The Rise of the OM-LoC: Opto-Microfluidic Enabled Lab-on-Chip.

The integration of optical circuits with microfluidic lab-on-chip (LoC) devices has resulted in a new era of potential in terms of both sample manipulation and detection at the micro-scale. On-chip optical components increase both control and analytical capabilities while reducing reliance on expensive laboratory photonic equipment that has limited microfluidic development. Notably, in-situ LoC devices for bio-chemical applications such as diagnostics and environmental monitoring could provide great value as low-cost, portable and highly sensitive systems. Multiple challenges remain however due to the complexity involved with combining photonics with micro-fabricated systems. Here, we aim to highlight the progress that optical on-chip systems have made in recent years regarding the main LoC applications: (1) sample manipulation and (2) detection. At the same time, we aim to address the constraints that limit industrial scaling of this technology. Through evaluating various fabrication methods, material choices and novel approaches of optic and fluidic integration, we aim to illustrate how optic-enabled LoC approaches are providing new possibilities for both sample analysis and manipulation.

Fractal Structure in Silica and Composites Aerogels.

Silica aerogels are known to be materials with exceptional characteristics, such as ultra-low density, high surface area, high porosity, high adsorption, and low-thermal conductivity. In addition, these unique properties are mainly related to their specific processing. Depending on the aerogel synthesis procedure, the aerogels texture can be tailored with meso and/or macroporosity. Fractal geometry has been observed and used to describe silica aerogels at nanoscales in certain conditions. In this review paper, we describe the fractal structure of silica aerogels that can develop depending on the synthesis conditions. X-ray and neutron scattering measurements allow to show that silica aerogels can exhibit a fractal structure over one or even more than two orders of magnitude in length. The fractal dimension does not depend directly on the material density but can vary with the synthesis conditions. It ranges typically between 1.6 and 2.4. The effect of the introduction of silica particles or of further thermal treatment or compression of the silica aerogels on their microstructure and their fractal characteristics is also resumed.

Mechanical Properties and Brittle Behavior of Silica Aerogels.

Sets of silica gels: aerogels, xerogels and sintered aerogels, have been studied in the objective to understand the mechanical behavior of these highly porous solids. The mechanical behaviour of gels is described in terms of elastic and brittle materials, like glasses or ceramics. The magnitude of the elastic and rupture modulus is several orders of magnitude lower compared to dense glass. The mechanical behaviours (elastic and brittle) are related to the same kinds of gel characteristics: pore volume, silanol content and pore size. Elastic modulus depends strongly on the volume fraction of pores and on the condensation reaction between silanols. Concerning the brittleness features: rupture modulus and toughness, it is shown that pores size plays an important role. Pores can be considered as flaws in the terms of fracture mechanics and the flaw size is related to the pore size. Weibull's theory is used to show the statistical nature of flaw. Moreover, stress corrosion behaviour is studied as a function of environmental conditions (water and alcoholic atmosphere) and temperature.

Aeropectin: fully biomass-based mechanically strong and thermal superinsulating aerogel.

Monolithic pectin aerogels, aeropectins, were prepared via dissolution-gelation-coagulation and subsequent drying with supercritical CO2. Aeropectin had pore sizes that varied from mesopores to small macropores and compression moduli in the range from 4 to 18 MPa. Aeropectins show plastic deformation up to 60% strain before the pore walls collapse. Pectin aerogels have a thermal conductivity below that of air in ambient conditions, making them new thermal superinsulating fully biomass-based materials. The contribution of gas and solid conduction plus radiative heat transfer were determined and discussed.

Prevalence of antiphospholipid antibodies in psychiatric patients users and non-users of antipsychotics.

Past reports have suggested that antiphospholipid (aPL) antibodies may emerge as a response to antipsychotics treatment, as a high prevalence of aPL antibodies in antipsychotics users has been observed. However, no control group of non-medicated psychiatric patients was included in these reports. In a cross sectional study we determined the prevalence of aPL antibodies in 333 psychiatric inpatients. We compared the proportions of positive aPL antibodytests between users and non-users of antipsychotics with adjustments for potential confounders. The proportion of antipsychotics users carrying at least one aPL antibody ranged from 10·8% to 27·0% compared with 6·8% to 27·2% in non-users (P = 0·24, P = 0·24) depending on the method of detection of lupus anticoagulant (LA). The prevalence of LA detected by dilute Russell viper venom time or partial thromboplastin time-LA was not different between antipsychotics users and non-users (8·1% vs. 5·4%, P = 0·53 and 18·4% vs. 18·2%, P = 0·22), as well as the prevalence of IgM and IgG anti-ß2-glycoprotein-I antibodies, IgM and IgG anti-cardiolipin antibodies(3·8% vs. 2·0%, P = 0·75, 0·0% vs. 0·0%, P = not applicable, 1·1 vs. 1·4%, P = 0·91, 2·7% vs. 3·4%, P = 0·71). In conclusion, aPL antibodies were frequently found in patients with psychiatric diseases and no significant increase in the prevalence of aPL antibodies was observed in antipsychotics users.

Incidence of venous thromboembolism in psychiatric units.

INTRODUCTION: Incidence and risk factors of venous thromboembolism (VTE) are well established in surgical and medical settings, but data in psychiatric units are lacking. The aim of this study was to estimate the incidence of VTE in hospitalized psychiatric patients, and to assess the risk factors for VTE in this specific population. MATERIALS AND METHODS: All consecutive adult patients, admitted for a psychiatric disorder for at least seven days in psychiatric units were considered for inclusion. Patients were evaluated for signs and symptoms of VTE during hospitalization. At Day 10, all participants were interviewed and a systematic compression ultrasonography of the lower limbs was performed. Patients were followed-up until Day 90. RESULTS: Among the 471 included patients, 449 were evaluable at Day 10, and 458 were followed-up until Day 90. Ten deep vein thromboses (DVT) were diagnosed by Day 10 leading to an incidence of VTE of 2.2% (95% CI, 1.1%-4.1%). Six additional symptomatic VTE occurred between Day 10 and Day 90, leading to a 3.5% incidence at Day 90 (95% CI, 2.0%-5.6%). The main factors associated with VTE were age, bed rest, and diagnosis of dementia. The incidence of VTE in patients aged 75 or over with a diagnosis of dementia reached 8.2% at Day 10 and 12.5% at Day 90. CONCLUSIONS: The incidence of VTE in psychiatric units appeared low. However, in older patients, especially those with dementia, the incidence of VTE increased considerably. Further studies are needed to confirm these results.

Gas permeability: a new quantitative method to assess endodontic leakage.

AIM: The aim of this study was to evaluate a new endodontic leakage measurement method. MATERIALS AND METHODS: Permeability was assessed measuring the gas flow passing through the root. Positive and negative tests were carried out to assess the validity of the method. We used glass capillaries for calibration (diameters of 15, 30, 40, 50 and 75 microm). The applicability of the method was assessed with human teeth using three sealing methods: GuttaFlow (GF) and a single cone; Pulp Canal Sealer (PCS) and a single cone; PCS and system B. RESULTS: This method demonstrated to be highly reproducible as the standard deviation was approximately 1% on average with glass capillaries. Significantly higher leakage (p<0.05) was recorded for endodontic treatment with GF and single cone compared to PCS and single cone and PCS with system B. CONCLUSION: Gas permeability is quantitative, sensitive, non-destructive and reproducible and seems appropriate for endodontic tests. It would participate in the indirect comprehension of leakage phenomena.

Hypertension in high-risk patients: beware of the underuse of effective combination therapy (results of the PRATIK study).

OBJECTIVE: To determine whether blood pressure control in a general practice setting is influenced by the presence of additional risk factors, and to analyse the role of antihypertensive therapy in this relationship. DESIGN: A cross-sectional study was conducted with a sample of 3153 general practitioners. SETTING: Primary care. PARTICIPANTS: The first five hypertensive patients presenting at the practitioner's office were included. MAIN OUTCOME MEASURES: Cardiovascular risk factors, antihypertensive drugs and cardiovascular history were reported. Blood pressure was measured. The analysis was conducted in treated patients who were divided in three groups: no other risk factors (group I); 1-2 risk factors (group II); 3 or more risk factors or target-organ damage or diabetes or associated cardiovascular disease (group III). RESULTS: Data were available for all variables in the 14 066 treated hypertensive individuals who form the basis of this report. Blood pressure control had been achieved in a lower percentage of individuals in group III (27%) than in group I (42.9%). To control hypertension, combination therapies were more frequently required in group III (55.8%) than in group II (43.5%) or group I (34.2%). Among individuals with uncontrolled hypertension, about 39% of patients in group III were receiving monotherapy and the percentage receiving two-drug treatments identified as effective in the 1999 WHO guidelines was significantly lower in group III. CONCLUSION: The study shows that, in general practice, control of blood pressure decreases as the number of risk factors present increases. An underuse of combination therapy, especially effective two-drug treatment in patients with several risk factors, may account for this finding.

Acute blood pressure response to trandolapril and captopril in patients with left ventricular dysfunction after acute myocardial infarction.

OBJECTIVE: Our purpose was to compare the blood pressure response to short-term treatment with captopril or trandolapril in patients with left ventricular (LV) dysfunction after acute myocardial infarction (AMI). METHODS: A multicenter, randomized, double-blind, double-dummy, parallel group study was performed. Treatment was initiated 3 to 10 days after the onset of symptoms. On day 1, patients received a single dose of captopril 6.25 mg, trandolapril 0.5 mg, or placebo in the morning. Treatment was then titrated upward over the next 5 days. Blood pressure was monitored with an automated device for the first 12 hours after dosing on day 1. Conventional blood pressure measurements were performed throughout the study. RESULTS: Of 205 patients treated in the study, 193 patients were evaluated for first-dose effects. In the captopril group, the maximum decrease in blood pressure occurred after 2 hours, and the magnitude of this decrease was significantly greater than in the other 2 groups: 8.8 +/- 12/6.3 +/- 8 mm Hg (captopril) versus 5.4 +/- 10/3.1 +/- 8 mm Hg (trandolapril) versus 2.4 +/- 9/1.4 +/- 7 mm Hg (placebo) (P <.01). In the trandolapril group, the maximum decrease occurred after 7 hours and the magnitude of this effect was similar in all 3 groups: 5.9 +/- 11/3.6 +/- 8 mm Hg (trandolapril) versus 4.3 +/- 10/3.5 +/- 8 mm Hg (captopril) versus 3.1 +/- 11/2.8 +/- 8 mm Hg (placebo) (not significant). Although there was a higher incidence of hypotension on day 1 in the captopril group, the overall incidence of hypotension during the study period was similar in both active treatment groups. CONCLUSION: Because of differences in initial blood pressure response profiles, short-term treatment with trandolapril tended to be better tolerated than captopril in post-AMI patients with LV dysfunction.