gebhart/patrepeval huggingface dataset:
4-(1 <i>H</i> )-Quinolones and 1,2,3,4-Tetrahydroacridin-9(10 <i>H</i> )-Ones Prevent the Transmission of Plasmodium falciparum to Anopheles freeborni (2013)

Malaria kills approximately 1 million people a year, mainly in sub-Saharan Africa. Essential steps in the life cycle of the parasite are the development of gametocytes, as well as the formation of oocysts and sporozoites, in the Anopheles mosquito vector. Preventing transmission of malaria through the mosquito is necessary for the control of the disease; nevertheless, the vast majority of drugs in use act primarily against the blood stages. The study described herein focuses on the assessment of the transmission-blocking activities of potent antierythrocytic stage agents derived from the 4(1H)-quinolone scaffold. In particular, three 3-alkyl- or 3-phenyl-4(1H)-quinolones (P4Qs), one 7-(2-phenoxyethoxy)-4(1H)-quinolone (PEQ), and one 1,2,3,4-tetrahydroacridin-9(10H)-one (THA) were assessed for their transmission-blocking activity against the mosquito stages of the human malaria parasite (Plasmodium falciparum) and the rodent parasite (P. berghei). Results showed that all of the experimental compounds reduced or prevented the exflagellation of male gametocytes and, more importantly, prevented parasite transmission to the mosquito vector. Additionally, treatment with ICI 56,780 reduced the number of sporozoites that reached the Anopheles salivary glands. These findings suggest that 4(1H)-quinolones, which have activity against the blood stages, can also prevent the transmission of Plasmodium to the mosquito and, hence, are potentially important drug candidates to eradicate malaria.
Initial events at the bioactive glass surface in contact with protein-containing solutions (2000)

Upon implantation, bioactive glass undergoes a series of reactions that leads to the formation of a calcium phosphate-rich layer. Most in vitro studies of the changes that occur on the surface of bioactive glass have employed the use of buffer solutions with compositions reflecting the ionic composition of interstitial fluid. Although these studies have documented the physical and chemical changes associated with bioactive glass immersed in aqueous media, they do not reveal the effect of serum proteins and cells that are present at the implantation site. In the present study, we document, using atomic force microscopy (AFM) and Rutherford backscattering spectrometry (RBS), significant differences in the reaction layer composition, thickness, morphology, and kinetics of formation arising from the presence of serum proteins. The data reveal that the uniform and rapid adsorption of serum proteins on the surface may serve to protect the surface from further direct interaction with the aqueous media, slowing down the transformation reactions. This finding is in agreement with previous studies that have shown that the presence of serum proteins significantly delays the formation of hydroxyapatite at the surface of bioactive glass. These data also support the hypothesis that initial reaction layers in vivo interact with cells in order to produce the tissue-bioactive glass interface typically observed on ex vivo specimens.
[A review of researches on electroencephalogram decoding algorithms in brain-computer interface]. (2019)

Brain-computer interface (BCI) provides a direct communicating and controlling approach between the brain and surrounding environment, which attracts a wide range of interest in the fields of brain science and artificial intelligence. It is a core to decode the electroencephalogram (EEG) feature in the BCI system. The decoding efficiency highly depends on the feature extraction and feature classification algorithms. In this paper, we first introduce the commonly-used EEG features in the BCI system. Then we introduce the basic classical algorithms and their advanced versions used in the BCI system. Finally, we present some new BCI algorithms proposed in recent years. We hope this paper can spark fresh thinking for the research and development of high-performance BCI system.
Prion protein (PrP) synthetic peptides induce cellular PrP to acquire properties of the scrapie isoform. (1995)

Conversion of the cellular isoform of prion protein (PrPC) into the scrapie isoform (PrPSc) involves an increase in the beta-sheet content, diminished solubility, and resistance to proteolytic digestion. Transgenetic studies argue that PrPC and PrPSc form a complex during PrPSc formation; thus, synthetic PrP peptides, which mimic the conformational pluralism of PrP, were mixed with PrPC to determine whether its properties were altered. Peptides encompassing two alpha-helical domains of PrP when mixed with PrPC produced a complex that displayed many properties of PrPSc. The PrPC-peptide complex formed fibrous aggregates and up to 65% of complexed PrPC sedimented at 100,000 x g for 1 h, whereas PrPC alone did not. These complexes were resistant to proteolytic digestion and displayed a high beta-sheet content. Unexpectedly, the peptide in a beta-sheet conformation did not form the complex, whereas the random coil did. Addition of 2% Sarkosyl disrupted the complex and rendered PrPC sensitive to protease digestion. While the pathogenic A117V mutation increased the efficacy of complex formation, anti-PrP monoclonal antibody prevented interaction between PrPC and peptides. Our findings in concert with transgenetic investigations argue that PrPC interacts with PrPSc through a domain that contains the first two putative alpha-helices. Whether PrPC-peptide complexes possess prion infectivity as determined by bioassays remains to be established.
Dynamic OCT measurements of corneal biomechanical properties after UV cross-linking in the rabbit (2013)

Structural properties of the cornea determine the shape and optical quality of the eye. Keratoconus, a structural degeneration of the cornea, is often treated with UV-induced collagen cross-linking to increase tissue resistance to further deformation and degeneration. Optimal treatments would be customized to the individual and consider preexisting structural properties as well as the effects induced by treatment and this requires the capability to noninvasively measure tissue properties. The purpose of this study is to use novel methods of optical elastography to study the effects of UV-induced corneal collagen cross-linking in the rabbit eye. Low-amplitude (<1μm) elastic flexural waves were generated using focused air-pulse stimulation. Elastic wave propagation was measured over a 10x10mm area using Phase Stabilized Swept Source Optical Coherence Elastography (PhS-SSOCE) with a sensitivity of ~ 10 nm. Wave amplitude and velocity were computed and compared in tissues before and after UV cross-linking. Wave amplitude was decreased by the cross-linking treatment, while wave velocity was greater in cross-linked tissue than it was in the untreated cornea. Decreased wave amplitude and increased wave velocity after cross-linking is consistent with increased tissue stiffness. This was confirmed by conventional mechanical tension testing. These results demonstrate that the combination of the PhS-SSOCE and focused air pulse stimulation is capable of measuring low amplitude tissue motion and quantifying corneal stiffness.
ChemInform Abstract: Reaction of Grignard Reagents with Diisopropylaminoborane. Synthesis of Alkyl, Aryl, Heteroaryl and Allyl Boronic Acids from Organo(diisopropyl)aminoborane by a Simple Hydrolysis. (2013)

Abstract Boronic acids (III) are synthesized by Grignard reaction of aminoborane (I), whereas boronic acids (V) are synthesized by reaction of (I) with in situ formed Grignard reagents (Barbier conditions).
Holey fibers: fundamentals and applications (2003)

Summary form only given. Holey fiber technology promises the development of fibers with a wide range of unique optical properties suitable for use in ultrafast optics applications. These include sources based on soliton effects (e.g. pulse compressors, wavelength tunable sources based on the soliton self frequency shift (SSFS)), and white light sources based on supercontinuum generation. Such fibers are also of interest for telecommunications applications. Holey fibers, with small holes and large hole spacings offer extremely large mode areas (and correspondingly low optical nonlinearities). Large mode area fibers have potential applications in high power optical delivery including laser welding and machining, and high power fiber lasers and amplifiers. Holey fiber technology is also of relevance to the production of doped fibers, as required for example in fiber laser and amplifier systems.
A temperature independent pH (TIP) buffer for biomedical biophysical applications at low temperatures (2007)

A temperature independent pH buffer has been developed from a combination of buffers of opposite-sign temperature coefficients, and utility in low temperature spectroscopy and storage of pH sensitive compounds is demonstrated.
Refractory Silicides of Titanium and Tantalum for Low-Resistivity Gates and Interconnects (1980)

A study of the refractory-gate metallization schemes had been undertaken to provide a low-resistivity metallization for LSI and VLSI. In this paper, we describe an overview of the efforts made in this direction and present two different metallization schemes which lead to a resistivity of <=20 and 40 /spl mu//spl Omega/spl dot/cm at the gate level. These schemes involve formation of titanium and tantalum silicides on polysilicon gates, respectively. The recommended structure ia a metal or a cosputtered alloy/polysilicon/gate oxide/substrate which, when sintered, gives the desired structure silicide/polysilicon/gate oxide substrate. By the use of 1000-/spl aring/ Ti or Ta, the sheet resistance of nearly 1 or 2 Omega//spl square/, respectively, can be routinely obtained. The silicides are mechanically strong and can be dry etched using radial-flow or barrel-type plasma reactors. The Ta silicide structure is found to be very stable throughout standard processing and can be retrofitted in the present processing sequence. Ti silicide structures are similarly stable except for the reactivity of the silicide with HF-containing reagents. The Ti silicide metallization scheme can therefore be employed in processing with changes incorporated to avoid HF-silicide contact.
Colonic wall thickness using level sets for CT virtual colonoscopy visual assessment and polyp detection (2007)

The detection of polyps in virtual colonoscopy is an active area of research. One of the critical elements in detecting cancerous polyps using virtual colonoscopy, especially in conjunction with computer-aided detection, is the accurate segmentation of the colon wall. The large CT attenuation difference between the lumen and inner, mucosal layer of the colon wall makes the segmentation of the lumen easily performed by traditional threshold segmentation techniques. However, determining the location of the colon outer wall is often difficult due to the low contrast difference between the colon wall's outer serosal layer and the fat surrounding the colon. We have developed an automatic, level set based method to determine from a CT colonography scan the location of the colon inner boundary and the colon outer wall boundary. From the location of the inner and outer colon wall boundaries, the wall thickness throughout the colon can be computed. Color mapping of the wall thickness on the colon surface allows for easy visual determination of potential regions of interest. Since the colon wall tends to be thicker at polyp locations, potential polyps also can be detected automatically at sites of increased colon wall thickness. This method was validated on several CT colonography scans containing optical colonoscopy-proven polyps. The method accurately determined thicker colonic wall regions in areas where polyps are present in the ground truth datasets and detected the polyps at a false positive rate between 44.4% and 82.8% lower than a state-of-the-art curvature-based method for initial polyp detection.
Spectrally resolved bioluminescence tomography with adaptive finite element analysis: methodology and simulation (2007)

As a molecular imaging technique, bioluminescence tomography (BLT) with its highly sensitive detection and facile operation can significantly reveal molecular and cellular information in vivo at the whole-body small animal level. However, because of complex photon transportation in biological tissue and boundary detection data with high noise, bioluminescent sources in deeper positions generally cannot be localized. In our previous work, we used achromatic or monochromatic measurements and an a priori permissible source region strategy to develop a multilevel adaptive finite-element algorithm. In this paper, we propose a spectrally solved tomographic algorithm with a posteriori permissible source region selection. Multispectral measurements, and anatomical and optical information first deal with the nonuniqueness of BLT and constrain the possible solution of source reconstruction. The use of adaptive mesh refinement and permissible source region based on a posteriori measures not only avoids the dimension disaster arising from the multispectral measured data but also reduces the ill-posedness of BLT and therefore improves the reconstruction quality. Reconsideration of the optimization method and related modifications further enhance reconstruction robustness and efficiency. We also incorporate into the method some improvements for reducing computational burdens. Finally, using a whole-body virtual mouse phantom, we demonstrate the capability of the proposed BLT algorithm to reconstruct accurately bioluminescent sources in deeper positions. In terms of optical property errors and two sources of discernment in deeper positions, this BLT algorithm represents the unique predominance for BLT reconstruction.
Coherence properties of short cavity swept lasers (2017)

It has been shown theoretically and experimentally that short cavity swept lasers are passively mode locked. We develop a mathematical model of these lasers and the light field solutions are used to predict the coherence length and coherence revival behavior. The calculations compare favorably with data from a 990-1100 nm laser swept at 100 kHz suitable for optical coherence tomography applications.
Reverse biased safe operating area of emitter switched thyristors (1996)

The reverse biased safe operating area (RBSOA) of 600 V and 2500 V EST devices has been analyzed by numerical simulation for the first time and compared with those for the IGBT and MCT. The dependence of the RBSOA upon the P-base resistance in the main thyristor structure of the EST has also been investigated. Two types of destructive failure mechanisms have been identified: one due to the voltage-induced avalanche multiplication, and the other associated with current-induced latch-up of the parasitic thyristor. It is demonstrated that, although the voltage-induced limit is identical for all three devices, the current induced RBSOA for the EST can be improved over the IGBT and MCT with little sacrifice of the on-state characteristics. In addition, a comparison of the RBSOA with the forward biased safe operating area (FBSOA) has been performed.
Hyperspectral thermoreflectance imaging for power devices (2017)

This paper presents a novel method for obtaining optimized, accurate, and fully calibrated images of the thermal behavior of complex semiconductor devices with submicron features. To thermally analyze the growing number of high power devices, such as microwave amplifiers for wireless mobile applications, a technique is required for high speed transient and high spatial resolution thermal characterization. Thermoreflectance imaging has been shown to have an advantage in measuring the time-dependent thermal response. A challenge, however, has been a noisy spatial response due to an optical artifact and/or the complex reflection of the layers of thin-films and geometries which comprise the transistor features. To intuitively understand the thermal profile, which is a great advantage of imaging, this nonphysical response can sometimes result in confusion. Wavelength dependent reflectance is a property of the material and the material's surface characteristics. A multiple wavelength or a full spectrum (hyperspectral) illumination, rather than a single wavelength, can be employed to achieve much greater accuracy and a clearer thermal image for all regions on a complex integrated circuit. A single heating wire deposited on a substrate is used to experimentally demonstrate how this technique works. The results show a very good hyperspectral thermoreflectance fitting for all materials on the test structure.
Expression, purification and crystallization of human phosphotyrosine phosphatase 1B (1994)

Protein phosphotyrosine phosphatases are believed to be involved in the regulation of the activity of cellular proteins, such as receptor tyrosine kinases, by controlling their phosphorylation status. One of the best described and characterized protein of this class of enzymes is the phosphotyrosine phosphatase 1B. To obtain sufficient quantities for structural investigations, truncated forms of PTP1B encompassing the catalytic domain were over-expressed in Escherichia coli and purified to apparent homogeneity by conventional chromatography. The activity of these purified enzymes has been compared with the wild-type enzyme expressed in mammalian cells. By measuring the activities against p-nitrophenyl phosphate, the pH dependence of this activity, and responses to different modulators, it could be demonstrated that the truncated forms of PTP1B retained the same characteristics as the full-length mammalian enzyme, but are not subject to inhibition of enzymic activity mediated by the C-terminus. Due to their improved solubility, it can be assumed that the catalytic domains are advantageous for crystallization studies in comparison to the natural enzyme. In a screening for crystallization conditions, we obtained protein crystals indicating that the quality of the purified protein is sufficient for crystallographic studies.
A novel self conjugate halftone image watermarking technique (2003)

In this paper, we propose a novel way called Data Hiding Self Conjugate Error Diffusion to hide invisible patterns in a single error diffused halftone image. The hidden patterns would appear on the halftone image when the halftone image is folded or overlaps with its own rotated version. Simulation results show that the halftone images have good visual quality and the hidden pattern is visible clearly.
Unconventional computing with diffusive memristors (2018)

Diffusive memristors with Ag active metal species are volatile threshold switches featuring spontaneous rupture of conduction channels at small electrical bias. The unique temporal dynamics of the conductance evolution originates from the underlying electrochemical and diffusive dynamics of the active metals in dielectrics, which can be explored for a variety of novel applications in unconventional computing. The superior I-V nonlinearity enables large crossbar arrays for high density non-volatile memories. The relaxation dynamics and the delay dynamics of the conductance evolution lead to faithful synaptic emulators and single-device threshold logic neurons, respectively. Unsupervised learning has been demonstrated with a fully memristive neural network consisting of these artificial synapses and neurons for the first time. In addition, the intrinsic stochasticity of the delay mechanism has been used to realize a true random number generators for security solutions.
The Effects of Synthetic<i>α</i>-Subunit Peptides on Thyroid-Stimulating Immunoglobulin Activity* (1988)

Synthetic peptides, representing specific portions of the alpha-subunit of the human glycoprotein hormones, can inhibit both the binding of labeled TSH to thyroid membranes and adenylate cyclase stimulation by TSH in vitro. The same synthetic peptides (alpha 26-46 and alpha 31-45) significantly (P less than 0.05) inhibited the adenylate cyclase-stimulating activity of thyroid-stimulating immunoglobulins (TSI) from 10 patients with hyperthyroid Graves' disease. Peptide alpha 26-46 was the most potent, resulting in 79.1 +/- 8.8% (+/- SE) inhibition at 133 micrograms/mL, while peptide alpha 31-45 inhibited TSI activity by 36.3 +/- 5.2%. Peptides alpha 61-75 and alpha 81-92, that had only minimal ability to inhibit TSH-mediated cAMP generation, did not significantly inhibit TSI activity. The inhibitory action of alpha 26-46 was dose dependent, and a significant negative correlation was found between the maximum TSI activity of the serum sample and the inhibition achieved by the synthetic peptide, suggesting that differences in TSI affinity and/or titer may account for the variable inhibitory activity of the peptides. These results suggest that TSI interact with the TSH receptor at the site that recognizes the portion of the TSH alpha-subunit represented by the synthetic peptide alpha 26-46 and, thus, support the concept that the TSH-binding site of the TSH receptor is the site of antigen binding between TSI and the thyroid cell.
Synthesis and Renin Inhibitory Properties of a New Soluble Pepstatin Derivative (1980)

A new pepstatin derivative, pepstatinyl arginine methyl ester hydrochloride (pepstatinyl-Arg-O-Me), was synthesized with the aim of increasing water solubility without altering capacity to inhibit the renin-angiotensinogen reaction. Pepstatinyl-Arg-O-Me was shown to inhibit in vitro the reaction between either rat or purified hog renin and the natural rat renin substrate. In a fluorimetric assay, this derivative competitively inhibited the reaction between purified hog renin and a synthetic N-acetyl-tetradecapeptide renin substrate with a Ki of the same order of magnitude as that of pepstatin. In urethaneanesthetized ganglion-blocked rats, binephrectomized 24 hr before the experiments, both the plasma reinin concentration and the rise in blood pressure following intravenous injection of hog renin were inhibited by pepstatinyl-Arg-O-Me disappeared within 60 min. Pepstatinyl-Arg-O-Me inhibited the 1.4 mumoles/kg. The in vivo inhibitory effect of 1.4 mumoles/kg of pepstatinyl-Arg-O-Me disappeared within 60 min. Pepstatinyl-Arg-Op-Me inhibited the reaction of endogenous and exogenous renin with plasma substrate both in vitro and in vivo.
KpsF Is the Arabinose-5-phosphate Isomerase Required for 3-Deoxy-d-manno-octulosonic Acid Biosynthesis and for Both Lipooligosaccharide Assembly and Capsular Polysaccharide Expression in Neisseria meningitidis (2002)

We have identified and defined the function of kpsF of Neisseria meningitidis and the homologues of kpsF in encapsulated K1 and K5 Escherichia coli. KpsF was shown to be the arabinose-5-phosphate isomerase, an enzyme not previously identified in prokaryotes, that mediates the interconversion of ribulose 5-phosphate and arabinose 5-phosphate. KpsF is required for 3-deoxy-d-manno-octulosonic acid (Kdo) biosynthesis in N. meningitidis. Mutation of kpsF or the gene encoding the CMP-Kdo synthetase (kpsU/kdsB) in N. meningitidis resulted in expression of a lipooligosaccharide (LOS) structure that contained only lipid A and reduced capsule expression in the five invasive disease-associated meningococcal serogroups (A, B, C, Y, and W-135). The step linking meningococcal capsule and LOS biosynthesis was shown to be Kdo production as the expression of capsule was wild type in a Kdo transferase (kdtA) mutant. Thus, in addition to lipooligosaccharide assembly, Kdo is required for meningococcal capsular polysaccharide expression. Furthermore, N. meningitidis, unlike enteric Gram-negative bacteria, can survive and synthesize only unglycosylated lipid A.