Regeneration of whole fertile plants from 30,000-y-old fruit tissue buried in Siberian permafrost

Whole, fertile plants of Silene stenophylla Ledeb. (Caryophyllaceae) have been uniquely regenerated from maternal, immature fruit tissue of Late Pleistocene age using in vitro tissue culture and clonal micropropagation. The fruits were excavated in northeastern Siberia from fossil squirrel burrows buried at a depth of 38 m in undisturbed and never thawed Late Pleistocene permafrost sediments with a temperature of -7 °C. Accelerator mass spectrometry (AMS) radiocarbon dating showed fruits to be 31,800 ± 300 y old. The total γ-radiation dose accumulated by the fruits during this time was calculated as 0.07 kGy; this is the maximal reported dose after which tissues remain viable and seeds still germinate. Regenerated plants were brought to flowering and fruiting and they set viable seeds. At present, plants of S. stenophylla are the most ancient, viable, multicellular, living organisms. Morphophysiological studies comparing regenerated and extant plants obtained from modern seeds of the same species in the same region revealed that they were distinct phenotypes of S. stenophylla. The first generation cultivated from seeds obtained from regenerated plants progressed through all developmental stages and had the same morphological features as parent plants. The investigation showed high cryoresistance of plant placental tissue in permafrost. This natural cryopreservation of plant tissue over many thousands of years demonstrates a role for permafrost as a depository for an ancient gene pool, i.e., preexisting life, which hypothetically has long since vanished from the earth's surface, a potential source of ancient germplasm, and a laboratory for the study of rates of microevolution.     

Aripiprazole for the treatment of pediatric bipolar I disorder: a 30‐week,randomized, placebo‐controlled study

Objective: To evaluate the long‐term efficacy, safety, and tolerability of aripiprazole in pediatric subjects with bipolar I disorder. Methods: A randomized, double‐blind, 30‐week, placebo‐controlled study of aripiprazole (10 or 30 mg/day) in youths (10–17 years) with bipolar I disorder (manic or mixed) ± psychotic features (n = 296) was performed. After four weeks, acute treatment completers continued receiving ≤26 weeks of double‐blind treatment (n = 210). The primary outcome was Young Mania Rating Scale (YMRS) total score change. Results: Of the 210 subjects who entered the 26‐week extension phase, 32.4% completed the study (45.3% for aripiprazole 10 mg/day, 31.0% for aripiprazole 30 mg/day, and 18.8% for placebo). Both aripiprazole doses demonstrated significantly (p < 0.001) greater improvements in YMRS total score at endpoint compared with placebo in protocol‐specified last observation carried forward analyses, but not in observed case or mixed‐model repeated measures at week 30. Overall time to all‐cause discontinuation was longer for aripiprazole 10 mg/day (15.6 weeks) and aripiprazole 30 mg/day (9.5 weeks) compared with placebo (5.3 weeks; both p < 0.05 versus placebo). Both aripiprazole doses were significantly superior to placebo regarding response rates, Children’s Global Assessment of Functioning and Clinical Global Impressions‐Bipolar severity of overall and mania scores at endpoint in all analyses. Commonly reported adverse events included headache, somnolence, and extrapyramidal disorder. Conclusions: Aripiprazole 10 mg/day and 30 mg/day were superior to placebo and generally well tolerated in pediatric subjects with bipolar I disorder up to 30 weeks. Despite the benefits of treatment, completion rates were low in all treatment arms.     

Biological Activity of sym-Triazines with Acetylcholine-like Substitutions as Multitarget Modulators of Alzheimer’s Disease

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Reliable assessment of general surgeons' non-technical skills based on video-recordings of patient simulated scenarios

Background

Nontechnical skills are essential for safe and efficient surgery. The aim of this study was to evaluate the reliability of an assessment tool for surgeons' nontechnical skills, Non-Technical Skills for Surgeons dk (NOTSSdk), and the effect of rater training.

Methods

A 1-day course was conducted for 15 general surgeons in which they rated surgeons' nontechnical skills in 9 video recordings of scenarios simulating real intraoperative situations. Data were gathered from 2 sessions separated by a 4-hour training session.

Results

Interrater reliability was high for both pretraining ratings (Cronbach's α = .97) and posttraining ratings (Cronbach's α = .98). There was no statistically significant development in assessment skills. The D study showed that 2 untrained raters or 1 trained rater was needed to obtain generalizability coefficients >.80.

Conclusions

The high pretraining interrater reliability indicates that videos were easy to rate and Non-Technical Skills for Surgeons dk easy to use. This implies that Non-Technical Skills for Surgeons dk (NOTSSdk) could be an important tool in surgical training, potentially improving safety and quality for surgical patients.     

Polygenic effects of common single-nucleotide polymorphisms on life span: when association meets causality

Recently we have shown that the human life span is influenced jointly by many common single-nucleotide polymorphisms (SNPs), each with a small individual effect. Here we investigate further the polygenic influence on life span and discuss its possible biological mechanisms. First we identified six sets of prolongevity SNP alleles in the Framingham Heart Study 550K SNPs data, using six different statistical procedures (normal linear, Cox, and logistic regressions; generalized estimation equation; mixed model; gene frequency method). We then estimated joint effects of these SNPs on human survival. We found that alleles in each set show significant additive influence on life span. Twenty-seven SNPs comprised the overlapping set of SNPs that influenced life span, regardless of the statistical procedure. The majority of these SNPs (74%) were within genes, compared to 40% of SNPs in the original 550K set. We then performed a review of current literature on functions of genes closest to these 27 SNPs. The review showed that the respective genes are largely involved in aging, cancer, and brain disorders. We concluded that polygenic effects can explain a substantial portion of genetic influence on life span. Composition of the set of prolongevity alleles depends on the statistical procedure used for the allele selection. At the same time, there is a core set of longevity alleles that are selected with all statistical procedures. Functional relevance of respective genes to aging and major diseases supports causal relationships between the identified SNPs and life span. The fact that genes found in our and other genetic association studies of aging/longevity have similar functions indicates high chances of true positive associations for corresponding genetic variants.     

Influence of the cathode microstructure on the stability of inverted planar perovskite solar cells

One of the main challenges for perovskite solar cells (PSC) is their environmental stability, as oxygen and water induced aging may result in mobile decomposition compounds, which can enhance the recombination rate and react with charge carrier extraction layers or the contact metallization. In this contribution the importance of the microstructure of the contact metallization on the environmental cell stability is investigated. For this purpose, the storage stability of inverted planar methylammonium lead iodide (MAPI)-based perovskite solar cells without encapsulation is tested, using the metals aluminum (Al), silver (Ag), gold (Au) and nickel (Ni) as representative cathode materials. For this study, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis of the different electrodes as well as the perovskite is correlated with PSC device current–voltage (J–V) and impedance measurements. Our findings substantiate that the metal microstructure has a significant influence on the PSC aging properties. While a strong perovskite decomposition and iodide diffusion to the contacts were detected for devices using Al, Ag or Au cathodes with a polycrystalline microstructure, these effects were strongly reduced when Ni metallization was employed, where a nanocrystalline microstructure was exhibited under the chosen process conditions.

The microstructure of the metal contact has a significant influence on the PSC aging properties. In this contribution we show that perovskite decomposition and iodide diffusion can be suppressed by using nanocrystalline Ni metallization.