148 research outputs found
Novel MXene sensors based on fast healing vitrimers
Soft matter containing Ti3C2Tx MXenes exhibits promising potential in electromechanical sensor development. Current systems suffer from a decrease in sensibility up to complete breakdown due to small structural defects that will be generated during their longtime practical service. Various non-covalent hydrogel systems, based on hydrogen bonding and ionic coupling, have been employed to improve their durability related to their repairability. However, Ti3C2Tx MXenes are not stable in those networks, since they will be irreversibly oxidized in high humidity environment during practical application. Here, we report the use of a novel dynamic covalent bond based network – a MXene acrylate vitrimer network (MAVIN) with a low glass transition temperature, which can not only be repaired fast with high efficiency but also protects the MXenes in sensor applications from oxidation under working conditions. In addition, owing to the strong microwave absorptivity of Ti3C2Tx and of the flexible dynamic covalent bond network, a damaged MAVIN sensor can be repaired by microwave radiation with a high healing efficiency of 92.4% within 1 minute, which is as good as the best healing efficiency reported in literature so far but 30 times faster. With stability at a voltage of 3 V and fast healing demonstrated, MAVIN promises potential usage in reliable and sustainable strain sensors
Lightweight Triboelectric Nanogenerators Based on Hollow Stellate Cellulose Films Derived from Juncus effusus L. Aerenchyma
This study reports a facile delignification and natural drying process for synthesizing cellulose films using the unique surface roughness, porosity, and lightness of the hollow stellate cellulose (HSC) united aerenchyma of the wetland weed Juncus effusus L. By controlling the grafted amino/fluorine-bearing group content of various silane coupling agents, this work successfully manipulates the triboelectric polarities of HSC films after silanization. Subsequently, a layer of Ag nanowire electrodes is coated on one side of the silanized HSC friction layers, resulting in flexible, lightweight, semi-transparent HSC-based triboelectric nanogenerators (HSC-TENGs) featuring both macro-scale surface roughness and micro-nano inner pores. These all-in-one HSC-TENGs achieve the highest output voltage of 4.86 V, which is 28 times that of TENGs employing two pristine HSC films as triboelectric layers (PHSC-TENG). Finally, the HSC-TENG with the optimum output power is applied as a wearable self-powered sensor for gait analysis, demonstrating stable and sustainable performances in distinguishing different body motions such as walking, running, jumping, and calf raising. This study not only proposes a new cellulose-based TENG for future in-depth body locomotion analysis but also paves the way for converting differently structured aerenchyma from abundant problematic aquatic or wetland weeds into promising structural templates in multifunctional cellulose-based applications.</p
Lightweight Triboelectric Nanogenerators Based on Hollow Stellate Cellulose Films Derived from Juncus effusus L. Aerenchyma
This study reports a facile delignification and natural drying process for synthesizing cellulose films using the unique surface roughness, porosity, and lightness of the hollow stellate cellulose (HSC) united aerenchyma of the wetland weed Juncus effusus L. By controlling the grafted amino/fluorine-bearing group content of various silane coupling agents, this work successfully manipulates the triboelectric polarities of HSC films after silanization. Subsequently, a layer of Ag nanowire electrodes is coated on one side of the silanized HSC friction layers, resulting in flexible, lightweight, semi-transparent HSC-based triboelectric nanogenerators (HSC-TENGs) featuring both macro-scale surface roughness and micro-nano inner pores. These all-in-one HSC-TENGs achieve the highest output voltage of 4.86 V, which is 28 times that of TENGs employing two pristine HSC films as triboelectric layers (PHSC-TENG). Finally, the HSC-TENG with the optimum output power is applied as a wearable self-powered sensor for gait analysis, demonstrating stable and sustainable performances in distinguishing different body motions such as walking, running, jumping, and calf raising. This study not only proposes a new cellulose-based TENG for future in-depth body locomotion analysis but also paves the way for converting differently structured aerenchyma from abundant problematic aquatic or wetland weeds into promising structural templates in multifunctional cellulose-based applications.</p
New insights in polydopamine formation via surface adsorption
Polydopamine is a biomimetic self-adherent polymer, which can be easily deposited on a wide variety of materials. Despite the rapidly increasing interest in polydopamine-based coatings, the polymerization mechanism and the key intermediate species formed during the deposition process are still controversial. Herein, we report a systematic investigation of polydopamine formation on halloysite nanotubes; the negative charge and high surface area of halloysite nanotubes favour the capture of intermediates that are involved in polydopamine formation and decelerate the kinetics of the process, to unravel the various polymerization steps. Data from X-ray photoelectron and solid-state nuclear magnetic resonance spectroscopies demonstrate that in the initial stage of polydopamine deposition, oxidative coupling reaction of the dopaminechrome molecules is the main reaction pathway that leads to formation of polycatecholamine oligomers as an intermediate and the post cyclization of the linear oligomers occurs subsequently. Furthermore, TRIS molecules are incorporated into the initially formed oligomers
Gemeinsame Entscheidungsfindung in der Behandlung von Patienten mit schweren psychischen Erkrankungen:Eine Fokusgruppenuntersuchung
Objective: Shared decision-making during the course of treatment is important for people with severe mental illness. However, there is still insufficient knowledge about how people with mental illness view decisions, what kind of decisions are made and how patients experience and perceive the process of participation in routine care. Methods: A qualitative study with focus groups was conducted with patients with chronic mental illness currently receiving outpatient care (N=23). Interviews were audio-taped, transcribed, coded and content analysed. Results: Three main themes were extracted from the data: 1. perception of the clinician and participation, 2. process of communication and flow of information, 3. decisions and transfer. Conclusions: The perception of participation in the decision process depends on a good patient-doctor relationship. Decisions made in the course of an outpatient long-term treatment are complex and are often not made during one single appointment. Frequently, patients seek the advice of people from their social network and/or other health professionals.</p
Nitrogen-Doped TiCT Coated with a Molecularly Imprinted Polymer as Efficient Cathode Material for Lithium-Sulfur Batteries
Due to their high energy density (2600 Wh/kg), low cost, and low
environmental impact, lithium-sulfur batteries are considered a promising
alternative to lithium-ion batteries. However, their commercial viability
remains a formidable scientific challenge mainly because of the sluggish
reaction kinetics at the cathode and the so-called "shuttling effect" of
soluble polysulfides, which results in capacity decay and a shortened lifespan.
Herein, molecular imprinting with LiS as a target molecule in
combination with a two-dimensional material, MXene, is proposed to overcome
these issues. Molecularly imprinted polymer-coated nitrogen-doped Ti-based
MXene was successfully synthesized and demonstrated to exhibit an appealing
electrochemical performance, namely a high specific capacity of 1095 mAh/g at
0.1 C and an extended cycling stability (300 mAh/g at 1.0 C after 300 cycles).
X-ray photoelectron spectroscopy was applied to elucidate the underlying
mechanisms and proved that LiS-imprinted polymer polyacrylamide serves
as a polysulfide trap through strong chemical affinity towards the long-chain
lithium polysulfides, while N-doped Ti-based MXene promotes the redox kinetics
by accelerating the conversion of lithium polysulfides. This distinct
interfacial strategy is expected to result in more effective and stable Li-S
batteries
ATRT-02. Neuropsychological function in infant atypical teratoid/rhabdoid tumor versus low-grade glioma survivors reflects tumor malignancy and multimodal treatment [Abstract]
BACKGROUND: Therapy of infants with brain tumors predisposes these patients to increased risks for cognitive sequelae, especially following radiotherapy. Neuropsychological outcome gains importance for those 40-60% of patients with an atypical teratoid/rhabdoid tumor (ATRT) who survive beyond 2 years. Still, reports on cognitive late-effects in children with ATRT are scarce compared to other pediatric brain tumor groups. We analyzed neuropsychological outcome for long-term ATRT-survivors registered in EU-RHAB and infant low-grade glioma (LGG) survivors from the SIOP-LGG 2004-study and LGG-registry. PATIENTS+METHODS: Age at diagnosis of both cohorts was 0-36 months. ATRT-patients (n=13) treated with up to 54Gy radiotherapy (median age 22 months (±7.1)) were evaluated with the “ATRT-Neuropsychology” tool based on SIOPE-BTG QoS-Group recommendations at median 6.8 years (±2.8) after diagnosis. LGG-patients (n=15) treated without radiotherapy (4/15 with chemotherapy) were analyzed with the German “Neuropsychological-Basic-Diagnostic” tool 5.2 years (±0.6) post-diagnosis. RESULTS: The ATRT- vs. LGG-cohorts were comparable for median age at diagnosis, sex-ratio and tumor-localization, though they differed slightly in median age at assessment (9.5/7.2 years (±2.5/1.1)). Results of age-appropriate tests showed increased impairments for ATRT-patients in fluid intelligence (FI) (p=.006, d=1.214) and in visual-spatial processing (VSP) (p<.001, d=2.233) compared to LGG-patients. The median for neuropsychological test results of ATRT-patients spanned from considerably below the normal to the lower normal range (median=65-90), while results of LGG-patients were mostly in the lower normal range (median=83-103). Results for psychomotor speed abilities (PMS) were distinctly below the norm for both patient groups (p=.002-.007). CONCLUSION: Infant ATRT- and LGG-patients develop significant impairments in PMS abilities following multimodal treatment. Long-term survivors of ATRT suffer from additional FI and VSP deficits. Our data suggest that high malignancy requiring multimodal treatment determines the inferior cognitive outcome for the ATRT-cohort. Long-term neuropsychological monitoring (and treatment options) should be implemented as standard of care in ATRT- and LGG-trials
A Systematic Mapping Approach of 16q12.2/FTO and BMI in More Than 20,000 African Americans Narrows in on the Underlying Functional Variation: Results from the Population Architecture using Genomics and Epidemiology (PAGE) Study
Genetic variants in intron 1 of the fat mass- and obesity-associated (FTO) gene have been consistently associated with body mass index (BMI) in Europeans. However, follow-up studies in African Americans (AA) have shown no support for some of the most consistently BMI-associated FTO index single nucleotide polymorphisms (SNPs). This is most likely explained by different race-specific linkage disequilibrium (LD) patterns and lower correlation overall in AA, which provides the opportunity to fine-map this region and narrow in on the functional variant. To comprehensively explore the 16q12.2/FTO locus and to search for second independent signals in the broader region, we fine-mapped a 646-kb region, encompassing the large FTO gene and the flanking gene RPGRIP1L by investigating a total of 3,756 variants (1,529 genotyped and 2,227 imputed variants) in 20,488 AAs across five studies. We observed associations between BMI and variants in the known FTO intron 1 locus: the SNP with the most significant p-value, rs56137030 (8.3Ă—10-6) had not been highlighted in previous studies. While rs56137030was correlated at r2>0.5 with 103 SNPs in Europeans (including the GWAS index SNPs), this number was reduced to 28 SNPs in AA. Among rs56137030 and the 28 correlated SNPs, six were located within candidate intronic regulatory elements, including rs1421085, for which we predicted allele-specific binding affinity for the transcription factor CUX1, which has recently been implicated in the regulation of FTO. We did not find strong evidence for a second independent signal in the broader region. In summary, this large fine-mapping study in AA has substantially reduced the number of common alleles that are likely to be functional candidates of the known FTO locus. Importantly our study demonstrated that comprehensive fine-mapping in AA provides a powerful approach to narrow in on the functional candidate(s) underlying the initial GWAS findings in European populations
- …