Many freshwater systems receive substantial inputs of terrestrial organic matter. Terrestrially derived dissolved organic carbon (t‐DOC) inputs can modify light availability, the spatial distribution ...of primary production, heat, and oxygen in aquatic systems, as well as inorganic nutrient bioavailability. It is also well‐established that some terrestrial inputs (such as invertebrates and fruits) provide high‐quality food resources for consumers in some systems.
In small to moderate‐sized streams, leaf litter inputs average approximately three times greater than the autochthonous production. Conversely, in oligo/mesotrophic lakes algal production is typically five times greater than the available flux of allochthonous basal resources.
Terrestrial particulate organic carbon (t‐POC) inputs to lakes and rivers are comprised of 80%–90% biochemically recalcitrant lignocellulose, which is highly resistant to enzymatic breakdown by animal consumers. Further, t‐POC and heterotrophic bacteria lack essential biochemical compounds that are critical for rapid growth and reproduction in aquatic invertebrates and fishes. Several studies have directly shown that these resources have very low food quality for herbivorous zooplankton and benthic invertebrates.
Much of the nitrogen assimilated by stream consumers is probably of algal origin, even in systems where there appears to be a significant terrestrial carbon contribution. Amino acid stable isotope analyses for large river food webs indicate that most upper trophic level essential amino acids are derived from algae. Similarly, profiles of essential fatty acids in consumers show a strong dependence on the algal food resources.
Primary production to respiration ratios are not a meaningful index to assess consumer allochthony because respiration represents an oxidised carbon flux that cannot be utilised by animal consumers. Rather, the relative importance of allochthonous subsidies for upper trophic level production should be addressed by considering the rates at which terrestrial and autochthonous resources are consumed and the growth efficiency supported by this food.
Ultimately, the biochemical composition of a particular basal resource, and not just its quantity or origin, determines how readily this material is incorporated into upper trophic level consumers. Because of its highly favourable biochemical composition and greater availability, we conclude that microalgal production supports most animal production in freshwater ecosystems.
Subclinical Atrial Fibrillation and the Risk of Stroke Healey, Jeff S; Connolly, Stuart J; Gold, Michael R ...
New England journal of medicine/The New England journal of medicine,
01/2012, Letnik:
366, Številka:
2
Journal Article
Recenzirano
Odprti dostop
A cohort of 2580 patients with pacemakers or defibrillators were monitored for 3 months to detect subclinical atrial tachyarrhythmias. Patients with subclinical atrial tachyarrhythmias had a ...significantly increased risk of subsequent ischemic stroke.
Atrial fibrillation may be asymptomatic and consequently subclinical.
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Epidemiologic studies indicate that many patients with atrial fibrillation on screening electrocardiograms had not previously received a diagnosis of atrial fibrillation.
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About 15% of strokes are attributable to documented atrial fibrillation, and 50 to 60% to documented cerebrovascular disease,
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but in about 25% of patients who have ischemic strokes, no etiologic factor is identified.
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Subclinical atrial fibrillation is often suspected to be the cause of stroke in these patients.
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However, the prevalence and prognostic value of subclinical atrial fibrillation has been difficult to assess.
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An . . .
We showed that severe acute respiratory syndrome coronavirus 2 is probably a novel recombinant virus. Its genome is closest to that of severe acute respiratory syndrome-related coronaviruses from ...horseshoe bats, and its receptor-binding domain is closest to that of pangolin viruses. Its origin and direct ancestral viruses have not been identified.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Illuminating gravitational waves Kasliwal, M. M.; Nakar, E.; Singer, L. P. ...
Science (American Association for the Advancement of Science),
12/2017, Letnik:
358, Številka:
6370
Journal Article
Recenzirano
Odprti dostop
Merging neutron stars offer an excellent laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic ...counterpart (EM170817) with gravitational waves (GW170817) detected from merging neutron stars. By synthesizing a panchromatic data set, we demonstrate that merging neutron stars are a long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma rays seen in EM170817 are dissimilar to classical short gamma-ray bursts with ultrarelativistic jets. Instead, we suggest that breakout of a wide-angle, mildly relativistic cocoon engulfing the jet explains the low-luminosity gamma rays, the high-luminosity ultraviolet-optical-infrared, and the delayed radio and x-ray emission. We posit that all neutron star mergers may lead to a wide-angle cocoon breakout, sometimes accompanied by a successful jet and sometimes by a choked jet.
While a number of human coronaviruses are believed to be originated from ancestral viruses in bats, it remains unclear if bat coronaviruses are ready to cause direct bat-to-human transmission. Here, ...we report the isolation of a MERS-related coronavirus, Tylonycteris-bat-CoV-HKU4, from lesser bamboo bats. Tylonycteris-bat-CoV-HKU4 replicates efficiently in human colorectal adenocarcinoma and hepatocarcinoma cells with cytopathic effects, and can utilize human-dipeptidyl-peptidase-4 and dromedary camel-dipeptidyl-peptidase-4 as the receptors for cell entry. Flow cytometry, co-immunoprecipitation and surface plasmon resonance assays show that Tylonycteris-bat-CoV-HKU4-receptor-binding-domain can bind human-dipeptidyl-peptidase-4, dromedary camel-dipeptidyl-peptidase-4, and Tylonycteris pachypus-dipeptidyl-peptidase-4. Tylonycteris-bat-CoV-HKU4 can infect human-dipeptidyl-peptidase-4-transgenic mice by intranasal inoculation with self-limiting disease. Positive virus and inflammatory changes were detected in lungs and brains of infected mice, associated with suppression of antiviral cytokines and activation of proinflammatory cytokines and chemokines. The results suggest that MERS-related bat coronaviruses may overcome species barrier by utilizing dipeptidyl-peptidase-4 and potentially emerge in humans by direct bat-to-human transmission.
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Objective. To evaluate the prevalence and pattern of arterial calcification in patients with rheumatoid arthritis (RA).
Background. Patients with RA are prone to premature atherosclerosis; ...nonetheless the prevalence and extent of atherosclerosis in different vascular beds and their relationship to each other remain unknown.
Methods. We studied the distribution and extent of arterial calcification in 85 RA patients and 85 age‐and sex‐matched controls. Arterial calcification as determined by calcium score (CS) were measured using multi‐detector computed tomography in thoracic aorta, coronary and carotid arteries.
Results. Compared with controls, RA patients had a significantly higher average CS and prevalence of CS > 0 in aorta, coronary and carotid arteries and overall arteries (all P < 0.05). After adjusting for age and sex, RA patients had a significantly higher relative risk of developing calcification in the aorta Odds Ratio (OR) = 19.5, 95% Confidence Interval (CI): 8.0–47.6, followed by the carotid arteries (OR = 5.7, 95% CI:1.7–18.7) and coronary arteries (OR = 5.0, 95% CI:2.2–11.1) compared with controls (all P < 0.01). Amongst RA patients aged >60, 90% had diffuse arterial calcification, especially over the thoracic aorta, compared with 55% of controls who had arterial calcification clustered in the coronary arteries (P < 0.05). RA patients with total CS > 0 were older with a higher urea level and C‐reactive protein than those without arterial calcification, no factor was found to be independently predictive for arterial calcification (all P > 0.05).
Conclusions. Our results demonstrated that RA patients had earlier onset, more diffuse arterial calcification over multiple vascular beds and more preferential involvement of thoracic aorta, rather than coronary artery when compared with control.
Thioamides antithyroid‐drugs (ATDs) are important in hyperthyroid disease management. Identification of the susceptibility locus of ATD‐induced agranulocytosis is important for clinical management. ...We performed a genome‐wide association study (GWAS) involving 20 patients with ATD‐induced agranulocytosis and 775 healthy controls. The top finding was further replicated. A single‐nucleotide polymorphism (SNP), rs185386680, showed the strongest association with ATD‐induced agranulocytosis in GWAS (odds ratio (OR) = 36.4; 95% confidence interval (CI) = 12.8–103.7; P = 1.3 × 10‐24) and replication (OR = 37; 95% CI = 3.7–367.4; P = 9.6 × 10‐7). HLA‐B*38:02:01 was in complete linkage disequilibrium with rs185386680. High‐resolution HLA typing confirmed that HLA‐B*38:02:01 was associated with carbimazole (CMZ)/methimazole (MMI)‐induced agranulocytosis (OR = 265.5; 95% CI = 27.9–2528.0; P = 2.5 × 10‐14), but not associated with propylthiouracil (PTU). The positive and negative predictive values of HLA‐B*38:02:01 in predicting CMZ/MMI‐induced agranulocytosis were 0.07 and 0.999. Approximately 211 cases need to be screened to prevent one case. Screening for the risk allele will be useful in preventing agranulocytosis in populations in which the frequency of the risk allele is high.
In the last decade, as a result of the widespread use of PCR and DNA sequencing, 16S rDNA sequencing has played a pivotal role in the accurate identification of bacterial isolates and the discovery ...of novel bacteria in clinical microbiology laboratories. For bacterial identification, 16S rDNA sequencing is particularly important in the case of bacteria with unusual phenotypic profiles, rare bacteria, slow-growing bacteria, uncultivable bacteria and culture-negative infections. Not only has it provided insights into aetiologies of infectious disease, but it also helps clinicians in choosing antibiotics and in determining the duration of treatment and infection control procedures. With the use of 16S rDNA sequencing, 215 novel bacterial species, 29 of which belong to novel genera, have been discovered from human specimens in the past 7 years of the 21st century (2001–2007). One hundred of the 215 novel species, 15 belonging to novel genera, have been found in four or more subjects. The largest number of novel species discovered were of the genera Mycobacterium (n = 12) and Nocardia (n = 6). The oral cavity/dental-related specimens (n = 19) and the gastrointestinal tract (n = 26) were the most important sites for discovery and/or reservoirs of novel species. Among the 100 novel species, Streptococcus sinensis, Laribacter hongkongensis, Clostridium hathewayi and Borrelia spielmanii have been most thoroughly characterized, with the reservoirs and routes of transmission documented, and S. sinensis, L. hongkongensis and C. hathewayi have been found globally. One of the greatest hurdles in putting 16S rDNA sequencing into routine use in clinical microbiology laboratories is automation of the technology. The only step that can be automated at the moment is input of the 16S rDNA sequence of the bacterial isolate for identification into one of the software packages that will generate the result of the identity of the isolate on the basis of its sequence database. However, studies on the accuracy of the software packages have given highly varied results, and interpretation of results remains difficult for most technicians, and even for clinical microbiologists. To fully utilize 16S rDNA sequencing in clinical microbiology, better guidelines are needed for interpretation of the identification results, and additional/supplementary methods are necessary for bacterial species that cannot be identified confidently by 16S rDNA sequencing alone.
The discovery of Hp-BatCoV HKU25 bridges the evolutionary gap between MERS-CoV and existing bat viruses, and suggests that bat viruses may have evolved to generate MERS-CoV through modulation of the ...spike protein for binding to hDPP4.
Abstract
Although bats are known to harbor Middle East Respiratory Syndrome coronavirus (MERS-CoV)-related viruses, the role of bats in the evolutionary origin and pathway remains obscure. We identified a novel MERS-CoV-related betacoronavirus, Hp-BatCoV HKU25, from Chinese pipistrelle bats. Although it is closely related to MERS-CoV in most genome regions, its spike protein occupies a phylogenetic position between that of Ty-BatCoV HKU4 and Pi-BatCoV HKU5. Because Ty-BatCoV HKU4 but not Pi-BatCoV HKU5 can use the MERS-CoV receptor human dipeptidyl peptidase 4 (hDPP4) for cell entry, we tested the ability of Hp-BatCoV HKU25 to bind and use hDPP4. The HKU25-receptor binding domain (RBD) can bind to hDPP4 protein and hDPP4-expressing cells, but it does so with lower efficiency than that of MERS-RBD. Pseudovirus assays showed that HKU25-spike can use hDPP4 for entry to hDPP4-expressing cells, although with lower efficiency than that of MERS-spike and HKU4-spike. Our findings support a bat origin of MERS-CoV and suggest that bat CoV spike proteins may have evolved in a stepwise manner for binding to hDPP4.
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