gebhart/patrepeval huggingface dataset:
Phospho-tau with subthreshold tau-PET predicts increased tau accumulation rates in amyloid-positive individuals (2022)

Different tau biomarkers become abnormal at different stages of Alzheimer's disease, with CSF phospho-tau typically becoming elevated at subthreshold levels of tau-PET binding. To capitalize on the temporal order of tau biomarker-abnormality and capture the earliest changes of tau accumulation, we implemented an observational study design to examine longitudinal changes in tau-PET, cortical thickness and cognitive decline in amyloid-β-positive individuals with elevated CSF p-tau levels (P+) but subthreshold Tau-PET retention (T-). To this end, individuals without dementia (i.e. cognitively unimpaired or mild cognitive impairment, n = 231) were selected from the BioFINDER-2 study. Amyloid-β-positive (A+) individuals were categorized into biomarker groups based on cut-offs for abnormal CSF p-tau217 and 18F-RO948 (Tau) PET, yielding groups of tau-concordant-negative (A+P-T-; n = 30), tau-discordant (i.e. A+P+T-; n = 48) and tau-concordant-positive (A+P+T+; n = 18) individuals. In addition, 135 amyloid-β-negative, tau-negative, cognitively unimpaired individuals served as controls. Differences in annual change in regional tau-PET, cortical thickness and cognition between the groups were assessed using general linear models, adjusted for age, sex, clinical diagnosis and (for cognitive measures only) education. Mean follow-up time was ∼2 years. Longitudinal increase in tau-PET was faster in the A+P+T- group than in the control and A+P-T- groups across medial temporal and neocortical regions, with the highest accumulation rates in the medial temporal lobe. The A+P+T- group showed a slower rate of increase in tau-PET compared to the A+P+T+ group, primarily in neocortical regions. We did not detect differences in yearly change in cortical thickness or in cognitive decline between the A+P+T- and A+P-T- groups. The A+P+T+ group, however, showed faster cognitive decline compared to all other groups. Altogether, these findings suggest that the A+P+T- biomarker profile in persons without dementia is associated with an isolated effect on increased tau-PET accumulation rates but not on cortical thinning and cognitive decline. While this suggests that the tau-discordant biomarker profile is not strongly associated with short-term clinical decline, this group does represent an interesting population for monitoring the effects of interventions with disease-modifying agents on tau accumulation in early Alzheimer's disease, and for examining the emergence of tau aggregates in Alzheimer's disease. Further, we suggest updating the AT(N) criteria for Alzheimer's disease biomarker classification to APT(N).
The Regionalization of Ventral Hernia Repair: Occurrence and Outcomes over a Decade (2013)

Ventral hernia repairs (VHRs) have always been considered standard general surgery cases. Recently, there has been a call for "Centers of Excellence." We sought to investigate outcomes and trends between high- and low-volume centers. The Nationwide Inpatient Sample (NIS) data were analyzed from 1998-1999 (T1) and 2008-2009 (T2) for all VHRs. Hospitals were stratified into high-, medium-, and low-volume centers (HVC/MVC/LVC). Demographics, comorbidities, and outcomes were compared. Surgical cases totaled 22,771 in T1 and 37,044 in T2. In T1, 34.3 per cent were performed in HVC versus 64.2 per cent in T2 (P < 0.0001). LVC cases decreased between eras: 32.6 versus 16.1 per cent (P < 0.0001). Comorbidities and emergent admissions increased with time (P < 0.0001). Mortality was similar in both eras and between volume centers. Length of stay was less in LVC in T2 only (4.2 vs 4.8 days, P < 0.0001). Total charges were higher in HVCs in both eras (P < 0.0001). These remained significant in T2 in multivariate regression (MVR). Hospital volume was not associated with most complications or death in either era with MVR. Charlson comorbidity score, age, and emergent admission were predictors of complications and death. Regionalization has occurred for VHRs. However, most complication and mortality rates are unrelated to volume and are linked to comorbidities, age, and emergencies.
Combined Use of Serum and Urinary Antibody for Diagnosis of Tuberculosis (2003)

Efforts to devise immunoassays for tuberculosis (TB) that can be adapted to rapid formats are ongoing. The present study was aimed at determining whether urinary anti-Mycobacterium tuberculosis antibodies are present in patients with TB, to evaluate the feasibility of developing a urine antibody-based diagnostic test. Urinary antibodies directed against the culture filtrate proteins of M. tuberculosis, MPT 32, and the 81-kDa GlcB protein were detectable in patients with TB, although the sensitivity of antibody detection was lower (53%-64%), compared with serum antibodies (68%-77%). Surprisingly, with all 3 antigens, the use of paired serum and urine samples provided higher sensitivities of antibody detection than either single specimen, and anti-GlcB antibodies were present in the serum and/or urine of 39 (90%) of 43 smear-positive patients with TB. Although, with the current methods and antigens, the level of sensitivity is insufficient to design a urinary antibody diagnostic test, these studies provide the foundation for further studies on the development of a urine antibody-based immunoassay for TB.
Transient gain and cross talk in erbium-doped fiber amplifiers (1989)

Transient gain saturation and recovery with 110-340-microsec time constants were observed in erbium-doped fiber amplifiers. This slow response reduces the effects of saturation-induced cross talk and intermodulation distortion associated with multichannel signal amplification. In a two-channel amplification experiment, negligible saturation-induced cross talk was measured at signal modulation frequencies >5 kHz. Increased suppression of saturation-induced cross talk was achieved through feed-forward compensation to reduce low-frequency gain fluctuations.
Multispectral optoacoustic tomography (MSOT) scanner for whole-body small animal imaging (2009)

A major difficulty arising from whole-body optoacoustic imaging is the long acquisition times associated with recording signals from multiple spatial projections. The acquired signals are also generally weak and the signal-to-noise-ratio is low, problems often solved by signal averaging, which complicates acquisition and increases acquisition times to an extent that makes many in vivo applications challenging or even impossible. Herein we present a fast acquisition multispectral optoacoustic tomography (MSOT) scanner for whole-body visualization of molecular markers in small animals. Multi-wavelength illumination offers the possibility to resolve exogenously administered fluorescent probes, biomarkers, and other intrinsic and exogenous chromophores. The system performance is determined in phantom experiments involving molecular probes and validated by imaging of small animals of various scales.
A lightweight, low-power electroadhesive clutch and spring for exoskeleton actuation (2016)

Clutches can be used to enhance the functionality of springs or actuators in robotic devices. Here we describe a lightweight, low-power clutch used to control spring engagement in an ankle exoskeleton. The clutch is based on electrostatic adhesion between thin electrode sheets coated with a dielectric material. Each electrode pair weighs 1.5 g, bears up to 100 N, and changes states in less than 30 ms. We placed clutches in series with elastomer springs to allow control of spring engagement, and placed several clutched springs in parallel to discretely adjust stiffness. By engaging different numbers of springs, the system produced six different levels of stiffness. Force at peak displacement ranged from 14 to 501 N, and the device returned 95% of stored mechanical energy. Each clutched spring element weighed 26 g. We attached one clutched spring to an ankle exoskeleton and used it to engage the spring only while the foot was on the ground during 150 consecutive walking steps. Peak torque was 7.3 N·m on an average step, and the device consumed 0.6 mW of electricity. Compared to other electrically-controllable clutches, this approach results in three times higher torque density and two orders of magnitude lower power consumption per unit torque. We anticipate this technology will be incorporated into exoskeletons that tune stiffness online and into new actuator designs that utilize many lightweight, low-power clutches acting in concert.
The Last Few Minutes Prior to a Fatigue Blade Failure in an Axial Compressor: Observations of Blade Vibration and Blade Lean (2007)

Blade-tip measurement systems are in development for monitoring and prognosis of rotor health and blade health in turbomachinery. The preliminary development of these systems suffers from lack of experience with failure signatures; technical staff are improvising with a combination of test and inspired guesswork. Perhaps mistakes are being made; it may be that mature systems of the future will use logic very different from what is being implemented by the developers today. This paper makes a small contribution to the knowledge base of failure modes and failure signatures in axial compressors. The paper describes observed signatures in data taken with a turbomachinery tip-timing system in the final 12 minutes of operation of an axial compressor before one of the blades of this axial compressor was liberated by growing crack. The crack growth was driven by a resonant vibration of that blade. The data file ends when the blade is liberated. The data system employed for this test used non-intrusive sensors. Each sensor launched a laser beam into the compressor inlet from several feet range. The blades were driven at a 2/rev synchronous resonance. This paper details signatures of impending failure on both leading edge and trailing edge measurements.
Minimizing the Number of Voltage Sources and Fluid Reservoirs for Electrokinetic Valving in Microfluidic Devices (1999)

A microchip gated valve is demonstrated that uses a single voltage source and three fluid reservoirs. The fluidic valve is a cross intersection, and the channels are dimensioned to perform the appropriate voltage division, simplifying the voltage control hardware. A single voltage source is applied directly to the sample reservoir and through a high-voltage relay to the buffer reservoir, and the waste reservoir is grounded. The volume of sample dispensed is determined by the duration that the high-voltage relay is open. Volumetric reproducibility is demonstrated to be <0.5% relative standard deviation for volumes of ≥20 pL. The valve is tested for the minimum applied voltage necessary for leakage-free operation, i.e., sample diffusing from the cross intersection into the analysis channel. Moreover, appropriate channel dimensions are used to minimize the number of fluid reservoirs allowing effluent from the analysis and waste channels to be combined into a single reservoir.
Encapsulation of Plasmid DNA in Stabilized Plasmid – Lipid Particles Composed of Different Cationic Lipid Concentration for Optimal Transfection Activity (2000)

In previous work (Wheeler et al. (1999) Gene Therapy 6, 271-281) we have shown that plasmid DNA can be entrapped in "stabilized plasmid lipid particles" (SPLP) using low levels (5-10 mol%) of cationic lipid, the fusogenic lipid dioleoylphosphatidylethanolamine (DOPE), and a polyethyleneglycol (PEG) coating for stabilization. The PEG moieties are attached to a ceramide anchor containing an arachidoyl acyl group (PEG-CerC20). However, these SPLP exhibit low transfection potencies in vitro as compared to plasmid/cationic lipid complexes formed with liposomes composed of cationic and neutral lipid at a 1:1 lipid ratio. The objective of this study was to construct SPLPs with increased cationic lipid contents that result in maximum transfection levels. A phosphate buffer detergent dialysis technique is described resulting in formation of SPLP containing 7-42.5 mol% DODAC with reproducible encapsulation efficiency of up to 80%. An octanoyl acyl group was used as anchor for the PEG moiety (PEG-CerC8) permitting a quick exchange out of the SPLP to further optimize the in vitro and in vivo transfection. We have demonstrated that this technique can be used to encapsulate either linearized DNA or supercoiled plasmids ranging from 3-20 kb. The SPLP formed could be isolated from empty vesicles by sucrose density gradient centrifugation, and exhibited a narrow size distribution of approximately 75 +/- 6 nm as determined by cryo-electron microscopy. The high plasmid-to-lipid ratio observed corresponded to one plasmid per particle. The SPLP consist of a lipid bilayer surrounding the plasmid DNA as visualized by cryo-electron microscopy. SPLP containing a range of DODAC concentrations were tested for in vitro and in vivo transfection. In vitro, in COS-7 cells transfection reached a maximum after 48 h. The transfection efficiency increased when the DODAC concentration in the SPLP was decreased from 42.5 to 24 mol% DODAC. Decreasing the cationic lipid concentration improved transfection in part due to decreased toxicity. In vivo studies using an intraperitoneal B16 tumor model and intraperitoneal administration of SPLP showed maximum transfection activity for SPLP containing 24 mol% DODAC. Gene expression observed in tumor cells was increased by approximately one magnitude as compared to cationic lipid/DNA complexes. The SPLP were stable and upon storage at 4 degrees C no significant change in the transfection activity was observed over a one-year period. Thus this phosphate buffer detergent dialysis technique can be used to generate SPLP formulations containing a wide range of cationic lipid concentrations to determine optimal SPLP composition for high transfection activity and low toxicity.
Determination of the Antibacterial and Lipopolysaccharide-Neutralizing Regions of Guinea Pig Neutrophil Cathelicidin Peptide CAP11 (2006)

Previously, we revealed that a cationic antibacterial polypeptide of 11 kDa (CAP11), a member of the cathelicidins isolated from guinea pig neutrophils, exhibits not only potent antibacterial activity but also lipopolysaccharide (LPS)-neutralizing activity. In this study, to determine the biologically active regions of CAP11, we isolated or synthesized the partial peptides of CAP11 and evaluated their antibacterial and LPS-neutralizing activities. Although CAP11 has a unique homodimeric structure with a disulfide bridge, the biological activities of dimeric and monomeric forms of CAP11 were almost the same. Moreover, the G(1)-E(33) peptide of CAP11 showed the same activities as CAP11, whereas the C-terminal region (Y(34) to I(43)) possessed no biological activities. In addition, the three 18-mer peptides (G(1)-R(18), T(9)-K(26), and L(16)-E(33)) with overlapping sequences were synthesized, and their activities were determined. The three 18-mer peptides retained the antibacterial activities, and G(1)-R(18) was the most potent. In contrast, the LPS-neutralizing activities of these peptides were markedly reduced. Together, these observations indicate that the active region with antibacterial activity is localized at G(1) to R(18) of CAP11, whereas longer sequences (such as G(1) to E(33)) would be required for the expression of LPS-neutralizing activity. Furthermore, the C-terminal region (Y(34) to I(43)) and a disulfide bridge are not essential for the antibacterial and LPS-neutralizing activities of CAP11.
Mapping of submerged aquatic vegetation with a physically based process chain (2004)

Mapping the submerse vegetation is of prime importance for the ecological evaluation of an entire lake. Remote sensing techniques are efficient for such mapping tasks, if the retrieval algorithms and processing methods are robust and mostly independent from additional ground truth measurements. The Modular Inversion Program (MIP) follows this concept. It is a processing tool designed for the recovery of hydro-biological parameters from multi- and hyper-spectral remote sensing data. The architecture of the program consists of physical inversion schemes that derive bio-physical parameters from the measured radiance signal at the sensor. Program modules exist for the retrieval of aerosols, sun glitter correction, atmospheric corrections, retrieval of water constituents among others. For the purpose of mapping the bottom coverage in optically shallow waters, two modules have been added to MIP. The first module calculates the bottom reflectance using the subsurface reflectance, the depth and an approximation of the water constituent concentrations as input. The second module fractionalizes the bottom reflectance to three endmembers of specific reflectance spectra by linear unmixing. The three endmembers are specific reflectance spectra of bottom sediments, small growing macrophytes (Characeae) and tall macrophytes such as Potamogeton perfoliatus & P. pectinatus. The processing system has been tested with data collected from the multi-spectral airborne scanner Daedalus AADS1268 at Lake Constance, Germany, for multi- temporal analysis.
Temperature dependent DC/RF performance of Si/SiGe resonant interband tunnelling diodes (2005)

The temperature dependent DC/RF performance of Si-based resonant interband tunnelling diodes (RITDs) grown by low temperature molecular beam epitaxy was studied. Both DC and RF performance were measured at various temperatures from 20 to 150°C. At 20°C, the RITD exhibits a peak current density ( Jp) of 22 kA/cm2 with peak-to-valley current ratio (PVCR) of 2.0. The maximum resistive cutoff frequency (fr0) of 2.4 GHz was obtained by biasing the diode at 320 mV. Increasing temperature slightly degrades the PVCR and fr0. At 150°C, the PVCR and fr0 reduced to 1.8 and 1.9 GHz, respectively. The observed weak temperature dependence of the DC/RF performance and the GHz operating frequency make Si/SiGe RITDs a good candidate for high power microwave applications.
Photonic Bandgap Composites (2001)

A procedure for generating robust polymeric composites that exhibit photonic bandgap (PBG) and mechanochromic properties is presented (see Figure). The long-range order in colloidal arrays is stabilized through encapsulation in a robust and water-free matrix. These systems may be useful in optical sensors or switching applications.
Development and Characterization of a Modular CRISPR and RNA Aptamer Mediated Base Editing System (2021)

Conventional CRISPR approaches for precision genome editing rely on the introduction of DNA double-strand breaks (DSB) and activation of homology-directed repair (HDR), which is inherently genotoxic and inefficient in somatic cells. The development of base editing (BE) systems that edit a target base without requiring generation of DSB or HDR offers an alternative. Here, we describe a novel BE system called Pin-point<sup>TM</sup> that recruits a DNA base-modifying enzyme through an RNA aptamer within the gRNA molecule. Pin-point is capable of efficiently modifying base pairs in the human genome with precision and low on-target indel formation. This system can potentially be applied for correcting pathogenic mutations, installing premature stop codons in pathological genes, and introducing other types of genetic changes for basic research and therapeutic development.
Polymerization of lactams. 59. Anionic polymerization of 2‐pyrrolidone accelerated by 1‐(1‐pyrrolin‐2‐yl)‐2‐pyrrolidone (1983)

Abstract An exceptional acceleration of the bulk heterogeneous polymerization of 2‐pyrrolidone, initiated with the potassium salt of 2‐pyrrolidone, was attained by addition of 1‐(1‐pyrrolin‐2‐yl)‐2‐pyrrolidone (PDPD). The kinetic analysis shows that the mechanism of this polymerization is complex, but that the polymerization resembles a nonactivated polymerization by several features. The function of PDPD cannot be decided for the present, but it seems to be rather a regulator than an activator of polymerization.
Matched spectral-null codes for partial-response channels (1991)

A new family of codes that improve the reliability of digital communication over noisy, partial-response channels is described. The codes are intended for use on channels where the input alphabet size is limited. These channels arise in the context of digital data recording and certain data transmission applications. The codes-called matched-spectral-null codes-satisfy the property that the frequencies at which the code power spectral density vanishes correspond precisely to the frequencies at which the channel transfer function is zero. It is shown that matched-spectral-null sequences provide a distance gain on the order of 3 dB and higher for a broad class of partial-response channels. The embodiment of the system incorporates a sliding-block code and a Viterbi detector based upon a reduced-complexity trellis structure. The detectors are shown to achieve the same asymptotic average performance as maximum-likelihood sequence detectors, and the sliding-block codes exclude quasi-catastrophic trellis sequences in order to reduce the required path memory length and improve worst-case detector performance. Several examples are described in detail.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Gastric electrical stimulation parameter dependently alters ventral medial hypothalamic activity and feeding in obese rats (2011)

Gastric electrical stimulation (GES) has been used to treat obesity with unclear mechanisms and limited parameter ranges. This study explores effects of GES parameters on ventral medial hypothalamic (VMH) activity, feeding, and body weight in diet-induced obese (DIO) rats. For experiment 1, discharge rates were recorded in 39 gastric distension-responsive (GD-R) neurons in 12 DIO rats. Basal rates were compared with rates under GES using varied pulse amplitudes, widths, frequencies, and train-on times. For experiment 2, a crossover experiment in 16 DIO rats measured food intake and weight effects of GES pulse width, the parameter with the steepest neuronal response gradient in experiment 1. Treatments were sham and 0.5-, 2.0-, and 5.0-ms pulse GES. In experiment 1, 11 of 13 GES parameter sets tested produced significantly (P < 0.05) altered discharge rates of GD-R neurons. Increases in pulse amplitude (P < 0.05) and width (P < 0.0001) produced significant upward linear trends in response over the range tested, with the trend being strongest for pulse width. In experiment 2, over 4 days of 0.5-, 2.0-, and 5.0-ms GES treatment, food intake was 9.6% (P < 0.05), 21.0% (P < 0.0001), and 47.3% (P < 0.0001) lower than under sham-GES, whereas body weight changes were 0.7 (P = 0.48), 2.2 (P < 0.05), and 3.5 (P < 0.002) percentage points lower, respectively. We concluded that GES pulse width increases had the largest effect on VMH neuronal activity, and these effects were paralleled by pulse width-dependent reductions in food intake and body weight. Lengthening pulse width beyond the range used in prior clinical studies may be critical to making GES a viable obesity treatment.
New high sensitive micromanometer (1980)

An instrument is described where the downwards or upwards displacement of menisci under the action of a pressure differential in a U-tube arrangement is magnified by a factor of 104 or more. This is accomplished by determining the volume of manometer fluid displaced via the very precise observation of motion of an air bubble inside a horizontal capillary tube connecting the large and equal diameter vertical legs of the manometer. Means of introducing and initially placing the air bubble are described as well as the use of a long capillary spirally coiled in one plane. This plane does not need to be placed horizontally because buoyancy forces cannot influence the bubble displacement. An instrument has been built and checked for surface tension effects which proved to be negligibly small. The instrument was used to measure velocity distribution of air flowing laminarly through a tube. The agreement between data and theory is excellent.