We aim to establish the scaling laws for both the minimum rate of flow attainable in the steady cone-jet mode of electrospray, and the size of the resulting droplets in that limit. Use is made of a ...small body of literature on Taylor cone-jets reporting precise measurements of the transported electric current and droplet size as a function of the liquid properties and flow rate. The projection of the data onto an appropriate non-dimensional parameter space maps a region bounded by the minimum rate of flow attainable in the steady state. To explain these experimental results, we propose a theoretical model based on the generalized concept of physical symmetry, stemming from the system time invariance (steadiness). A group of symmetries rising at the cone-to-jet geometrical transition determines the scaling for the minimum flow rate and related variables. If the flow rate is decreased below that minimum value, those symmetries break down, which leads to dripping. We find that the system exhibits two instability mechanisms depending on the nature of the forces arising against the flow: one dominated by viscosity and the other by the liquid polarity. In the former case, full charge relaxation is guaranteed down to the minimum flow rate, while in the latter the instability condition becomes equivalent to the symmetry breakdown by charge relaxation or separation. When cone-jets are formed without artificially imposing a flow rate, a microjet is issued quasi-steadily. The flow rate naturally ejected this way coincides with the minimum flow rate studied here. This natural flow rate determines the minimum droplet size that can be steadily produced by any electrohydrodynamic means for a given set of liquid properties.
We study both numerically and experimentally the steady cone-jet mode of electrospraying close to the stability limit of minimum flow rate. The leaky dielectric model is solved for arbitrary values ...of the relative permittivity and the electrohydrodynamic Reynolds number. The linear stability analysis of the base flows is conducted by calculating their global eigenmodes. The minimum flow rate is determined as that for which the growth factor of the dominant mode becomes positive. We find a good agreement between this theoretical prediction and experimental values. The analysis of the spatial structure of the dominant perturbation may suggest that instability originates in the cone-jet transition region, which shows the local character of the cone-jet mode. The electric relaxation time is considerably smaller than the residence time of a fluid particle in the cone-jet transition region (defined as the region where the surface and bulk intensities are of the same order of magnitude) except for the high-polarity case, where these characteristic times are commensurate with each other. The superficial charge is not relaxed within the cone-jet transition region except for the high-viscosity case, because significant inner electric fields arise in the cone-jet transition region. However, those electric fields are not large enough to invalidate the scaling laws that do not take them into account. Viscosity and polarization forces compete against the driving electric shear stress in the cone-jet transition region for small Reynolds numbers and large relative permittivities, respectively. Capillary forces may also play a significant role in the minimum flow rate stability limit. The experiments show the noticeable stabilizing effect of the feeding capillary for diameters even two orders of magnitude larger than that of the jet. Stable jets with electrification levels higher than the Rayleigh limit are produced. During the jet break-up, two consecutive liquid blobs may coalesce and form a bigger emitted droplet, probably due to the jet acceleration. The size of droplets exceeds Rayleigh’s prediction owing to the stabilizing effect of both the axial electric field and viscosity.
The disintegration of liquid drops with low electrical conductivity and subject to an electric field is investigated both theoretically and experimentally. This disintegration takes place through the ...development of a conical cusp that eventually ejects an ultrathin liquid ligament. A first tiny drop is emitted from the end of this ligament. Due to its exceptionally small size and large electric charge per unit volume, that drop has been the object of relevant recent studies. In this paper, universal scaling laws for the diameter and electric charge of the first issued droplet are proposed and validated both numerically and experimentally. Our analysis shows how charge relaxation is the mechanism that differentiates the onset of electrospray, including the first droplet ejection, from the classical steady cone-jet mode. In this way, our study identifies when and where charge relaxation and electrokinetic phenomena come into play in electrospray, a subject of live controversy in the field.
We analyse both numerically and experimentally the stability of the steady jetting tip streaming produced by focusing a liquid stream with another liquid current when they coflow through the orifice ...of an axisymmetric nozzle. We calculate the global eigenmodes characterizing the response of this configuration to small-amplitude perturbations. In this way, the critical conditions leading to the instability of the steady jetting tip streaming are determined. The unstable perturbations are classified according to their oscillatory character and to the region where they originate (convective and absolute instability). We derive and explain in terms of the velocity field a simple scaling law to predict the diameter of the emitted jet. The numerical stability limits are compared with experimental results, finding reasonable agreement. The experiments confirm the existence of the two instability mechanisms predicted by the global stability analysis.
BACKGROUNDMajor depressive disorder (MDD) and obesity are global health problems that frequently co-occur. Among shared etiological factors, genetic variation at the brain-derived neurotrophic factor ...(BDNF) gene is interesting since its implication in energy balance regulation, food intake and synaptic function. Thus, the aim of this study was to investigate the influence of the BDNF Val66Met polymorphism in relation to MDD and body mass index (BMI) in two large independent cohorts.METHODSThe sample consisted of 2646 individuals with MDD and 3835 controls from the PISMA-ep and Radiant studies. Linear regressions were performed to test the association between the polymorphism and BMI and the interaction between the polymorphism and MDD on BMI. A meta-analysis across cohorts was conducted.RESULTSNo association was found between the polymorphism and BMI. However, we found an association with MDD, showing these individuals higher BMI than controls in both cohorts. No differences were found in BMI depending on Val66Met genotype and no interaction between this polymorphism and MDD in relation to BMI was found. Although a tendency towards an interaction was found in the Radiant sample, the results of the meta-analysis did not support this finding.LIMITATIONSThe use of self-reported height and weight measures to calculate BMI values.CONCLUSIONSWe provide evidence for an association between BMI and MDD confirming previous results. Our meta-analysis including two large cohorts showed no interaction between BDNF, BMI and MDD. Future studies will be needed to confirm the role of this polymorphism in the relationship between BMI and MDD.
Aims
To determine the immune gene expression response of gilthead seabream (Sparus aurata) that is experimentally infected with the lymphocystivirus LCDV‐Sa.
Methods and Results
Viral DNA and ...transcripts were detected by qPCR in all samples from fish injected with LCDV‐Sa, demonstrating that the virus establish a systemic and asymptomatic infection. The expression of 23 immune‐related genes was also analysed by RT‐qPCR in the head kidney (HK) and intestine at several times post‐infection (dpi). In HK, the expression of five type I interferon (IFN)‐related genes (ifn, irf3, mx2, mx3 and isg15), il10 and ck10 was upregulated at 1–3 dpi, while genes related to the inflammation process (tnfα, il1ß, il6, casp1) were not differentially expressed or even downregulated. The expression profile in the intestine was different regarding type I INF‐related genes. An upregulated c3 and ighm expression was observed in both HK and intestine at 3–8 dpi. Finally, the transcription of nccrp1 and mhcIIα was induced in HK, whereas tcrβ expression was downregulated in both organs.
Conclusions
LCDV‐Sa seems to trigger an immune response in gilthead seabream characterized by a partial activation of type I IFN system and a lack of systemic inflammatory response which may be related to viral persistence.
Significance and Impact of the Study
The immune response observed in gilthead seabream infected by LCDV‐Sa could be implicated in the establishment of an asymptomatic persistent infection.
A new technique is proposed in this paper to produce jets, droplets, and emulsions with sizes ranging from tens of microns down to the submicrometer scale. Liquid is injected at a constant flow rate ...through a hypodermic needle to form a film over the needle's outer surface. This film flows toward the needle tip until a liquid ligament is steadily ejected. Both the film motion and the liquid ejection are driven by the viscous and pressure forces exerted by a coflowing fluid stream. If this stream is a high-speed gas current, the outcome is a capillary jet which breaks up into droplets due to the Rayleigh instability. Micrometer emulsions are also produced by this instability mechanism when the injected liquid is focused by a viscous liquid stream. The minimum flow rates reached with the proposed technique are two orders of magnitude lower than those of the standard flow focusing configuration. This sharp reduction of the minimum flow rate allows one to form steady jets with radii down to the submicrometer scale. The stability of this new configuration is analyzed experimentally for both gas-liquid and liquid-liquid systems. In most of the cases, the loss of stability must be attributed to the liquid source because the critical Weber (capillary) number for the gas-liquid (liquid-liquid) case was significantly greater than the value corresponding to the convective/absolute instability transition in the jet.
To estimate the incidence of T2DM and assess the effect of pre-T2DM (isolated impaired fasting glucose iIFG, isolated impaired glucose tolerance iIGT or both) on progress to T2DM in the adult ...population of Madrid.
Population-based cohort comprising 1,219 participants (560 normoglycaemic and 659 preT2DM 418 iIFG, 70 iIGT or 171 IFG-IGT). T2DM was defined based on fasting plasma glucose or HbA1c or use of glucose-lowering medication. We used a Cox model with normoglycaemia as reference category.
During 7.26 years of follow-up, the unadjusted incidence of T2DM was 11.21 per 1000 person-years (95 %CI, 9.09–13.68) for the whole population, 5.60 (3.55–8.41) for normoglycaemic participants and 16.28 (12.78–20.43) for pre-T2DM participants. After controlling for potential confounding factors, the baseline glycaemic status was associated with higher primary effect on developing T2DM was iIGT (HR = 3.96 95 %CI, 1.93–8.10) and IFG-IGT (3.42 1.92–6.08). The HR for iIFG was 1.67 (0.96–2.90). Obesity, as secondary effect, was strongly significantly associated (HR = 2.50 1.30–4.86).
Our incidence of T2DM is consistent with that reported elsewhere in Spain. While baseline iIGT and IFG-IGT behaved a primary effect for progression to T2DM, iIFG showed a trend in this direction.
•In Spanish T2DM patients, depression was associated with high all-cause mortality.•The Mortality Rate Ratio was less than 1.0 in under 65 years of age.•T2DM patients who reported alcohol consumption ...had a lower risk of mortality.
To assess the effect of depression on all-cause mortality in patients with type 2 diabetes mellitus (T2DM) followed up during 8 years in primary care in Spain.
Depression was diagnosed according to MINI 5.0.0 questionnaire, physician-diagnosis or following antidepressant therapy for at least two months in 3923 people with T2DM. We analyzed mortality-rates/10,000 person-years. We compared survival according to baseline depression with Kaplan-Meier estimates and the log-rank test. We performed Cox proportional hazard model analyses.
Baseline depression was diagnosed in 22.1% of participants. Mortality was higher in patients with depression (31.9% vs. 26.9%; p = 0.003), who had a significantly poorer survival (median survival = 7.4 vs. 7.8 years, respectively; Log Rank = 15.83; p < 0.001). Depression showed an adjusted mortality hazard ratio (HR) = 1.40 (95%CI:1.20–1.65; p < 0.001). The strongest predictive factors were: age >75 years (HR = 6.04; 95%CI:4.62–7.91; p < 0.001), insulin use (HR = 2.37; 95%CI:1.86–3.00; p < 0.001), lower limb amputation (HR = 1.99; 95%CI:1.28–3.11; p = 0.002), heart failure (HR = 1.94; 95%CI:1.63–2.30; p < 0.001), and male gender (HR = 1.90; 95%CI:1.59–2.27).
In a Spanish cohort of older T2DM patients, depression was associated with a higher mortality risk. More efforts are needed to minimize the influence of depression on mortality in people with T2DM and to implement measures that allow its early diagnosis and effective treatment.
Purpose
To evaluate the prevalence, risk factors and evolution of diabetes mellitus (DM) after targeted treatment in patients with primary aldosteronism (PA).
Methods
A retrospective multicenter ...study of PA patients in follow-up at 27 Spanish tertiary hospitals (SPAIN-ALDO Register).
Results
Overall, 646 patients with PA were included. At diagnosis, 21.2% (n = 137) had DM and 67% of them had HbA1c levels < 7%. In multivariate analysis, family history of DM (OR 4.00 1.68–9.53), the coexistence of dyslipidemia (OR 3.57 1.51–8.43) and advanced age (OR 1.04 per year of increase 1.00–1.09) were identified as independent predictive factors of DM. Diabetic patients were on beta blockers (46.7% (n = 64) vs. 27.5% (n = 140), P < 0.001) and diuretics (51.1% (n = 70) vs. 33.2% (n = 169), p < 0.001) more frequently than non-diabetics. After a median follow-up of 22 months IQR 7.5–63.0, 6.9% of patients developed DM, with no difference between those undergoing adrenalectomy and those treated medically (HR 1.07 0.49–2.36, p = 0.866). There was also no significant difference in the evolution of glycemic control between DM patients who underwent surgery and those medically treated (p > 0.05).
Conclusion
DM affects about one quarter of patients with PA and the risk factors for its development are common to those of the general population. Medical and surgical treatment provides similar benefit in glycemic control in patients with PA and DM.
PDF
