679 research outputs found
Experimental Investigation of the Effect of Pilot Tone Modulation on Partial Response Modulation Formats
This paper presents an experimental investigation of 8% pilot tone modulation
depth is a system transmitting NRZ, PAM4 and Duobinary. The penalty from the
pilot tone increases with signal amplitude levels and reaches a received power
penalty of 3 dB.Comment: Project BlueSpace (EU funding No. 762055
Color singlet suppression of quark-gluon plasma formation
The rate of quark-gluon plasma droplet nucleation in superheated hadronic
matter is calculated within the MIT bag model. The requirements of color
singletness and (to less extent) fixed momentum suppress the nucleation rate by
many orders of magnitude, making thermal nucleation of quark-gluon plasma
droplets unlikely in ultrarelativistic heavy-ion collisions if the transition
is first order and reasonably described by the bag model.Comment: 9 pages, 3 ps figures. To appear in PhysRevC (April 1996
Response to: the metabolic cost of whistling is low but measurable in dolphins
Author Posting. © Company of Biologists, 2020. This article is posted here by permission of Company of Biologists for personal use, not for redistribution. The definitive version was published in Journal of Experimental Biology 223(11), (2020): jeb224915, doi: 10.1242/jeb.224915.Costs of sound production have been investigated only sparsely incetaceans, despite recent efforts to understand how increasinganthropogenic noise affects these animals that rely extensively onsound for communication and foraging. Theoretical estimates suggestthat metabolic costs of whistling for bottlenose dolphins should be<0.54% of resting metabolic rate (RMR) (Jensen et al., 2012),whereas empirical studies of a single whistling dolphin surprisinglyclaimed that sound production costs were around 20% of RMR (Holtet al., 2015; Noren et al., 2013). Addressing this discrepancy, wefound that costs of whistling were significantly less than 20% RMRand not statistically different from theoretical estimates (Pedersenet al., 2020). In their correspondence, Noren et al., 2020 argue thatthey did not claim whistling was‘costly’and questioned aspects ofour methods, and we address these points here.2021-06-0
Experimental model for CAPD studies in the rabbit
An animal model suitable for bioeompatibility studies of peritoneal dialysis solutions is presented. It permits fluid exchanges to be performed 3 times a day for at least 28 days. thus simulating Continuous Ambulatory Peritoneal Dialysis (CAPD) in humans.The surgical procedure is lenient, without omentectomy and nephrectomy. A closed, subcutaneous placed eatheter-system permits the animals to thrive well and move freely between dialysis-fluid exchanges. A Y-shaped dialysis equipment whichprevents air- and over-infusion was developed and is presented.The surgical procedure and the implanted catheter caused only minor histological changes of the peritoneum. No catheter-tunnel infections were observed.Our findings suggest that a slight peritoneal irritation is caused by the C:\PD-solutions, as non-infected, dialysed animals had a slightly higher body-temperature than controls and as the LD content of the dialysate was high probably indicatingcell-lysis.Though peritonitis was not avoided this experimental model using rabbits was found suitable for long term CAPD studies
Vital Indicators of the Rural and Agricultural Population in the S. R. Croatia — The Demographical Breakdown
Stanovništvo SR Hrvatske nalazi se na kraju razdoblja
demografske tranzicije. Godine 1982. imalo
je natalitet 14,5 promila, mortalitet 11,0 promila,
prirodni priraštaj 3,5 promila, a vitalni indeks 134,4.
Ovakvo kretanje biovitalnih stopa rezultat je utjecaja
industrijalizacijskih procesa na demografski razvitak,
napose deagrarizacije.
Postoje tipična seoska područja sa sekularnim trendovima
niskog nataliteta, a nagli je pad naročito
izražen između dva posljednja popisna razdoblja
(1971—1981), tako da je 1981. imalo negativni prirodni
priraštaj čak 49 općina, u kojima živi 24%
ukupnog stanovništva republike.
Na osnovi popisa stanovništva podataka i demografske
statistike, autor analizira promjene u demografskim
strukturama seoskog i poljoprivrednog stanovništva
(po zajednicama općina i regijama), usporedno
kretanje reproduktivnih stopa poljoprivrednog i
nepoljoprivrednog stanovništva te seoskog i »neseoskog
« stanovništva, starenje seoskog i poljoprivrednog
stanovništva te obrazovnu strukturu poljoprivrednog
stanovništva. Zaključno ističe da je većina
seoskog i poljoprivrednog stanovništva u poodmakloj
dobi, da je biološko pomlađivanje simbolično,
te da su i dalje naglašene aspiracije prema nepoijoprivrednim
zanimanjima.The population of the S. R. Croatia
is at the end of a period of
demographic transition. In 1982
the birth rate was 14.5 per thousand,
the death rate 11.0 per thousand,
the natural population increase
3.5 per thousand, and the
viital index 134.4. This change in
biovital rates is the result of the
influence of industrialization on
demographic development, and in
particular the result of deagrarization.
Some rural regions have typical
age-old trends towards a low
birth-rate, but the sudden decrease
came to expression especially
between the last two censuses
(1971—1981), so that as many as
49 communes had a negative natural
population increase in
1981. 24% of the total population
of the republic lives in these communes.
The author uses data from population
censuses and demographic
statistics to analyze changes in
the demographic structure of the
rural and agricultural population
(according to communities and
regions). He compares changes in
rates of reproduction between
the agricultural and the non-agricultural
population, and between
the rural and the »non-rural« population,
studies the ageing of the
rural and agricultural population,
and the educational structure
of the agricultural population. He
concludes that most of the rural
and agricultural population is
aged, that biological rejuvenation
is symbolic, and that aspirations
towards noo-agricultural occupationstions
are still very strong
Molecular Basis of Enhanced Activity in Factor VIIa-Trypsin Variants Conveys Insights into Tissue Factor-mediated Allosteric Regulation of Factor VIIa Activity
The complex of coagulation factor VIIa (FVIIa), a trypsin-like serine protease, and membrane-bound tissue factor (TF) initiates blood coagulation upon vascular injury. Binding of TF to FVIIa promotes allosteric conformational changes in the FVIIa protease domain and improves its catalytic properties. Extensive studies have revealed two putative pathways for this allosteric communication. Here we provide further details of this allosteric communication by investigating FVIIa loop swap variants containing the 170 loop of trypsin that display TF-independent enhanced activity. Using x-ray crystallography, we show that the introduced 170 loop from trypsin directly interacts with the FVIIa active site, stabilizing segment 215–217 and activation loop 3, leading to enhanced activity. Molecular dynamics simulations and novel fluorescence quenching studies support that segment 215–217 conformation is pivotal to the enhanced activity of the FVIIa variants. We speculate that the allosteric regulation of FVIIa activity by TF binding follows a similar path in conjunction with protease domain N terminus insertion, suggesting a more complete molecular basis of TF-mediated allosteric enhancement of FVIIa activity
Clean Colorectum at Diagnostic Colonoscopy:Subsequent Detection of Extracolonic Malignancies by Plasma Protein Biomarkers?
Introduction: Most of the subjects undergoing diagnostic colonoscopy do not have neoplastic bowel lesions. Potentially, some of the symptoms may therefore be caused by extracolonic malignancy, and subjects with persisting symptoms may need subsequent examinations. Blood-based, cancer-associated biomarkers may aid in directing the examinations for other specific malignant diseases. Methods: EDTA plasma samples available from a previous prospective study of subjects undergoing diagnostic colonoscopy were used for analysis of 18 protein biomarkers. The study population of 3732 subjects included 400 patients with colorectal cancer (CRC) and 177 patients with extracolonic malignancies. Univariable analysis of the association of specific biomarkers and extracolonic cancers included those with 10 or more cases. Subsequently, reduced models of 4 or 6 biomarkers, respectively, were established by choosing those with the highest likelihood; age and sex were included as well. Results: Univariable analyses showed that CyFra21-1 had an area under curve (AUC) of 0.87 for lung cancers (n = 33), CA19-9 had an AUC of 0.85 for pancreatic cancer (n = 22), CA125 had an AUC of 0.95 for ovary cancer (n = 16), B2M had an AUC of 0.81 for non-Hodgkin lymphoma (n = 12), and total prostate-specific antigen had an AUC of 0.99 for prostate cancer (n = 10). The multivariable analysis of 4 or 6 biomarkers plus age and sex as explanatory variables showed AUCs of 0.82 to 0.85 both for extracolonic cancers and CRC. The 4 biomarkers included in the model for detection of extracolonic cancers were CA125, hsCRP, CA19-9, and CyFra21-1; the 2 additional for the 6 biomarkers model were CEA and Galectin-3. Similarly, the 4 biomarkers included in the model for detection of CRC were CEA, CyFra21-1, Ferritin, and HE4; the two additional for the 6 biomarkers model were hsCRP and Pepsinogen 2. Conclusions: Results of this study indicate that it may be possible to detect subjects that have an increased risk of extracolonic cancer following a colonoscopy without findings of neoplastic lesions. Combinations of various protein biomarkers may direct subsequent examination after colonoscopy with clean colorectum. The results, although preliminary, may form the basis for additional research directed both for primary examinations of subjects with symptoms of malignancy and subsequent examinations after colonoscopy
A systematic approach for evaluating the role of surface-exposed loops in trypsin-like serine proteases applied to the 170 loop in coagulation factor VIIa
Proteases play a major role in many vital physiological processes. Trypsin-like serine proteases (TLPs), in particular, are paramount in proteolytic cascade systems such as blood coagulation and complement activation. The structural topology of TLPs is highly conserved, with the trypsin fold comprising two β-barrels connected by a number of variable surface-exposed loops that provide a surprising capacity for functional diversity and substrate specificity. To expand our understanding of the roles these loops play in substrate and co-factor interactions, we employ a systematic methodology akin to the natural truncations and insertions observed through evolution of TLPs. The approach explores a larger deletion space than classical random or directed mutagenesis. Using FVIIa as a model system, deletions of 1–7 amino acids through the surface exposed 170 loop, a vital allosteric regulator, was introduced. All variants were extensively evaluated by established functional assays and computational loop modelling with Rosetta. The approach revealed detailed structural and functional insights recapitulation and expanding on the main findings in relation to 170 loop functions elucidated over several decades using more cumbersome crystallization and single deletion/mutation methodologies. The larger deletion space was key in capturing the most active variant, which unexpectedly had a six-amino acid truncation. This variant would have remained undiscovered if only 2–3 deletions were considered, supporting the usefulness of the methodology in general protease engineering approaches. Our findings shed further light on the complex role that surface-exposed loops play in TLP function and supports the important role of loop length in the regulation and fine-tunning of enzymatic function throughout evolution
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