Detection of clinically relevant antimicrobial resistance determinants in warm-blooded marine animals in Livingston Island (South Shetland Islands, Antarctica): A field-based molecular genetics study.

Molecular genetic studies of stools were performed to assess the spread of some clinically relevant antimicrobial resistance determinants (ARD) in a gentoo penguin (Pygoscelis papua) and an Antarctic fur seal (Arctocephalus gazella) on Livingston Island. Glycopeptide resistance genes (vanA/vanD and vanB) were detected in both fecal samples, while the penguin's one was also mecA-positive and blaNDM-positive. Because of the remoteness and the isolation of the sampling locations, the carriage of vancomycin-resistant Enterococcus spp., methicillin-resistant Staphylococcus aureus, and NDM-producing Enterobacterales or other gram-negative bacilli suggested an ocean pollution with antibiotic resistant bacteria (ARB). Additionally, due to the type of ARD we detected, our results are alarming, and they cannot be explained only with agricultural and/or aquacultural pollution. Even though the current study is a preliminary one, it also demonstrates the potential of the field genetics analyses carried out with minimal equipment as a reliable monitoring tool for pollution with ARB.

How do employment conditions and psychosocial workplace exposures impact the mental health of young workers? A systematic review.

PURPOSE: To assess the quality of the research about how employment conditions and psychosocial workplace exposures impact the mental health of young workers, and to summarize the available evidence. METHODS: We undertook a systematic search of three databases using a tiered search strategy. Studies were included if they: (a) assessed employment conditions such as working hours, precarious employment, contract type, insecurity, and flexible work, or psychosocial workplace exposures such as violence, harassment and bullying, social support, job demand and control, effort-reward imbalance, and organizational justice; (b) included a validated mental health measure; and (c) presented results specific to young people aged ≤ 30 years or were stratified by age group to provide an estimate for young people aged ≤ 30 years. The quality of included studies was assessed using the Risk of Bias in Non-randomized Studies of Exposures (ROBINS-E) tool. RESULTS: Nine studies were included in the review. Four were related to employment conditions, capturing contract type and working hours. Five studies captured concepts relevant to psychosocial workplace exposures including workplace sexual harassment, psychosocial job quality, work stressors, and job control. The quality of the included studies was generally low, with six of the nine at serious risk of bias. Three studies at moderate risk of bias were included in the qualitative synthesis, and results of these showed contemporaneous exposure to sexual harassment and poor psychosocial job quality was associated with poorer mental health outcomes among young workers. Longitudinal evidence showed that exposure to low job control was associated with incident depression diagnosis among young workers. CONCLUSIONS: The findings of this review illustrate that even better studies are at moderate risk of bias. Addressing issues related to confounding, selection of participants, measurement of exposures and outcomes, and missing data will improve the quality of future research in this area and lead to a clearer understanding of how employment conditions and psychosocial workplace exposures impact the mental health of young people. Generating high-quality evidence is particularly critical given the disproportionate impact of COVID-19 on young people's employment. In preparing for a post-pandemic world where poor-quality employment conditions and exposure to psychosocial workplace exposures may become more prevalent, rigorous research must exist to inform policy to protect the mental health of young workers.

Durability and Wear Resistance of Laser-Textured Hardened Stainless Steel Surfaces with Hydrophobic Properties.

Hydrophobic surfaces are of high interest to industry. While surface functionalization has attracted significant interest, from both industry and research, the durability of engineered surfaces remains a challenge, as wear and scratches deteriorate their functional response. In this work, a cost-effective combination of surface engineering processes on stainless steel was investigated. Low-temperature plasma surface alloying was applied to increase surface hardness from 172 to 305 HV. Then, near-infrared nanosecond laser patterning was deployed to fabricate channel-like patterns that enabled superhydrophobicity. Abrasion tests were carried out to examine the durability of such engineered surfaces during daily use. In particular, the evolution of surface topographies, chemical composition, and water contact angle with increasing abrasion cycles were studied. Hydrophobicity deteriorated progressively on both hardened and raw stainless steel samples, suggesting that the major contributing factor to hydrophobicity was the surface chemical composition. At the same time, samples with increased surface hardness exhibited a slower deterioration of their topographies when compared with nontreated surfaces. A conclusion is made about the durability of laser-textured hardened stainless steel surfaces produced by applying the proposed combined surface engineering approach.

Encapsulation of Au Nanoparticles on a Silicon Wafer During Thermal Oxidation.

We report the behavior of Au nanoparticles anchored onto a Si(111) substrate and the evolution of the combined structure with annealing and oxidation. Au nanoparticles, formed by annealing a Au film, appear to "float" upon a growing layer of SiO2 during oxidation at high temperature, yet they also tend to become partially encapsulated by the growing silica layers. It is proposed that this occurs largely because of the differential growth rates of the silica layer on the silicon substrate between the particles and below the particles due to limited access of oxygen to the latter. This in turn is due to a combination of blockage of oxygen adsorption by the Au and limited oxygen diffusion under the gold. We think that such behavior is likely to be seen for other metal-semiconductor systems.

Anodically bonded submicron microfluidic chambers.

We demonstrate the use of anodic bonding to fabricate cells with characteristic size as large as 7 x 10 mm(2), with height of approximately 640 nm, and without any internal support structure. The cells were fabricated from Hoya SD-2 glass and silicon wafers, each with 3 mm thickness to maintain dimensional stability under internal pressure. Bonding was carried out at 350 degrees C and 450 V with an electrode structure that excluded the electric field from the open region. We detail fabrication and characterization steps and also discuss the design of the fill line for access to the cavity.

A newly discovered bacteriocin produced by Enterococcus faecalis 3915.

Different Enterococci, isolated from starters for the production of the traditional Bulgarian yellow cheese 'Kashkaval' were screened for bacteriocin production, and one of them, Enterococcus faecalis 3915 demonstrated bacteriocin activity. In this study, we investigated the growth parameters of the producer strain as well as the production kinetics and preliminary characterisation of the produced bacteriocin named enterocin 3915. For the growth modelling, the logistic model was used, while bacteriocin production was monitored. Experiments on inducibility were conducted, and strain was checked for the presence of plasmids. The peptide was crudely purified by ammonium sulphate precipitation followed by preparative PAGE. The approximate molecular mass was determined electrophoretically, and the activity was visualised by electrophoresis and agar overlay technique. It was found that E. faecalis 3915 produces a bacteriocin with constitutive synthesis and chromosomal localisation of its genetic determinants. The peptide revealed to be relatively heat-stable with a molecular mass of about 6.5 kDa. As E. faecalis 3915 originates from cheese starter it can be classified as generally recognised as safe (GRAS). The inhibitory activity of enterocin 3915 comprises commensals or pathogens, so properties generally accepted as probiotic could be attributed to the producer, and potential application in the dairy industry is not to be excluded.

Controlling large-scale film morphology by phase manipulation in interference lithography.

An experimental arrangement is described where a Babinet-Soleil compensator is inserted into the path of one of the three beams used for noncoplanar beam interference lithography. This birefringent element can change the phase of the beam so that either a positive two-dimensional pattern or an inverselike structure is generated in a photoresist without disturbing the mechanical geometry of the setup. Simulations are presented that confirm the validity of this approach. Large defect-free sample areas (>1 cm(2)) with submicrometer periodic patterns were obtained by expanding the laser beams used in the lithography experiment.

[Antibodies to Brucella in caspian seals]. / Antitela k brutsellam u kaspiiskikh tiulenei.

As the result of the study of Caspian seals, the presence of antibodies to Brucella was detected in the blood serum of these animals. The annual dynamics of the proportion of seropositive animals was noted. These data indicate the possibility of the circulation of the infective agent of brucellosis in the population of Caspian seals.

Quantitative elemental analysis for rhodium and palladium in minerals by time-of-flight resonance ionization mass spectrometry.

Results are presented for the trace analysis of Pd and Rh by time-of-flight-resonance ionization mass spectrometry (TOF-RIMS). The spectrometer, developed at the Advanced Mineral Technology Laboratory (Ontario, Canada), is based on a commercial laser-induced mass analyzer with upgrades that include independent laser ablation and ionization sources and pulsed ion optics to minimize noise caused by primary ion formation. The schemes presented for Rh and particularly for Pd detection are simpler than others reported in the literature. The experimental laser fluences were found to be in reasonable agreement with theoretical estimates. The TOF-RIMS measurements were quantified on the basis of calibration curves derived using reference samples covering 3 orders of magnitude in concentration. Minimum detection limits of ~15 parts per billion were found for both metals, with a precision of ~ +/-15%. Samples from sulfide, iron oxide, and silicate minerals were also examined. The results are in excellent agreement with those obtained using dynamics secondary ion mass spectrometry.

Drosophila melanogaster ferritin: cDNA encoding a light chain homologue, temporal and tissue specific expression of both subunit types.

Drosophila melanogaster secreted ferritin like the cytosolic ferritins of other organisms is composed of two subunits, a heavy chain homologue (HCH) and a light chain homologue (LCH). We report the cloning of a cDNA encoding the ferritin LCH of this insect. As predicted from the gene sequence, it contains no iron responsive element (IRE). Northern blot analysis reveals two mRNAs that differ in length due to the choice of polyadenylation signals. Message levels vary through the life cycle of the fly and are markedly increased by high levels of dietary iron. The gut is the main site of increased message synthesis and iron preferentially increases the amount of shorter messages. Western blotting reveals that LCH is the predominant ferritin subunit in all life stages. The amount of LCH protein corresponds well with the message levels in control animals, while in iron-fed animals LCH does not increase proportionally with the message levels. In contrast, the amount of HCH is less than that would be predicted from message levels in control animals, but corresponds well in iron-fed animals. Ferritin is abundant in gut and hemolymph of larvae and adults and in ovaries of adult flies. At pupariation, ferritin becomes more abundant in hemolymph than in other tissues.

Analysis of Xanthate Derivatives by Vacuum Ultraviolet Laser-Time-of-Flight Mass Spectrometry.

A series of liquid O,S-dialkyl dithiocarbonates (xanthate esters) have been synthesized, and time-of-flight (TOF) mass spectra were recorded for their vapors using both ultraviolet (UV) and vacuum ultraviolet (VUV) laser excitation. These compounds are chemical derivatives of low vapor pressure xanthate salts which have found important commercial application as collectors in mineral sulfide flotation circuits. Our experiments demonstrate that esters ionized by short-wavelength VUV light can be detected by parent mass with high efficiency and minimal fragmentation. In contrast, the mass spectra of the same compounds obtained by UV light excitation exhibit a large number of low molecular mass peaks. A preliminary quantitative analysis of the composition of a gas-phase mixture of xanthate esters has also been achieved, which indicates possible subfemtomole detection limits.

Single-strand-specific DNase activity is an inherent property of the 140-kDa protein of the snake venom exonuclease.

Polyclonal antibodies against the exonuclease from Crotalus adamanteus venom (the 140-kDa protein) inhibit both the exonucleolytic and the single-strand-specific endonucleolytic activities, present in the exonuclease preparation. The antibodies also diminish the ability of the enzyme to split the negatively supercoiled Bluescript KS+ in the AT-rich fragment near-by the transcription termination site of the Ampicillin gene. Therefore the single-strand-specific endonucleolytic activity was attributed to the protein molecule of the exonuclease. The processivity of the exonucleolytic action was found to be less than 3 monomers as indicated by the heparin trapping method.

Synthesis and antitumour activity of several new 4-aroyl-1-nitrosohydrazinecarboxamides.

Six new analogues of nitrosoureas containing aroylhydrazine residue have been synthesized: (I) 4-(2-fluorobenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarboxamide++ +; (II) 4-(4-bromobenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarboxam ide; (III) 4-(4-hydroxybenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarboxamide+ ++; (IV) 4-(3-methoxybenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarbox amide; (V) 4-(4-methoxybenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarbox amide; (VI) 4-(4-fluorophenylacetyl)-1-(2-chloroethyl)-1-nitrosohydrazineca rboxamide. All six compounds showed a dose-dependent in vivo activity against leukaemias L1210 and P388. Compounds I and III were soluble in water. The antitumour effects were highly expressed in compound III, yielding a T/C% value of 402% in leukaemia P388, and in compound VI, 356% in leukaemia L1210.

Incidence of spinal cord injuries in Plovdiv and Plovdiv region, Bulgaria.

This retrospective study was conducted to evaluate the incidence of spinal cord injuries in Plovdiv and Plovdiv region, Bulgaria. The study material comprised 980 patients treated over a period of 10 years (1983-1992) in the Clinics of Traumatic and Orthopaedic Surgery and Neurosurgery, University of Medicine, Plovdiv, which are the only therapeutic establishment in this region with a population of 750,000 to admit and treat this type of injury. Conservative treatment was applied in 34.46% of the patients using various methods: the method of Gorinevska-Dreving, immobilisation in either a plaster jacket or minerva depending on the injury site, the reclination methods of Davis-Erie or Watson-Jones, cranial extension by Crutchfield. Operative treatment also was used and included posterior stabilisation with or without bone plastics, anterior vertebrodesis in the cervical and thoracolumbar regions from a transpleural and retroperitoneal approaches and anterior vertebrodesis with a partial or complete replacement of the vertebral body.

Differences between some properties of acetylated and nonacetylated forms of HMG1 protein.

There are data suggesting that HMG1 protein may be involved in DNA replication. Recently we have found that only the acetylated form of the protein generates tetramers, stimulates the activity of DNA polymerase alpha (EC 2.7.7.7) (with activated DNA as a template) and forms a specific complex with it. This paper compares some properties of the acetylated and nonacetylated forms of HMG1 protein and shows that it is only the acetylated form which serves as a histone assembly factor, increases the melting temperature of poly d[(A-T)] and stimulates the activity of DNA polymerase alpha when histone H1-depleted chromatin is used as a template.

Optimization of the pumping conditions for Nd:YAG lasers.

In this paper we report on the results of comparative investigations of different pump cavities. Numerical estimations of the geometrical transfer efficiency of various cavities are presented. An experimental study of the pumping efficiency and pumping uniformity of the laser heads with respect to the cavity geometry, types of flashlamp, and reflecting coatings have been carried out. The influence of the discharge circuit on the pumping efficiency is also discussed.

Allylglycine and brain excitability. Electrophysiological investigation in cats.

The effect of DL-allylglycine (DL-AG) in two doses (40 and 60 mg/kg i.v.) was studied on cats under acute conditions. DL-AG provoked the appearance of epileptiform EEG patterns either spontaneous or in response to intermittent light stimulation with a frequency of 5-25 Hz. The effect was dose-dependent. The paroxysmal EEG was restricted to or began in the cortex and later it appeared in the thalamus and mesencephalic reticular formation. This finding together with the observation that after DL-AG the visual evoked potentials increased in the primary visual cortex and decreased in the centre median nucleus and in the reticular formation support the view about the role of the cortex in the increased brain excitability and in the increased photosensitivity after allylglycine. The photosensitive of spontaneous epileptiform EEG activity in cats pretreated with DL-allylglycine could be an useful experimental model of epilepsy for assessing the efficacy of anticonvulsant drugs.