Slatergriffin4064

Though beam-based lattices have dominated mechanical metamaterials for the past two decades, low structural efficiency limits their performance to fractions of the Hashin-Shtrikman and Suquet upper bounds, i.e. the theoretical stiffness and strength limits of any isotropic cellular topology, respectively. While plate-based designs are predicted to reach the upper bounds, experimental verification has remained elusive due to significant manufacturing challenges. Here, we present a new class of nanolattices, constructed from closed-cell plate-architectures. Carbon plate-nanolattices are fabricated via two-photon lithography and pyrolysis and shown to reach the Hashin-Shtrikman and Suquet upper bounds, via in situ mechanical compression, nano-computed tomography and micro-Raman spectroscopy. Demonstrating specific strengths surpassing those of bulk diamond and average performance improvements up to 639% over the best beam-nanolattices, this study provides detailed experimental evidence of plate architectures as a superior mechanical metamaterial topology.The ingestion of plastics appears to be widespread throughout the animal kingdom with risks to individuals, ecosystems and human health. Despite growing information on the location, abundance and size distribution of plastics in the environment, it cannot be assumed that any given animal will ingest all sizes of plastic encountered. Here, we use published data to develop an allometric relationship between plastic consumption and animal size to estimate the size distribution of plastics feasibly ingested by animals. Based on more than 2000 gut content analyses from animals ranging over three orders of magnitude in size (lengths 9 mm to 10 m), body length alone accounts for 42% of the variance in the length of plastic an animal may ingest and indicates a size ratio of roughly 201 between animal body length and the largest plastic the animal may ingest. We expect this work to improve global assessments of plastic pollution risk by introducing a quantifiable link between animals and the plastics they can ingest.Characterization of microstructure, chemistry and function of energy materials remains a challenge for instrumentation science. This active area of research is making considerable strides with methodologies that employ bright X-rays, electron microscopy, and optical spectroscopy. However, further development of instruments capable of multimodal measurements, is necessary to reveal complex microstructure evolution in realistic environments. In this regard, laser-based instruments have a unique advantage as multiple methodologies are easily combined into a single instrument. A pump-probe method that uses optically generated acoustic phonons is expanding standard optical characterization by providing depth resolved information. Here we report on an extension of this method to image grain microstructure in ceria. Rich information regarding the orientation of individual crystallites is obtained by noting how the polarization of the probe beam influences the detected signal amplitude. When paired with other optical microscopies, this methodology will provide new perspectives for characterization of ceramic materials.Microglia, the brain-resident macrophages, exhibit highly dynamic functions in neurodevelopment and neurodegeneration. Human microglia possess unique features as compared to mouse microglia, but our understanding of human microglial functions is largely limited by an inability to obtain human microglia under homeostatic states. Here, we develop a human pluripotent stem cell (hPSC)-based microglial chimeric mouse brain model by transplanting hPSC-derived primitive macrophage progenitors into neonatal mouse brains. Single-cell RNA-sequencing of the microglial chimeric mouse brains reveals that xenografted hPSC-derived microglia largely retain human microglial identity, as they exhibit signature gene expression patterns consistent with physiological human microglia and recapitulate heterogeneity of adult human microglia. Importantly, the engrafted hPSC-derived microglia exhibit dynamic response to cuprizone-induced demyelination and species-specific transcriptomic differences in the expression of neurological disease-risk genes in microglia. read more This model will serve as a tool to study the role of human microglia in brain development and degeneration.Downsizing of animal communities due to defaunation is prevalent in many ecosystems. Yet, we know little about its consequences for ecosystem functions such as seed dispersal. Here, we use eight seed-dispersal networks sampled across the Andes and simulate how downsizing of avian frugivores impacts structural network robustness and seed dispersal. We use a trait-based modeling framework to quantify the consequences of downsizing-relative to random extinctions-for the number of interactions and secondary plant extinctions (as measures of structural robustness) and for long-distance seed dispersal (as a measure of ecosystem function). We find that downsizing leads to stronger functional than structural losses. For instance, 10% size-structured loss of bird species results in almost 40% decline of long-distance seed dispersal, but in less than 10% of structural loss. Our simulations reveal that measures of the structural robustness of ecological networks underestimate the consequences of animal extinction and downsizing for ecosystem functioning.BACKGROUND The incidence of cutaneous melanoma (cM) has increased in the last decades. Germline mutations in the high-penetrance melanoma susceptibility gene CDKN2A (Cyclin- dependent kinase inhibitor 2A) are associated with a younger age at diagnosis and an increased risk to develop pancreatic cancer. METHODS We retrospectively analysed the data of patients with prior diagnosis of cM referring to our service from January 2005 to May 2017. The aim was to investigate the rate of multiple cMs (MPM), assessing their clinical/pathological features. Moreover, the genetic tests of patients who had undergone CDKN2A/CDKN2B, CDK4 and MITF screening were evaluated. RESULTS 115 patients (9.26%) were diagnosed with MPMs 70 males (60.87%) and 45 women (39.13%). 75 patients (43 males and 32 females) underwent genetic screening for germline mutations. The screening revealed that 4/75 patients (5.33%) were carriers of the non-synonymous missense variation c.442G>A (p.Ala148Thr) in CDKN2A exon 2 in heterozygosis, 3 of whom had at least one in-situ melanoma. In 1 patient (1.33%) we detected the variation c.249C>A, p.His83Gln in CDKN2A exon 2 in heterozygosis and in 1 patient (1.33%) the mutation c.952G>A (p.Glu318Lys) in MITF gene was found. CONCLUSIONS This study confirms the need for a full body skin examination and a prolonged surveillance in patients affected by cM, as MPMs were detected in up to 10% of total cases in our series and synchronous lesions in 1/5. Moreover, it reflects the great variability of cM high- susceptibility genes mutational status within the Italian territory. Patients carrying c.952G>A (p.Glu318Lys) MITF mutation have a higher risk to develop a nodular cM.BACKGROUND Retinal degeneration causes irreversible blindness. Human retinal progenitor cells (hRPCs) have the potential to treat retinal diseases. The vitreous cavity is a relatively immune-privileged site that is suitable for stem cell transplantation in the treatment of retinal diseases. This study aimed to evaluate the therapeutic efficacy and safety of intravitreal injection of hRPCs in retinal degeneration therapy. MATERIAL AND METHODS hRPCs were primary-cultured and injected into the vitreous cavity of RCS rats. To determine whether hRPCs formed teratomas in immune-deficient mice, hRPCs at different passages were transplanted into BALB/c-nu mice. The visual function was detected by electroretinography recording. Changes in the outer nuclear layer (ONL) were analyzed by histological testing and cell counting. The protective mechanism was further assessed by cytokine antibody array. RESULTS Intravitreal transplantation of hRPCs maintained retinal function and preserved retinal morphology. Importantly, grafted cells in the vitreous cavity were well tolerated, with no adverse effects. Teratoma was not formed in BALB/c-nu mice after hRPCs transplantation. The number of hRPCs-injected eyes and thickness of ONL in the hRPCs-treated group were higher than those in the untreated group and HBSS injection group. The cytokine antibody array revealed that hRPCs expressed GDF-15, PDGF-AA, EGF, and NT-4. CONCLUSIONS Our findings show that intravitreal injection of hRPCs is effective and safe in protecting photoreceptor cells in RCS rats, but were no longer effective at 12 weeks after transplantation. Moreover, hRPCs released multiple neurotrophic factors that may be involved in treating retinal disease.BACKGROUND This study aimed to elucidate the possible activity of the mitochondrial-mediated apoptotic pathway (MMAP) in obstructive sleep apnea-hypopnea syndrome (OSAHS). MATERIAL AND METHODS A control group, a mild OSAHS group, a moderate OSAHS group, and a severe OSAHS group were included. Masson staining, hematoxylin and eosin staining, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay were performed to assess collagen fiber hyperplasia, pathological morphology, and cell apoptosis, respectively, in muscle samples. RESULTS In the OSAHS groups, the palatopharyngeal muscle fibers were larger, with apparent hypertrophy and increased elastic fiber content. The proportions of type I fibers were markedly higher in the control group than in the moderate and severe OSAHS groups (P0.05). CONCLUSIONS A decrease in the proportion of the different fiber types can result in collapse of the upper airway. The pathogenesis of OSAHS appears to involve muscle cell apoptosis via MMAP.BACKGROUND Brain edema and neuronal apoptosis are closely associated with loss of neurological function and death in rats with subarachnoid hemorrhage (SAH). The present study investigated the effect of wogonoside on brain edema induced by SAH in rats and studied the mechanism involved. MATERIAL AND METHODS The rats were intra-gastrically administered 10, 20, 50, 100, 150 and 200 mg/kg doses of wogonoside 24 h prior to SAH induction. Western blotting was used to assess levels of pro-apoptotic protein, SIRT1, ZO-1, and p53 protein expression. Apoptotic nuclei were detected using immunofluorescence and TUNEL staining. RESULTS Wogonoside treatment significantly suppressed edema formation in SAH-induced rats. Pre-treatment with wogonoside exhibited an inhibitory effect on SAH-induced extravascular Evans blue staining in rats. The expression of ZO-1, Occludin, and Claudin-5 proteins was increased by wogonoside in the SAH-induced rats. The inhibitory effect of SAH was completely reversed in the rats treated with the 200 mg/kg dose of wogonoside. The expression of SIRT1 protein was upregulated, and p53 and AC-p53 were downregulated by wogonoside in SAH rats. Wogonoside treatment significantly reduced SAH-mediated promotion of Bax, Puma, Noxa, Bid, and cleaved Caspase-3 expression. In the SAH-induced rats, pre-treatment with wogonoside reduced the TUNEL-positive cell count. CONCLUSIONS The present study demonstrated that wogonoside prevents brain edema development and apoptosis of neurons in rats by promoting SIRT1 expression and suppression of p53 activation. Therefore, wogonoside has therapeutic potential for the treatment of edema and needs to be investigated further to completely define the mechanism involved.