Prevalence,Antimicrobial Resistance,and Virulence Characteristics of mecA‐Encoding Coagulase‐Negative Staphylococci Isolated from Soft Cheese in Brazil

Coagulase‐negative staphylococci (CoNS), which are generally neglected as foodborne bacteria, are emerging as significant opportunistic pathogens that may be highly resistant to available antimicrobial drugs. In this study, antimicrobial susceptibility patterns, mecA gene occurrence, and virulence‐associated characteristics were evaluated in CoNS isolated from soft cheese in Brazil. A total of 227 bacterial isolates were recovered from 35 cheese samples belonging to 5 batches with 7 different trademarks. The CoNS counts ranged from 10⁶ to 10⁷ CFU/g. High antimicrobial resistance percentages were observed for oxacillin (76.2%), penicillin (78.5%), erythromycin (67.8%), gentamicin (47.2%), clindamycin (35.7%), rifampicin (26.8%), azithromycin (14.7%), tetracycline (14.7%), levofloxacin (14.2%), and sulfamethoxazole‐trimethoprim (11.9%). A low antimicrobial resistance percentage was observed for chloramphenicol (2.3%), and all of the tested bacteria were susceptible to vancomycin and linezolid. In total, a multiple antibiotic resistance (MAR) index of >0.2 was observed for 80.6% of the isolated CoNS. However, the MAR index ranged from 50% to 92.6% when only bacterial cheese isolates belonging to the same trademark were considered. Regarding to the prevalence of CoNS carrying mecA gene, 81.5% of the isolated strains were mecA⁺, and 76.2% of these were phenotypically resistant to oxacillin. Three isolates carried the enterotoxin A gene (sea), 29.5% produced biofilm in a laboratory test, and α‐ or ß‐hemolysis were observed for 3% and 5.2%, respectively. This study highlights the extent of the antimicrobial resistance phenomenon in neglected foodborne microorganisms and the potential public health risks that are related to the consumption of CoNS‐contaminated soft cheese.     

Monocyclic Quinone Structure-Activity Patterns: Synthesis of Catalytic Inhibitors of Topoisomerase II with Potent Antiproliferative Activity

The monocyclic 1,4-benzoquinone, HU-331, the direct oxidation product of cannabidiol, inhibits the catalytic activity of topoisomerase II but without inducing DNA strand breaks or generating free radicals, and unlike many fused-ring quinones exhibits minimal cardiotoxicity. Thus, monocyclic quinones have potential as anticancer agents, and investigation of the structural origins of their biological activity is warranted. New syntheses of cannabidiol and (±)-HU-331 are here reported. Integrated synthetic protocols afforded a wide range of polysubstituted resorcinol derivatives; many of the corresponding novel 2-hydroxy-1,4-benzoquinone derivatives are potent inhibitors of the catalytic activity of topoisomerase II, some more so than HU-331, whose monoterpene unit replaced by a 3-cycloalkyl unit conferred increased antiproliferative properties in cell lines with IC₅₀ values extending below 1 mM, and greater stability in solution than HU-331. The principal pharmacophore of quinones related to HU-331 was identified. Selected monocyclic quinones show potential for the development of new anticancer agents.     

The use of statistical experimental design procedures in the development and “robust” manufacture of a water-based, corrosion-inhibiting adhesive primer

Details of the statistical experimental design techniques used to prepare a robust, water-based, corrosion-inhibiting, adhesive primer of low toxicity are given and the results are used to illustrate the efficacy of the approach to both manufacture and performance of the end product.     

The value of communicative skills for developing an energy strategy

A case study is presented of how a public-sector client organization engaged with a political directive on energy efficiency in buildings. The value of communication skills of built environment professionals is explored during a strategic change process. An interpretative approach is used to study the organizational discussions and interactions between mainly a senior engineer (an energy expert), the management team and officials. It demonstrates how the political directive led to an initially ambiguous energy target, but was successfully framed, contextualized and anchored within the organization. This change process was shaped by key actors’ ability to influence others. Use of discursive competence is important for explaining what stakeholders may gain from the changes needed to meet the energy target. The focus on the role of a senior engineer (middle management rather than top management) provides a novel perspective on how strategies develop and are adopted in organizations.     

The Traveling Agent Problem

 This paper considers a sequencing problem which arises naturally in the scheduling of software agents. We are given n sites at which a certain task might be successfully performed. The probability of success is p _i at the ith site and these probabilities are independent. Visiting site i and trying the task there requires time (or some other cost metric) t _i whether successful or not. Latencies between sites i and j are l _ij, that is, the travel time between those two sites. Should the task be successfully completed at a site then any remaining sites do not need to be visited. The Traveling Agent Problem is to find the sequence which minimizes the expected time to complete the task. The general formulation of this problem is NP-Complete. However, if the latencies are constant we show that the problem can be solved in polynomial time by sorting the ratios t _i/p _i according to increasing value and visiting the sites in that order. This result then leads to an efficient algorithm when groups of sites form subnets in which latencies within a subnet are constant but can vary across subnets. We also study the case when there are deadlines for solving the problem in which case the goal is to maximize probability of success subject to satisfying the deadlines. Applications to mobile and intelligent agents are described. Date received: February 10, 1998. Date revised: November 16, 1999.     

Computer Supported Social Networking For Augmenting Cooperation

The exploration of social networks is essential for finding capable cooperators who can help problem-solving and for augmenting cooperation between workers in an organization. This paper describes PeCo-Mediator-II to seek capable cooperators through a chain of personal connections (PeCo) in a networked organization. Moreover, this system helps to gather, explore, and visualize social networks in an organization. The experimental results show that the system facilitates users' encounters with cooperators and develops new helpful connections with the cooperators.     

UV–Vis observation of different F0 → D0 transitions for both isomeric species in Eu(III) DOTA-like complexes

The presence of the two isomeric species (M and m) of Eu(III) (DOTA-like) complexes has been detected in aqueous solution by UV–Vis absorbance spectrophotometry. It shows that the ⁷F₀ → ⁵D₀ transition in Eu(III) complexes does not only depend on the coordinating atoms present in the first coordination sphere but that it may also be influenced by small differences in the coordination geometry. The absorbance spectra could be well fitted with the K=M/m equilibrium constants measured by NMR. The wavelength variation between the two isomers is found to be 0.20 nm (DTMA), 0.14 nm (DOTA) and about 0.25 nm (DOTAM) (DTMA=1,4,7,10-tetrakis-(methylcarbamoylmethyl)-1,4,7,10-tetraazacyclo-dodecane; DOTA=1,4,7,10-tetraaza-1,4,7,10-tetrakis(carboxymethyl)-cyclododecane; DOTAM=1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane). This is small enough not to affect the quantitative determination of water coordination equilibria in solution as hydration equilibria produce differences of about 0.5 nm.     

Fractionation of essential oils with biocidal activity using supercritical CO2—Experiments and modeling

Supercritical fluid extraction is an interesting alternative for the fractionation of essential oils, in order to obtain concentrates or compounds of interest. This technique requires information about the distribution of the components of the mixture between the phases present at different conditions of pressure, temperature and composition. In this work equilibrium information of three bioactive essential oils (Salvia officinalis, Mentha piperita and Tagetes minuta oil) with near-critical and supercritical carbon dioxide is measured using a dynamic apparatus in the range of 313-323 K and 60-120 bar. The distribution of monoterpenes, oxygenated terpenes and sesquiterpenes in the extract phase is determined by gas chromatography in order to explore the best operating conditions for the separation of the fractions or compounds with higher biocidal activity. Predictive calculations are performed using the group contribution equation of state (GC-EOS) and compared with the experimental data.     

钢结构防火涂料的性能测试方法和配方设计研究

介绍了钢结构防火涂料的性能测试方法,并结合工作实践介绍了钢结构防火涂料的配方设计原则。重点介绍了厚涂型、薄涂型、超薄膨胀型室外型钢结构防火涂料的研究及应用范围。     

Crystallization behavior and crystallite morphology control of poly(L‐lactic acid) through N,N′‐bis(benzoyl)sebacic acid dihydrazide

Adding a nucleating agent is one of the best ways to accelerate the crystallization rate of poly(L ‐lactic acid) (PLLA) so as to obtain a high degree of crystallinity during the process, which will improve the heat distortion temperature of final products. In the work reported, N, N′‐bis(benzoyl)sebacic acid dihydrazide (BSAD) was synthesized and used as a nucleating agent for PLLA. Isothermal and non‐isothermal crystallization behaviors were investigated using differential scanning calorimetry (DSC). The addition of BSAD successfully enhances the crystallization rate of PLLA. A unique phase separation behavior of PLLA/BSAD blends is found from DSC as well as from polarized optical microscopy, which explains the difference of optimal BSAD concentration between isothermal and non‐isothermal crystallization. This is the first recording of a phase separation peak in PLLA/nucleating agent blends using DSC. In thermogravimetric analysis, the enhanced thermal stability indicates that there are strong hydrogen bonds between BSAD and PLLA matrix. BSAD can dissolve in PLLA melt below its melting point through intermolecular hydrogen bonding with PLLA and self‐assemble upon cooling, leading to the surface being capable of nucleating PLLA. Different phase separation temperatures can be used to control the morphology of BSAD, which finally determines the crystallite morphology of PLLA. © 2012 Society of Chemical Industry