du Bonnet, Manitoba
Authors: Lau J S O
Published: July 2020

In support of Atomic Energy of Canada Limited's in situ stress measurement program at the Underground Research Laboratory, biaxial tests and biaxial tests with axial load were conducted at the Canada Centre for Mineral and Energy Technology (CANMET) to examine
the effect of axial and side loads on the strains measured on the inside and on the outside of overcored rock samples obtained in the URL and the elastic constants derived from them. The rock is a massive, grey, medium to coarse grained porphyritic granite. With axial loading, cell pressures as high
as 36 MPa could be applied on the overcored specimens without causing disking. Without axial loading, a cell pressure as low as 13 MPa could cause disking. There were fairly good agreements between the secant Young's modulus values obtained on the outside and on the inside of the hollow rock
specimens in both the biaxial tests and the biaxial tests with axial load. The secant Young's modulus values in the axial direction were found to be approximately 10 GPa higher than the modulus values in the circumferential direction, indicating that the rock specimens were highly anisotropic and
the anisotropy was probably caused by the microcracks present in the specimens. The secant Young's modulus values obtained in the biaxial tests with axial load at pressure levels above 28 MPa were very high. Selected uniaxial compression tests should be conducted on the overcored specimens to check
the effect of end constraint on the modulus values as well as to shed some light on the discrepancies in some of the axial strain readings.
Interpreted seismic reflection profiles, sediment thickness and bedrock topography in Lake Erie, Ontario, Canada and Michigan, Ohio, Pennsylvania and New York, U.S.A.
Authors: Morgan N A , Todd B J , Lewis C F
M
Published: July 2020

In 1964, interpreted seismic reflection profiles, a sediment isopach map, and a map of depth to bedrock in Lake Erie were included in the unpublished Ph.D. thesis of Dr. Nabil Assad Morgan of the Department of Physics at the University of Toronto. These
interpretations and compilations have never been published in the scientific literature. Ongoing research in the Great Lakes by geoscientists within the Geological Survey of Canada, and their colleagues in Canada and the Unites States, means that it is now essential to revive Dr. Morgan's work and
release it in an Open File for general access.
Clinical outcomes of microdissection testicular sperm extraction-intracytoplasmic sperm injection with fresh or cryopreserved sperm in patients with nonobstructive azoospermia
Authors: Zhang Hong-Liang , Mao Jia-Ming , Liu De-Feng , Zhao Lian-Ming , Tang Wen-Hao , Hong Kai , Zhang Li , Lian Ying , Lin Hao-Cheng , Jiang Hui
Published: July 2020

We performed this study to evaluate the clinical outcomes of microdissection testicular sperm extraction-intracytoplasmic sperm injection (micro-TESE-ICSI) treatment that used fresh or cryopreserved sperm in patients with nonobstructive azoospermia (NOA). A total of 338 NOA patients with 344 consecutive cycles received treatment in the reproductive medicine center of Peking University Third Hospital in Beijing, China, from January 2014 to December 2017. Fresh oocytes and fresh sperm were used in 222 patients with 234 cycles (Group A). Fresh oocytes and cryopreserved sperm were used in 116 patients with 110 cycles (Group B). We compared patient characteristics, embryonic development, and pregnancy outcomes between Groups A and B. There was no statistical difference in the patient characteristics, and no differences were observed with fertilization or quality embryo rates between Groups A and B. The rates of clinical pregnancy and live birth were both higher for Group A than those for Group B (both P < 0.05). In conclusion, fresh testicular sperm appears to produce better ICSI outcomes than cryopreserved testicular sperm in patients with NOA.
A novel screening strategy for clinically significant prostate cancer in elderly men over 75 years of age
Authors: Iwamoto Hiroaki , Izumi Kouji , Kadomoto Suguru , Makino Tomoyuki , Naito Renato , Yaegashi Hiroshi , Shigehara Kazuyoshi , Kadono Yoshifumi , Mizokami Atsushi
Published: July 2020

A standard modality for prostate cancer detection in men 75 years and older has not been established. A simple screening method for elderly patients is needed to avoid unnecessary biopsies and to effectively diagnose prostate cancer. A retrospective study was conducted on elderly patients who had prostate biopsy at Kanazawa University Hospital (Kanazawa, Japan) between 2000 and 2017. Of the 2251 patients who underwent prostate biopsy, 254 had clinically significant prostate cancer (CSPC) with a Gleason score (GS) of ≥7 and 273 had a GS of <7 or no malignancy. In this study, patients aged 75 years or older were classified as elderly patients. GS ≥7 was characterized by a prostate-specific antigen (PSA) of the maximum area under the curve of 12 ng ml−1 with a sensitivity of 76.2% and a specificity of 73.2%. For PSA levels between 4 ng ml−1 and 12 ng ml−1, based on the maximum area under the curve, patients with three or four of the following factors may present a GS of ≥7: percent free PSA >24, PSA density ≥0.24 ng ml−2, positive findings on digital rectal examination, and transrectal with 90.0% sensitivity and 67.4% specificity. In this study, we found that raising the PSA cutoff to 12 ng ml−1 for CSPC in elderly individuals can significantly reduce unnecessary prostate biopsies. Furthermore, CSPC could be efficiently discovered by combining the four supplementary markers in patients with a PSA level of 4–12 ng ml−1. By performing this screening for elderly men over 75 years of age, unnecessary biopsies may be reduced and CSPC may be detected efficiently.
Human apoptosis antibody array-membranes studying the apoptotic effect of marine bacterial exopolysaccharides in HepG2 cells
Authors: Abdelnasser Salma M. , M. Yahya Shaymaa M. , Mohamed Wafaa F. , Gadallah Magdy A. , Abu Shady Hala M. , Mahmoud Manal G. , S. Asker Mohsen M.
Published: July 2020

Background:

Hepatocellular carcinoma (HCC) is considered as the third leading cause of cancer-related deaths, in spite of great advances in its treatment. The carbohydrate polymers, exopolysaccharides (EPSs), showed anticancer activity in diverse cancers.

Objective:

The purpose of this study is to investigate a panel of 43 apoptotic proteins to assess the possible apoptotic induction effect of bacterial EPSs showing promising cytotoxic effects in HepG2 cells in our previous study, in an attempt to introduce exopolysaccharides as new source for cancer treatment.

Materials and Methods:

Apoptosis-related proteins panel were examined through the analysis of Human Apoptosis Antibody Array-Membrane (43 targets).

Results:

EPS-6 induces apoptosis through upregulation of different pro-apoptotic proteins as cytochrome C (9.52 fold) and tumor necrosis factor-related apoptosis-inducing ligand receptor (TRAIL-R1) (153.49 fold). EPS-RS induces apoptosis through up regulation of second mitochondria-derived activator of caspases (SMAC) (15.75 fold) and the six insulin-like growth factors binding proteins (IGFBP-1 through – 6) (76.81 fold, 7.68 fold, 55.15 fold, 4.9 × 107 fold, 29.69 fold, and 28.92 fold), respectively.

Conclusion:

Our results suggested that EPS-6 and EPS-RS could be considered as promising agents in hepatocellular carcinoma treatment.
Structure of globally hyperbolic spacetimes-with-timelike-boundary
Authors: Aké Hau Luis , Flores Dorado José Luis , Sánchez Caja Miguel
Published: July 2020

Globally hyperbolic spacetimes-with-timelike-boundary

(\overline{M} = M \cup \partial M, g)

are the natural class of spacetimes where regular boundary conditions (eventually asymptotic, if

\partial M

is obtained by means of a conformal embedding) can be posed.

\partial M

represents the naked singularities and can be identified with a part of the intrinsic causal boundary. Apart from general properties of

\partial M

, the splitting of any globally hyperbolic

(\overline{M},g)

as an orthogonal product

\mathbb{R}\times \bar\Sigma

with Cauchy slices-with-boundary

\{t\}\times \bar\Sigma

is proved. This is obtained by constructing a Cauchy temporal function

\tau

with gradient

\nabla \tau

tangent to

\partial M

on the boundary. To construct such a

\tau

, results on stability of both global hyperbolicity and Cauchy temporal functions are obtained. Apart from having their own interest, these results allow us to circumvent technical difficulties introduced by

\partial M

. The techniques also show that

\overline{M}

is isometric to the closure of some open subset in a globally hyperbolic spacetime (without boundary). As a trivial consequence, the interior

M

both splits orthogonally and can be embedded isometrically in some

\mathbb{L}^N

, extending so properties of globally spacetimes without boundary to a class of causally continuous ones.
Toward a quasi-Möbius characterization of invertible homogeneous metric spaces
Authors: Freeman David , Le Donne Enrico
Published: July 2020

We study locally compact metric spaces that enjoy various forms of homogeneity with respect to Möbius self-homeomorphisms. We investigate connections between such homogeneity and the combination of isometric homogeneity with invertibility. In particular, we provide a new characterization of snowflakes of boundaries of rank-one symmetric spaces of non-compact type among locally compact and connected metric spaces. Furthermore, we investigate the metric implications of homogeneity with respect to uniformly strongly quasi-Möbius self-homeomorphisms, connecting such homogeneity with the combination of uniform bi-Lipschitz homogeneity and quasi-invertibility. In this context we characterize spaces containing a cut point and provide several metric properties of spaces containing no cut points. These results are motivated by a desire to characterize the snowflakes of boundaries of rank-one symmetric spaces up to bi-Lipschitz equivalence.
Diagnóstico e tratamento da síndrome do intestino irritável
Authors: Silva Matheus Taveira , Leite Fernanda Moema Mendes , Santiago Fernanda Vidal Pacheco , Albuquerque Ícaro Giovanni Sousa de , Brito Ana Paula Santos Oliveira , Garcia Hamilton Cezar Rocha
Published: July 2020

Objetivo: é realizar uma revisão sistemática da literatura afim de reunir os métodos diagnósticos e terapêuticos Síndrome do intestino irritável. Método: foi realizada uma revisão bibliográfica nas bases PubMed, Lilacs, Scielo, Google acadêmico, a partir do ano de 2015, com exceção de um artigo que foi publicado no ano de 2012 e foi usado como referência para uma farmacoterapia e outro de 2014 que abrangia da patogenia ao tratamento. Resultados: Na busca realizada em todas as bases de dados, foram encontrados cerca de 226 resultados com base nos descritores e, destes, foram selecionados 16 segundo os critérios de inclusão e 210 foram descartados para esta pesquisa, sendo divididos em 1 no Lilacs, 1 no Scielo, 8 no Pubmed e 6 do Google Acadêmico. Conclusão: o diagnóstico é prioritariamente clínico, de exclusão, levando em consideração todos os fatores de risco e sinais de alarme. Dessa forma, as condutas mais prevalentes são aquelas de orientações gerais para uma boa alimentação, atividade física e terapia farmacológica apenas para casos mais complicados, ambos com fortes evidências nas literaturas atuais.
Claudia da Silva Ferreira, Mulher Arrastada, Não!
Authors: Boaventura Júlio Cesar Salles , De Carvalho Aline Da Silva Azevedo
Published: July 2020

O presente artigo discute a circulação de discursos sobre o assassinato de Cláudia da Silva Ferreira, moradora do subúrbio de Madureira-RJ e seus efeitos performativos (BUTLER, 1997) em diferentes espaços-tempo. Pretendemos:  contextualizar o caso da "mulher arrastada” e explicitar a noção de linguagem; explorar os conceitos de biopolítica (FOUCAULT, 2008), soberania (FOUCAULT, 2008; AGAMBEN, 2004) e necropolítica (MBEMBE, 2011; 2014) na compreensão do genocídio da população negra no Rio de Janeiro; abordar a relação entre linguagem e violência e, a partir de um recorte de dados de uma pesquisa de doutorado em andamento, expor práticas discursivas de resistência em ambientes virtuais que buscam conferir reconhecimento a essa mulher sem nome, sem rosto e sem identidade.