gebhart/patrepeval huggingface dataset:
Engineered Biosynthesis of a Complete Macrolactone in a Heterologous Host (1994)

Macrocyclic polyketides have been subjects of great interest in synthetic and biosynthetic chemistry because of their structural complexity and medicinal activities. With expression of the entire 6-deoxyerythronolide B synthase (DEBS) (10,283 amino acids) in a heterologous host, substantial quantities of 6-deoxyerythronolide B (6dEB), the aglycone of the macrolide antibiotic erythromycin, and 8,8a-deoxyoleandolide, a 14-membered lactone ring identical to 6dEB except for a methyl group side chain in place of an ethyl unit, were synthesized in Streptomyces coelicolor. The biosynthetic strategy utilizes a genetic approach that facilitates rapid structural manipulation of DEBS or other modular polyketide synthases (PKSs), including those found in actinomycetes with poorly developed genetic methods. From a technological viewpoint, this approach should allow the rational design of biosynthetic products and may eventually lead to the generation of diverse polyketide libraries by means of combinatorial cloning of naturally occurring and mutant PKS modules.
Inhibitory signaling blocks activating receptor clustering and induces cytoskeletal retraction in natural killer cells (2011)

Natural killer (NK) lymphocytes use a variety of activating receptors to recognize and kill infected or tumorigenic cells during an innate immune response. To prevent targeting healthy tissue, NK cells also express numerous inhibitory receptors that signal through immunotyrosine-based inhibitory motifs (ITIMs). Precisely how signals from competing activating and inhibitory receptors are integrated and resolved is not understood. To investigate how ITIM receptor signaling impinges on activating pathways, we developed a photochemical approach for stimulating the inhibitory receptor KIR2DL2 during ongoing NK cell-activating responses in high-resolution imaging experiments. Photostimulation of KIR2DL2 induces the rapid formation of inhibitory receptor microclusters in the plasma membrane and the simultaneous suppression of microclusters containing activating receptors. This is followed by the collapse of the peripheral actin cytoskeleton and retraction of the NK cell from the source of inhibitory stimulation. These results suggest a cell biological basis for ITIM receptor signaling and establish an experimental framework for analyzing it.
Potential Induced Degradation of solar cells and panels (2010)

Since solar energy generation is getting more and more important worldwide PV systems and solar parks are becoming larger consisting of an increasing number of solar panels being serially interconnected. As a consequence panels are frequently exposed to high relative potentials towards ground causing High Voltage Stress (HVS). The effect of HVS on long term stability of solar panels depending on the leakage current between solar cells and ground has been first addressed by NREL in 2005. This potential degradation mechanism is not monitored by the typical PV tests listed in IEC 61215. Depending on the technology different types of Potential Induced Degradation (PID) occur. This paper is focusing on PID of wafer based standard p-type silicon technology aiming on increasing life times for solar panels once exposed to external potentials in the field. A test setup is presented for simulation of the PID in the lab and the influence of cell properties on PID is demonstrated in order to reveal the cell being the precondition for the PID. However, PID can also be stopped or minimized on panel and system level as shown in the paper.
Entry of protein toxins in polarized epithelial cells. (1993)

The action of a number of toxins used in the formation of immunotoxins was studied in polarized cells. Diphtheria toxin inhibited protein synthesis most efficiently when added to the basolateral side of the kidney cells, MDCK-I, MDBK and Pt K2, and the colon carcinoma cell Caco-2. Similar findings were made with Pseudomonas aeruginosa exotoxin A in MDCK-I, Pt K2, and Caco-2 cells, and with modeccin and volkensin in MDCK-I cells. In accordance with the toxicity data, diphtheria toxin bound specifically to the basolateral side of MDCK-I cells but not to the apical side. On the other hand, in the trophoblastic BeWo cell line there was little or no difference in the toxic effect of P. aeruginosa exotoxin A and modeccin added to the two sides. The plant toxins ricin and abrin and the bacterial Shigella toxin inhibited protein synthesis approximately equally well in all cell lines tested whether they were added apically or basolaterally. The results indicate that protein toxins are able to enter cells from both the apical and basolateral sides provided receptors are present. The consequences for the preparation of immunotoxins are discussed.
Synthesis and characterization of Co-Zn ferrite nanoparticles for application to magnetic hyperthermia (2017)

Co-Zn ferrite nanoparticles have been investigated, aiming at a further improvement of the magnetic hyperthermia properties for bio-medical applications. We precisely tune the magnetic and the thermal properties of Co x Zn1−x Fe2O4 nanoparticles, prepared by using a high-temperature thermal-decomposition method, by chemically controlling the cation. The structure and the magnetic properties as well as the AC-heating characteristics of the synthesized Co x Zn1−x Fe2O4 were measured by using X-ray diffraction (XRD), vibrating sample magnetometer, magneTherm device and Mössbauer spectroscopy. The analysis of the XRD patterns confirmed the spinel phase, the crystalline size, and the lattice parameter. The magnetic behavior of Co-Zn ferrite was studied with M-H hysteresis curve measurements at room temperature. Also, the thermal properties were measured under an external applied field of 250 Oe at 112 kHz. In addition, we plasma-treated the samples with magnetic and thermal excellent characteristics for 30 min at room temperature. The cation distribution was investigated with Mössbauer spectroscopy and further analyzed with one sextet for the tetrahedral A site and four six-lines for the octahedral B1, B2, B3, and B4 sites.
Histone H2AX Is Phosphorylated in an ATR-dependent Manner in Response to Replicational Stress (2001)

H2AX, a member of the histone H2A family, is rapidly phosphorylated in response to ionizing radiation. This phosphorylation, at an evolutionary conserved C-terminal phosphatidylinositol 3-OH-kinase-related kinase (PI3KK) motif, is thought to be critical for recognition and repair of DNA double strand breaks. Here we report that inhibition of DNA replication by hydroxyurea or ultraviolet irradiation also induces phosphorylation and foci formation of H2AX. These phospho-H2AX foci colocalize with proliferating cell nuclear antigen (PCNA), BRCA1, and 53BP1 at the arrested replication fork in S phase cells. This response is ATR-dependent but does not require ATM or Hus1. Our findings suggest that, in addition to its role in the recognition and repair of double strand breaks, H2AX also participates in the surveillance of DNA replication.
Hydrolysis of palm olein catalyzed by solid heteropolyacids (2002)

Abstract The hydrolysis activity of superacids on palm olein, including tungstophosphoric acid and molybdophosphoric acid and their partially ion‐exchanged cesium (Cs) salt, were investigated and compared with macroporous cation‐exchanged resin and aluminum‐incorporated mesoporous molecular sieve. The activities of the superacids supported on the resin and silica were also determined. The reactions were carried out in a stirred batch reactor with continuous steam injection at temperatures from 140 to 180°C. The reaction kinetics, obtained by regression, are first order with respect to TG of the superacids and Cs salts. Of the catalysts studied, the superacids loaded onto cation‐exchanged resins were the most active on a weight basis. However, in terms of the turnover number per acid site, the Cs salt of tungstophosphoric acid had 13 times the activity of the cation‐exchanged resin. The original superacids had lower activities than the Cs salts in terms of their turnover number. The observations are qualitatively in line with the higher acid strengths of the catalysts, as confirmed by the low activity of the aluminum silicate mesoporous molecular sieve, which is known to have a high concentration of low‐to moderate‐strength acid sites. The activation energy of the reaction with the Cs salts was ∼49 kJ mol −1 . This is rather low as compared to that catalyzed by the cation‐exchanged resin.
Electroless nickel plated contacts on porous silicon (1996)

We have presented the electroless nickel plating technique as a preferred method for making ohmic or rectifying contacts on porous silicon. Nickel, plated by this technique, penetrates the pores and forms contact on an effective area, about 4.5 times the actual area of the sample. High-temperature annealing of the plated metal produced excellent ohmic contacts with porous silicon formed on n-type silicon. The properties of this contact are shown to be much superior to that of conventional evaporated and alloyed ohmic contacts made on p-type porous silicon of identical characteristics. Contacts made under similar conditions by electroless nickel plating on p-type porous silicon, on the other hand, showed good rectifying diode characteristics. The observed electrical properties of electroless nickel contacts are believed to be due to the presence of minute amounts of phosphorous with the plated metal.
An Indoor Variance-Based Localization Technique Utilizing the UWB Estimation of Geometrical Propagation Parameters (2018)

A novel localization framework is presented based on ultra-wideband (UWB) channel sounding, employing a triangulation method using the geometrical properties of propagation paths, such as time delay of arrival, angle of departure, angle of arrival, and their estimated variances. In order to extract these parameters from the UWB sounding data, an extension to the high-resolution RiMAX algorithm was developed, facilitating the analysis of these frequency-dependent multipath parameters. This framework was then tested by performing indoor measurements with a vector network analyzer and virtual antenna arrays.The estimated means and variances of these geometrical parameters were utilized to generate multiple sample sets of input values for our localization framework. Next to that, we consider the existence of multiple possible target locations, which were subsequently clustered using a Kim–Parks algorithm, resulting in a more robust estimation of each target node. Measurements reveal that our newly proposed technique achieves an average accuracy of 0.26, 0.28, and 0.90 m in line-of-sight (LoS), obstructed-LoS, and non-LoS scenarios, respectively, and this with only one single beacon node. Moreover, utilizing the estimated variances of the multipath parameters proved to enhance the location estimation significantly compared to only utilizing their estimated mean values.
Human Adenoviruses and Coliphages in Urban Runoff-Impacted Coastal Waters of Southern California (2001)

A nested-PCR method was used to detect the occurrence of human adenovirus in coastal waters of Southern California. Twenty- to forty-liter water samples were collected from 12 beach locations from Malibu to the border of Mexico between February and March 1999. All sampling sites were located at mouths of major rivers and creeks. Two ultrafiltration concentration methods, tangential flow filtration (TFF) and vortex flow filtration (VFF), were compared using six environmental samples. Human adenoviruses were detected in 4 of the 12 samples tested after nucleic acid extraction of VFF concentrates. The most probable number of adenoviral genomes ranged from 880 to 7,500 per liter of water. Coliphages were detected at all sites, with the concentration varying from 5.3 to 3332 PFU/liter of water. F-specific coliphages were found at 5 of the 12 sites, with the concentration ranging from 5.5 to 300 PFU/liter. The presence of human adenovirus was not significantly correlated with the concentration of coliphage (r = 0.32) but was significantly correlated (r = 0.99) with F-specific coliphage. The bacterial indicators (total coliforms, fecal coliforms, and enterococci) were found to exceed California recreational water quality daily limits at 5 of the 12 sites. However, this excess of bacterial indicators did not correlate with the presence of human adenoviruses in coastal waters. The results of this study call for both a reevaluation of our current recreational water quality standards to reflect the viral quality of recreational waters and monitoring of recreational waters for human viruses on a regular basis.
Effect of Surface Microstructure on Electrochemical Performance of Garnet Solid Electrolytes (2015)

Cubic garnet phases based on Al-substituted Li7La3Zr2O12 (LLZO) have high ionic conductivities and exhibit good stability versus metallic lithium, making them of particular interest for use in next-generation rechargeable battery systems. However, high interfacial impedances have precluded their successful utilization in such devices until the present. Careful engineering of the surface microstructure, especially the grain boundaries, is critical to achieving low interfacial resistances and enabling long-term stable cycling with lithium metal. This study presents the fabrication of LLZO heterostructured solid electrolytes, which allowed direct correlation of surface microstructure with the electrochemical characteristics of the interface. Grain orientations and grain boundary distributions of samples with differing microstructures were mapped using high-resolution synchrotron polychromatic X-ray Laue microdiffraction. The electrochemical characteristics are strongly dependent upon surface microstructure, with small grained samples exhibiting much lower interfacial resistances and better cycling behavior than those with larger grain sizes. Low area specific resistances of 37 Ω cm(2) were achieved; low enough to ensure stable cycling with minimal polarization losses, thus removing a significant obstacle toward practical implementation of solid electrolytes in high energy density batteries.
Optical observation of contrast agent destruction (2000)

Fragmentation of an ultrasound contrast agent on the time scale of microseconds provides opportunities for the advancement of microvascular detection, blood flow velocity estimation, and targeted drug delivery. Images captured by high-speed imaging systems show destruction of a microbubble during compression. Peak wall velocity of −700 m/s and peak acceleration of 1.2×1012 m/s2 is observed for insonation with a peak pressure of −1.1 MPa and a center frequency of 2.4 MHz. Theoretical calculations of wall velocity and acceleration using a modified Rayleigh–Plesset model predict a peak negative wall velocity of −680 m/s and peak acceleration of 2×1012 m/s2.
Local birefringence measurements in single-mode fibers with coherent optical frequency-domain reflectometry (1998)

Measurements of intrinsic and induced birefringence of optical fibers are performed at 1550 nm using the optical frequency-domain reflectometry technique. The experiment confirms the theoretical analysis, which predicts the appearance of oscillations on the detected Rayleigh backscattering intensity, with periods equal to the polarization beat length L/sub b/ and to L/sub b//2. Polarization mode-coupling length values are obtained from local birefringence and polarization mode dispersion measurements.
A single point mutation in ecdysone receptor leads to increased ligand specificity: Implications for gene switch applications (2002)

The ecdysone receptor (EcR), a member of the nuclear receptor superfamily, plays an important role in regulating development and reproduction in insects. The EcR binds to ecdysteroids and regulates transcription of genes that contain ecdysone response elements. The EcR has been used to develop inducible gene switches for efficient regulation of foreign genes in applications such as gene therapy, protein production, and functional genomics. An EcR [Choristoneura fumiferana EcR (CfEcR)] homology model was constructed, and 17 amino acid residues were identified as critical for 20-hydroxyecdysone binding. Mutation of these amino acids followed by analysis of these mutants in transactivation (in insect and mammalian cells and in vivo in mice) and ligand-binding assays identified one particular mutant (A110P) that failed to respond to steroids, but its response to the diacylhydrazine nonsteroidal ligands RG-102240 (GS(TM)E) and RG-102317 was unaffected. This steroid-insensitive EcR mutant has potential gene switch applications in insects and plants that have endogenous ecdysteroids. In addition, this mutant would be also useful for developing orthogonal EcR-ligand pairs for simultaneous regulation of multiple genes in the same cell.
An auto-calibration method for Unattended Ground Sensors (2002)

We present an algorithm for locating and orienting a set of sensor arrays that have been deployed in a scene at unknown locations and orientation angles. This self-calibration problem is solved using a number of source signals also deployed in the scene. We assume each array can estimate the time-of-arrival and direction-of-arrival of every source. From this information we compute the array locations and orientations. We consider four subproblems, in which the source signals or emission times are either known or unknown. We develop necessary conditions for solving the self-calibration problem and provide a maximum likelihood solution and corresponding location error estimate.
Loss of transforming growth factor-β type II receptor promotes metastatic head-and-neck squamous cell carcinoma (2006)

The prognosis of head-and-neck squamous cell carcinoma (HNSCC) has not been improved in the past 20 years. Validation of HNSCC biomarkers for targeted therapy has been hindered by a lack of animal models mimicking human HNSCC at both the pathological and molecular levels. Here we report that overexpression of K-ras or H-ras and loss of transforming growth factor-beta type II receptor (TGFbetaRII) are common events in human HNSCC. Activation of either K-ras or H-ras in combination with TGFbetaRII deletion from mouse head-and-neck epithelia caused HNSCC with complete penetrance, some of which progressed to metastases. These tumors displayed pathology indistinguishable from human HNSCCs and exhibited multiple molecular alterations commonly found in human HNSCCs. Additionally, elevated endogenous TGFbeta1 in these lesions contributed to inflammation and angiogenesis. Our data suggest that targeting common oncogenic pathways in tumor epithelia together with blocking the effect of TGFbeta1 on tumor stroma may provide a novel therapeutic strategy for HNSCC.
Stimulation of Matrix Metalloproteinase Production by Recombinant Extracellular Matrix Metalloproteinase Inducer from Transfected Chinese Hamster Ovary Cells (1997)

Many of the tumor-associated matrix metalloproteinases that are implicated in metastasis are produced by stromal fibroblasts within or surrounding the tumor in response to stimulation by factors produced by tumor cells. In this study we transfected Chinese hamster ovary cells with putative cDNA for human extracellular matrix metalloproteinase inducer (EMMPRIN), a transmembrane glycoprotein that is attached to the surface of many types of malignant human tumor cells and that has previously been implicated in stimulation of matrix metalloproteinase production in fibroblasts. We show that these transfected cells synthesize EMMPRIN that is extensively post-translationally processed; this recombinant EMMPRIN stimulates human fibroblast production of interstitial collagenase, stromelysin-1, and gelatinase A (72-kDa type IV collagenase). We propose that EMMPRIN regulates matrix metalloproteinase production during tumor invasion and other processes involving tissue remodeling. Many of the tumor-associated matrix metalloproteinases that are implicated in metastasis are produced by stromal fibroblasts within or surrounding the tumor in response to stimulation by factors produced by tumor cells. In this study we transfected Chinese hamster ovary cells with putative cDNA for human extracellular matrix metalloproteinase inducer (EMMPRIN), a transmembrane glycoprotein that is attached to the surface of many types of malignant human tumor cells and that has previously been implicated in stimulation of matrix metalloproteinase production in fibroblasts. We show that these transfected cells synthesize EMMPRIN that is extensively post-translationally processed; this recombinant EMMPRIN stimulates human fibroblast production of interstitial collagenase, stromelysin-1, and gelatinase A (72-kDa type IV collagenase). We propose that EMMPRIN regulates matrix metalloproteinase production during tumor invasion and other processes involving tissue remodeling.
On minimizing hierarchical mesh coding overhead: (HASM) hierarchical adaptive structured mesh approach (2002)

This paper presents an efficient mesh coding technique suitable for MPEG-4 video applications. The proposed technique significantly reduces the number of bits that are used to describe the mesh topology. It uses an adaptive structured mesh from coarse to fine, which can be coded as a count of splitting instead of nodes' locations. In the case of the quadtree, less than one bit per node can be achieved. This reduction induces an improvement of either the image quality or the global bit rate.
Cellular Maintenance and Repair of the Kidney (2010)

The mammalian kidney is a highly complex organ that requires the precise structural arrangement of multiple cell types for effective function. The need to filter large volumes of plasma at the glomerulus followed by active reabsorption of nearly 99% of that filtrate by the tubules creates vulnerability in both compartments for cell injury. Thus maintenance of cell viability and replacement of those cells that are lost are essential for functional stability of the kidney. This review addresses our current understanding of how cells from the glomerular, tubular, and interstitial compartments arise during development and the manner in which they may be regenerated in the adult organ. In addition, we discuss the data regarding the role of organ-specific and bone marrow-derived stem and progenitor cells in the replacement/repair process, as well as the potential for ex vivo programming of stem cells toward a renal lineage.
Vapor-liquid-solid growth of germanium nanostructures on silicon (2004)

The pressure and temperature dependencies for vapor-liquid-solid (VLS) growth of Ge nanostructures on Si using chemical vapor deposition are reported. Gold nanodots self-assembled by evaporation on clean hydrogen-terminated and heated Si substrates are used to seed the liquid eutectic VLS growth. Digermane pressures are varied from 4×10−5 to 1×10−2Torr and substrate temperatures from 400 to 600°C for heteroepitaxial growth on Si(111). Two types of nanostructures are identified, nanowires and nanopillars, with a transition from nanopillar growth to nanowire growth occurring with increasing pressure. Nanowires are characterized by rapid vertical growth, long-aspect-ratio structures, and linear dependence of the growth rate on pressure. At lower pressures a transition to nanopillars is observed; these exhibit both vertical and lateral growth with typical aspect ratios of 1:2. For Si(111) substrates nanowires grow epitaxially with their growth axis along the ⟨111⟩ direction. High-resolution transmission electron microscopy shows that the Ge nanowires are relaxed to their equilibrium lattice spacings a short distance from the Si substrate interface.