Эффективность работы сплит-системы в режиме теплового насоса

Рассмотрены проблемы, возникающие во время работы сплит-системы в режиме теплового насоса и предложена экспериментальная установка, которая даст возможность их исследовать, решить или минимизировать. Разработана методика проведения исследования, обработки полученных данных и расчета показателей эффективности работы сплит-системы в режиме воздушного теплового насоса. Введено понятие цикличности работы сплит-системы и выполнено разделение рабочего цикла на отдельные самостоятельные составляющие. Предложено использовать поправочный коэффициент, который дает возможность получать действительные значения эффективности любого воздушного теплового насоса сплит-системы. Проведена апробация полученных результатов с данными фирм-производителей сплит-систем и выделены особенности, влияющие на значение коэффициента трансформации при использовании разных методов расчета.The problems arising in the operation of the split systems in the thermal pump mode are considered and an experimental unit is proposed which will enable to study, to solve or to minimize them. The methods of the studying, data obtained processing and calculation of the efficiency indices for the split system operation in the mode of the air thermal pump are developed. The notion of cyclicity of the split system operation is introduced and the operation cycle division into separate independent components is provided. It is proposed to use coefficient of correction which enables to obtain actual efficiency values of any air thermal pump of the split system. Testing and comparison of the data obtained with the data of the split system manufacturing companies and their approbation are carried out. The specific features having an influence on the value of transformation ratio when using different methods of calculation are singled out

Spatial encoding in spinal sensorimotor circuits differs in different wild type mice strains

<p>Abstract</p> <p>Background</p> <p>Previous studies in the rat have shown that the spatial organisation of the receptive fields of nociceptive withdrawal reflex (NWR) system are functionally adapted through experience dependent mechanisms, termed somatosensory imprinting, during postnatal development. Here we wanted to clarify 1) if mice exhibit a similar spatial encoding of sensory input to NWR as previously found in the rat and 2) if mice strains with a poor learning capacity in various behavioural tests, associated with deficient long term potention, also exhibit poor adaptation of NWR.</p> <p>The organisation of the NWR system in two adult wild type mouse strains with normal long term potentiation (LTP) in hippocampus and two adult wild type mouse strains exhibiting deficiencies in corresponding LTP were used and compared to previous results in the rat. Receptive fields of reflexes in single hindlimb muscles were mapped with CO₂laser heat pulses.</p> <p>Results</p> <p>While the spatial organisation of the nociceptive receptive fields in mice with normal LTP were very similar to those in rats, the LTP impaired strains exhibited receptive fields of NWRs with aberrant sensitivity distributions. However, no difference was found in NWR thresholds or onset C-fibre latencies suggesting that the mechanisms determining general reflex sensitivity and somatosensory imprinting are different.</p> <p>Conclusion</p> <p>Our results thus confirm that sensory encoding in mice and rat NWR is similar, provided that mice strains with a good learning capability are studied and raise the possibility that LTP like mechanisms are involved in somatosensory imprinting.</p

Comparison of Extended-Spectrum beta-Lactamase (ESBL) CTX-M Genotypes in Franklin Gulls from Canada and Chile

Migratory birds have been suggested to contribute to long-distance dispersal of antimicrobial resistant bacteria, but tests of this hypothesis are lacking. In this study we determined resistance profiles and genotypes of ESBL-producing bacteria in randomly selected Escherichia coli from Franklin's gulls (Leucophaeus pipixcan) at breeding sites in Canada and compared with similar data from the gulls' wintering grounds in Chile. Resistant E. coli phenotypes were common, most notably to ampicillin (30.1%) and cefadroxil (15.1%). Furthermore, 17.0% of the gulls in Canada carried ESBL producing bacteria, which is higher than reported from human datasets from the same country. However, compared to gulls sampled in Chile (30.1%) the prevalence of ESBL was much lower. The dominant ESBL variants in Canada were bla(CTX-M-14) and bla(CTX-M-15) and differed in proportions to the data from Chile. We hypothesize that the observed differences in ESBL variants are more likely linked to recent exposure to bacteria from anthropogenic sources, suggesting high local dissemination of resistant bacteria both at breeding and non-breeding times rather than a significant trans-hemispheric exchange through migrating birds

Carriage of CTX-M type extended spectrum beta-lactamases (ESBLs) in gulls across Europe

Background: Extended spectrum beta-lactamases (ESBLs), a group of enzymes conferring resistance to third generation cephalosporins have rapidly increased in Enterobacteriacae and pose a major challenge to human health care. Resistant isolates are common in domestic animals and clinical settings, but prevalence and genotype distribution varies on a geographical scale. Although ESBL genes are frequently detected in bacteria isolated from wildlife samples, ESBL dissemination of resistant bacteria to the environment is largely unknown. To address this, we used three closely related gull species as a model system and collected more than 3000 faecal samples during breeding times in nine European countries. Samples were screened for ESBL-producing bacteria, which were characterized to the level of ESBL genotype groups (SHV, TEM), or specific genotypes (CTX-M). Results: ESBL-producing bacteria were frequently detected in gulls (906 of 3158 samples, 28.7 %), with significant variation in prevalence rates between countries. Highest levels were found in Spain (74.8 %), The Netherlands (37.8 %) and England (27.1 %). Denmark and Poland represented the other extreme with no, or very few positive samples. Genotyping of CTX-M isolates identified 13 different variants, with bla(CTX-M-1) and bla(CTX-M-14) as the most frequently detected. In samples from England, Spain and Portugal, blaCTX-M-14 dominated, while in the rest of the sampled countries blaCTX-M-1 (except Sweden where bla(CTX-M-15) was dominant) was the most frequently detected genotype, a pattern similar to what is known from studies of human materials. Conclusions: CTX-M type ESBLs are common in the faecal microbiota from gulls across Europe. The gull ESBL genotype distribution was in large similar to published datasets from human and food-production animals in Europe. The data suggests that the environmental dissemination of ESBL is high from anthropogenic sources, and widespread occurrence of resistant bacteria in common migratory bird species utilizing urban and agricultural areas suggests that antibiotic resistance genes may also be spread through birds

The Ecology of Emerging Infectious Diseases in Migratory Birds: An Assessment of the Role of Climate Change and Priorities for Future Research

Pathogens that are maintained by wild birds occasionally jump to human hosts, causing considerable loss of life and disruption to global commerce. Preliminary evidence suggests that climate change and human movements and commerce may have played a role in recent range expansions of avian pathogens. Since the magnitude of climate change in the coming decades is predicted to exceed climatic changes in the recent past, there is an urgent need to determine the extent to which climate change may drive the spread of disease by avian migrants. In this review, we recommend actions intended to mitigate the impact of emergent pathogens of migratory birds on biodiversity and public health. Increased surveillance that builds upon existing bird banding networks is required to conclusively establish a link between climate and avian pathogens and to prevent pathogens with migratory bird reservoirs from spilling over to humans

Characterization of avian influenza virus attachment patterns to human and pig tissues

Wild birds of Anseriformes and Charadriiformes are natural reservoirs of influenza A viruses (IAVs). Occasionally, IAVs transmit and adapt to mammalian hosts, and are maintained as epidemic strains in their new hosts. Viral adaptions to mammalian hosts include altered receptor preference of host epithelial sialylated oligosaccharides from terminal alpha 2,3-linked sialic acid (SA) towards alpha 2,6-linked SA. However, alpha 2,3-linked SA has been found in human respiratory tract epithelium, and human infections by avian IAVs (AIVs) have been reported. To further explore the attachment properties of AIVs, four AIVs of different subtypes were investigated on human and pig tissues using virus histochemistry. Additionally, glycan array analysis was performed for further characterization of IAVs' receptor structure tropism. Generally, AIV attachment was more abundant to human tissues than to pig tissues. The attachment pattern was very strong to human conjunctiva and upper respiratory tract, but variable to the lower respiratory tract. AIVs mainly attached to alpha 2,3-linked SA, but also to combinations of alpha 2,3-and alpha 2,6-linked SA. The low attachment of these AIV isolates to pig tissues, but high attachment to human tissues, addresses the question whether AIVs in general require passage through pigs to obtain adaptions towards mammalian receptor structures.De två första författarna delar förstaförfattarskapet.</p

Candidatus Neoehrlichia mikurensis in Ticks from Migrating Birds in Sweden

Candidatus Neoehrlichia mikurensis (CNM; family Anaplasmataceae) was recently recognized as a potential tick-borne human pathogen. The presence of CNM in mammals, in host-seeking Ixodes ticks and in ticks attached to mammals and birds has been reported recently. We investigated the presence of CNM in ornithophagous ticks from migrating birds. A total of 1,150 ticks (582 nymphs, 548 larvae, 18 undetermined ticks and two adult females) collected from 5,365 birds captured in south-eastern Sweden was screened for CNM by molecular methods. The birds represented 65 different species, of which 35 species were infested with one or more ticks. Based on a combination of morphological and molecular species identification, the majority of the ticks were identified as Ixodes ricinus. Samples were initially screened by real-time PCR targeting the CNM 16S rRNA gene, and confirmed by a second real-time PCR targeting the groEL gene. For positive samples, a 1260 base pair fragment of the 16S rRNA gene was sequenced. Based upon bacterial gene sequence identification, 2.1% (24/1150) of the analysed samples were CNM-positive. Twenty-two out of 24 CNM-positive ticks were molecularly identified as I. ricinus nymphs, and the remaining two were identified as I. ricinus based on morphology. The overall CNM prevalence in I. ricinus nymphs was 4.2%. None of the 548 tested larvae was positive. CNM-positive ticks were collected from 10 different bird species. The highest CNM-prevalences were recorded in nymphs collected from common redpoll (Carduelis flammea, 3/7), thrush nightingale (Luscinia luscinia, 2/29) and dunnock (Prunella modularis, 1/17). The 16S rRNA sequences obtained in this study were all identical to each other and to three previously reported European strains, two of which were obtained from humans. It is concluded that ornithophagous ticks may be infected with CNM and that birds most likely can disperse CNM-infected ticks over large geographical areas.Funding for this study came from the Medical Research Council of Southeast Sweden (grant numbers FORSS-307591 and FORSS-387231), Carl Trygger's Foundation for Scientific Research, Langmanska kulturfonden, Magnus Bergvall's Foundation for Scientific Research, Helge Ax:son Johnson's Foundation and the EU Interreg IVA project ScandTick.</p

Candidatus Neoehrlichia mikurensis in Ticks from Migrating Birds in Sweden

Candidatus Neoehrlichia mikurensis (CNM; family Anaplasmataceae) was recently recognized as a potential tick-borne human pathogen. The presence of CNM in mammals, in host-seeking Ixodes ticks and in ticks attached to mammals and birds has been reported recently. We investigated the presence of CNM in ornithophagous ticks from migrating birds. A total of 1,150 ticks (582 nymphs, 548 larvae, 18 undetermined ticks and two adult females) collected from 5,365 birds captured in south-eastern Sweden was screened for CNM by molecular methods. The birds represented 65 different species, of which 35 species were infested with one or more ticks. Based on a combination of morphological and molecular species identification, the majority of the ticks were identified as Ixodes ricinus. Samples were initially screened by real-time PCR targeting the CNM 16S rRNA gene, and confirmed by a second real-time PCR targeting the groEL gene. For positive samples, a 1260 base pair fragment of the 16S rRNA gene was sequenced. Based upon bacterial gene sequence identification, 2.1% (24/1150) of the analysed samples were CNM-positive. Twenty-two out of 24 CNM-positive ticks were molecularly identified as I. ricinus nymphs, and the remaining two were identified as I. ricinus based on morphology. The overall CNM prevalence in I. ricinus nymphs was 4.2%. None of the 548 tested larvae was positive. CNM-positive ticks were collected from 10 different bird species. The highest CNM-prevalences were recorded in nymphs collected from common redpoll (Carduelis flammea, 3/7), thrush nightingale (Luscinia luscinia, 2/29) and dunnock (Prunella modularis, 1/17). The 16S rRNA sequences obtained in this study were all identical to each other and to three previously reported European strains, two of which were obtained from humans. It is concluded that ornithophagous ticks may be infected with CNM and that birds most likely can disperse CNM-infected ticks over large geographical areas.Funding for this study came from the Medical Research Council of Southeast Sweden (grant numbers FORSS-307591 and FORSS-387231), Carl Trygger's Foundation for Scientific Research, Langmanska kulturfonden, Magnus Bergvall's Foundation for Scientific Research, Helge Ax:son Johnson's Foundation and the EU Interreg IVA project ScandTick.</p