233 research outputs found
Early Improvement in Glycemic Metabolism after Laparoscopic Sleeve Gastrectomy in Obese Patients -A Prospective Study
Rezumat Ameliorarea rapidã a metabolismului glucidic dupã gastrectomia longitudinalã laparoscopicã la pacienåii cu obezitate -studiu prospectiv Introducere: Conform Organizaåiei Mondiale a Sãnãtãåii, existau în 2014 peste 600 de milioane de adulåi cu obezitate (mai mult decât dublu faåã de anul 1980) care prezintã un risc crescut de dezvoltare a sindromului metabolic, deci inclusiv pentru diabetul zaharat de tip 2. Datoritã controlului slab glicemic în urma tratamentului conservator al DZ tip 2, chirurgia metabolicã a fost capabilã sã câaetige un rol important în managementul pacientului cu DZ tip 2 aei obezitate, cu remisii sau îmbunãtãåiri semnificative raportate în literatura de specialitate. Obiectiv: studierea efectelor gastrectomiei longitudinale laparoscopice (LSG) asupra metabolismului glucidic la pacienåii cu obezitate, cu sau fãrã DZ tip 2. Metodã: 60 de pacienåi consecutivi, operaåi în spitalul Ponderas pentru obezitate prin gastrectomie longitudinalã laparoscopicã, au fost incluaei într-un studiu prospectiv, în perioada FebruarieMartie 2013. IMC-ul (indicele de masã corporalã), circumferinåã abdominalã aei parametrii glicemici au fost studiaåi pre-operator, la 10 zile aei 6 luni postoperator. Rezultate: controlul glicemic a fost semnificant îmbunãtãåit începând cu ziua 10 postoperatorie. Imbunãtãåiri semnificative statistic au fost notate la 6 luni postoperator în valorile IMCului (p<0.0001), circumferinåa abdominalã (p<0.0001), glicemie (p<0.0001), insulinemie (p<0.0001), peptid C (p<0.0001) aei HOMA. Concluzii: o îmbunãtãåire rapidã a metabolismului glucidic, atât la pacienåii cu obezitate aei DZ tip 2 cât aei la cei fãrã DZ tip 2, se regãseaete înaintea scãderii ponderale semnificative (10 zile postoperator). La 6 luni postoperator, când se asociazã aei o scãdere ponderalã semnificativã, atât pacienåii diabetici cât aei cei nediabetici prezintã o îmbunãtãåire suplimentarã a metabolismului glicemic, care poate susåine ideea ca gastrectomia longitudinalã laparoscopicã este o metodã eficientã pentru tratamentul pacienåilor cu obezitate aei sindrom metabolic. Aceste modificãri benefice pot explica atât remisia DZ tip 2 dar aei prevenåia acestuia la pacienåii cu obezitate supuaei tratamentului chirurgical metabolic. Cuvinte cheie: obezitate, metabolism glucidic, gastrectomie longitudinalã laparoscopicã, remisia aei prevenåia diabetului zaharat tip 2 Abstract Background: according to W.H.O. in 2014 more than 600 million adults were obese, (more than doubled since 1980), and face a major risk for the onset of metabolic syndrome, including T2DM. Due to the poor control of glycemic imbalance for the conservative treatment of T2DM, the metabolic surgery was able to gain an important role in modern management of T2DM, with significant reported improvements or remissions for these patients. Objective: to study the effects of laparoscopic sleeve gastrec- BMI, waist circumference and glycemic parameters were studied at the moment of entering the study, 10 days after surgery and at 6 months follow up. Results: the glycemic control was significantly improved starting with postoperative day 10. Statistically significant improvements were noticed after six months postoperatively in BMI values (p<0,0001), waist circumference (p<0,0001), glycemic levels (p<0,0001), insulin (p<0,0001), C-peptide (p<0,0001) and HOMA. Conclusions: a rapid induced improvement of glucose metabolism in both diabetic and non-diabetic patients occurs before a significant weight loss (POD 10). At 6 months, when associated with an important weight loss, both diabetic and non-diabetic patients present a furthermore improvement in glycemic metabolism, that enables us to consider that sleeve gastrectomy is an efficient method for a sustained improvement in the metabolic status of patients with obesity. These beneficial changes that can explain the remission of T2DM can also explain the prevention of T2DM after metabolic surgery
Strong Gravitational Lensing and Dark Energy Complementarity
In the search for the nature of dark energy most cosmological probes measure
simple functions of the expansion rate. While powerful, these all involve
roughly the same dependence on the dark energy equation of state parameters,
with anticorrelation between its present value w_0 and time variation w_a.
Quantities that have instead positive correlation and so a sensitivity
direction largely orthogonal to, e.g., distance probes offer the hope of
achieving tight constraints through complementarity. Such quantities are found
in strong gravitational lensing observations of image separations and time
delays. While degeneracy between cosmological parameters prevents full
complementarity, strong lensing measurements to 1% accuracy can improve
equation of state characterization by 15-50%. Next generation surveys should
provide data on roughly 10^5 lens systems, though systematic errors will remain
challenging.Comment: 7 pages, 5 figure
Time-Varying Dark Energy Constraints From the Latest SN Ia, BAO and SGL
Based on the latest SNe Ia data provided by Hicken et al. (2009) with using
MLCS17 light curve fitter, together with the Baryon Acoustic Oscillation(BAO)
and strong gravitational lenses(SGL), we investigate the constraints on the
dark energy equation-of-state parameter in the flat universe, especially
for the time-varying case . The constraints from SNe data
alone are found to be: (a) as the best-fit
results; (b) for
the two parameters in the time-varying case after marginalizing the parameter
; (c) the likelihood of parameter has a high non-Gaussian
distribution; (d) an extra restriction on is necessary to improve
the constraint of the SNe Ia data on the parameters (, ). A joint
analysis of SNe Ia data and BAO is made to break the degeneracy between and
, and leads to the interesting maximum likelihoods and
. When marginalizing the parameter , the fitting results are
found to be . After
adding the splitting angle statistic of SGL data, a consistent constraint is
obtained and the constraints on time-varying
dark energy are further improved to be , which indicates that the phantom type models are
disfavored.Comment: 24 pages, 9 figures, to be published in JCA
Compressed-Liquid Energy Storage with an Adsorption-based Vapor Accumulator for Solar-Driven Vapor Compression Systems in Residential Cooling
A cycle-integrated energy storage strategy for vapor-compression refrigeration is proposed wherein thermo-mechanical energy is stored as compressed liquid.A compressed-liquid tank is integrated into the liquid line of the system by means of an adsorption-based vapor accumulator in the vapor line. Energy is retrieved through expansion of the compressed liquid, which allows for a tunable evaporator temperature. A thermodynamic model is developed to assess the system performance, with storage incorporated, for solar residential cooling in two locations with contrasting ambient temperature profiles. Ammonia, R134a, and propane, all paired with activated carbon as adsorbent, are evaluated.A high cold thermal energy storage density is achieved when operated with ammonia. However, the accumulator suppresses the coefficient of performance of the system because work is required to extract refrigerant from the adsorbent. Practical feasibility of the proposed storage strategy calls for the development of nontoxic refrigerant–adsorbent pairs with more favorable adsorption behavior
A propane water-to-water heat pump booster for sanitary hot water production: Seasonal performance analysis of a new solution optimizing COP
[EN] Electrical heat pumps for sanitary hot water production achieve a high performance with a
good matching of water and refrigerant temperature profiles during the heat rejection
stage, as it happens in CO2 systems. This work considers the thermodynamic possibility to
adapt the condenser pressure of a propane heat pump to maximize the COP, while producing
sanitary hot water up to 60 C from a heat sink equal to 15 or 25 C. The performance
of the heat pump is calculated through specific models which, in combination with
a TRNSYS model of the whole system, allowed to assess its seasonal performance for a
hotel in Strasbourg, also varying the control logic and the size of the storage tank. Results
obtained led to the conclusion that, for achieving a high seasonal performance, the control
logic of the tank has the largest influence.Part of the results of this study were developed in the mainframe of the FP7 European project ‘Next Generation of Heat Pumps working with Natural fluids’ (NxtHPG). Part of the work presented was carried by M. Tammaro during his visit at the Instituto de Ingenierı´a Energetica, Universitat Politecnica de Val encia and by C. Montagud during her visit at the Department of Industrial Engineering, Federico
II University of Naples, with the financial support of the POLIGRID project.Tammaro, M.; Montagud Montalvá, CI.; Corberán Salvador, JM.; Mauro, AW.; Mastrullo, R. (2015). A propane water-to-water heat pump booster for sanitary hot water production: Seasonal performance analysis of a new solution optimizing COP. International Journal of Refrigeration. 51:59-69. https://doi.org/10.1016/j.ijrefrig.2014.12.008S59695
The amplitude of mass fluctuations and mass density of the Universe constrained by strong gravitational lensing
We investigate the linear amplitude of mass fluctuations in the universe,
, and the present mass density parameter of the Universe,
, from the statistical strong gravitational lensing. We use
the two populations of lens halos model with fixed cooling mass scale
M_\mathrm{c}=3\times 10^{13}h^{-1}M_{\sun} to match the observed lensing
probabilities, and leave or as a free parameter
to be constrained by data. Another varying parameter is the equation of state
of dark energy , and its typical values of -1, -2/3, -1/2 and -1/3 are
investigated. We find that is degenerate with in
a way similar to that suggested by present day cluster abundance as well as
cosmic shear lensing measurements: (Bahcall & Bode\cite{bahcall03a} and references therein). However, both
and can be safely ruled out, the
best value is when , and .
This result is different from that obtained by Bahcall & Bode
(\cite{bahcall03a}), who gives and . For , higher value of requires
and requires .Comment: 9 pages, 4 figures, references update
Single-objective versus multiobjective optimization of water distribution systems accounting for greenhouse gas emissions by carbon pricing
Previous research has demonstrated that there are significant trade-offs between the competing objectives of minimizing costs and greenhouse gas (GHG) emissions for water distribution system (WDS) optimization. However, upon introduction of an emission trading scheme, GHG emissions are likely to be priced at a particular level. Thus, a monetary value can be assigned to GHG emissions, enabling a single-objective optimization approach to be used. This raises the question of whether the introduction of carbon pricing under an emission trading scheme will make the use of a multiobjective optimization approach obsolete or whether such an approach can provide additional insights that are useful in a decision-making context. In this paper, the above questions are explored via two case studies. The optimization results obtained for the two case studies using both single-objective and multiobjective approaches are analyzed. The analyses show that the single-objective approach results in a loss of trade-off information between the two objectives. In contrast, the multiobjective approach provides decision makers with more insight into the trade-offs between the two objectives. As a result, a multiobjective approach is recommended for the optimization of WDSs accounting for GHG emissions when considering carbon pricing. © 2010 ASCE.Wenyan Wu, Holger R. Maier, and Angus R. Simpso
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