Magnetotunneling Between Two-dimensional Electron Gases in InAs-AlSb-GaSb Heterostructures

We have observed that the tunneling magnetoconductance between two-dimensional (2D) electron gases formed at nominally identical InAs-AlSb interfaces most often exhibits two sets of Shubnikov-de Haas oscillations with almost the same frequency. This result is explained quantitatively with a model of the conductance in which the 2D gases have different densities and can tunnel between Landau levels with different quantum indices. When the epitaxial growth conditions of the interfaces are optimized, the zero-bias magnetoconductance shows a single set of oscillations, thus proving that the asymmetry between the two electron gases can be eliminated.Comment: RevTeX format including 4 figures; submit for publicatio

CASR (Calcium-Sensing Receptor)

Review on CASR, with data on DNA/RNA, on the protein encoded and where the gene is implicated

Worldwide research trends on the use of chemical-mechanical caries removal products over the years: a critical review

[EN] Background Chemical¿mechanical caries removal (CMCR) products are in constant evolution and were recommended during the COVID-19 pandemic as substitutes for conventional caries removal. Aim Characterize the worldwide scientifc literature about CMCR products, over the years, by means of a critical review. Design Electronic search was performed on Medline/PubMed, Scopus, Web of Science, Cochrane Library, Lilacs, and Embase up to November 2020. Year, journal, country of authors, and type of study were the data extracted from the retrieved studies. Additional data of the clinical studies and systematic reviews were investigated. Results 2221 records were identifed, 397 selected. 2011¿2020 period concentrates higher number of publications (n=169), in the Journal of Dental Research (n=51), developed in Brazil (n=45) and India (n=44). Most studies were in vitro (n=211) and clinical trials (n=101). Carisolv¿ (n=48) and Papacarie Duo Gel¿ (n=33) were the most used products, prescript in isolated usage (n=101), and compared with drills (n=77). CMCR were more studied in primary teeth (n=78), receiving glass ionomer cement (GIC) (n=51) as restorative material. The most evaluated outcomes were time spent (n=48) and pain (n=41). Clinical application of CMCR takes more time than other techniques, but can also reduce patient anxiety, pain, and need for anesthesia. Conclusion In vitro and clinical studies with CMCR products have been increasing, mostly carried out in developing countries, evaluating Carisolv¿ and Papacarie Duo Gel¿. Clinical studies tend to evaluate the time spent and pain compared to drills for removing caries in primary teeth, posteriorly restored with GIC. CMCR clinical application reduces anxiety, pain, and need for anesthesia, despite increase treatments¿ time.This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brazil (CAPES) -Finance code 001, and Fundacao Carlos Chagas de Amparo a Pesquisa no Estado do Rio de Janeiro (FAPERJ)-Finance code E-26/202.766/2019, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) -Finance code 401058/2016-6 -for the VantagePointT software. This study is part of the Master's thesis of the primary author.Souza, TF.; Martins, ML.; Magno, MB.; Vicente Gomila, JM.; Fonseca-Goncalves, A.; Maia, LC. (2022). Worldwide research trends on the use of chemical-mechanical caries removal products over the years: a critical review. European Archives of Paediatric Dentistry. 23(6):869-883. https://doi.org/10.1007/s40368-022-00726-686988323

BATTERY-POWERED DEVICE FOR MONITORING PHYSICAL DISTANCING THROUGH WIRELESS TECHNOLOGY

One method for preventing the spread of the coronavirus and other contagious diseases is through social distancing. Therefore, creating a tool to measure and quickly discover the precise distance is necessary. In order to prevent physical contact between individuals, this study aimed to detects individuals’ physical distance, through an inaugurated battery-powered device that monitors physical distance through wireless technology. Specifically, in public or crowded areas, to lessen the spread of the virus. This study focuses on detecting people’s physical distance in the region of interest utilizing an Ultrasonic and VL53L0X sensors and determining the significant difference between the two sensors in monitoring physical distance. This study employs an applied experimental research design. The efficiency of both sensors in measuring physical distance was evaluated through analysis. The Ultrasonic and VL53L0X sensors underwent 15 tests. Furthermore, the researchers effectuated a t-test to determine the significant difference between the two sensors. Data gathered revealed that the sensors’ combined mean in terms of measuring physical distance indicates that the ultrasonic sensor performed better than VL53L0X, measuring 134.7 cm, notwithstanding 99.8 cm for the VL53L0X sensor. Complementary to this, the results of the t-test show that the VL53L0X sensor and Ultrasonic sensor have a significant difference in terms of distance precision

Transient developmental imbalance of cortical interneuron subtypes presages long-term changes in behavior

Cortical GABAergic interneurons are generated in large numbers in the ganglionic eminences and migrate into the cerebral cortex during embryogenesis. At early postnatal stages, during neuronal circuit maturation, autonomous and activity-dependent mechanisms operate within the cortex to adjust cell numbers by eliminating naturally occurring neuron excess. Here, we show that when cortical interneurons are generated in aberrantly high numbers—due to a defect in precursor cell proliferation during embryogenesis—extra parvalbumin interneurons persist in the postnatal mouse cortex during critical periods of cortical network maturation. Even though cell numbers are subsequently normalized, behavioral abnormalities remain in adulthood. This suggests that timely clearance of excess cortical interneurons is critical for correct functional maturation of circuits that drive adult behavior

Transmission beam pattern and dynamics of a spinner dolphin (Stenella longirostris)

Author Posting. © Acoustical Society of America, 2019. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 145(6), (2019): 3595, doi:10.1121/1.5111347.Toothed whales possess a sophisticated biosonar system by which ultrasonic clicks are projected in a highly directional transmission beam. Beam directivity is an important biosonar characteristic that reduces acoustic clutter and increases the acoustic detection range. This study measured click characteristics and the transmission beam pattern from a small odontocete, the spinner dolphin (Stenella longirostis). A formerly stranded individual was rehabilitated and trained to station underwater in front of a 16-element hydrophone array. On-axis clicks showed a mean duration of 20.1 μs, with mean peak and centroid frequencies of 58 and 64 kHz [standard deviation (s.d.) ±30 and ±12 kHz], respectively. Clicks were projected in an oval, vertically compressed beam, with mean vertical and horizontal beamwidths of 14.5° (s.d. ± 3.9) and 16.3° (s.d. ± 4.6), respectively. Directivity indices ranged from 14.9 to 27.4 dB, with a mean of 21.7 dB, although this likely represents a broader beam than what is normally produced by wild individuals. A click subset with characteristics more similar to those described for wild individuals exhibited a mean directivity index of 23.3 dB. Although one of the broadest transmission beams described for a dolphin, it is similar to other small bodied odontocetes.The authors would like to thank the staff at Ocean Adventure for their time and assistance, Laura Kloepper for her assistance and advice on the data analysis, and Andy Solow for his help with the statistical analysis. The array system was originally designed by Stuart Ibsen. This work was funded by a research grant from the Sea World Busch Gardens Conservation Fund awarded to A.F.P. All work was conducted in compliance with University of Hawaii at Manoa IACUC and conducted under NMFS permit No. 16053 to P.E.N. This is contribution No. 1761 from the Hawaii Institute of Marine Biology.2019-12-1

Analysis of the Transport Process Providing Spin Injection through an Fe/AlGaAs Schottky Barrier

Electron spin polarizations of 32% are obtained in a GaAs quantum well via electrical injection through a reverse-biased Fe/AlGaAs Schottky contact. An analysis of the transport data using the Rowell criteria demonstrates that single step tunneling is the dominant transport mechanism. The current-voltage data show a clear zero-bias anomaly and phonon signatures corresponding to the GaAs-like and AlAs-like longitudinal-optical phonon modes of the AlGaAs barrier, providing further evidence for tunneling. These results provide experimental confirmation of several theoretical analyses indicating that tunneling enables significant spin injection from a metal into a semiconductor.Comment: 4 pages, 4 figures, submitted to AP

Influence of Nanoparticle Size and Shape on Oligomer Formation of an Amyloidogenic Peptide

Understanding the influence of macromolecular crowding and nanoparticles on the formation of in-register $\beta$-sheets, the primary structural component of amyloid fibrils, is a first step towards describing \emph{in vivo} protein aggregation and interactions between synthetic materials and proteins. Using all atom molecular simulations in implicit solvent we illustrate the effects of nanoparticle size, shape, and volume fraction on oligomer formation of an amyloidogenic peptide from the transthyretin protein. Surprisingly, we find that inert spherical crowding particles destabilize in-register $\beta$-sheets formed by dimers while stabilizing $\beta$-sheets comprised of trimers and tetramers. As the radius of the nanoparticle increases crowding effects decrease, implying smaller crowding particles have the largest influence on the earliest amyloid species. We explain these results using a theory based on the depletion effect. Finally, we show that spherocylindrical crowders destabilize the ordered $\beta$-sheet dimer to a greater extent than spherical crowders, which underscores the influence of nanoparticle shape on protein aggregation