Search

N‐methylcyclohexylamine (MCA) and N‐cyclohexyl‐1,3‐propanediamine (CHAP) have been suggested, in mixtures with lipophilic amines, as potential phase change solvents for CO2 capture applications, and subsequently studied as promising alternatives to monoethanolamine (MEA) for minimizing the desorber's energy requirements. In this study, new high pressure experimental data were obtained for the solubility of CO2 in aqueous solutions containing MCA or CHAP at 313 and 333 K. The obtained data were used to parameterize the modified Kent–Eisenberg model. In this direction, CHAP was modeled assuming a "principle of independent reactivity," that is, that the reactivity of each amine group does not depend on the potential reaction of the other one. It was shown that through this approach the model can be successfully applied to diamines using the relevant equations of amine mixtures. [ABSTRACT FROM AUTHOR]

Wool-focused economies yielded a pastoralist materiality that visibly shaped the lived experiences of Central Asian populations today. In this paper, we investigate the earlier application of fibers through a key mountain corridor for social interactions during Prehistory. We focus on the site of Chap 1 located in the highlands of the Tien Shan Mountains of Kyrgyzstan where researchers have found a complex agropastoral subsistence culture was established from at least ca. 3,000 BCE. The perishable materials that would have accompanied the early spread of cultural and technological traditions related to fiber-based crafts throughout this area are under-documented due to poor organic preservation. Hence, there has been little consideration of the role that textiles played in highland occupation and how woven fabrics might have facilitated settlement in the extreme climates of Central Asia. We address this ongoing problem through a multi-application survey of Chap’s unpublished textile evidence preserved as impressions in coarseware ceramics of its Final Bronze Age. We consider evidence that sheep wool formed a key cultural adaptation for surviving the extreme winters of Central Asia’s highland regions.

Streptococcus agalactiae (Group B Streptococcus , GBS) is primarily known as a major neonatal pathogen. In adults, these bacteria often colonize the gastrointestinal and urogenital tracts. Treatment of infections using antibiotics is often complicated by recurrences caused by multi-resistant streptococci. Endolysin EN534 from prophage A2 of human isolate Streptococcus agalactiae KMB-534 has a modular structure consisting of two terminal catalytic domains, amidase_3 and CHAP, and one central binding domain, LysM. The EN534 gene was cloned into an expression vector, and the corresponding recombinant protein EN534-C was expressed in Escherichia coli in a soluble form and isolated by affinity chromatography. The lytic activity of this endolysin was tested on cell wall substrates from different GBS serotypes, B. subtilis , L. jensenii, and E. coli. The enzyme lysed streptococci, but not beneficial vaginal lactobacilli. The isolated protein is stable in a temperature range of 20–37 °C. Calcium ions enhanced the activity of the enzyme in the pH range from 5.0 to 8.0. The exolytic activity of EN534-C was observed by time-lapse fluorescence microscopy on a S. agalactiae CCM 6187 substrate. Recombinant endolysin EN534-C may have the potential to become an antimicrobial agent for the treatment of S. agalactiae infections. [Display omitted] • Endolysin EN534-C from streptococcal prophage was cloned and characterized. • EN534-C contains three domains - catalytic amidase_3 and CHAP and binding LysM. • EN534-C showed significant exolytic activity towards human pathogen S. agalactiae GBS. [ABSTRACT FROM AUTHOR]

Background: To identify novel myofibrillar components of the Drosophila flight muscles, we carried out a proteomic analysis of chemically demembranated flight muscle myofibrils, and characterized the knockdown phenotype of a novel gene identified in the screen, CG1674. Results: The CG1674 protein has some similarity to vertebrate synaptopodin 2‐like, and when expressed as a FLAG‐tagged fusion protein, it was localized during development to the Z‐disc and cytoplasm. Knockdown of CG1674 expression affected the function of multiple muscle types, and defective flight in adults was accompanied by large actin‐rich structures in the flight muscles that resembled overgrown Z‐discs. Localization of CG1674 to the Z‐disc depended predominantly upon presence of the Z‐disc component alpha‐actinin, but also depended upon other Z‐disc components, including Mask, Zasp52, and Sals. We also observed re‐localization of FLAG‐CG1674 to the nucleus in Alpha‐actinin and sals knockdown animals. Conclusions: These studies identify and characterize a previously unreported myofibrillar component of Drosophila muscle that is necessary for proper myofibril assembly during development. Key Findings: We characterize the Drosophila flight muscle myofibril proteomeWe identify a novel myofibrillar component, CG1674CG1674 localizes to the Z‐discKnockdown of CG1674 results in actin‐rich structures in the muscle [ABSTRACT FROM AUTHOR]

Calcium hydroxyapatite (Ca10(PO4)6(OH)2,CHAp) has unique characteristics and can be used as artificial material for the recovering of bones and teeth, for drug delivery systems, as adsorbent and catalyst. The specific chemical, structural and morphological properties of calcium hydroxyapatite are highly sensitive to the changes in chemical composition and processing conditions. Various kinds of transition metal and other cations can be readily accommodated into the apatite framework based on their large cation exchangeability. The traces of metal ions introduced in apatite structure can affect the lattice parameters, crystallinity, dissolution kinetics and other physical properties of apatite. The aim of this study was to find more economically accessible metal-substituted calcium hydroxyapatite–based catalyst. In this paper, the sol-gel and co-precipitation synthesis methods were used for the preparation of metal-substituted (M = Mg2+, Zn2+ and Na+) calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp) samples. The synthesized powders were characterized by powder X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and gas chromatography-mass spectrometry (GC-MS). The CHAp:M samples prepared by co-precipitation method were almost single-phase at different concentrations of substituents, while the sol-gel-derived CHAp:M specimens contained additional impurity phases. Metal-containing CHAp samples were tested as catalysts in a solvent-free synthesis of 2-adamantylidene(phenyl)amine. It was demonstrated that the zinc-containing CHAp improved the yield of Schiff base. [ABSTRACT FROM AUTHOR]

Domain Name System (DNS) is one of few services on the Internet which is allowed through every security barrier. It mostly depends on the User Datagram Protocol (UDP) as the transport protocol, which is a connectionless protocol with no built-in authentication mechanism. On top of that, DNS responses are substantially larger than their corresponding requests. These two key features made DNS a fabulous attacking tool for cybercriminals to reflect and amplify a huge volume of requests to consume their victim's resources. Recent incidents revealed how harsh DNS could be when it is abused with great complexity by attackers. Moreover, these events had proven that any defense mechanism with single point deployment couldn't accurately and efficiently overcome an attack volume with high dynamicity. In this paper, we proposed the Efficient Distributed-based Defense Scheme (EDDS) to overcome the shortcomings of a centralizedbased defense mechanism. By using an authentication message exchange, which is a Challenge-Handshake Authentication Protocol (CHAP)-based authentication mechanism. It is deployed on multiple nodes to determine the legitimacy of the DNS request. Moreover, it significantly reduces the impact of the amplification factor for the fake DNS requests without having any side effects on legitimate ones. Then, a Stateful Packet Inspection (SPI)- based packet filtering is proposed to distinguish legitimate requests from fake ones by considering the results of the authentication procedure. Both authentication-message exchange and SPI-based filtering are introduced to provide detection accuracy without reducing the quality of service for legitimate users. As the simulation results show, the proposed mechanism can efficiently and accurately detect, isolate, and discard the bogus traffic with minimal overhead on the system. [ABSTRACT FROM AUTHOR]

Bacterial cell wall hydrolases, including amidases and peptidases, play a critical role in peptidoglycan turnover during growth, impacting daughter cell separation, and cell death, through autolysis. When exploring the regulation of protein expression across the growth cycle of an acid-resistant strain of Lactobacillus paracasei, GCRL 46, we observed temporal up-regulation of proteins in the 40–45 kDa molecular weight range for whole-cell extracts when culturing in fermenters at a controlled pH of 4.0 versus optimum growth pH of 6.3. Up-regulation of proteins in this size range was not detected in SDS-PAGE gels of the cytosolic fraction, but was routinely detected following growth at low pH in whole cells and cell debris obtained after bead beating and centrifugation, indicating a cell surface location. N-terminal sequencing and in silico analyses showed sequence similarity with proteins in the L. casei group (L. casei, L. paracasei and L. rhamnosus) which were variously annotated as uncharacterized proteins, surface antigens, possible TrsG proteins, CHAP (cysteine, histidine-dependent amidohydrolases/peptidases)-domain proteins or putative peptidoglycan d,l-endopeptidase due to the presence of a CwlO domain. This protein is a homologue of the p40 (Msp2) secreted protein of L. rhamnosus LGG, which is linked to probiotic functionality in this species, and is phylogenetically related to structurally-similar proteins found in Enterococcus, Streptococcus and Bifidobacterium species, including the glucan-binding (GbpB), surface antigen (SagA) proteins detected in pathogenic group A streptococci species as secreted, immunoglobulin-binding (SibA) proteins (also named PcsB). Three-dimensional (3D) modelling predicted structural similarities in the CHAP proteins from the L. casei group and streptococcal species, indicating retention of overall architecture despite sequence divergence, and an implied retention of function during evolution. A phylogenetically-related hydrolase also contained the CwlO domain with a NLPC_P60 domain, and showed similar overall but distinct architecture to the CHAP proteins. We concluded that the surface-located, CHAP protein in L. casei is up-regulated during long-term exposure to acidic conditions during growth but not during acid shock.

The Community Health Assessment Program-Philippines (CHAP-P) is an international collaboration of investigators whose aim is to adapt a previously proven Canadian community-based cardiovascular awareness and prevention intervention to the Philippines and other low-middle-income countries. Choosing a method of blood pressure measurement for the research program presents a challenge. There is increasing consensus globally that blood pressure measurement with automated devices is preferred. Recommendations from low-middle-income countries, including the Philippines, are less supportive of automated blood pressure devices. The value placed on factors including device accuracy, durability, cost, energy source, and complexity differ with local context. Our goal was to support the progress of local policy concerning blood pressure measurement while testing a comprehensive approach to community-based screening for cardiovascular risk. The authors describe the challenges in making a choice of blood pressure device and the approach to determine optimal method of measurement for our research program. [ABSTRACT FROM AUTHOR]

A systematic method is presented whereby material from a full course of psychoanalytic treatment is analyzed to assess changes and identify patterns of change. Through an analysis of session notes, changes were assessed using the CHange After Psychotherapy scales (CHAP; Sandell 1987a), which evaluate changes in five rating variables (symptoms, adaptive capacity, insight, basic conflicts, and extratherapeutic factors). Change incidents were identified in nearly every session. Early in the analysis, relatively more change incidents related to insight were found than were found for the other types of change. By contrast, in the third year and part of the fourth year, relatively more change incidents related to basic conflicts and adaptive capacity were found. While changes related to symptoms occurred throughout the course of treatment, such changes were never more frequent than other types of change. A content analysis of the change incidents allowed a determination of when in the treatment the patient’s main conflicts (identified clinically) were overcome. A crossing of quantitative data with clinical and qualitative data allowed a better understanding of the patterns of change. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a dangerous bacterial pathogen whose clinical impact has been amplified by the emergence and rapid spread of antibiotic resistance. In the search for more effective therapeutic strategies, great effort has been placed on the study and development of staphylolytic enzymes, which benefit from high potency activity toward drug-resistant strains, and a low inherent susceptibility to emergence of new resistance phenotypes. To date, the majority of therapeutic candidates have derived from either bacteriophage or environmental competitors of S. aureus. Little to no consideration has been given to cis-acting autolysins that represent key elements in the bacterium's endogenous cell wall maintenance and recycling machinery. In this study, five putative autolysins were cloned from the S. aureus genome, and their activities were evaluated. Four of these novel enzymes, or component domains thereof, demonstrated lytic activity toward live S. aureus cells, but their potencies were 10s to 1000s of times lower than that of the well-characterized therapeutic candidate lysostaphin. We hypothesized that their poor activities were due in part to suboptimal cell wall targeting associated with their native cell wall binding domains, and we sought to enhance their antibacterial potential via chimeragenesis with the peptidoglycan binding domain of lysostaphin. The most potent chimera exhibited a 140-fold increase in lytic rate, bringing it within 8-fold of lysostaphin. While this enzyme was sensitive to certain biologically relevant environmental factors and failed to exhibit a measurable minimal inhibitory concentration, it was able to kill lysostaphin-resistant S. aureus and ultimately proved active in lung surfactant. We conclude that the S. aureus proteome represents a rich and untapped reservoir of novel antibacterial enzymes, and we demonstrate enhanced bacteriolytic activity via improved cell wall targeting of autolysin catalytic domains. [ABSTRACT FROM AUTHOR]

ABSTRACT Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol for encapsulating PPP frames inside Ethernet frames. It is widely used by commercial Internet service providers to provide Internet surfing for customers who pay bills. In this paper, we analyze the security of PPPoE network. We find that we can easily collect information about both the peers and the PPPoE authentication servers. We can use such information to recover the peer's authentication password by silently impersonating the server, which is undetectable in the network. We impersonate the server in the peers' LAN and get their passwords by hijacking the peers' PPPoE connections and negotiating for using the Password Authentication Protocol (PAP). We further propose an efficient password recovery attack against the Challenge-Handshake Authentication Protocol (CHAP). We first recover the length of the used password through on-line queries, based on the weakness of MD5 input pre-processing. Then, we crack the known-length password off-line, using the probabilistic context-free grammars. We point out that PPPoE cannot be used anymore until all of the weak authentication protocols including PAP, CHAP, and Microsoft CHAP are abolished right now and replaced with more secure Extensible Authentication Protocols. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses the use of comparative modeling to predict the three-dimensional (3D) structure of cysteine, histidine-dependent amidohydrolase and peptidase domain of the LysK endolysin (CHAP k protein) which is derived from bacteriophage K. It notes the presence of highly conserved amino acid residues in CHAP proteins which include an invariant cystine (Cys), and histidine (His). The author also cites the use of web-based servers, and visualization programs in the comparative analysis.

The article discusses the use of comparative modeling to predict the three-dimensional (3D) structure of cysteine, histidine-dependent amidohydrolase and peptidase domain of the LysK endolysin (CHAP k protein) which is derived from bacteriophage K. It notes the presence of highly conserved amino acid residues in CHAP proteins which include an invariant cystine (Cys), and histidine (His). The author also cites the use of web-based servers, and visualization programs in the comparative analysis.

Abstract: An alternative treatment for staphylococcal infections caused by antibiotic-resistance strains is to lyse staphylococci with peptidoglycan hydrolases, for example, a cysteine, histidine-dependent amidohydrolase/peptidase (CHAP). Here, CHAPs were analyzed in 12 Staphylococcus aureus genomes and 44 staphylococcal phage genomes. There are 234 putative CHAP-containing proteins and only 64 non-identical CHAP sequences. These CHAPs can be classified into phage CHAPs encoded in phages/prophages and bacterial CHAPs encoded on chromosomes and plasmids. The phage CHAPs contain a sequence signature ‘F-[IV]-R’, and the bacterial CHAPs mainly do not. The phage CHAPs are mostly positioned at the protein N-termini whereas the bacterial CHAPs are all positioned at the C-termini. The cell wall targeting domains LysM and SH3_5 are associated with the bacterial CHAPs and the phage CHAPs, respectively. The homology modeling reveals that five of six highly conserved residues are clustered at the putative active site and are exposed to the molecular surface. [ABSTRACT FROM AUTHOR]

Copyright of InfoM is the property of Belgrade University, Faculty of Organizational Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Poly-Ether-Ketone (PEEK) is a bioactive material capable of replacing traditional metal and ceramic components in biomedical applications but still lacks some strength and biological propertices compared with natural bone. In this research, calcium hydroxyapatite (cHAp) and reduced Graphene oxide (rGO) were combined with PEEK, and different lattice porose structures were produced to improve interfaces biocompatibility and mimick the bone. The FDM method was used to obtain PEEK, and rGOcHAP composites were coated, and Finite Element Analysis (FEA) was used to simulate the different lattice conditions of varying ratio. The new PEEK/rGO/cHAP composite characterisation was obtained by SEM analysis and the mechanical strength via compressive and tensile test. The composite with the highest proportion of rGO of 5% shows more biocompatibility and mechanical strength. The Young modulus and bulk modulus of PEEK increase exponentially with the increase of rGOcHAP from 3.85Gpa to 54.965% of 5 wt% addition of rGO. Also, PEEK/rGo/cHAp induces cell formation after several days of immersion in body fluids simulated with Dulbecco's Modified Eagle Medium (DMEM) and Nutrient Agar Solution (NAS) to determine their biological bioactivity. The In vivo experiments showed that cell aggregation and biological activity around PEEK/rGO/cHAP composite were higher than PEEK and the NAS shows more cell growth and bioactivity than DMEM. • To combine calcium hydroxyapatite (cHAp) and Reduced Graphene oxide (rGO) with PEEK to improve bioactivity. • Design different lattice porose structures of PEEK to mimic the bone structure. • Use FDM method to obtain PEEK 3D printing, and FEA to simulate the different lattice conditions. • Investigate morphological effects of cHAp and rGO on the biocompatibility of the surface of PEEK. [ABSTRACT FROM AUTHOR]

• Screening experiments for the CO 2 loading of aqueous DMCA/MAPA and DMCA/CHAP systems. • VLLE behavior was observed at various experimental conditions. • Various solvent systems were evaluated in terms of CO 2 absorption and cyclic capacity. • Densities of liquid phases in equilibrium were measured. Solvent-based absorption/desorption is a promising CO 2 capture technology, but its wide industrial implementation is prohibited by the high energetic requirements incurred by conventional amine solvents. Such challenges can be addressed by phase-change solvents that have been shown to enable both lower energy consumption and capture costs. Despite their clear advantages, the limited availability of detailed phase equilibrium data hinders their consideration in scaling-up studies of phase-change CO 2 capture processes. In this study, CO 2 loading and phase compositions of novel phase change aqueous amine solutions are experimentally investigated. Phase equilibrium experiments are carried out to measure the CO 2 loading of aqueous mixtures containing N,N -dimethylcyclohexylamine (DMCA) with 3-methylaminopropylamine (MAPA) and N,N -dimethylcyclohexylamine (DMCA) with N Cyclohexyl-1,3-propanediamine (CHAP) at 40, 60 and 90 °C. It is observed that both systems exhibit phase change behavior, while DMCA-CHAP presents higher cyclic capacity and rather low volatility losses. [ABSTRACT FROM AUTHOR]

Bacterial cell wall hydrolases, including amidases and peptidases, play a critical role in peptidoglycan turnover during growth, impacting daughter cell separation, and cell death, through autolysis. When exploring the regulation of protein expression across the growth cycle of an acid-resistant strain of Lactobacillus paracasei, GCRL 46, we observed temporal up-regulation of proteins in the 40–45 kDa molecular weight range for whole-cell extracts when culturing in fermenters at a controlled pH of 4.0 versus optimum growth pH of 6.3. Up-regulation of proteins in this size range was not detected in SDS-PAGE gels of the cytosolic fraction, but was routinely detected following growth at low pH in whole cells and cell debris obtained after bead beating and centrifugation, indicating a cell surface location. N-terminal sequencing and in silico analyses showed sequence similarity with proteins in the L. casei group (L. casei, L. paracasei and L. rhamnosus) which were variously annotated as uncharacterized proteins, surface antigens, possible TrsG proteins, CHAP (cysteine, histidine-dependent amidohydrolases/peptidases)-domain proteins or putative peptidoglycan d,l-endopeptidase due to the presence of a CwlO domain. This protein is a homologue of the p40 (Msp2) secreted protein of L. rhamnosus LGG, which is linked to probiotic functionality in this species, and is phylogenetically related to structurally-similar proteins found in Enterococcus, Streptococcus and Bifidobacterium species, including the glucan-binding (GbpB), surface antigen (SagA) proteins detected in pathogenic group A streptococci species as secreted, immunoglobulin-binding (SibA) proteins (also named PcsB). Three-dimensional (3D) modelling predicted structural similarities in the CHAP proteins from the L. casei group and streptococcal species, indicating retention of overall architecture despite sequence divergence, and an implied retention of function during evolution. A phylogenetically-related hydrolase also contained the CwlO domain with a NLPC_P60 domain, and showed similar overall but distinct architecture to the CHAP proteins. We concluded that the surface-located, CHAP protein in L. casei is up-regulated during long-term exposure to acidic conditions during growth but not during acid shock. [ABSTRACT FROM AUTHOR]