gebhart/patrepeval huggingface dataset:
Ultrafast Electron Microscopy of Nanoscale Charge Dynamics in Semiconductors (2022)

The ultrafast dynamics of charge carriers in solids plays a pivotal role in emerging optoelectronics, photonics, energy harvesting, and quantum technology applications. However, the investigation and direct visualization of such non-equilibrium transport phenomena remains as a long-standing challenge, owing to the nanometer-femtosecond spatio-temporal scales at which the charge carriers evolve. Here, we propose and demonstrate a novel interaction mechanism enabling nanoscale imaging of the femtosecond dynamics of charge carriers in solids. This imaging modality, which we name charge dynamics electron microscopy (CDEM), exploits the strong interaction between terahertz (THz) electromagnetic near fields produced by the moving charges and synchronized free-electron pulses in an ultrafast scanning transmission electron microscope. The measured free-electron energy at different spatio-temporal coordinates allows us to directly retrieve the THz near-field amplitude and phase, from which we reconstruct movies of the generated charges by comparison with microscopic theory. The introduced CDEM technique thus allows us to investigate previously inaccessible spatio-temporal regimes of charge dynamics in solids, for example revealing new insight into the photo-Dember effect, showing oscillations of photo-generated electron-hole distributions inside a semiconductor. Our work lays the foundation for exploring a wide range of previously inaccessible charge-transport phenomena in condensed matter using ultrafast electron microscopy.
Efficient numerical CAD technique for RF and microwave amplifiers (1998)

The real frequency technique (RFT) is an efficient numerical method to design the matching networks of microwave active circuits. It provides several advantages over most of the usual techniques. By directly including measured scattering and noise parameter data, it does not require any rational functions or circuit models. Moreover, a predetermined matching circuit topology is not necessary. The described method also allows the design of stability-guaranteed broadband circuits when employing potentially unstable transistors. With the Levenberg–Merquardt algorithm, the RFT can be applied to simultaneously optimize transducer power gain, input and output VSWRs, noise figure, and group delay of a multistage microwave active circuit. Applications as different as low-noise amplifier, active filter, or broadband amplifier are possible. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 131–141, 1998.
Natural Occurrence of Left-Handed (Z) Regions in PM2 DNA (1983)

Bacteriophage PM2 DNA, a ccc genome of high apparent superhelical density, contains left-handed (Z) regions as detected by competitive radioimmunoassay, agarose gel electrophoresis of DNA: antibody complexes and immunoelectron microscopy. The latter technique, in conjunction with partial blockage of restriction endonuclease sites by bound antibody, was used to map the left-handed regions along the DNA molecule. A cluster of four to five antibody molecules (approximately 25% of bound antibody) was located within map units 0.05-0.18 of the single Hpa II restriction site. Sequence analysis of part of this region showed the presence of several areas of high alternating purine-pyrimidine content. A strong correlation is observed between alternating pyrimidine-purine tracts of significant length and antibody binding sites.
Accurate Manipulation of Delay-based Internet Geolocation (2017)

Delay-based Internet geolocation techniques are repeatedly positioned as well suited for security-sensitive applications, e.g., location-based access control, and credit-card verification. We present new strategies enabling adversaries to accurately control the forged location. Evaluation showed that using the new strategies, adversaries could misrepresent their true locations by over 15000km, and in some cases within 100km of an intended geographic location. This work significantly improves the adversary's control in misrepresenting its location, directly refuting the appropriateness of current techniques for security-sensitive applications. We finally discuss countermeasures to mitigate such strategies.
New Developments in Full Color Flexible Reflective Cholesteric Liquid Crystal Displays (2011)

We present recent developments in full color bistable reflective cholesteric liquid crystal displays on flexible substrates. The approaches include stacking of three reflective layers (red, green and blue) on top of each other or a spatial separation (area sharing approach) of reflective layers from each other within one layer. Stacking is possible due to selective reflection properties of cholesteric layers. Each layer of the display can be addressed independently to vary the reflectance of each color yielding many possible colors. The advantage of the approach is that the display is producing a full brightness of each primary color. The advantage of the area sharing approach is its superior contrast and simplicity, as only one layer is required; that can significantly reduce the cost of the device. The developed cholesteric materials for full color displays can be easily laminated between the flexible substrates, and, possible, coated or printed. We are currently successfully implementing the developed technologies enabling low cost, low power, low weight and rugged display applications, such as writing tablets, electronic skins and electronic books.
Locked Nucleic Acid Synthesis (2004)

Methods and protocols for automated synthesis and purification of locked nucleic acid (LNA), a class of oligonucleotides obeying the Watson-Crick base-pairing rules but displaying unprecedented binding affinities toward complementary deoxyribonucleic acid (cDNA) and ribonucleic acid (RNA), is described. LNA and LNA-DNA chimeras containing phosphordiester or phosphorothioate linkages, or a mixture thereof, can be assembled by standard DNA synthesizers using 2-cyanoethyl DNA phosphoramidites and 2-cyanoethyl LNA phosphoramidites. Compared to the standard protocols used for DNA synthesis, slightly longer coupling time and oxidation time are needed for efficient oligomerization of LNA phosphoramidites. When the LNA has been assembled, it is removed from the solid support as the 5'-end-O-dimethoxytrityl (DMT) protected LNA oligomer by treatment with concentrated aqueous ammonia that also removes the phosphate and nucleobase protecting groups. The crude DMT protected LNA product can be purified using, for example, reversed-phase chromatography.
Knockdown of the Cell Cycle Inhibitor p21 Enhances Cartilage Formation by Induced Pluripotent Stem Cells (2014)

The limited regenerative capacity of articular cartilage contributes to progressive joint dysfunction associated with cartilage injury or osteoarthritis. Cartilage tissue engineering seeks to provide a biological substitute for repairing damaged or diseased cartilage, but requires a cell source with the capacity for extensive expansion without loss of chondrogenic potential. In this study, we hypothesized that decreased expression of the cell cycle inhibitor p21 would enhance the proliferative and chondrogenic potential of differentiated induced pluripotent stem cells (iPSCs). Murine iPSCs were directed to differentiate toward the chondrogenic lineage with an established protocol and then engineered to express a short hairpin RNA (shRNA) to reduce the expression of p21. Cells expressing the p21 shRNA demonstrated higher proliferative potential during monolayer expansion and increased synthesis of glycosaminoglycans (GAGs) in pellet cultures. Furthermore, these cells could be expanded ∼150-fold over three additional passages without a reduction in the subsequent production of GAGs, while control cells showed reduced potential for GAG synthesis with three additional passages. In pellets from extensively passaged cells, knockdown of p21 attenuated the sharp decrease in cell number that occurred in control cells, and immunohistochemical analysis showed that p21 knockdown limited the production of type I and type X collagen while maintaining synthesis of cartilage-specific type II collagen. These findings suggest that manipulating the cell cycle can augment the monolayer expansion and preserve the chondrogenic capacity of differentiated iPSCs, providing a strategy for enhancing iPSC-based cartilage tissue engineering.
SU-D-116-01: A Novel Reconstuction Framework of Prior Image Constrained Compressed Sensing (PICCS) Enabling the Use of Prior Images with Major Deviations (2013)

Purpose: To develop and investigate an improved reconstruction framework of Prior Image Constrained Compressed Sensing (PICCS) using prior images with major deviations. Methods: The novel idea of our reconstruction framework is the incorporation of a weighting matrix into the PICCS algorithm. This modification decomposes the prior image into areas that can be taken as a priori information (certain areas) and those regions that are not reliable due to motion or change in structure for the time series (uncertain areas).We applied our method to the problem of image reconstruction from few projections. Simulations were performed with the Shepp-Logan-Phantom considering 7 to 20 projections and different noise levels. Compared to the target image, the prior image contained major variations in shape and position of the interior structures. Objective function minimization was based on the ASD-POCS framework using the Ordered-Subset Simultaneous Algebraic Reconstruction Technique. For all simulations, an onboard imaging system at a linac was mimic (Source-Detector-Distance=1536mm, Source-Axis-Distance=1000mm, 512 bins detector with an overall length of 409.6mm). The size of the image array was 256×256 pixels with a resolution of 1×1mm2. The projections were generated from equidistant angles covering 196°.Image quality was quantified by the root-mean-squared-error (RMSE). Results: Our method allowed accurate reconstruction of highly undersampled data. In comparison to the PICCS standard, image quality was severely improved. The increased image quality was clearly visible and is reflected in a decreased RMSE of up to 79% for noiseless and 40% for noisy projections. Conclusion: Our algorithm based on PICCS, using location dependent uncertainties of the prior image, enabled image reconstruction with increased quality even when prior images with major deviations were used. The concept indicates the potential for dose reduction while maintaining good image quality. Further development concerning registration of the prior image and real data reconstruction is currently in preparation.
Methylation is an inactivating mechanism of the p16 gene in multiple myeloma associated with high plasma cell proliferation and short survival (2002)

In order to gain further insights into the role of the p16 gene in cell cycle regulation and the prognostic implications of its inactivation, we investigated the methylation status of the p16 gene in 98 untreated patients using a polymerase chain reaction assay based on the inability of some restriction enzymes to digest methylated sequences. Forty-one patients showed a p16 methylated gene (42%). The percentage of S-phase plasma cells (PC) in these patients was almost three times higher than in those with an unmethylated p16 gene (4.16% +/- 3.37%vs 1.5% +/- 1.41%, P < 0.001). The presence of p16 methylation also correlated with both elevated beta2-microglobulin serum levels and high C-reactive protein values. Patients with a p16 methylated gene had shorter overall and progression-free survival than those patients without p16 methylation. However, this feature did not retain independent prognostic influence on multivariate analysis, probably due to its association with the S-phase PC, which had more potent statistical significance in the Cox model. These findings showed methylation of the p16 gene was a frequent event inMM patients at diagnosis, and was associated with an increased proliferative rate of plasma cells and a poor prognosis, indicating an important role for p16 gene in the cell cycle regulation of multiple myeloma tumour cells, and thus in the clinical outcome of the disease.
Parenterally transmitted hepatitis: viruses, vaccines, and antiviral therapy. (1993)

The introduction of safe and effective vaccines as well as the identification of antiviral therapy that eradicates virus in many infected patients augurs well for the control of HBV and, by extension, HDV infection. The key to ultimate success will be the universal availability of immunization. The recent elucidation of the hepatitis C genomic structure will eventually lead to fundamental understanding of the mechanisms underlying the life cycle of HCV, which appears to elude both natural and synthetic defensive measures. The best hope for control of this virus in the near future rests in careful screening of the blood supply and alteration of high-risk lifestyles. The next phase of antiviral and vaccine development for all of these agents will depend on recently acquired knowledge of virus-specific enzymatic processes, molecular interactions between viruses and host cells, and our ability to interfere selectively with these processes.
Polymeric carrier-mediated intracellular delivery of phosphatidylinositol-3,4,5-trisphosphate to overcome insulin resistance (2015)

Inducing insulin actions by intracellular PIP3 delivery (PEI-25/PIP3 complexes) in some forms of insulin-resistant cells provides the first proof-of-principle for the potential therapeutic use of PIP3 in a "second-messenger agonist" approach. In addition, utilization of an artificial bio-mimetic membrane platform to screen for highly efficient PIP3 delivery predicts biological function in cells.
A low cost drive for three-phase operation of Brushless DC motors (2011)

This paper presents a novel drive topology that allows three-phase operation of Brushless DC (BLDC) motors without an intermediate DC link capacitor. The proposed motor drive uses a unique six-step Pulse Width Modulated (PWM) switching algorithm to facilitate three-phase operation of the BLDC motors. The proposed drive system is modelled using Matlab/Simulink with SimPower Systems toolbox for a 320 W BLDC motor. With the proposed unique switching algorithm, the motor can be operated either in speed control or electromagnetic torque control mode. The paper explains the derivation of the switching algorithm, and illustrates the Matlab/Simulink model, which is used to validate the drive system by simulations. Simulated results indicate that the theoretical performance of the proposed drive system is comparable to existing techniques. In addition, the proposed drive system is simple to implement and low in cost without an intermediate DC link capacitor. Thus the proposed topology would be an attractive alternative for low cost BLDC motor drives, where the torque ripple is not a concern.
A Dataflow Language for Decentralised Orchestration of Web Service Workflows (2013)

Orchestrating centralised service-oriented workflows presents significant scalability challenges that include: the consumption of network bandwidth, degradation of performance, and single points of failure. This paper presents a high-level dataflow specification language that attempts to address these scalability challenges. This language provides simple abstractions for orchestrating large-scale web service workflows, and separates between the workflow logic and its execution. It is based on a data-driven model that permits parallelism to improve the workflow performance. We provide a decentralised architecture that allows the computation logic to be moved "closer" to services involved in the workflow. This is achieved through partitioning the workflow specification into smaller fragments that may be sent to remote orchestration services for execution. The orchestration services rely on proxies that exploit connectivity to services in the workflow. These proxies perform service invocations and compositions on behalf of the orchestration services, and carry out data collection, retrieval, and mediation tasks. The evaluation of our architecture implementation concludes that our decentralised approach reduces the execution time of workflows, and scales accordingly with the increasing size of data sets.
Supplemental Figures and Legends from Metabolic Screening of Cytotoxic T-cell Effector Function Reveals the Role of CRAC Channels in Regulating Lethal Hit Delivery (2023)

&lt;p&gt;Supplemental Figures and Legends for Supplemental Figures S1-S8, and Movie Legends for Movies 1-7&lt;/p&gt;
GC‐MS aroma characterization of vegetable matrices: Focus on 3‐alkyl‐2‐methoxypyrazines (2018)

Abstract 3‐Alkyl‐2‐methoxypyrazines (MPs) are a very important class of volatile organic compounds (VOCs), intensively characterizing the aroma of several food products including fruits and vegetables. Due to the very low orthonasal sensory threshold, low amounts of MPs may act as key positive or negative aroma compounds. The analysis of these volatiles in foods is then remarkably important, and it may be very challenging as confirmed by the scarce literature focused on MPs, particularly with respect to quantitative data. In the attempt to fill this gap, in this work, presence and quantification of MPs in four different vegetables, namely, green bell pepper ( Capsicum annuum L. var grossum ), green pea ( Pisum sativum L. and Pisum spp), carrot ( Daucus carota subsp sativus ), and cucumber ( Cucumis sativus L.) have been investigated. Two different volatile extraction techniques (solid phase microextraction [SPME] and simultaneous distillation‐extraction [SDE]) in conjunction with VOC qualitative analysis by gas chromatography‐mass spectrometry (GC‐MS) methods were applied. Solid phase microextraction coupled with GC‐MS in single ion monitoring (SIM) mode showed the best performances in sensitivity to detect MPs on the different vegetable matrices. Therefore, a headspace (HS) SPME‐GC‐MS quantitative method was developed and optimized, and dominant MPs quantified. 3‐Isopropyl‐2‐methoxypyrazine (IPMP), 3‐sec‐butyl‐2‐methoxypyrazine ( s BMP), and 3‐isobutyl‐2‐methoxypyrazine (IBMP) have been detected and quantified in all the vegetables. 3‐Isopropyl‐2‐methoxypyrazine was the prevalent MP in peas and cucumber while IBMP in bell pepper. These MPs were detected for the first time in carrot and cucumber. Finally, s BMP has been confirmed to be the most important MP in carrot. The developed method allowed to characterize the VOC pattern and, in particular, to quantify MPs in four vegetables. Results highlight the feasibility of further applications of the analytical approach to determine MPs in other food matrices where an excessive amount of these aromas may negatively affect their flavor (eg, coffee).
Mapping Neutralizing Antibody Epitope Specificities to an HIV Env Trimer in Immunized and in Infected Rhesus Macaques (2020)

BG505 SOSIP is a well-characterized near-native recombinant HIV Envelope (Env) trimer that holds promise as part of a sequential HIV immunogen regimen to induce broadly neutralizing antibodies (bnAbs). Rhesus macaques are considered the most appropriate pre-clinical animal model for monitoring antibody (Ab) responses. Accordingly, we report here the isolation of 45 BG505 autologous neutralizing antibodies (nAbs) with multiple specificities from SOSIP-immunized and BG505 SHIV-infected rhesus macaques. We associate the most potent neutralization with two epitopes: the C3/V5 and V1/V3 regions. We show that all of the nAbs bind in close proximity to known bnAb epitopes and might therefore sterically hinder elicitation of bnAbs. We also identify a "public clonotype" that targets the immunodominant C3/V5 nAb epitope, which suggests that common antibody rearrangements might help determine humoral responses to Env immunogens. The results highlight important considerations for vaccine design in anticipation of results of the BG505 SOSIP trimer in clinical trials.
Oxidized metal Schottky contact with high-κ dielectric field plate for low-loss high-power vertical β-Ga2O3 Schottky diodes (2022)

We report on vertical β-Ga2O3 power diodes with oxidized-metal Schottky contact (PtOx) and high permittivity (high-κ) dielectric (ZrO2) field plate to improve reverse blocking at both Schottky contact surfaces and edges. The PtOx diodes showed excellent forward transport with near unity ideality factor and similar minimum specific on-resistance as Pt. Moreover, the PtOx contacts facilitated higher breakdown voltage and lower leakage current due to their higher Schottky barrier height (SBH) by more than 0.5 eV compared to that of Pt. Most importantly, the reduced off-state leakage of PtOx diodes enabled orders of magnitude less power dissipation than Pt ones for all duty cycles ≤0.5, indicating their great potential to realize low-loss and efficient, high-power β-Ga2O3 switches. The ZrO2 field-oxide further reduced edge leakage with a consistent increase in breakdown voltage. Device simulation demonstrated that the high permittivity of ZrO2 also led to the peak electric field occurring in β-Ga2O3 instead of the dielectric. These results indicate that the combined integration of oxidized-metal contacts to increase SBH and high-κ dielectric field plate to assist edge termination can be promising to enhance the performance of vertical β-Ga2O3 Schottky diodes.
Improving Human Action Recognition Using Fusion of Depth Camera and Inertial Sensors (2014)

This paper presents a fusion approach for improving human action recognition based on two differing modality sensors consisting of a depth camera and an inertial body sensor. Computationally efficient action features are extracted from depth images provided by the depth camera and from accelerometer signals provided by the inertial body sensor. These features consist of depth motion maps and statistical signal attributes. For action recognition, both feature-level fusion and decision-level fusion are examined by using a collaborative representation classifier. In the feature-level fusion, features generated from the two differing modality sensors are merged before classification, while in the decision-level fusion, the Dempster-Shafer theory is used to combine the classification outcomes from two classifiers, each corresponding to one sensor. The introduced fusion framework is evaluated using the Berkeley multimodal human action database. The results indicate that because of the complementary aspect of the data from these sensors, the introduced fusion approaches lead to 2% to 23% recognition rate improvements depending on the action over the situations when each sensor is used individually.