336 research outputs found
Direct Fabrication of Atomically Defined Pores in MXenes
Controlled fabrication of nanopores in atomically thin two-dimensional
material offers the means to create robust membranes needed for ion transport,
nanofiltration, and DNA sensing. Techniques for creating nanopores have relied
upon either plasma etching or direct irradiation using electrons or ions;
however, aberration-corrected scanning transmission electron microscopy (STEM)
offers the advantage of combining a highly energetic, sub-angstrom sized
electron beam for atomic manipulation along with atomic resolution imaging.
Here, we utilize a method for automated nanopore fabrication with real-time
atomic visualization to enhance our mechanistic understanding of beam-induced
transformations. Additionally, an electron beam simulation technique,
Electron-Beam Simulator (E-BeamSim) was developed to observe the atomic
movements and interactions resulting from electron beam irradiation. Using the
2D MXene Ti3C2Tx, we explore the influence of temperature on nanopore
fabrication by tracking atomic transformation pathways and find that at room
temperature, electron beam irradiation induces random displacement of atoms and
results in a pileup of titanium atoms at the nanopore edge. This pileup was
confirmed and demonstrated in E-BeamSim simulations around the small, milled
area in the MXene monolayer. At elevated temperatures, the surface functional
groups on MXene are effectively removed, and the mobility of atoms increases,
which results in atomic transformations that lead to the selective removal of
atoms layer by layer. Through controllable manufacture using e-beam milling
fabrication, the production and then characterization of the fabricated defects
can be better understood for future work. This work can lead to the development
of defect engineering techniques within functionalized MXene layers.Comment: Experimental and simulations on the electron beam interactions with
MXene monolayers to form nanopores as a function of temperatur
Gold-on-glass microwave split-ring resonators with PDMS microchannels for differential measurement in microfluidic sensing
This paper describes a microwave resonator incorporating microfluidic lab-on-chip sensor system capable of performing simultaneous differential measurement based sensing of liquid samples. The resonators are split-ring resonator shapes made of gold on glass substrates. Directly bonded on glass substrates are polydimethylsiloxane microchannels. Sensor system design incorporates a pair of identical resonators, one of which performs reference reading from the background. Tracking the difference of the responses of both resonators simultaneously, rather than a single one, is used to obtain a more linear and noise-free reading. The sensor system was produced with conventional fabrication techniques. It is compatible with low-cost, simple, easy to handle sensing applications. Results indicate that reliable differential measurement was possible owing to a well-matched pair of sensors with a response error as low as 0.1%. It was also demonstrated that differential measurement capability enables sensing with improved linearity. Measurements were performed with glucose solutions in the range of 3.2β16.1βmM, achieving a sensitivity of 0.16βMHz/mM
Atypical STAT5B deficiency, severe short stature and mild immunodeficiency associated with a novel homozygous STAT5B Variant
STAT5B deficiency, a rare autosomal recessive disorder characterized by severe growth hormone insensitivity (GHI) and immunodeficiency, can manifest as fatal pulmonary complications. We describe atypical STAT5B deficiency associated with a novel homozygous frame-shift STAT5B variant [c.1453delG, p.(Asp485Thrfs*29)] identified in a young 17.6 yr old female subject who had severe postnatal growth impairment, biochemistries typical of GHI, an immune profile notable for hypergammaglobulinaemia and elevated B lymphocytes, and lack of pulmonary disease. Marked elevation of serum prolactin and pathologically diagnosed eczema were evident. In reconstitution studies, the STAT5B p.(Asp485Thrfs*29) was expressed although expression was reduced compared to wild-type STAT5B and a previously identified STAT5B p.(Gln368Profs*9) variant. Both truncated STAT5B peptides could not be activated by GH, nor mobilize to the nucleus. We conclude that an intact, func-tional, STAT5B is essential for normal GH-mediated growth, while expressed loss-of-function STAT5B variants may alleviate severe immune and pulmonary issues normally associated with STAT5B deficiency.Genetics of disease, diagnosis and treatmen
Adhesive capsulitis and dynamic splinting: a controlled, cohort study
<p>Abstract</p> <p>Background</p> <p>Adhesive Capsulitis (AC) affects patient of all ages, and stretching protocols are commonly prescribed for this condition. Dynamic splinting has been shown effective in contracture reduction from pathologies including Trismus to plantar fasciitis. The purpose of this study was to examine the efficacy of dynamic splinting on patients with AC.</p> <p>Methods</p> <p>This controlled, cohort study, was conducted at four physical therapy, sports medicine clinics in Texas and California. Sixty-two patients diagnosed with Stage II Adhesive Capsulitis were grouped by intervention. The intervention categories were as follows: Group I (Control); Group II (Physical Therapy exclusively with standardized protocols); Group III; (Shoulder Dynasplint system exclusively); Group IV (Combined treatment with Shoulder Dynasplint and standardized Physical Therapy). The duration of this study was 90 days for all groups, and the main outcome measures were change in active, external rotation.</p> <p>Results</p> <p>Significant difference was found for all treatment groups (p < 0.001) following a one-way ANOVA. The greatest change with the smallest standard deviation was for the combined treatment group IV, (mean change of 29Β°).</p> <p>Conclusion</p> <p>The difference for the combined treatment group was attributed to patients' receiving the best PT combined with structured "home therapy" that contributed an additional 90 hours of end-range stretching. This adjunct should be included in the standard of care for adhesive Capsulitis.</p> <p>Trial Registration</p> <p><b>Trial Number</b>: NCT00873158</p
Blinding Techniques in Randomized Controlled Trials of Laser Therapy: An Overview and Possible Solution
Low-level laser therapy has evidence accumulating about its effectiveness in a variety of medical conditions. We reviewed 51 double blind randomized controlled trials (RCTs) of laser treatment. Analysis revealed 58% of trials showed benefit of laser over placebo. However, less than 5% of the trials had addressed beam disguise or allocation concealment in the laser machines used. Many of the trials used blinding methods that rely on staff cooperation and are therefore open to interference or bias. This indicates significant deficiencies in laser trial methodology. We report the development and preliminary testing of a novel laser machine that can blind both patient and operator to treatment allocation without staff participation. The new laser machine combines sealed preset and non-bypassable randomization codes, decoy lights and sound, and a conical perspex tip to overcome laser diode glow detection
Meta-Analysis of the Prognostic Impact of Anemia in Patients Undergoing Percutaneous Coronary Intervention
This study was funded by an award from the North Staffordshire Medical Institute, Stoke-on-Trent, United Kingdom.Peer reviewedPostprin
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