577 research outputs found
Non equilibrium anisotropic excitons in atomically thin ReS
We present a systematic investigation of the electronic properties of bulk
and few layer ReS van der Waals crystals using low temperature optical
spectroscopy. Weak photoluminescence emission is observed from two
non-degenerate band edge excitonic transitions separated by 20 meV. The
comparable emission intensity of both excitonic transitions is incompatible
with a fully thermalized (Boltzmann) distribution of excitons, indicating the
hot nature of the emission. While DFT calculations predict bilayer ReS to
have a direct fundamental band gap, our optical data suggests that the
fundamental gap is indirect in all cases
Plasma levels of apelin are reduced in patients with liver fibrosis and cirrhosis but are not correlated with circulating levels of bone morphogenetic protein 9 and 10
Background:
The peptide apelin is expressed in human healthy livers and is implicated in the development of hepatic fibrosis and cirrhosis. Mutations in the bone morphogenetic protein receptor type II (BMPR-II) result in reduced plasma levels of apelin in patients with heritable pulmonary arterial hypertension. Ligands for BMPR-II include bone morphogenetic protein 9 (BMP9), highly expressed in liver, and BMP10, expressed in heart and to a lesser extent liver. However, it is not known whether reductions in BMP9 and/or BMP10, with associated reduction in BMPR-II signalling, correlate with altered levels of apelin in patients with liver fibrosis and cirrhosis.
Methods:
Plasma from patients with liver fibrosis (n = 14), cirrhosis (n = 56), and healthy controls (n = 25) was solid-phase extracted using a method optimised for recovery of apelin, which was measured by ELISA.
Results:
Plasma apelin was significantly reduced in liver fibrosis (8.3 ± 1.2 pg/ml) and cirrhosis (6.5 ± 0.6 pg/ml) patients compared with controls (15.4 ± 2.0 pg/ml). There was no obvious relationship between apelin and BMP 9 or BMP10 previously measured in these patients. Within the cirrhotic group, there was no significant correlation between apelin levels and disease severity scores, age, sex, or treatment with β-blockers.
Conclusions:
Apelin was significantly reduced in plasma of patients with both early (fibrosis) and late-stage (cirrhosis) liver disease. Fibrosis is more easily reversible and may represent a potential target for new therapeutic interventions. However, it remains unclear whether apelin signalling is detrimental in liver disease or is beneficial and therefore, whether an apelin antagonist or agonist have clinical use
Non equilibrium anisotropic excitons in atomically thin ReS2
We present a systematic investigation of the electronic properties of bulk and few layer ReS2 van der Waals crystals using low temperature optical spectroscopy. Weak photoluminescence emission is observed from two non-degenerate band edge excitonic transitions separated by similar to 20 meV. The comparable emission intensity of both excitonic transitions is incompatible with a fully thermalized (Boltzmann) distribution of excitons, indicating the hot nature of the emission. While DFT calculations predict bilayer ReS2 to have a direct fundamental band gap, our optical data suggests that the fundamental gap is indirect in all cases
Pancreatic ductal adenocarcinoma cell secreted extracellular vesicles containing ceramide-1-phosphate promote pancreatic cancer stem cell motility
The high mortality rate associated with pancreatic ductal adenocarcinoma (PDAC) is in part due to lack of effective therapy for this highly chemoresistant tumor. Cancer stem cells, a subset of cancer cells responsible for tumor initiation and metastasis, are not targeted by conventional cytotoxic agents, which renders the identification of factors that facilitate cancer stem cell activation useful in defining targetable mechanisms. We determined that bioactive sphingolipid induced migration of pancreatic cancer stem cells (PCSC) and signaling was specific to ceramide-1-phosphate (C1P). Furthermore, PDAC cells were identified as a rich source of C1P. Importantly, PDAC cells express the C1P converting enzyme ceramide kinase (CerK), secrete C1P-containing extracellular vesicles that mediate PCSC migration, and when co-injected with PCSC reduce animal survival in a PDAC peritoneal dissemination model. Our findings suggest that PDAC secrete C1P-containing extracellular vesicles as a means of recruiting PCSC to sustain tumor growth therefore making C1P release a mechanism that could facilitate tumor progression
Psychedelic experience dose-dependently modulated by cannabis: results of a prospective online survey
Rationale. Classic psychedelics are currently being studied as novel treatments for a range of psychiatric disorders. However, research on how psychedelics interact with other psychoactive substances remains scarce. Objectives The current study aimed to explore the subjective effects of psychedelics when used alongside cannabis. Methods Participants (n = 321) completed a set of online surveys at 2 time points: 7 days before, and 1 day after a planned experience with a serotonergic psychedelic. The collected data included demographics, environmental factors (so-called setting) and five validated questionnaires: Mystical Experience Questionnaire (MEQ), visual subscales of Altered States of Consciousness Questionnaire (ASC-Vis), Challenging Experience Questionnaire (CEQ), Ego Dissolution Inventory (EDI) and Emotional Breakthrough Inventory (EBI). Participants were grouped according to whether they had reported using no cannabis (n = 195) or low (n = 53), medium (n = 45) or high (n = 28) dose, directly concomitant with the psychedelic. Multivariate analysis of covariance (MANCOVA) and contrasts was used to analyse differences in subjective effects between groups while controlling for potential confounding contextual ‘setting’ variables. Results The simultaneous use of cannabis together with classic serotonergic psychedelics was associated with more intense psychedelic experience across a range of measures: a linear relationship was found between dose and MEQ, ASC-Vis and EDI scores, while a quadratic relationship was found for CEQ scores. No relationship was found between the dose of cannabis and the EBI. Conclusions Results imply a possible interaction between the cannabis and psychedelic on acute subjective experiences; however, design limitations hamper our ability to draw firm inferences on directions of causality and the clinical implications of any such interactions
Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics
The celebrated electronic properties of graphene have opened way for
materials just one-atom-thick to be used in the post-silicon electronic era. An
important milestone was the creation of heterostructures based on graphene and
other two-dimensional (2D) crystals, which can be assembled in 3D stacks with
atomic layer precision. These layered structures have already led to a range of
fascinating physical phenomena, and also have been used in demonstrating a
prototype field effect tunnelling transistor - a candidate for post-CMOS
technology. The range of possible materials which could be incorporated into
such stacks is very large. Indeed, there are many other materials where layers
are linked by weak van der Waals forces, which can be exfoliated and combined
together to create novel highly-tailored heterostructures. Here we describe a
new generation of field effect vertical tunnelling transistors where 2D
tungsten disulphide serves as an atomically thin barrier between two layers of
either mechanically exfoliated or CVD-grown graphene. Our devices have
unprecedented current modulation exceeding one million at room temperature and
can also operate on transparent and flexible substrates
Human embryonic stem cell-derived cardiomyocyte platform screens inhibitors of SARS-CoV-2 infection.
Patients with cardiovascular comorbidities are more susceptible to severe infection with SARS-CoV-2, known to directly cause pathological damage to cardiovascular tissue. We outline a screening platform using human embryonic stem cell-derived cardiomyocytes, confirmed to express the protein machinery critical for SARS-CoV-2 infection, and a SARS-CoV-2 spike-pseudotyped virus system. The method has allowed us to identify benztropine and DX600 as novel inhibitors of SARS-CoV-2 infection in a clinically relevant stem cell-derived cardiomyocyte line. Discovery of new medicines will be critical for protecting the heart in patients with SARS-CoV-2, and for individuals where vaccination is contraindicated
Pušenje među makedonskim radnicima pet godina nakon kampanje protiv pušenja
To assess the efficacy of a nationwide anti-smoking campaign, we compared the findings of a study on worker smoking performed in 2005 with our latest cross-sectional study completed in 2010. It included 753 randomly selected workers, of whom 126 office, 108 construction, 93 agricultural, 97 petroleum refinery, 114 textile, 117 food processing workers, and 98 cleaners. Information was collected with a selfadministered questionnaire. The prevalence of current smokers among all workers was 35.4 %, ranging from 30.2 % in office workers to 43.5 % in construction workers. It did not significantly differ from the prevalence recorded in 2005 (35.4 % vs. 36.8 %, respectively; P=0.441). Mean pack-years smoked among all smokers was 12.4±2.3, ranging from 10.9 in administrative workers to 13.7 in agricultural workers. We did not find any significant difference in the prevalence of current smokers between male and female workers and between workers aged less or more than 40 years, as well as between workers of higher and lower education. The prevalence of ex-smokers was 10.5 %, ranging from 8.4 % in construction workers to 12.1 % in administrative workers, whereas the prevalence of passive smokers was 29.1 %, ranging from 26.2 % in food processing workers to 32.9 % in agricultural workers. Our findings indicate that the prevalence of current and passive smokers has remained high regardless of the anti-smoking campaign and call for stricter implementation of anti-smoking regulations.Želeći utvrditi djelotvornost kampanje protiv pušenja u Makedoniji, usporedili smo rezultate istraživanja o pušenju u radničkoj populaciji provedenog 2005. s rezultatima našega najnovijega presječnoga randomiziranog ispitivanja koje je dovršeno 2010. Ispitivanje je obuhvatilo 753 radnika, od kojih je 126 uredskih, 108 građevinskih, 93 poljoprivrednih, 97 u rafineriji nafte, 114 tekstilnih, 117 prehrambenih te 98 čistač(ic)a. Podaci su prikupljeni s pomoću upitnika koji su ispunjavali ispitanici. Prevalencija aktivnih pušača među svim radnicima bila je 35,4 %, od 30,2 % u uredskih radnika do 43,5 % u građevinskih. Nije se značajno razlikovala od prevalencije zabilježene 2005. (35,4 % odnosno 36,8 %, P=0,441). Srednja vrijednost kutija/godina u pušača bila je 12,4±2,3, od 10,9 u uredskih do 13,7 u poljoprivrednih radnika. Značajnih razlika u aktivnome pušenju nije bilo među ženama i muškarcima, radnicima starijim i mlađima od 40 godina, niti među radnicima višeg i nižeg obrazovanja. Prevalencija bivših pušača bila je 10,5 %, od 8,4 % u građevinskih do 12,1 % u uredskih radnika, dok je prevalencija pasivnih pušača bila 29,1 %, od 26,2 % u radnika u preradi hrane do 32,9 % u poljoprivrednih radnika. Naši rezultati pokazuju da je prevalencija aktivnih i pasivnih pušača ostala visoka bez obzira na kampanju protiv pušenja te pozivaju na strožu provedbu propisa koji ograničavaju pušenje
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