nils-herrmann/clean_scirepeval huggingface dataset:
Primary structure determination of peptides and proteins by mass spectrometry

A pressing problem in modern organic chemistry is the determination of the structure of polypeptides and proteins, for it is here that the needs and interests of biochemistry have far surpassed present chemical possibilities, while elucidation of many a biological problem on the molecular level requires a clear understanding of the relation between structure and biological function. I should like to survey here the studies we have carried out in recent years that have led to the proposal of a new, general method for determining the amino acid sequence in peptides and proteins by means of mass spectrometry. As is well known the primary structure of proteins determines the architecture of the molecule as a whole, including its conformational specificities and in the long run its biological properties. Therefore, determination of the amino acid sequence is one of the basic requisites for further progress in physicochemical and biological investigations of proteins. What means do we actually possess for making such a determination? At present the selective chemical or enzymatic degradation of the protein molecule into polypeptide fragments and their separation presents no basic difficulties. However, determination of the amino acid sequence in these polypeptide fragments rapidly and with unequivocal results is not always an easy task, particularly in view of the fact that in the majority of cases one has to deal with microquantities of substance. All methods used for this purpose are based on the stepwise chemical or enzymatic cleavage of the amino acid residues, beginning with the Nor C-terminus. Usually thereby the positions of not more than 1—3 residues can reliably be established. The only exception is Edman's phenylthiohydantoin method which allows determination of 4—6 N-terminal amino acid residues. Possibly, using Edman's automatic "sequenator" the method will permit determination directly in the protein chain of much larger fragments1. However, the sequenator has not left the experimental stage. At the same time the problem of the primary structure elucidation of proteins is so important and the aims are so varied that it is necessary to have available several fundamentally differing methods, not only for the sake of mutual control, but also for the solution of the particular problems. For instance, the sequenator cannot be used to determine the primary structure

Field of study: Chemistry
THE SHORT-LEG SHEAR WALL ELEMENT BASED ON THE ANALYTICAL TRIAL FUNCTION METHOD

Based on the analytical trial function method,a new beam-shell element is developed for the analysis of short-leg shear walls and tie-beams. The proposed element is constructed directly in the Cartesian coordinate system. In order to obtain high-order assumed displacement fields,some basic analytical solutions for elastic planar problems are taken as the trial functions,and the deformation characteristics of short-leg shear walls and tie-beams are also considered. Numerical examples show that the resulting element model possesses better precision in the analysis of various engineering structures of the short-leg shear wall and tie-beam,and it is insensitive to mesh the distortion caused by the aspect ratio. It also demonstrates that the present strategy is an effective way for developing high performance finite element models with simple formulations.

Field of study: Engineering
Using constructed analogs to improve the skill of National Multi-Model Ensemble March–April–May precipitation forecasts in equatorial East Africa

In this study we implement and evaluate a simple ‘hybrid’ forecast approach that uses constructed analogs (CA) to improve the National Multi-Model Ensemble’s (NMME) March–April–May (MAM) precipitation forecasts over equatorial eastern Africa (hereafter referred to as EA, 2°S to 8°N and 36°E to 46°E). Due to recent declines in MAM rainfall, increases in population, land degradation, and limited technological advances, this region has become a recent epicenter of food insecurity. Timely and skillful precipitation forecasts for EA could help decision makers better manage their limited resources, mitigate socio-economic losses, and potentially save human lives. The ‘hybrid approach’ described in this study uses the CA method to translate dynamical precipitation and sea surface temperature (SST) forecasts over the Indian and Pacific Oceans (specifically 30°S to 30°N and 30°E to 270°E) into terrestrial MAM precipitation forecasts over the EA region. In doing so, this approach benefits from the post-1999 teleconnection that exists between precipitation and SSTs over the Indian and tropical Pacific Oceans (Indo-Pacific) and EA MAM rainfall. The coupled atmosphere-ocean dynamical forecasts used in this study were drawn from the NMME. We demonstrate that while the MAM precipitation forecasts (initialized in February) skill of the NMME models over the EA region itself is negligible, the ranked probability skill score of hybrid CA forecasts based on Indo-Pacific NMME precipitation and SST forecasts reach up to 0.45.

Field of study: Environmental science
Die Hyperfeinstruktur der übergÄnge65Cu, 5s2S1/2-4p2P1/2 und 3d10 4p2P1/2-3d9 4s2m2D3/2und das Quadrupolmoment von65Cu

ZusammenfassungUnter Verwendung von isotopenreinem Kupfer 65 wurde die Hyperfeinstruktur der übergÄnge65Cu, 5s2S1/2 −4p2P1/2 und 3d10 4p2P1/2 −3d94s2m2D3/2 interferenzspektroskopisch untersucht. Aus demB-Faktor des Termsm2D3/2 wird für das Quadrupolmoment von Kupfer 65 der WertQ(65Cu)=−(0,16±0,01) · 10−24 cm2 ermittelt.

Field of study: Physics
Endocrine effects of meternal alcoholization: plasma and brain testosterone, dihydrotestosterone, estradiol, and corticosterone.

Maternal ethanol consumption was associated with reduced levels of dihydrotestosterone in the brains of 1--2-day-old male rats when compared to those of sex-matched pups obtained from dames that were fed sucrose. In contrast, brain levels of corticosterone were increased significantly in the pups of ethanol-fed animals when compared to those from sucrose-fed controls. Brain and plasma estradiol did not differ between groups. These results suggest that maternal ethanol consumption may influence the central nervous system and plasma levels of certain steroidal hormones in the offspring.

Field of study: Medicine
A Radio-to-mm Census of Star-forming Galaxies in Protocluster 4C23.56 at Z = 2.5: Gas Mass and Its Fraction Revealed with ALMA

We investigate gas contents of star-forming galaxies associated with protocluster 4C23.56 at z = 2.49 by using the redshifted CO (3-2) and 1.1 mm dust continuum with the Atacama Large Millimeter/submillimeter Array. The observations unveil seven CO detections out of 22 targeted Hα emitters (HAEs) and four out of 19 in 1.1 mm dust continuum. They have high stellar mass ({M}\star > 4× {10}10 M ⊙) and exhibit a specific star-formation rate typical of main-sequence star-forming galaxies at z˜ 2.5. Different gas-mass estimators from CO (3-2) and 1.1 mm yield consistent values for simultaneous detections. The gas mass ({M}{gas}) and gas fraction ({f}{gas}) are comparable to those of field galaxies, with {M}{gas}=[0.3,1.8]× {10}11× ({α }{CO}/(4.36× A(Z))) {M}⊙ , where {α }{CO} is the CO-to-H2 conversion factor and A(Z) is the additional correction factor for the metallicity dependence of {α }{CO}, and =0.53+/- 0.07 from CO (3-2). Our measurements place a constraint on the cosmic gas density of high-z protoclusters, indicating that the protocluster is characterized by a gas density higher than that of the general fields by an order of magnitude. We found ρ ({H}2)˜ 5× {10}9 {M}⊙ {{Mpc}}-3 with the CO(3-2) detections. The five ALMA CO detections occur in the region of highest galaxy surface density, where the density positively correlates with global star-forming efficiency (SFE) and stellar mass. Such correlations possibly indicate a critical role of the environment on early galaxy evolution at high-z protoclusters, though future observations are necessary for confirmation.

Field of study: Physics
Time-dependent Hartree-Fock study of Octupole vibrations in doubly magic nuclei

Octupole vibrations are studied in some doubly magic nuclei using the time-dependent Hartree-Fock (TDHF) theory with a Skyrme energy density functional. Through the use of the linear response theory, the energies and transition amplitudes of the low-lying vibrational modes for each of the nuclei were determined. Energies were found to be close to experimental results. However, transition amplitudes, quantified by the deformation parameter β 3 , are underestimated by TDHF. A comparison with single-particle excitations on the Hartree-Fock ground-state shows that the collective octupole vibrations have their energy lowered due to attractive RPA residual interaction.

Field of study: Physics
Tomographic retrieval approach for mesoscale gravity wave observations by the PREMIER Infrared Limb-Sounder

PREMIER is one of three candidates for ESA's 7th Earth Explorer mission that are currently undergoing feasibility studies. The main mission objective of PREMIER is to quantify processes controlling atmospheric composition in the mid/upper troposphere and lower stratosphere, a region of particular importance for climate change. To achieve this objective, PREMIER will employ the first satellite Fourier transform infrared limb-imager with a 2-D detector array combined with a millimetre-wave limb-sounder. The infrared limb-imager can be operated in a high spatial resolution mode ("dynamics mode") for observations of small-scale structures in atmospheric temperatures and trace gas fields with unprecedented 3-D sampling (0.5 km in the vertical direction, 50 km along track, 25 km across track). In this paper, a fast tomographic retrieval scheme is presented, which is designed to fully exploit the high-resolution radiance observations of the dynamics mode. Based on a detailed analysis of the "observational filter", we show that the dynamics mode provides unique information on global distributions of gravity waves (GW). The achievable vertical resolution for GW observations has values between the vertical sampling (0.5 km) of the dynamics mode and the vertical field of view (about 0.75 km). The horizontal across track resolution corresponds to the horizontal across track sampling of 25 km. Since the achievable along track horizontal resolution is about 70 km, the dynamics mode will provide GW limb-observations with a horizontal resolution comparable to nadir sounders. Compared to previous observations, PREMIER will therefore considerably extend the range of detectable GWs in terms of horizontal and vertical wavelength.

Field of study: Environmental science
LATE PLEISTOCENE GLACIATION OF EASTERN NEWFOUNDLAND

Melting of the late Pleistocene ice sheet has left a semicircle of glacial deposits around the coast of eastern Newfoundland west of the Avalon Peninsula. A discontinuous end moraine accentuates the curvature and separates ground moraine on the coastal side (outer drift zone) from slightly younger eskers, kames, and ground moraine on the inner side (inner drift zone). The distribution of ground moraine, glacial striations, indicator boulders, and glaciated bedrock ridges in the two drift zones indicates that an ice sheet once covered all eastern Newfoundland west of the Avalon Peninsula. The ice center was somewhere in western Newfoundland. At about the same time local ice caps existed on the Avalon Peninsula. Small valley glaciers persisted in a few elevated regions of the north and south coasts west of longitude 55° after the retreat of the main ice sheet. Eastern Newfoundland appears to be tilting upward toward the northwest, with a zero isobase passing through Trinity and Placentia bays. Northwest of this axis the coast is emerging; southeast of it (on the Avalon Peninsula) the coast is submerging. The zero isobase veers west along the south shore of Newfoundland, parts of which are submerging, parts emerging.

Field of study: Geology
Design Optimization of Radiation-Hardened CMOS Integrated Circuits

Ionizing-radiation-induced threshold voltage shifts in CMOS integrated circuits will drastically degrade circuit performance unless the design parameters related to the fabrication process are properly chosen. To formulate an approach to CMOS design optimization, experimentally observed analytical relationships showing strong dependences between threshold voltage shifts and silicon dioxide thickness are utilized. These measurements were made using radiation-hardened aluminum-gate CMOS inverter circuits and have been corroborated by independent data taken from MOS capacitor structures. Knowledge of these relationships allows one to define ranges of acceptable CMOS design parameters based upon radiation-hardening capabilities and post-irradiation performance specifications. Furthermore, they permit actual design optimization of CMOS integrated circuits which results in optimum pre-and post-irradiation performance with respect to speed, noise margins, and quiescent power consumption. Theoretical and experimental results of these procedures, the applications of which can mean the difference between failure and success of a CMOS integrated circuit in a radiation environment, are presented.

Field of study: Physics
Sensitivity of the epeiric sea carbon isotope record to local-scale carbon cycle processes: Tales from the Mohawkian Sea

Ancient marine carbon isotope records derived from epeiric sea carbonates can bear a strong influence of local-scale carbon cycling processes. Across the Late Ordovician Mohawkian Sea of eastern Laurentia, the carbon isotope compositions (d 13 C) of contemporaneous sediments range from ! 2x in the interior of the sea to +2.5x along the margin. Here we use a box model to explore the relative importance of carbon fluxes within the Mohawkian Sea from a mass balance perspective. In the model, the Mohawkian Sea carbon reservoir is coupled to but distinct from the ocean and atmosphere carbon reservoirs. At initial steady state conditions, the residence time of carbon in the Mohawkian Sea is less than 10 years. We find that to produce model d 13 C values representative of the range in d 13 C across the Mohawkian Sea we must divide the sea into an inner region and an outer region and limit dissolved inorganic carbon (DIC) exchange between the two to 15% of the initial steady state unrestricted exchange rate. It is also necessary to supply low d 13 C carbon (! 29x) to the inner region of the sea at a rate of 17.4" 10 12 mol C yr ! 1 . The required flux of low d 13 C carbon could not have been sustained over the long term by remineralization of organic carbon stored in sediments of the inner region of the Mohawkian Sea, and the geographic d 13 C pattern is unlikely to have been generated by upwelling along the Sebree Trough. Rather, the low d 13 C flux might have been derived from bryophytedominated terrestrial ecosystems, suggesting an important role for terrestrial carbon cycling prior to the advent of vascular plants. Aninterestingfeatureofthemodelisthattheisotopiccompositionsofboththeepeiric seaandthelargerocean-atmospheresystem are sensitive to changes in exchange rates within the epeiric sea. This has important implications for interpreting global d 13 C

Field of study: Environmental science, Geography
Organized Interests and American Political Development

The striking resonance of these quotations from leading interest group scholars generations apart suggests that something remarkably similar may have been happening at both ends of the twentieth century. Contemporary political science offers no shortage of careful research on the behavior of organized interest groups and their place in democratic theory. Yet this impressive body of scholarship routinely concentrates on the past half century of interest group politics. This article highlights the need to expand the time horizons of

Field of study: Political science
Evaluation of Phytotoxicity of Soyasaponin Against Some Problematic Weeds

The Phytotoxic properties of plant chemicals can he exploited as a tool for weed control. Phytotoxicity of soyasaponin isolated from soybean (Glycine max L.) seeds was tested on shoot and root growth of most problematic weeds of rice and wheat fields viz. Echinochloa colona, Vicia sativa and Ischaemum rogusum. Soyasaponin was extracted from defatted seed powder of soybean seeds and identified by thin layer chromatography. Results showed that soyasaponin isolated from G. max has the potential to completely inhibit the growth of E. colona at 1.25% and I. rogusum and V. sativa at 5 and 10 % concentrations, respectively under lab condition.

Field of study: Biology
Research on Friction Behavior in Powder Compaction Process

The friction coefficient in the powder compaction process was measured by adopting plane shearing friction method. The results show that the friction coefficient is a dynamic parameter. When the nether slider starts to move, the friction coefficient increases dramatically. After it reaches the peak, it tends to be gentle and at last stable. With the increase of pressure, the friction coefficient declines while the density of the blank is enhanced gradually.

Field of study: Materials science
Improvement of a Forward-Secure Multi-Proxy Signature Scheme

This paper shows some insecurities in Xu’s forward secure multi-proxy signature scheme. There are two kinds of attacks on this scheme: (1) anyone can forge some certain messages which to be sign and cannot detect by the signature verifier. (2) This scheme can’t resist the dishonest signer forgery attack by forging its own public key. After that, the paper proposed two new forward-secure multi-proxy signature schemes based on discrete logarithm problem and quadratic residues. With verifying all the signers’ public keys, the improved schemes can resist lots of outsider attack and insider attack as above mentioned. The validity of the new scheme can be verified, and they are secure multi-signature schemes.

Field of study: Computer science
Study of Interaction of Fluorescein Sodium and Bovine Serum Albumin by Capillary Electrophoresis/Frontal Analysis and Molecular Modeling Technology

The interaction between fluorescein sodium and bovine serum albumin was investigated by capillary electrophoresis/frontal analysis.Free drugs′ concentrations of fluorescein sodium in different systems of fluorescein sodium blended with BSA by different concentration ratio were known through standard curve of drug concentration and plateau peak height.The experimental data were fitted respectively by a Klotz linear and non-linear regression curve fitting program.The binding constant,the numbers of binding sites and thermodynamic parameters were obtained in the temperatures of 286 K and 294 K.The hydrophobic force was determined by thermodynamic parameters.Finally,computer software was also used to simulate the interaction.

Field of study: Chemistry
Sensitivity Improvement of TOFPET by the Utilization of the Inter-Slice Coincidences

Conventional multi-slice positron tomographs have suffered from an inefficient use of the inter-slice coincidence information due to a lack of an appropriate reconstruction algorithm. In order to overcome this deficiency, most multi-slice tomographs use the nearest neighbor coincidence lines and approximate the position of the slice by summing the two sets of lines. This still leaves a fair number of coincidence lines which are discarded. TOFPET, with its ability to localize the positions of the annihilation, overcomes this limitation with a new technique of utilizing all the inter-slice coincidence lines. Each coincidence event is localized in three dimensions and then placed in one of the imaae slices for tomographic reconstruction. With a proper design of the positron camera, this can result in a sensitivity increase of 60% over cameras of similar design but utilizing only the nearest neighbor inter-slice coincidences. We show how this new technique is implemented in the TOFPET camera being constructed at our institution.

Field of study: Physics
Predation scar frequencies in chemosymbiotic bivalves at an Oligocene seep deposit and their potential relation to inferred sulfide tolerances

Three species of chemosymbiotic bivalves with different inferred sulfide tolerances and life habits from a lower Oligocene seep deposit in eastern Hokkaido, Japan, were investigated for drill holes and scars of durophagous predation. The thyasirid Conchocele bisecta had the lowest inferred sulfide tolerance and showed the highest frequencies of repair (0.4) and drilling predation (0.1), and specimens with drill holes were on average smaller than non-drilled specimens, indicating that large size is a refuge from drilling predation in this species. The bathymodiolin Bathymodiolus inouei and the vesicomyid Hubertschenckia ezoensis are inferred to have lived at higher sulfide concentrations than C. bisecta based on comparisons to their living relatives, and show lower repair frequencies (0.24 in B. inouei and 0.17 in H. ezoensis ). Based on the assumption that increased sulfide concentrations are increasingly toxic to predators, we conclude that the frequency of shell injuries in the three investigated species is inversely related to the sulfide concentrations that these species are able to tolerate. Thus when applied carefully, the frequency of shell injuries among shelled invertebrates at fossil seeps may be used to infer their relative tolerances toward sulfide, and may thus represent a tool to assess the life habits of extinct invertebrates that inhabited methane seeps in the geologic past.

Field of study: Environmental science, Geography
Research and Test on the Reform of the Burner in the 1 025 t/h Lean Coal-Fired Boiler

The characteristics of the horizontal -shade burners were introduced in this paper.By comparing the parameters of the burners in 300MW boiler before and afer reformation,it was proved that horizontal -shade burner can improve performance of the boiler at low load effectively ,and at the same time the efficiency of the boiler was improved.

Field of study: Engineering, Physics
Inhibitory properties and X-ray crystallographic study of the binding of AR-101, AR-102 and iclaprim in ternary complexes with NADPH and dihydrofolate reductase from Staphylococcus aureus.

Iclaprim is a novel dihydrofolate reductase (DHFR) inhibitor belonging to the 2,4-diaminopyrimidine class of antibiotics, of which trimethoprim (TMP) is the most well known representative. Iclaprim exhibits potent bactericidal activity against major Gram-positive pathogens, notably methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) phenotypes, including TMP-resistant strains. The inhibition properties of racemic iclaprim and of the two enantiomers, termed AR-101 and AR-102, towards S. aureus wild-type DHFR and TMP-resistant F98Y mutant DHFR were determined and compared. Similar to TMP, AR-101, AR-102 and iclaprim are all competitive inhibitors with respect to the substrate dihydrofolate. Iclaprim, AR-101 and AR-102 demonstrated little or no difference in activity towards these enzymes and were significantly more potent than TMP. The crystal structures of S. aureus DHFR and F98Y mutant DHFR were determined as ternary complexes with NADPH and either AR-101, AR-102 or iclaprim. The binding modes of the inhibitors were analysed and compared. The X-ray crystallographic data explain the binding modes of all molecules well and can be used to rationalize the equipotent affinity of AR-101, AR-102 and iclaprim, which is also reflected in their antibacterial properties.

Field of study: Chemistry