Elimination of Interface Energy Barriers Using Dendrimer Polyelectrolytes with Fractal Geometry

In this work we study conjugated polyelectrolyte (CPE) films based on polyamidoamine (PAMAM) dendrimers of generations G1 and G3. These fractal macromolecules are compared to branched polyethylenimine (b-PEI) polymer using methanol as the solvent. All of these materials present a high density of amino groups, which protonated by methoxide counter-anions create strong dipolar interfaces. The vacuum level shift associated to these films on n-type silicon was 0.93 eV for b-PEI, 0.72 eV for PAMAM G1 and 1.07 eV for PAMAM G3. These surface potentials were enough to overcome Fermi level pinning, which is a typical limitation of aluminium contacts on n-type silicon. A specific contact resistance as low as 20 mΩ·cm2 was achieved with PAMAM G3, in agreement with the higher surface potential of this material. Good electron transport properties were also obtained for the other materials. Proof-of-concept silicon solar cells combining vanadium oxide as a hole-selective contact with these new electron transport layers have been fabricated and compared. The solar cell with PAMAM G3 surpassed 15% conversion efficiency with an overall increase of all the photovoltaic parameters. The performance of these devices correlates with compositional and nanostructural studies of the different CPE films. Particularly, a figure-of-merit (Vσ) for CPE films that considers the number of protonated amino groups per macromolecule has been introduced. The fractal geometry of dendrimers leads to a geometric increase in the number of amino groups per generation. Thus, investigation of dendrimer macromolecules seems a very good strategy to design CPE films with enhanced charge-carrier selectivity.

Depression and suicidality severity among TRD patients after 1-year under standard of care: Findings from the TRAL study, a multicenter, multinational, observational study in Latin America

INTRODUCTION

Treatment resistant depression (TRD) is one of the most pressing issues in mental healthcare in LatAm. However, clinical data and outcomes of standard of care (SOC) are scarce. The present study reported on the Treatment-Resistant Depression in America Latina (TRAL) project 1-year follow-up of patients under SOC assessing clinical presentation and outcomes.

MATERIALS AND METHODS

420 patients with clinical diagnoses of TRD from Argentina, Brazil, Colombia and Mexico were included in a 1-year follow-up to assess clinical outcomes of depression (MADRS) and suicidality (C-SSRS), as well as evolution of clinical symptoms of depression. Patients were assessed every 3 months and longitudinal comparison was performed based on change from baseline to each visit and end of study (12 months). Socio demographic characterization was also performed.

RESULTS

Most patients were female (80.9%), married (42.5%) or single (34.4%), with at least 10 years of formal education (71%). MDD diagnosis was set at 37.29 (SD=14.00) years, and MDD duration was 11.11 years (SD=10.34). After 1-year of SOC, 79.1% of the patients were still symptomatic, and 40% of the patients displayed moderate/severe depression. Only 44.1% of the patients achieved a response (≥50% improvement in MADRS), and 60% of the sample failed to achieve remission. Suicidal ideation was reported by more than half of the patients at the end of study.

CONCLUSIONS

Depression and suicidality symptoms after a 1-year of SOC is of great concern. Better therapeutic options are needed to tackle this debilitating and burdensome disease.

Preliminary results of a network meta-analysis on the efficacy of long-acting injectable antipsychotics in schizophrenia

Introduction

Long-acting injectable antipsychotics (LAIs) are currently the most effective alternative for patients with schizophrenia who exhibit poor adherence. Although a recent meta-analysis reported similar efficacy between first and second-generation LAIs, these results were only based on 3 studies due to the limited number of head-to-head comparisons.

Objectives

Present the preliminary results of a network meta-analysis on the comparative efficacy of LAIs in schizophrenia.

Methods

Studies were obtained from a previous study, where we carried out a systematic search from until May 2019 in various databases. Included trials of adults with schizophrenia compared the efficacy of LAI vs LAI or placebo through the Positive and Negative Syndrome Scale (PANSS). Efficacy was evaluated through the mean differences (MD) from baseline to endpoint in the PANSS total scores. Network meta-analysis was performed in MetaInsight through direct and indirect comparisons using a Bayesian approach.

Results

from 12 studies are presented in Figures 1 and 2. All LAIs except zuclopenthixol were more effective than placebo. There were no significant differences between LAIs except for aripiprazole and risperidone, which were more efficacious than zuclopenthixol. The largest change occurred with aripiprazole LAI, but was not significantly higher than haloperidol.

Figure 1. Comparison of treatment pairs. Effect sizes are presented as MD and 95% confidence intervals (*p<0.05).

Figure 1. Overall change in symptoms

Conclusions

Preliminary results from a network meta-analysis also suggest that in the long-term haloperidol decanoate is equally effective in overall symptom changes compared to other LAIs. Further analyses are needed to obtain a better perspective on these drugs.

Disclosure

No significant relationships.

Genome-wide association study of psychiatric and substance use comorbidity in Mexican individuals

The combination of substance use and psychiatric disorders is one of the most common comorbidities. The objective of this study was to perform a genome-wide association study of this comorbidity (Com), substance use alone (Subs), and psychiatric symptomatology alone (Psych) in the Mexican population. The study included 3914 individuals of Mexican descent. Genotyping was carried out using the PsychArray microarray and genome-wide correlations were calculated. Genome-wide associations were analyzed using multiple logistic models, polygenic risk scores (PRSs) were evaluated using multinomial models, and vertical pleiotropy was evaluated by generalized summary-data-based Mendelian randomization. Brain DNA methylation quantitative loci (brain meQTL) were also evaluated in the prefrontal cortex. Genome-wide correlation and vertical pleiotropy were found between all traits. No genome-wide association signals were found, but 64 single-nucleotide polymorphism (SNPs) reached nominal associations (p < 5.00e-05). The SNPs associated with each trait were independent, and the individuals with high PRSs had a higher prevalence of tobacco and alcohol use. In the multinomial models all of the PRSs (Subs-PRS, Com-PRS, and Psych-PRS) were associated with all of the traits. Brain meQTL of the Subs-associated SNPs had an effect on the genes enriched in insulin signaling pathway, and that of the Psych-associated SNPs had an effect on the Fc gamma receptor phagocytosis pathway.

Resonant Raman scattering of ZnSxSe1−x solid solutions: the role of S and Se electronic states

A combined theoretical and experimental study of the enhancement in the Raman mode intensities of ZnSSe compounds, under various resonant conditions, is presented, leading to more detailed insights into the role of chalcogen electronic states in the photon–matter interaction.

Ethanol production from eucalyptus wood hemicellulose hydrolysate by Pichia stipitis

Ethanol production was evaluated from eucalyptus wood hemicellulose acid hydrolysate using Pichia stipitis NRRL Y-7124. An initial lag phase characterized by flocculation and viability loss of the yeast inoculated was observed. Subsequently, cell regrowth occurred with sequential consumption of sugars and production of ethanol. Polyol formation was detected. Acetic acid present in the hydrolysate was an important inhibitor of the fermentation, reducing the rate and the yield. Its toxic effect was due essentially to its undissociated form. The fermentation was more effective at an oxygen transfer rate between 1.2 and 2.4 mmol/L h and an initial pH of 6.5. The hydrolysate used in the experiences had the following composition (expressed in grams per liter): xylose 30, arabinose 2.8, glucose 1.5, galactose 3.7, mannose 1.0, cellobiose 0.5, acetic acid 10, glucuronic acid 1.5, and galacturonic acid 1.0. The best values obtained were maximum ethanol concentration 12.6 g/L, fermentation time 75 h, fermentable sugar consumption 99% ethanol yield 0.35 g/g sugars consumed, and volumetric ethanol productivity 4 g/L day. (

Comparison between two cord blood collection strategies

BACKGROUND AND OBJECTIVES

Collection strategy is the first step for collecting good quality cord blood (CB) units. There are two principal different techniques to collect CB from the umbilical vein: in the delivery room while the placenta is still in the uterus by midwives and obstetricians or in an adjacent room after placental delivery by CB-bank trained personnel. In this study, the benefits and disadvantages between two different CB collection strategies were evaluated in order to improve CB bank methodology.

DESIGN AND METHODS

Valencia CB bank maintains the two different collection strategies aforementioned. Before processing CB units, volume was calculated and samples were drawn for cell counts. After processing and before cryopreservation, samples for cell counts, CD34 analysis, viability, clonogenic assays and microbiology were drawn directly from the bags. We compared the efficiency of the two collection techniques.

RESULTS

Obstetric date and umbilical CB was obtained from 848 vaginal (484 collected in uterus and 364 collected ex uterus). The proportion of excluded CB units before processing was 33% for ex uterus and 25% for in uterus. The difference was statistically significant. A larger volume and a higher number of total nucleated cells, CD34+ cells and CFUs were harvested in the in uterus collection group.

INTERPRETATION AND CONCLUSIONS

Based on our findings, we conclude that the mode of collection influences the hematopoietic content of CB donations. Collection before placental delivery is the best approach to CB collection and allows optimizing CB bank methodology.

Comparison between two strategies for umbilical cord blood collection

The use of cord blood (CB) for transplantation has increased greatly in recent years. The collection strategy is the first step in collecting good-quality CB units. There are two main techniques for collecting CB from the umbilical vein: in the delivery room while the placenta is still in the uterus by midwives and obstetricians or in an adjacent room after placental delivery by CB bank trained personnel. In this study, the benefits and disadvantages between the two different CB collection strategies were evaluated, in order to improve CB bank methodology. Valencia CB bank maintains the two different collection strategies. CB was obtained from 569 vaginal and 70 caesarean deliveries and obstetrical and clinical charts were reviewed. Before processing CB units, volume was calculated and samples were drawn for cell counts. After processing and before cryopreservation samples were drawn for cell counts, CD34+cell analysis, viability, clonogenic assays and microbiology were drawn directly from the bags. We compared the efficiency of the two collection techniques. Obstetric data and umbilical CB were obtained from 569 vaginal (264 collected in utero and 305 collected ex utero) and 70 caesarean deliveries. The proportion of excluded CB units before processing was 33% for vaginal ex utero, 25% for vaginal in utero and 46% for caesarean deliveries. Differences were statistically significant. For vaginal deliveries a larger volume and a higher number of nucleated cells, percentage of CD34+ cells and colony-forming units (CFUs) were harvested in the in utero collection group. There was no statistical difference between CB collected after placental expulsion from vaginal and caesarean deliveries. Comparison between all vaginal and caesarean deliveries did not show any difference. We conclude that the mode of collection influences the haematopoietic content of CB donations. Collection before placental delivery is the best approach to CB collection and allows optimisation of CB bank methodology. Caesarean deliveries seem to contain similar progenitor content to vaginal deliveries.

Exercise adaptation attenuates VEGF gene expression in human skeletal muscle

Angiogenesis is a component of the multifactoral adaptation to exercise training, and vascular endothelial growth factor (VEGF) is involved in extracellular matrix changes and endothelial cell proliferation. However, there is limited evidence supporting the role of VEGF in the exercise training response. Thus we studied mRNA levels of VEGF, using quantitative Northern analysis, in untrained and trained human skeletal muscle at rest and after a single bout of exercise. Single leg knee-extension provided the acute exercise stimulus and the training modality. Four biopsies were collected from the vastus lateralis muscle at rest in the untrained and trained conditions before and after exercise. Training resulted in a 35% increase in muscle oxygen consumption and an 18% increase in number of capillaries per muscle fiber. At rest, VEGF/18S mRNA levels were similar before (0.38 +/- 0.04) and after (1.2 +/- 0.4) training. When muscle was untrained, acute exercise greatly elevated VEGF/18S mRNA levels (16.9 +/- 6.7). The VEGF/18S mRNA response to acute exercise in the trained state was markedly attenuated (5.4 +/- 1.3). These data support the concept that VEGF is involved in exercise-induced skeletal muscle angiogenesis and appears to be subject to a negative feedback mechanism as exercise adaptations occur.