Strategies for Controlled Placement of Nanoscale Building Blocks

The capability of placing individual nanoscale building blocks on exact substrate locations in a controlled manner is one of the key requirements to realize future electronic, optical, and magnetic devices and sensors that are composed of such blocks. This article reviews some important advances in the strategies for controlled placement of nanoscale building blocks. In particular, we will overview template assisted placement that utilizes physical, molecular, or electrostatic templates, DNA-programmed assembly, placement using dielectrophoresis, approaches for non-close-packed assembly of spherical particles, and recent development of focused placement schemes including electrostatic funneling, focused placement via molecular gradient patterns, electrodynamic focusing of charged aerosols, and others

Associations of autozygosity with a broad range of human phenotypes

In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44–66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Phase I/II Trial of Dose-Reduced Capecitabine in Elderly Patients with Advanced Colorectal Cancer

Background: Combination chemotherapy is associated with improved outcomes in trials of selected fit patients with advanced colorectal cancer (aCRC). For older or less-fit patients, combination chemotherapy is associated with greater toxicity and less benefit. Capecitabine monotherapy is a reasonable option for those patients, but the optimal dose remains controversial. Methods: A multicentre phase I/II trial of reduced-dose capecitabine (2000 mg/m2, days 1–14 every 21 days) was conducted in 221 patients representing one or more of the following subsets: age greater than 65 years (n = 167), Eastern Cooperative Oncology Group (ECOG) performance status of 1 or greater (n = 139), elevated lactate dehydrogenase (LDH) (n = 105), or prior pelvic radiation (n = 54). Based on phase I results, patients with prior pelvic radiation received capecitabine 750 mg/m2 twice daily. The goal was to ascertain efficacy in a design that was unlikely to cause high levels of toxicity. Results: Median age in the patient cohort was 72 years. A median of 5 and a mean of 8 capecitabine cycles were given (range: 0–50 cycles). Grade 3 or 4 toxicity occurred in 25% of patients during the first 3 cycles (8.1% hand–foot syndrome, 7.7% diarrhea). The response rate was 13.6%, with a 69.7% disease control rate. Median progression-free survival (PFS) was 5.6 months. Post progression, 56 patients received further capecitabine monotherapy (median of 4 additional cycles). Median overall survival duration for the patients was 14.3 months. Median survival was significantly higher for those who, at baseline, had an ECOG performance status of 0 (compared with 1 or more) and normal LDH (compared with elevated LDH). Conclusions: Toxicity is less with dose-reduced capecitabine than with historical full-dose capecitabine, with only a small trade-off in efficacy, seen as a lower objective response rate. The improved tolerability could lead to an increased number of cycles of therapy, and PFS appears to be consistently higher at the lower dose. Those observations should, in the absence of a head-to-head clinical trial, be viewed as compelling evidence that 1000 mg/m2, or even 750 mg/m2, twice daily is an appropriate dose in elderly or frail patients with aCRC

The α(1A/C)- and α(1B)-adrenergic receptors are required for physiological cardiac hypertrophy in the double-knockout mouse

Catecholamines and α(1)-adrenergic receptors (α(1)-ARs) cause cardiac hypertrophy in cultured myocytes and transgenic mice, but heart size is normal in single KOs of the main α(1)-AR subtypes, α(1A/C) and α(1B). Here we tested whether α(1)-ARs are required for developmental cardiac hypertrophy by generating α(1A/C) and α(1B) double KO (ABKO) mice, which had no cardiac α(1)-AR binding. In male ABKO mice, heart growth after weaning was 40% less than in WT, and the smaller heart was due to smaller myocytes. Body and other organ weights were unchanged, indicating a specific effect on the heart. Blood pressure in ABKO mice was the same as in WT, showing that the smaller heart was not due to decreased load. Contractile function was normal by echocardiography in awake mice, but the smaller heart and a slower heart rate reduced cardiac output. α(1)-AR stimulation did not activate extracellular signal–regulated kinase (Erk) and downstream kinases in ABKO myocytes, and basal Erk activity was lower in the intact ABKO heart. In female ABKO mice, heart size was normal, even after ovariectomy. Male ABKO mice had reduced exercise capacity and increased mortality with pressure overload. Thus, α(1)-ARs in male mice are required for the physiological hypertrophy of normal postnatal cardiac development and for an adaptive response to cardiac stress

α(1)-Adrenergic receptors prevent a maladaptive cardiac response to pressure overload

An α(1)-adrenergic receptor (α(1)-AR) antagonist increased heart failure in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), but it is unknown whether this adverse result was due to α(1)-AR inhibition or a nonspecific drug effect. We studied cardiac pressure overload in mice with double KO of the 2 main α(1)-AR subtypes in the heart, α(1A) (Adra1a) and α(1B) (Adra1b). At 2 weeks after transverse aortic constriction (TAC), KO mouse survival was only 60% of WT, and surviving KO mice had lower ejection fractions and larger end-diastolic volumes than WT mice. Mechanistically, final heart weight and myocyte cross-sectional area were the same after TAC in KO and WT mice. However, KO hearts after TAC had increased interstitial fibrosis, increased apoptosis, and failed induction of the fetal hypertrophic genes. Before TAC, isolated KO myocytes were more susceptible to apoptosis after oxidative and β-AR stimulation, and β-ARs were desensitized. Thus, α(1)-AR deletion worsens dilated cardiomyopathy after pressure overload, by multiple mechanisms, indicating that α(1)-signaling is required for cardiac adaptation. These results suggest that the adverse cardiac effects of α(1)-antagonists in clinical trials are due to loss of α(1)-signaling in myocytes, emphasizing concern about clinical use of α(1)-antagonists, and point to a revised perspective on sympathetic activation in heart failure

Surfactant-nanotube interactions in water and nanotube separation by diameter: atomistic simulations

A non-destructive sorting method to separate single-walled carbon nanotubes (SWNTs) by diameter was recently proposed. By this method, SWNTs are suspended in water by surfactant encapsulation and the separation is carried out by ultracentrifugation in a density gradient. SWNTs of different diameters are distributed according to their densities along the centrifuge tube. A mixture of two anionic surfactants, namely sodium dodecylsulfate (SDS) and sodium cholate (SC), presented the best performance in discriminating nanotubes by diameter. Unexpectedly, small diameter nanotubes are found at the low density part of the centrifuge tube. We present molecular dynamics studies of the water-surfactant-SWNT system to investigate the role of surfactants in the sorting process. We found that surfactants can actually be attracted towards the interior of the nanotube cage, depending on the relationship between the surfactant radius of gyration and the nanotube diameter. The dynamics at room temperature showed that, as the amphiphile moves to the hollow cage, water molecules are dragged together, thereby promoting the nanotube filling. The resulting densities of filled SWNT are in agreement with measured densities.Brazilian Agencies FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq