917 research outputs found
Warfare in Late Neolithic\Early Chalcolithic Pisidia, southwestern Turkey. Climate induced social unrest in the late 7th millennium calBC
This paper proposes an association between climate forcing connected with the 8200 calBP ‘climate event’ and a postulated phase of internecine warfare and population collapse at Late Neolithic/Early Chalcolithic sites in Pisidia, southwestern Turkey. A summary of this evidence is provided and a hypothetical scenario considered in the context of contemporaneous developments in neighbouring regions
Release of K-, Cl- und S-Species during Co-Combustion of Coal and Straw
Straw as a renewable energy source can either be used alone or be used in existing coal-fired power plants (co-combustion). The objective of the present work was to investigate the influence of fuel composition and interactions between various types of straw and coal on the release of K, Cl, and S species during co-combustion of coal and straw at temperatures between 800 and 1100 degrees C. The amount of HCl released during co-combustion was higher than expected on the basis of the combustion results of the pure fuels because of the reaction of the straw KCl with the coal silica. However, the amount of potassium released in gaseous form is only slightly lower than expected. The relative amount of sulfur released during co-combustion in comparison to the expected amount depends upon the temperature and the biomass share of the blends. At higher temperatures or lower straw share, the release is increased because of the reaction of the straw K2SO4 with the coal clay minerals. At lower temperatures and high straw share, available straw potassium and calcium capture some coal sulfur
Use of Peptide Libraries for Identification and Optimization of Novel Antimicrobial Peptides.
The increasing rates of resistance among bacteria and to a lesser extent fungi have resulted in an urgent need to find new molecules that hold therapeutic promise against multidrug-resistant strains. Antimicrobial peptides have proven very effective against a variety of multidrug-resistant bacteria. Additionally, the low levels of resistance reported towards these molecules are an attractive feature for antimicrobial drug development. Here we summarise information on diverse peptide libraries used to discover or to optimize antimicrobial peptides. Chemical synthesized peptide libraries, for example split and mix method, tea bag method, multi-pin method and cellulose spot method are discussed. In addition biological peptide library screening methods are summarized, like phage display, bacterial display, mRNA-display and ribosomal display. A few examples are given for small peptide libraries, which almost exclusively follow a rational design of peptides of interest rather than a combinatorial approach
Associations Between Vocal Arousal and Dyadic Coping During Couple Interactions After a Stress Induction
It is well known that although relationship external stressors can harm couples, dyadic coping behavior can buffer the negative effects of stress. Thus far, however, less is known about how vocally encoded stress (i.e., f) might affect the stress-coping process in couples during an interaction. Therefore, the goal of the current study was to compare two different stress hypotheses (i.e., paraverbal communication stress hypothesis and emotional resonance hypothesis). We observed 187 mixed-gender couples (N = 374 participants) interacting naturally after an experimental stress induction (Trier Social Stress Test), for which couples were randomly allocated into three groups (women stressed, men stressed, and both stressed). Results of a multi-group actor-partner interdependence mediation model (APIMeM) show that either the paraverbal communication stress hypothesis or the emotional resonance hypothesis could be confirmed, depending on whether the man, the woman, or both partners were stressed
Cäsium-Sorptionsuntersuchungen an graphitischen Reaktorwerkstoffen
A Knudsen cell-mass spectrometer System has been developed for vapour pressure measurements to determine the sorption isotherms of Cs for graphitic reactor materials. Double Knudsen cells heated by high frequency were employed in this system. A highvacuum furnace with a specially designed oven-cell was used for isopiestic experiments carried out in addition ta the mass spectrometric studies. The Cs equilibrium partial pressure was measured at temperatures 950 and 1820 K oves A3-3 fuel elementmatrix with Cs concentrations between 0.17 and 34.76 mma1/kg. Sorptionisotherms of Cs according to Henry and Freundlich wereevaluated from the vapour pressure data. The sorption enthalpies for CsTob tained indicahte a strong boned by chemisorption. Cssorption of the "reactor graphites" A3-3, A3-27, ASR -1RG, ASR-1RS, ASR-2RS, PAN, P3-JHAN, PXA-2N, H-451, H-327, IG-110 and thecoat-mix materials Cm-100 and Cm-30 resulted by the isopiestic method. It could be shown that graphitic reactor materials wich phenolic resin binder are able to bind a substantially higher amount of Cs by sorption than "reactor graphites" without this binder. More information about the content of this report is given in chapter 8 "Zusammenfassung und Ausblick" (Summary and outlook)
A short artificial antimicrobial peptide shows potential to prevent or treat bone infections.
Infection of bone is a severe complication due to the variety of bacteria causing it, their resistance against classical antibiotics, the formation of a biofilm and the difficulty to eradicate it. Antimicrobial peptides (AMPs) are naturally occurring peptides and promising candidates for treatment of joint infections. This study aimed to analyze the effect of short artificial peptides derived from an optimized library regarding (1) antimicrobial effect on different bacterial species, (2) efficacy on biofilms, and (3) effect on osteoblast‑like cells. Culturing the AMP-modifications with Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus (including clinical isolates of MRSA and MSSA) and Staphylococcus epidermidis identified one candidate that was most effective against all bacteria. This AMP was also able to reduce biofilm as demonstrated by FISH and microcalorimetry. Osteoblast viability and differentiation were not negatively affected by the AMP. A cation concentration comparable to that physiologically occurring in blood had almost no negative effect on AMP activity and even with 10% serum bacterial growth was inhibited. Bacteria internalized into osteoblasts were reduced by the AMP. Taken together the results demonstrate a high antimicrobial activity of the AMP even against bacteria incorporated in a biofilm or internalized into cells without harming human osteoblasts
Comparison of a Short Linear Antimicrobial Peptide with Its Disulfide-Cyclized and Cyclotide-Grafted Variants against Clinically Relevant Pathogens.
According to the World Health Organization (WHO) the development of resistance against antibiotics by microbes is one of the most pressing health concerns. The situation will intensify since only a few pharmacological companies are currently developing novel antimicrobial compounds. Discovery and development of novel antimicrobial compounds with new modes of action are urgently needed. Antimicrobial peptides (AMPs) are known to be able to kill multidrug-resistant bacteria and, therefore, of interest to be developed into antimicrobial drugs. Proteolytic stability and toxicities of these peptides are challenges to overcome, and one strategy frequently used to address stability is cyclization. Here we introduced a disulfide-bond to cyclize a potent and nontoxic 9mer peptide and, in addition, as a proof-of-concept study, grafted this peptide into loop 6 of the cyclotide MCoTI-II. This is the first time an antimicrobial peptide has been successfully grafted onto the cyclotide scaffold. The disulfide-cyclized and grafted cyclotide showed moderate activity in broth and strong activity in 1/5 broth against clinically relevant resistant pathogens. The linear peptide showed superior activity in both conditions. The half-life time in 100% human serum was determined, for the linear peptide, to be 13 min, for the simple disulfide-cyclized peptide, 9 min, and, for the grafted cyclotide 7 h 15 min. The addition of 10% human serum led to a loss of antimicrobial activity for the different organisms, ranging from 1 to >8-fold for the cyclotide. For the disulfide-cyclized version and the linear version, activity also dropped to different degrees, 2 to 18-fold, and 1 to 30-fold respectively. Despite the massive difference in stability, the linear peptide still showed superior antimicrobial activity. The cyclotide and the disulfide-cyclized version demonstrated a slower bactericidal effect than the linear version. All three peptides were stable at high and low pH, and had very low hemolytic and cytotoxic activity
Vector Meson Photoproduction with an Effective Lagrangian in the Quark Model
A quark model approach to the photoproduction of vector mesons off nucleons
is proposed. Its starting point is an effective Lagrangian of the interaction
between the vector meson and the quarks inside the baryon, which generates the
non-diffractive s- and u- channel resonance contributions. Additional t-channel
and exchanges are included for the and
production respectively to account for the large diffractive behavior in the
small region as suggested by Friman and Soyeur. The numerical results are
presented for the and productions in four isospin channels with
the same set of parameters, and they are in good agreement with the available
data not only in and productions but also in the charged
productions where the additional t-channel exchange does not
contribute so that it provides an important test to this approach. The
investigation is also extended to the photoproduction, and the initial
results show that the non-diffractive behavior of the productions in the
large region can be described by the s- and u- channel contributions with
significantly smaller coupling constants, which is consistent with the findings
in the similar studies in the QHD framework. The numerical investigation has
also shown that polarization observables are essential for identifying
so-called "missing resonances".Comment: 36 pages, 10 PS figures, extended version of nucl-th/9711061 and
nucl-th/9803021, submitted to PR
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Redefining Peptide 14D: Substitutional Analysis for Accelerated TB Diagnosis and Enhanced Activity against Mycobacterium tuberculosis.
Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a predominant cause of mortality, especially in low- and middle-income nations. Recently, antimicrobial peptides have been discovered that at low concentrations could stimulate the growth of M. tuberculosis (hormetic response). In this study, such a peptide was used to investigate the effects on the time to positivity (TTP). A systematic substitution analysis of peptide 14D was synthesized using Spot synthesis technology, resulting in 171 novel peptides. Our findings revealed a spectrum of interactions, with some peptides accelerating M. tuberculosis growth, potentially aiding in faster diagnostics, while others exhibited inhibitory effects. Notably, peptide NH2-wkivfiwrr-CONH2 significantly reduced the TTP by 25 h compared to the wild-type peptide 14D, highlighting its potential in improving TB diagnostics by culture. Several peptides demonstrated potent antimycobacterial activity, with a minimum inhibitory concentration (MIC) of 20 µg/mL against H37Rv and a multidrug-resistant M. tuberculosis strain. Additionally, for two peptides, a strongly diminished formation of cord-like structures was observed, which is indicative of reduced virulence and transmission potential. This study underscores the multifaceted roles of antimicrobial peptides in TB management, from enhancing diagnostic efficiency to offering therapeutic avenues against M. tuberculosis
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