Cardiac output (CO) is an important haemodynamic parameter to monitor in patients during surgery. However, the majority of the techniques for measuring CO have a limited application in veterinary ...practice due to their invasive approach and associated complexity and risks. Transoesophageal echocardiography (TEE) is a technique used to monitor cardiac function in human patients during surgical procedures and allows CO to be measured non-invasively. This prospective clinical study aimed to compare the transoesophageal echocardiography using a transgastric view of the left ventricular outflow tract (LVOT) and the thermodilution (TD) technique for the assessment of CO during mean arterial pressure of 65-80 mmHg (normotension) and <65 mmHg (hypotension) in dogs undergoing elective surgery. Eight dogs were pre-medicated with acepromazine (0.05 mg/kg, IM), tramadol (4 mg/kg, IM) and atropine (0.03 mg/kg, IM), followed by anaesthetic induction with propofol (3-5 mg/kg IV) and maintenance with isoflurane associated with a continuous infusion rate of fentanyl (bolus of 3 μg/kg followed by 0.3 μg/kg/min). The CO was measured by TEE (CO
) and TD (CO
) at the end of expiration during normotension and hypotension (induced by isoflurane).
There was a strong positive correlation between CO
and CO
(r = 0.925; P < 0.0001). The bias between CO
and CO
was 0.14 ± 0.29 L/min (limits of agreement, -0.44 to 0.72 L/min). The percentage error of CO measured by the two methods was 12.32%. In addition, a strong positive correlation was found between CO
and CO
during normotension (r = 0.995; P < 0.0001) and hypotension (r = 0.78; P = 0.0223).
The results of this study indicated that the transgastric view of the LVOT by TEE was a minimally invasive alternative to clinically monitoring CO in dogs during anaesthesia. However, during hypotension, the CO obtained by TEE was less reliable, although still acceptable.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To investigate whether pulse pressure variation (PPV) can predict fluid responsiveness in healthy dogs during clinical surgery.
Prospective clinical study.
Thirty-three isoflurane-anesthetized dogs ...with arterial hypotension during orthopedic surgery.
Fluid challenge with lactated Ringer's solution (15 mL kg
in 15 minutes) was administered in mechanically ventilated dogs (tidal volume 10 mL kg
) with hypotension mean arterial pressure (MAP) < 65 mmHg. The volume expansion was considered effective if cardiac output (CO; transesophageal Doppler) increased by ≥ 15%. Cardiopulmonary data were analyzed using two-way ANOVA, receiver operating characteristics (ROC) curves and Spearman coefficient; p < 0.05 was considered significant.
Effective volume expansion, mean ± standard deviation 42 ± 4% increase in CO (p < 0.0001) was observed in 76% of the dogs, resulting in a decrease in PPV (p < 0.0001) and increase in MAP (p < 0.0001), central venous pressure (CVP; p = 0.02) and ejection fraction (p < 0.0001) compared with before the fluid challenge. None of these changes occurred when volume expansion resulted in a nonsignificant CO increase of 4 ± 5%. No significant differences were observed in blood gas analysis between responsive and nonresponsive dogs. The increase in CO was correlated with the decrease in PPV (r = -0.65; p < 0.0001) but absolute values of CO and PPV were not correlated. The PPV performance (ROC curve area: 0.89 ± 0.06, p = 0.0011) was better than that of CVP (ROC curve area: 0.54 ± 0.12) and MAP (ROC curve area: 0.59 ± 0.13) to predict fluid responsiveness. The best cut-off for PPV to distinguish responders and nonresponders was 15% (50% sensitivity and 96% specificity).
In mechanically ventilated, healthy, isoflurane-anesthetized dogs, PPV predicted fluid responsiveness to volume expansion, and MAP and CVP did not show such applicability.
Human diabetic patients may have increased lactate levels compared to non-diabetics. Despite the use of lactate levels in critical care assessment, information is lacking for diabetic dogs. ...Therefore, this prospective cross-sectional clinical study aimed to determine lactate concentrations in 75 diabetic dogs 25 newly diagnosed non-ketotic diabetics, 25 under insulin treatment, and 25 in diabetic ketoacidosis (DKA), compared to 25 non-diabetic dogs. Lactate levels (mmol/L) were not different among groups (
= 0.20); median and 25th to 75th percentile were 2.23 and P
= 1.46 to 2.83 for controls, 1.69 and P
= 1.09 to 2.40 for newly diagnosed non-ketotic diabetics, 2.27 and P
= 1.44 to 2.90 for dogs under insulin treatment for at least 30 days, and 2.40 and P
= 1.58 to 3.01 for dogs in DKA. Longitudinal studies assessing both isomers (L- and D-lactate) are needed to better elucidate the role of lactate in the pathophysiology of diabetes acid-base status in dogs.
In humans, left atrial enlargement and reduced contractile functions are associated with adverse cardiovascular events and a poor prognosis in many dilatation of the left atrium occurs with the ...gradual evolution of chronic mitral valve disease and is well diseases. The left atrium is the most compromised cardiac chamber in dogs with chronic mitral valve disease (CMVD). Therefore, this study aimed to compare the main parameters of left atrial enlargement (left atrium/aorta ratio, left atrial diameter and volume indices) and contractile function (transmitral flow peak velocity A wave and time velocity integral, atrial fraction, and atrial ejection force) at different stages of valve disease, and correlate the left atrial diameter, volume, and contractile function indices with echocardiographic variables predictive of heart failure in dogs (transmitral flow peak velocity E wave, E wave/IVRT ratio, E wave/E´wave ratio, and E wave/A wave ratio). The results showed that progressive characterized by the left atrium/aorta ratio and left atrium volume index. The left atrial diameter and volume indices and left atrium/aorta ratio correlated positively with the transmitral flow peak velocity E wave and E wave/IVRT ratio, which are important indices of diastolic function. The left atrial contractile function indices increased as CMVD evolved. Except for the atrial fraction, the left atrial contractile function indices correlated with the left ventricular filling pressure indices.
RESUMO: O tamanho e a função atrial esquerda estão relacionados em humanos com eventos cardiovasculares adversos e prognóstico nas principais cardiopatias. Na doença valvar crônica de mitral (DVCM) em cães, o átrio esquerdo é a câmara cardíaca mais comprometida. Portanto, os objetivos deste estudo foram comparar os principais parâmetros de aumento atrial esquerdo (relação átrio esquerdo/aorta, índice do diâmetro atrial esquerdo e índice do volume atrial esquerdo) e função contrátil de átrio esquerdo (velocidade máxima e integral de velocidade da onda A do fluxo transvalvar mitral, fração atrial e força de ejeção atrial) nos diferentes estágios da doença valvar; correlacionar diâmetro e volume atrial esquerdo e os índices de função contrátil atrial esquerda com as variáveis ecocardiográficas preditivas de insuficiência cardíaca em cães (velocidade máxima da onda E do fluxo transvalvar mitral, relação E/TRIV, relação E/E’par e relação E/A). Os resultados mostraram que com a evolução progressiva da doença valvar crônica de mitral, ocorre dilatação progressiva do átrio esquerdo, bem caracterizada pela relação átrio esquerdo/aorta e pelo índice de volume atrial esquerdo. O índice do diâmetro atrial esquerdo, o índice de volume atrial esquerdo e a relação átrio esquerdo/aorta correlacionam-se, positivamente, com a velocidade da onda E e com a relação E/TRIV, que são importantes índices de função diastólica. Os índices de função contrátil do átrio esquerdo aumentam à medida que a DVCM evolui. Os índices de função contrátil do átrio esquerdo apresentam correlação positiva com os índices de pressão de enchimento ventricular esquerdo, exceção feita à fração atrial.
This study measured the wake effect in a Brazilian onshore windfarm with 38 turbines located in complex terrain. The proposed methodology calculated the wind deficit in 3 different metmasts, by ...comparing the measurement periods in free-of-wake condition to measurement periods under wake effect. Uncertainties due to wind variability and seasonality effects have been avoided by performing MCP (Measure Correlate Predict) procedures making use of a fourth metmast in free-of-wake condition during the entire concurrent period. This methodology is free of uncertainties from Nacelle anemometry, power curve measurements and micrositing models' spatial extrapolation.
The calculation of the wind deficits was performed per sector, confirming the adherence of the resulting wake effect to the turbine layout configuration. Higher wind deficits were identified in the sectors were turbines under operation are present in the upwind direction. The results were combined to the power curves from the turbines closest to the metmasts, using the data from the turbine supplier's technical specification. This allowed the identification of the respective power deficit due to the wake effect in these locations.
The calculated wind- and power deficits were compared to the results of wake models used by two large international wind farms site assessment consultants (Coupled Eddy Viscosity and PARK), commonly accepted by banks for the financing of wind farms in Brazil. The results indicated that both models underestimate the effects in all 3 analyzed locations, with differences between the calculated and modeled power deficits higher than the respective uncertainties provided by both consultants.
The two main limitations of this analysis lie in the restriction of the wake effect measurement to the metmasts locations, and in that the results are respective to the terrain conditions of the analyzed wind farm. However, this study indicates that commonly used wake models need to be further developed and calibrated for onshore wind farms. The literature shows that wake models developments are frequently directed to offshore wind farms, where wake effects play a significant role. Onshore wind farms are less studied, even though the global installed capacity greatly surpasses that of the offshore wind farms.
Brazil has by the end of 2017 already 12.8 GW of installed capacity of wind power plants, and this number continues to increase steadily. With the continuous concentration of operating wind farms in regions of higher wind resource and transmission infrastructure, wake effects play a significant role in the sector. Bibliography shows that commonly used wake models tend to underestimate the energy losses due to this effect in offshore wind farms, making it important to study it also in onshore wind farms in complex terrain, which is the case of most Brazilian wind farms.
•Wake effect is measured in a Brazilian wind farm with 38 turbines in complex terrain.•Measurement of 3 metmasts are used, comparing periods free-of-wake and under wake.•Calculated direction and module of wind and power deficits agree to turbine layout.•Results compared to values from 2 wake models, indicating sub estimation of models.•Differences between results and wake models is higher than associated uncertainty.
•A method for evaluation of solar spectrum range selection to reduce heating losses.•Case study with real data using crystalline silicon modules.•The results indicate that the optical filter should ...reflect radiation with a wavelength greater than 1000 nm.•The construction of a film with such characteristics is technically feasible.
This paper proposes a method for evaluating and selecting the solar spectrum range to be absorbed by a photovoltaic cell to obtain a better relationship between radiation absorption for photovoltaic conversion and heating efficiency losses, in order to maximize the power generated by the cell. The methodology proposed considers the spectral response of the photovoltaic conversion technology and environmental operating conditions that affect the photovoltaic cell performance. The application of the methodology to a case study with real data from an equatorial location resulted in an optical filter that reflects wavelengths above 1000 nm. The application of this proposed filter reaches earnings between 6.8% and 1.1% in energy generated by crystalline silicon modules, depending on the reflectance of the filter.
Abstract
Phospholipases A
2
(
PLA
2
s) overexpression is closely associated with the malignant potential of breast cancers. Here, we showed for the first the antitumoral effects of γCdcPLI, a PLA
2
...inhibitor from
Crotalus durissus collilineatus
via PI3K/Akt pathway on MDA-MB-231 cell. Firstly, γCdcPLI was more cytotoxic to MDA-MB-231 breast cancer cells than other cell lines (MCF-7, HeLa, PC3 and A549) and did not affect the viability of non-tumorigenic breast cell (MCF 10A). In addition, γCdcPLI induced modulation of important mediators of apoptosis pathways such as p53, MAPK-ERK, BIRC5 and MDM2. γCdcPLI decreased MDA-MB-231 adhesion, migration and invasion. Interestingly, the γCdcPLI also inhibited the adhesion and migration of endothelial cells and blocked angiogenesis by inhibiting tube formation by HUVECs
in vitro
and sprouting elongation on aortic ring assay
ex vivo
. Furthermore, γCdcPLI reduced the production of vascular endothelial growth factor (VEGF). γCdcPLI was also able to decrease PGE2 levels in MDA-MB-231 and inhibited gene and protein expression of the PI3K/Akt pathway. In conclusion, γCdcPLI showed
in vitro
antitumoral, antimestatatic and anti-angiogenic potential effects and could be an attractive approach for futures studies in cancer therapy.
The goal of this study is to develop units of a photovoltaic (PV) cooling system and evaluate its performance, aiming at commercial electricity production, once the increase in electricity output is ...obtained by cooling down the temperature of the PV module. The methodology covers the description of production procedures, control and verification of three different models of the cooling system, of which two are sheet-and-tube types, with different diameters of coil curvature (85 and 140 mm), and one is a multi-channel type model. Results show that the production of the two sheet-and-tube models presented no issues during their construction and operating phases, while the multiple-channel model presented some complications at the construction phase (e.g. the thickness of the sheets hampered the welding process, leading to leakages during the tightness tests). The empirical control tests showed that the temperature of the PV module with a cooling system applied remains lower than the nominal operating cell temperature, whereas the PV modules without a cooling system presented temperatures higher than 68.1°C. Thus, the authors conclude that the most appropriate model for large-scale production applied at PV systems is the coil one, with 85 mm of the diameter of coil curvature.
This study presents the bases of a Preferential Plan obtained through a new methodology for energy planning, the IRP (Integrated Resources Planning of Energy) for the Power Sector, developed in ...GEPEA/EPUSP, Brazil. This Integrated Energy Resources Preferential Plan is a systemic compilation of energy resources obtained through an integrated in-time and geographic energy planning, denominated Integrated Resource Planning. The plan is developed using the methodology of Environmental and Energy Inventory; Listing and Drafting of Energy Resources; Calculation and Valuation of Energy Resources Full Potentials, Full Cost Analysis, Demand Forecasting and Resources Integration, after which the construction of plan effectively starts. Finally, the IRP Preferential Plan is a continuous up to date plan and a proposal for an alternative methodology for an energy planning for the power sector aimed at sustainable development through a complete overview among energy, environment and society, with its balanced importance.
The link between high-risk human Papillomavirus (HR-HPV) and other sexually transmitted diseases (STDs) in the risk of developing cervical cancer still unclear. Thus, in this report we investigated ...the rates of co-infections between HPV and other important non-HPV STDs in different cervical findings using a multiplex polymerase chain reaction (M-PCR) to simultaneously detect Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, HSV-1 and -2, and Treponema pallidum. A total of 838 women aged 18 to 68 years were screened using Papanicolaou smears for cervical abnormalities, HPV and non-HPV STDs using PCR and M-PCR methods. A total of 614 (73.3%) of the women had normal cytology (NILM) and 224 (26.7%) women exhibited abnormal cytology (≥ ASC-US). HPV-DNA prevalence was 33.9%, and HPV-16 was the most prevalent genotype in women with NILM and ≥ ASC-US cytology. Non-HPV STDs were detected in 30.4% women and T. vaginalis was the most prevalent one (11.6%). A higher increased risk of ≥ ASC-US and HSIL occurred in co-infections of HR-HPV with C. trachomatis and N. gonorrhoeae. Co-infections of HPV-DNA and HR-HPV with HSV-2 exhibited a similar increased risk but only with ≥ ASC-US. Co-infections of HPV-DNA and HR-HPV with T. vaginalis demonstrated a similar increased risk of ≥ ASC-US and HSIL. We found that C. trachomatis and N. gonorrhoeae were the primary pathogens associated with HR-HPV for the increased risk for all grades of cervical abnormalities but mainly for HSIL, suggesting a possible synergistic action in cervical lesions progression. Our results reinforce the hypothesis that some non-HPV STDs might play a role as co-factors in HPV-mediated cervical carcinogenesis. These data improve our understanding of the etiology of SCC and may also be useful for disease prevention.
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