Number Of Carriers Research Articles

Prevalence of BRCA1 and BRCA2 mutations in ovarian cancer patients from Yunnan Province in southwest China.

Carriers with germline breast cancer 1/2 gene mutations (BRCAm) are likely to develop ovarian cancer (OC). Therefore, identifying these mutations may enable individualized therapy for OC and preventive measures to reduce OC risk in BRCAm carrier families. Thus, we investigated the prevalence of BRCAm in OC patients from Yunnan Province in Southwest China. In total, 674 unselected OC patients were enrolled and tested for BRCAm via next-generation sequencing. Data on clinicopathological characteristics and personal/family history of cancer were collected. The prevalence rates of pathogenic/likely pathogenic BRCAm were 26.6% overall, 20.8% among BRCA1m carriers, 5.5% among BRCA2m carriers, and 0.3% among carriers of both BRCA1m and BRCA2m. The most common pathogenic mutation in the BRCA1 gene was c.5114T>C (n = 9). The number of BRCAm carriers was significantly greater among patients with serous cancer, a personal tumor history, a family history of hereditary breast and ovarian cancer (HBOC)-related tumors, and bilateral tumors. The most common pathogenic mutation in this cohort was c.5114T>C (n = 9) in BRCA1. The prevalence and spectrum of BRCAm in OC patients from Yunnan Province are different from those in other groups. BRCA status testing is advised for all OC patients, particularly those with a family history of HBOC.

TCAD-based investigation of 1/f noise in advanced 22 nm FDSOI MOSFETs

In this work, the mechanistic insights behind low-frequency noise (LFN) of the advanced ultrathin body and buried oxide fully depleted silicon-on-insulator based metal–oxide–semiconductor field effect transistor (MOSFET) are unveiled. The gate voltage-induced noise power spectral density (SVG) is inversely proportional to frequency f (i.e., SVG∝1/fγ, γ∼ 1 is the frequency exponent) for nMOSFET and pMOSFET. Detailed numerical simulations are performed and well calibrated to reported SVG vs f characteristics. Simulation results are consistent with the reported experimental observations. We demonstrate that LFN is caused by the charge carrier number fluctuation mechanism, which is originated by trapping and de-trapping of channel charge carriers via. bulk traps (from oxygen vacancies) in the hafnium dioxide (HfO2) layer, but not through traps at the silicon dioxide (SiO2)/channel interface. This work therefore explains the similar magnitude of SVG in both nMOSFET and pMOSFET observed experimentally and further suggests that oxygen vacancies inside gate oxides are critical to suppress the low-frequency noise in emerging high-k based MOSFETs.

Impact of quantum information encoding and metallic leads on dynamical multipartite correlation formation in semiconductor quantum dot arrays.

This study investigates quantum information scrambling (QIS) in a semiconductor quantum dot array. Starting with the 1D Transverse Field Ising model, we expand to more relevant quasi-2D frameworks such as the Heisenberg chain, super-extended Fermi-Hubbard and hardcore Fermi-Hubbard models. Assessing their relevance to semiconductor spin-qubit quantum computers, simulations of multipartite entanglement formation examine qubit encoding strategies' fidelity, stability, and robustness, revealing trade-offs among these aspects. Furthermore, we investigate the weakly coupled metallic injector/detector (I/D) leads' significant impact on QIS behavior by employing Ω lead N-single orbital impurities weakly coupled Anderson models. We observe sign flips in spatiotemporal tripartite mutual information I3 which result in significant effects on dynamical quantum entanglement structures and their formation. Exploring carrier number effects, we identify optimal regions for QIS enhancement. Our findings emphasize the necessity of proper qubit encoding and I/D lead influence on quantum devices amidst noise and impurities.

Distribution of Recessive Genetic Defect Carriers in Holstein Friesian Cattle: A Polish Perspective

Genetic disorders are caused by a hereditary change in the structure of DNA that may hurt the health and life of animals. Several recessive haplotypes and a few causative mutations are known in Holstein Friesian cattle: CDH (Holstein cholesterol deficiency), haplotypes with a homozygous deficiency in Holstein (HH1, HH3, HH4, HH5, HH6, HH7), BLAD (bovine leukocyte adhesion deficiency), DUMPS (deficiency of uridine monophosphate synthase), FXI (factor XI deficiency), HHM (mule foot, syndactyly), and BC (citrullinaemia). From a breeding point of view, these genetic diseases have highly negative effects and are a significant problem for breeders, exposing them to economic losses and hurting animal welfare. This study aimed to characterize the Polish population of Holstein Friesian dairy cattle, considering the carrier status of twelve selected genetic defects. This study was based on genotype data collected from 78,884 cows and 691 bulls of the Holstein Friesian variety. The studies were performed using Illumina Infinium microarrays. Among both bulls and cows, the highest numbers of carriers were detected for HH5 (appropriately 6.7% and 5.4%). The lowest numbers of carriers were detected for DUMPS, factor XI, and HHM. The study revealed one calf suffering from cholesterol deficiency.

1/f noise in semiconductors arising from the heterogeneous detrapping process of individual charge carriers

Abstract We propose a model of 1 / f noise in semiconductors based on the drift of individual charge carriers and their interaction with the trapping centers. We assume that the trapping centers are homogeneously distributed in the material. The trapping centers are assumed to be heterogeneous and have unique detrapping rates. We show that uniform detrapping rate distribution emerges as a natural consequence of the vacant trap depths following the Boltzmann distribution, and the detrapping process obeying Arrhenius law. When these laws apply, and if the trapping rate is low in comparison to the maximum detrapping rate, 1 / f noise in the form of Hooge’s relation is recovered. Hooge’s parameter, α H, is shown to be a ratio between the characteristic trapping rate and the maximum detrapping rate. The proposed model implies that 1 / f noise arises from the temporal charge carrier number fluctuations, not from the spatial mobility fluctuations.

The Excess of Carriers in Rare Disorders Suggests a Nonpathogenic Effect for Most Variants of Uncertain Significance.

Functional annotation and interpretation of genetic variants are a critical step in genetic diagnosis, as it may lead to personalized therapeutic options and genetic counseling. While the number of confirmed pathogenic genetic variants in an individual is relatively low, the number of variants of uncertain significance (VOUS) can be considerably higher, increasing the number of potential carriers of genetic disorders. Thus, reducing uncertainty and assessing the real effect of VOUS are crucial for clinical and medical genetics. In this study, we evaluated the efficacy of genetic screening technologies in accurately predicting pathogenic variants and their corresponding disease prevalence in a cohort of over 6000 healthy individuals involved in assisted reproduction programs. Using data from 305 genes associated with recessive disorders, we determined the frequency of carriers of pathogenic variants and VOUS in our dataset and compared the predicted prevalence based on this information with reported population prevalence data. The higher predicted prevalence in some disorders when considering VOUS suggests a mostly benign effect.

PALB2 analysis in the diagnostic process of breast cancer: An Italian monocentric experience.

The clinical utility of germline BRCA1 and BRCA2 testing is well established in patients with family history suggestive for hereditary breast and ovarian cancer syndrome. Recently, germline PALB2 pathogenic variants were also associated with an increased risk of breast and other cancers and, in the Italian population, it has been described in few studies without a systematic germline analysis of BRCA1, BRCA2 and PALB2. In this study, we described ASST Sette Laghi cancer genetic counselling services' experience in the analysis of 402 patients with suspected breast and ovarian cancer syndrome, by using BRCA1, BRCA2 and PALB2 germline genetic test. The frequency of PALB2 pathogenic variants was 1.2% compared to 3.5% and 3.2% for BRCA1 and BRCA2, respectively, whereas class 3 variants were detected in 0.3% and 0.5% of the BRCA1 and BRCA2 investigated patients, respectively. PALB2 pathogenic variants were identified in patients with a strong family history for breast cancer. Moreover, PALB2 variants were significantly associated with a younger age of breast cancer onset (mean age, 40.25 years) compared to wild-type patients (mean age 51.2 years, p-value = 0.0331). Similar to BRCA-associated breast cancer, the majority of PALB2 breast cancers were identified at an advanced clinical stage. Pedigree analysis revealed a family history of breast and ovarian cancer syndrome in all PALB2 pathogenic variants carriers (early breast cancer onset, bilateral breast cancer and ovarian cancer). In conclusion, the germline analysis of BRCA1, BRCA2 and PALB2 should be included in breast cancer clinical practice as a not negligible number of PALB2 carriers could be identified and referred to specific surveillance protocols.

Spatially resolved random telegraph fluctuations of a single trap at the Si/SiO2 interface

We use electrostatic force microscopy to spatially resolve random telegraph noise at the Si/SiO2 interface. Our measurements demonstrate that two-state fluctuations are localized at interfacial traps, with bias-dependent rates and amplitudes. These two-level systems lead to correlated carrier number and mobility fluctuations with a range of characteristic timescales; taken together as an ensemble, they give rise to a [Formula: see text] power spectral trend. Such individual defect fluctuations at the Si/SiO2 interface impair the performance and reliability of nanoscale semiconductor devices and will be a significant source of noise in semiconductor-based quantum sensors and computers. The fluctuations measured here are associated with a four-fold competition of rates, including slow two-state switching on the order of seconds and, in one state, fast switching on the order of nanoseconds which is associated with energy loss.

Understanding thickness-dependent stability of tungsten-doped indium oxide transistors

In this study, the influence of the thickness of the channel layer on the electrical properties and stability of tungsten-doped indium oxide (IWO) thin-film transistors (TFTs) was investigated. Although oxide-semiconductor TFTs, particularly indium gallium zinc oxide, are promising, problems related to oxygen vacancies have led to their instability. In contrast, IWO has proven to be a compelling alternative because of its robust resistance to oxygen vacancies. IWO TFTs with varying channel thicknesses (10, 20, and 30 nm) were fabricated, and the device parameters, such as threshold voltage (Vth), subthreshold swing (SS), field-effect mobility (μFE), and on/off current ratio (Ion/Ioff), were analyzed. It was found that as the channel thickness increased, Vth exhibited a negative shift and SS increased, indicating an increase in carrier concentration. This phenomenon is attributed to the bulk trap density, in particular to oxygen vacancies. Negative bias stress tests confirmed the influence of the oxygen vacancies, with thicker channels showing more pronounced shifts. Low-frequency noise measurements were consistent with the carrier number fluctuation model, indicating that defects within the channel region contribute to the observed noise. The study concludes that identifying an optimal channel thickness during device manufacturing is crucial for improved TFT performance, with 20 nm devices characterized by high μFE and comparable trap density to 10 nm. This study provides valuable insight into the nuanced relationship between the channel thickness, trap density, and electrical performance of IWO TFTs.

Tailoring Li+ Local Coordination Environment of Solid Polymer Electrolytes to Boom Ionic Conductivity.

The low ionic conductivity is the key issue of solid polymer electrolytes (SPEs), hampering their practical application. Great efforts have been devoted to reducing their crystallinity to increase ionic conductivity but ignored their Li+ local coordination environment influence. Here, Li+ local coordination environment tunable poly(vinylidene fluoride-co-hexafluoropropylene)-based solid-state electrolytes are experimentally realized via d-cellobiose octaacetate. d-cellobiose octaacetate competes with anions and polymer chains for coordination of Li+ thorough C═O groups to weaken their coordination of Li+, increase the number of carriers, and strengthen the transport kinetics of Li+, booming the ionic conductivity of SPEs at room temperature. When used in lithium metal symmetric batteries and full batteries, SPEs greatly improve their electrochemical performance at 25°C. This work clarifies the important influence of Li+ local coordination environment on Li+ transport and provides a promising strategy to improve the ionic conductivity of SPEs.

Interfacial capacitance in lithium disilicate glass: Experimental factors and charge carrier density

AbstractThe formation of an electric double‐layer (EDL) is an important phenomenon for many research areas, including energy storage technology. Although EDL is well‐known in electrochemistry, most of the studies involve the characterization of liquid electrolyte/electrode interfaces, and only a limited number of studies in solid‐solid contacts, such as solid electrolyte/electrode interface are available. This paper employed electrochemical impedance spectroscopy (EIS) to systematically investigate the influence of experimental factors in the interfacial capacitance arising from the electrode polarization in a lithium disilicate glass/gold electrode interface. It analyzed the influence of a.c. input voltage amplitude, samples' roughness (mechanical and chemomechanical polishing) and thickness, range of applied frequency and temperature, and the number of impedance cycles. In short, it was found that an input voltage range of 15–60 mV is indicated to minimize potential electrochemical processes during electrode polarization, where the data is reproducible from the second measurement cycle onward. Smoother surfaces closely approximated ideal electrode spike behavior, with surface treatment exhibiting influence on interfacial capacitance values. Moreover, as expected, we observed an increase in relative permittivity values with increasing thickness, accompanied by decreased capacitance values. Finally, by employing optimal experimental conditions and analyzing the inflection frequency () of the versus log() curve, we determined that the ratio between effective charge carriers () and the total number of charge carriers () falls within the range of 5–12% between 130°C and 280°C.

Ballistic Electron Source with Magnetically Controlled Valley Polarization in Bilayer Graphene.

The achievement of valley-polarized electron currents is a cornerstone for the realization of valleytronic devices. Here, we report on ballistic coherent transport experiments where two opposite quantum point contacts (QPCs) are defined by electrostatic gating in a bilayer graphene (BLG) channel. By steering the ballistic currents with an out-of-plane magnetic field we observe two current jets, a consequence of valley-dependent trigonal warping. Tuning the BLG carrier density and number of QPC modes (m) with a gate voltage we find that the two jets are present for m=1 and up to m=6, indicating the robustness of the effect. Semiclassical simulations confirm the origin of the signals by quantitatively reproducing the jet separations without fitting parameters. In addition, our model shows that the ballistic current jets have opposite valley polarization. As a consequence, by steering each jet toward the detector using a magnetic field, we achieve full control over the valley polarization of the collected currents, envisioning such devices as ballistic current sources with tunable valley polarization. We also show that collimation experiments are a sensitive probe to the trigonal warping of the Fermi surface.

Temperature dependence of the low-frequency noise in AlGaN/GaN fin field effect transistors

Low-frequency (LF) noise measurements are compared for Schottky-gate AlGaN/GaN heterostructure planar and fin field-effect transistors (FinFETs) as functions of gate voltage and measuring temperature. The noise of each device type is consistent with a carrier number fluctuation model. Similar effective defect-energy Eo distributions are derived for each of the two device architectures from measurements of excess drain-voltage noise-power spectral density vs temperature from 80 to 380 K. Defect- and/or impurity-related peaks are observed in the inferred energy distributions for Eo < 0.2 eV, Eo ≈ 0.45 eV, and Eo > 0.6 eV. Significant contributions to the LF noise are inferred for nitrogen vacancies and ON and FeGa impurity complexes. Ga dangling bonds at fin interfaces with gate metal are likely candidates for enhanced noise observed in FinFETs, relative to planar devices. Reducing the concentrations of these defects and impurity complexes should reduce the LF noise and enhance the performance, reliability, and radiation tolerance of GaN-based high electron mobility transistors.

Crystallite Size Effects on Electrical Properties of Nickel Chromite (NiCr2O4) Spinel Ceramics: A Study of Structural, Magnetic, and Dielectric Transitions

The effect of sintering temperature on the structural, magnetic, and dielectric properties of NiCr2O4 ceramics was investigated. A powder X-ray analysis indicates that the prepared nanocrystallites effectively inhibit the cooperative Jahn–Teller distortion, thereby stabilizing the high-temperature cubic phase structure with space group Fd-3m. Multiple transitions are confirmed by temperature-dependent magnetization M(T) data. Moreover, the magnetization value decreases and the Curie temperature increases with a decrease in the crystallite size. The low-temperature-dependent real permittivity (ε′-T) for a NiCr2O4 crystallite size of 78 nm exhibits a broad maximum at 40 K that is independent of frequency. This establishes a correlation between electric ordering and the underlying magnetic structure. The temperature dependency of the dielectric constant at fixed frequencies for both NiCr2O4 crystallite sizes rises with temperature for a certain range of frequencies. A significant improvement is evident: the dielectric constant (ε’) at room temperature reaches approximately 5738 for the sample with 28 nm crystallites, while the 78 nm crystallite sample shows a noticeable drop to ε’~174. The frequency-dependent conductivity curves for both types of NiCr2O4 nanocrystallites have different conductivity values. The lower-crystallite-size sample demonstrates higher conductivity values than the 78 nm crystallite size one. This observation is attributed to the decrease in crystallite size, which increases the number of grain boundaries and, consequently, scatters a higher number of charge carriers.

Modeling and characterization of low frequency noise in self-aligned top-gate coplanar IGZO thin-film transistors

Abstract A modified low-frequency noise (LFN) model was proposed to accurately estimate the quality of the gate dielectric in self-aligned top-gate (SA TG) coplanar structure indium–gallium–zinc oxide (IGZO) thin-film transistors (TFTs). The proposed LFN model was derived by modifying the conventional carrier number with correlated mobility fluctuation model considering the peculiar characteristics of SA TG coplanar IGZO TFTs such as the channel length reduction due to the diffusion of hydrogen atoms or oxygen vacancies from the source/drain to the channel, as well as the relatively large source/drain parasitic resistance. The proposed model was validated by demonstrating that the measured LFN values were in good agreement with the predicted values from the proposed model for all SA TG coplanar IGZO TFTs with SiO2 gate dielectrics deposited under different plasma-enhanced chemical vapor deposition (PECVD) power densities. The near-interface gate dielectric trap densities extracted from each TFT using the proposed LFN model revealed a clear increase as the PECVD power increased, which is considered a major cause of poor positive-bias-temperature-stress stability of the SA TG coplanar IGZO TFT with SiO2 gate dielectric deposited under high PECVD power conditions.

Viscous terahertz photoconductivity of hydrodynamic electrons in graphene.

Light incident upon materials can induce changes in their electrical conductivity, a phenomenon referred to as photoresistance. In semiconductors, the photoresistance is negative, as light-induced promotion of electrons across the bandgap enhances the number of charge carriers participating in transport. In superconductors and normal metals, the photoresistance is positive because of the destruction of the superconducting state and enhanced momentum-relaxing scattering, respectively. Here we report a qualitative deviation from the standard behaviour in doped metallic graphene. We show that Dirac electrons exposed to continuous-wave terahertz (THz) radiation can be thermally decoupled from the lattice, which activates hydrodynamic electron transport. In this regime, the resistance of graphene constrictions experiences a decrease caused by the THz-driven superballistic flow of correlated electrons. We analyse the dependencies of the negative photoresistance on the carrier density, and the radiation power, and show that our superballistic devices operate as sensitive phonon-cooled bolometers and can thus offer, in principle, a picosecond-scale response time. Beyond their fundamental implications, our findings underscore the practicality of electron hydrodynamics in designing ultra-fast THz sensors and electron thermometers.

Combinatorial Synthesis of Alkyl Chain-Capped Poly(β-Amino Ester)s for Effective siRNA Delivery.

Poly (β-amino ester) (PBAE) is a class of biodegradable polymers containing ester bonds in their main chain, extensively investigated as cationic polymer carriers for siRNA. Most current PBAE carriers rely on termination with hydrophilic or charged amines. In this study, a polymer platform consisting of 168 PBAE polymers with hydrophobic alkyl chain terminals is constructed through sequential aza-Michael addition. A large number of effective carriers are identified through in vitro screening of the PBAE platform for siLuc delivery to HeLa-Luc cells. Specifically, PA8-C6 and PA8-C8 achieve remarkable gene knockdown efficacies of up to 80% with low cytotoxicity. Certain materials from the PA2 and PA5 series demonstrate potent siRNA delivery capabilities associated with elevated cytotoxicity. The pKa value of PBAE is predominantly determined by the hydrophilic amine side chains rather than the end-capping groups. A pKa range of ≈6.2-6.5 may contribute to the excellent delivery capability for PA8 series carriers. The co-formulation of PBAE carriers with helper lipids leads to the reduced size and surface charges of the polyplex NPs with siRNA, consequently decreasing the cytotoxicity and enhancing siRNA delivery efficacy. These findings hold significant implications for the development of novel degradable polymer carriers for siRNA delivery.

Electrical Study of Changes in Impedance and Internal Parameters of Nano Structures of Molybdenum Disulfide Semiconductor Type (MoS2-2H/3R) with Changes in Temperature

MoS2 nanostructures were prepared using the hydrothermal method by reacting ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O244H2O) with citric acid monohydrate (C6H8O7H2O) in distilled water with the presence of sodium sulfide (Na2S), we have found from the Arenos diagram that the value of the activation energy of (MoS2 -2H/3R) is low and equal to Ea= 0.0505 (e.V). From the atomic force microscope (AFM) images, we found that the size of the surface aggregates of the sample (table - MoS2-2H/3R) ranges between (100-150) n m. From studying the changes in the impedance with different temperatures (T = 15, 30, and 60), we found that impedance is inversely proportional to both the applied frequency and the temperature, and at the frequencies the response corresponding to the temperature reaches a value of (Z = 20 K.Ω, T = 15°C). ) and at temperature (Z = 8.02 K.Ω, T = 30 °C), and at (Z = 17.1 K.Ω, T = 60 °C), It has been shown that the number of electric charge carriers (Nd) increases with increasing temperature. On the contrary, we found a decrease in the number of electronic traps (Ns) and a decrease in the relaxation time τP with increasing temperature.

Refined Analysis of the Correlated Carrier Number and Mobility Fluctuations Mechanism in MOSFETs

Refined Analysis of the Correlated Carrier Number and Mobility Fluctuations Mechanism in MOSFETs

Integration of variant annotations using deep set networks boosts rare variant association testing

Rare genetic variants can have strong effects on phenotypes, yet accounting for rare variants in genetic analyses is statistically challenging due to the limited number of allele carriers and the burden of multiple testing. While rich variant annotations promise to enable well-powered rare variant association tests, methods integrating variant annotations in a data-driven manner are lacking. Here we propose deep rare variant association testing (DeepRVAT), a model based on set neural networks that learns a trait-agnostic gene impairment score from rare variant annotations and phenotypes, enabling both gene discovery and trait prediction. On 34 quantitative and 63 binary traits, using whole-exome-sequencing data from UK Biobank, we find that DeepRVAT yields substantial gains in gene discoveries and improved detection of individuals at high genetic risk. Finally, we demonstrate how DeepRVAT enables calibrated and computationally efficient rare variant tests at biobank scale, aiding the discovery of genetic risk factors for human disease traits.