23 research outputs found

    Synthesis of Monochlorosilyl Derivatives of Dialkyloligothiophenes for Self-Assembling Mono layer Field-Effect Transistors

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    Unsymmetrical dimethylchlorosilyl-substituted α,α'-dialkylquater-, quinque-, and sexithiophenes were designed and successfully synthesized by a combination of Kumada and Suzuki cross-coupling reactions followed by hydrosilylation. Optimization possibilities of the hydrosilylation of low-soluble linear oligothiophenes by dimethylchlorosilane as well as the nonreactive byproducts formed are described. The molecular structures of the obtained dimethylchlorosilyl-functionalized oligothiophenes were proven by NMR and DCI MS techniques. These compounds were found to be stable and reactive enough, even in the presence of the nonreactive byproducts, to form semiconducting monolayers on dielectric hydroxylated SiO2 surfaces by self-assembly from solution. The semiconducting properties of these oligothiophene SAMs were as good as those of bulk oligothiophenes. This allowed the production of stable, even under ambient conditions, SAMFETs with a mobility of up to 0.04 cm2/(V s) and an on/off ratio up to 1 × 10^8.

    Do pharmacokinetic polymorphisms explain treatment failure in high-risk patients with neuroblastoma?

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    Missense variants in ANKRD11 cause KBG syndrome by impairment of stability or transcriptional activity of the encoded protein

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    Purpose Although haploinsufficiency of ANKRD11 is among the most common genetic causes of neurodevelopmental disorders, the role of rare ANKRD11 missense variation remains unclear. We characterized clinical, molecular, and functional spectra of ANKRD11 missense variants. Methods We collected clinical information of individuals with ANKRD11 missense variants and evaluated phenotypic fit to KBG syndrome. We assessed pathogenicity of variants through in silico analyses and cell-based experiments. Results We identified 20 unique, mostly de novo, ANKRD11 missense variants in 29 individuals, presenting with syndromic neurodevelopmental disorders similar to KBG syndrome caused by ANKRD11 protein truncating variants or 16q24.3 microdeletions. Missense variants significantly clustered in repression domain 2 at the ANKRD11 C-terminus. Of the 10 functionally studied missense variants, 6 reduced ANKRD11 stability. One variant caused decreased proteasome degradation and loss of ANKRD11 transcriptional activity. Conclusion Our study indicates that pathogenic heterozygous ANKRD11 missense variants cause the clinically recognizable KBG syndrome. Disrupted transrepression capacity and reduced protein stability each independently lead to ANKRD11 loss-of-function, consistent with haploinsufficiency. This highlights the diagnostic relevance of ANKRD11 missense variants, but also poses diagnostic challenges because the KBG-associated phenotype may be mild and inherited pathogenic ANKRD11 (missense) variants are increasingly observed, warranting stringent variant classification and careful phenotyping

    Unified description of potential profiles and electrical transport in unipolar and ambipolar organic field-effect transistors

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    Validation of models for charge transport in organic transistors is fundamentally important for their technological use. Usually current-voltage measurements are performed to investigate organic transistors. In situ scanning Kelvin probe microscopy measurements provide a powerful complementary technique to distinguish between models based on band and hopping transports. We perform combined current-voltage and Kelvin probe microscopy measurements on unipolar and ambipolar organic field-effect transistors. We demonstrate that by this combination we can stringently test these two different transport models and come up with a unified description of charge transport in disordered organic semiconductors.

    Analysis of serious weight gain in patients using alectinib for ALK positive lung cancer

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    INTRODUCTION: Alectinib is a standard of care treatment for metastatic anaplastic lymphoma kinase positive (ALK+) non-small cell lung cancer (NSCLC). Weight gain is an unexplored side effect reported in ∼10%. To prevent or intervene alectinib-induced weight gain, more insight in its extent and etiology is needed. METHODS: Change in body composition was analyzed in a prospective series of 46 patients with ALK+ NSCLC, treated with alectinib. Waist circumference, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and skeletal muscle (SM), were quantified using sliceOmatic software on computed tomography (CT) images at baseline, three months (3M) and one year (1Y). To investigate an exposure-toxicity relationship, alectinib plasma concentrations were quantified. Four patients with >10 kg weight gain were referred to Erasmus MC Obesity Center CGG for in-depth analysis (e.g. assessments of appetite, dietary habits, other lifestyle, medical and psychosocial factors and extensive metabolic/endocrine assessments, including resting energy expenditure). RESULTS: Mean increase in waist circumference was 9 cm (9.7%, p<0.001) in 1Y with a 40% increase in abdominal obesity (p=0.014). VAT increased 10.8 cm2 (15.0%, p=0.003) in 3M and 35.7 cm2 (39.0%, p<0.001) in 1Y. SAT increased 18.8 cm2 (12.4%, p<0.001) in 3M and 45.4 cm2 (33.3%, p<0.001) in 1Y. The incidence of sarcopenic obesity increased from 23.7% to 47.4% during 1Y of treatment. Baseline waist circumference was a positive predictor of increase in VAT (p=0.037). No exposure-toxicity relationship was found. In-depth analysis (n=4) showed increased appetite in two patients and metabolic syndrome in all four patients. CONCLUSION: Alectinib may cause significant increased sarcopenic abdominal obesity, with increases of both VAT and SAT, quickly after initiation. This may lead to many serious metabolic, physical, and mental disturbances in long-surviving patients

    Influence of Food With Different Fat Concentrations on Alectinib Exposure: A Randomized Crossover Pharmacokinetic Trial

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    BACKGROUND: Alectinib is the keystone treatment in advanced anaplastic lymphoma kinase-positive (ALK+) non-small cell lung cancer (NSCLC). An exposure-response threshold of 435 ng/mL has recently been established, albeit 37% of patients do not reach this threshold. Alectinib is orally administered, and absorption is largely influenced by food. Hence, further investigation into this relationship is needed to optimize its bioavailability. PATIENTS AND METHODS: In this randomized 3-period crossover clinical study in ALK+ NSCLC, alectinib exposure was compared among patients with different diets. Every 7 days, the first alectinib dose was taken with either a continental breakfast, 250-g of low-fat yogurt, or a self-chosen lunch, and the second dose was taken with a self-chosen dinner. Sampling for alectinib exposure (Ctrough) was performed at day 8, just prior to alectinib intake, and the relative difference in Ctrough was compared. RESULTS: In 20 evaluable patients, the mean Ctrough was 14% (95% CI, -23% to -5%; P=.009) and 20% (95% CI, -25% to -14%; P<.001) lower when taken with low-fat yogurt compared with a continental breakfast and a self-chosen lunch, respectively. Administration with a self-chosen lunch did not change exposure compared with a continental breakfast (+7%; 95% CI, -2% to +17%; P=.243). In the low-fat yogurt period, 35% of patients did not reach the threshold versus 5% with the other meals (P<.01). CONCLUSIONS: Patients and physicians should be warned for a detrimental food-drug interaction when alectinib is taken with low-fat yogurt, because it results in a clinically relevant lower alectinib exposure. Intake with a self-chosen lunch did not change drug exposure and could be a safe and patient-friendly alternative

    Monolayer coverage and channel length set the mobility in self-assembled monolayer field-effect transistors

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    The mobility of self-assembled monolayer field-effect transistors (SAMFETs) traditionally decreases dramatically with increasing channel length. Recently, however, SAMFETs using liquid-crystalline molecules have been shown to have bulk-like mobilities that are virtually independent of channel length. Here, we reconcile these scaling relations by showing that the mobility in liquid crystalline SAMFETs depends exponentially on the channel length only when the monolayer is incomplete. We explain this dependence both numerically and analytically, and show that charge transport is not affected by carrier injection, grain boundaries or conducting island size. At partial coverage, that is when the monolayer is incomplete, liquid-crystalline SAMFETs thus form a unique model system to study size-dependent conductance originating from charge percolation in two dimensions.
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