A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and ...patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (∼1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes.
Purpose
We aimed to study the relationship between aging and increased parathyroid hormone (PTH) values.
Methods
We performed a retrospective cross-sectional study with data from patients who ...underwent outpatient PTH measurements performed by a second-generation electrochemiluminescence immunoassay. We included patients over 18 years of age with simultaneous PTH, calcium, and creatinine measurements and 25-OHD measured within 30 days. Patients with glomerular filtration rate < 60 mL/min/1.73 m
2
, altered calcemia, 25-OHD level < 20 ng/mL, PTH values > 100 pg/mL or using lithium, furosemide or antiresorptive therapy were excluded. Statistical analyses were performed using the RefineR method.
Results
Our sample comprised 263,242 patients for the group with 25-OHD ≥ 20 ng/mL, that included 160,660 with 25-OHD ≥ 30 ng/mL. The difference in PTH values among age groups divided by decades was statistically significant (p < 0.0001), regardless of 25-OHD values, ≥ 20 or ≥ 30 ng/mL. In the group with 25-OHD ≥ 20 ng/mL and more than 60 years, the PTH values were 22.1–84.0 pg/mL, a different upper reference limit from the reference value recommended by the kit manufacturer.
Conclusion
We observed a correlation between aging and PTH increase, when measured by a second-generation immunoassay, regardless of vitamin D levels, if greater than 20 ng/mL, in normocalcemic individuals without renal dysfunction.
•Alginate/Hyaluronan composite hydrogels for wound dressing are proposed.•Hyaluronan at different concentrations does not interfere with internal gelation process.•Hyaluronan-containing hydrogels ...promote healing in Ad-MSC or HaCaT cell cultures as well as in a rat model of excised wound.•Alginate/Hyaluronan biofunctional hydrogels turn to be a versatile platform to translate in a clinical setting.
In this paper we propose polysaccharide hydrogels combining alginate (ALG) and hyaluronan (HA) as biofunctional platform for dermal wound repair. Hydrogels produced by internal gelation were homogeneous and easy to handle. Rheological evaluation of gelation kinetics of ALG/HA mixtures at different ratios allowed understanding the HA effect on ALG cross-linking process. Disk-shaped hydrogels, at different ALG/HA ratio, were characterized for morphology, homogeneity and mechanical properties. Results suggest that, although the presence of HA does significantly slow down gelation kinetics, the concentration of cross-links reached at the end of gelation is scarcely affected. The in vitro activity of ALG/HA dressings was tested on adipose derived multipotent adult stem cells (Ad-MSC) and an immortalized keratinocyte cell line (HaCaT). Hydrogels did not interfere with cell viability in both cells lines, but significantly promoted gap closure in a scratch assay at early (1 day) and late (5 days) stages as compared to hydrogels made of ALG alone (p<0.01 and 0.001 for Ad-MSC and HaCaT, respectively). In vivo wound healing studies, conducted on a rat model of excised wound indicated that after 5 days ALG/HA hydrogels significantly promoted wound closure as compared to ALG ones (p<0.001). Overall results demonstrate that the integration of HA in a physically cross-linked ALG hydrogel can be a versatile strategy to promote wound healing that can be easily translated in a clinical setting.
Two-dimensional piezotronics will benefit from the emergence of new crystals featuring high piezoelectric coefficients. Gallium phosphate (GaPO
) is an archetypal piezoelectric material, which does ...not naturally crystallise in a stratified structure and hence cannot be exfoliated using conventional methods. Here, we report a low-temperature liquid metal-based two-dimensional printing and synthesis strategy to achieve this goal. We exfoliate and surface print the interfacial oxide layer of liquid gallium, followed by a vapour phase reaction. The method offers access to large-area, wide bandgap two-dimensional (2D) GaPO
nanosheets of unit cell thickness, while featuring lateral dimensions reaching centimetres. The unit cell thick nanosheets present a large effective out-of-plane piezoelectric coefficient of 7.5 ± 0.8 pm V
. The developed printing process is also suitable for the synthesis of free standing GaPO
nanosheets. The low temperature synthesis method is compatible with a variety of electronic device fabrication procedures, providing a route for the development of future 2D piezoelectric materials.
The widespread availability of abdominal ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) scanning has increased the diagnosis of incidental renal tumors, which now comprise ...the vast majority of the new cases diagnosed each year. With the detection of renal tumors at an earlier stage, partial nephrectomy and nephron-sparing surgery have evolved as effective alternatives to radical nephrectomy. The poor prognostic findings of involved regional lymph nodes or ipsilateral adrenal metastases has led to more selective operations on those sites in the face of incidental tumor detection. Technological advances have allowed for the development by committed surgical investigators of techniques of laparoscopic and laparoscopically assisted nephrectomy. Although not widely employed, further improvements in technology may widen the appeal of these approaches to selected renal tumors. Advances in cardiovascular surgical techniques have made resection of renal cell carcinoma (RCC) with tumor thrombi involving the inferior vena cava (IVC) possible, although this approach is still associated with significant perioperative mortality depending on the degree of caval involvement. In highly selected cases, resection of limited metastatic disease is recommended, particularly if the disease-free interval is greater than 12 months and there is a only a single site of metastatic disease. Whether metastectomy is therapeutic or fits within the realm of the often long and unpredictable natural history of RCC is not known. Strategies for follow-up are based primarily on the pathologic stage of the operated tumor. Small incidental tumors have an excellent prognosis and require little in the way of postoperative imaging. As the pathologic stage increases, the likelihood of developing metastatic disease increases, necessitating biannual chest x-ray in addition to history and physical examination. Symptom-directed bone scans and CT scans are effective in identifying most recurrences in patients with large, poorly differentiated tumors. Patients requiring specialized follow-up programs include those treated by partial nephrectomy, and those with end-stage renal disease, acquired cystic disease of the kidney, or von Hippel-Lindau (VHL) disease.
•A new nonlinear ultrasonic technique “Narrowband SPC-I” is proposed.•It is able to monitor damage in composite plates as the impact energy increases.•Combining nonlinear and linear techniques is not ...needed when using narrowband SPC-I.
An improved technique for sensing damage initiation and progression in thermoplastic resin composite plate specimens is presented in this study. The composite plate specimens are investigated by using a nonlinear ultrasonic (NLU) technique called Sideband Peak Count Index or SPC-I. The technique presented in this paper is an improvement from the previous SPC-I technique. This improved technique provides more reliable and consistent results and can monitor the damage progression over a wide range. In this paper the narrow band SPC-I technique is introduced to replace the conventional wide band SPC-I technique. The method implemented here is improved in three ways. First and foremost the narrow band SPC-I technique is introduced. Secondly, the non-permanently adhered gel coupled Lead-Zirconate-Titanate (PZT) transducers are used to reduce inconsistency in transducer adhesion and manufacturing. Lastly, higher sampling rate equipment is used for better signal resolution and peak counting. The experiments are performed on 4 sets of composite plate specimens fabricated using two composite fiber materials (Glass and Basalt) that have increasing levels of damage. The composite plate specimens were damaged by a falling weight impact machine with increasing impact energy (0 J, 10 J, 20 J and 30 J). The composite plate specimens were examined by propagating a narrow band chirp signal through the specimens using gel coupled transducers in a transmission mode setup. The received signals were recorded and analyzed using the NLU SPC-I technique. The modified SPC-I technique proposed in this paper can reliably and consistently detect both initiation and progression of damage in the composite plate specimens.
The assessment of the local formability and mechanical behavior of weldments in tailor welded blanks (TWBs) made of advanced high strength steels is of crucial importance in the automotive industry, ...both for the mechanical design of tailored components, and to set up accurate sheet forming numerical simulations. This work investigates the formability of TWBs made of a twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) steel, determining the local elastoplastic behavior of the different regions of the weldment. To this purpose, several micro-samples were extracted along the weld seam and heat affected zones and then subjected to tensile tests. Tensile tests were also performed on macro-samples to assess the overall mechanical behavior of the TWBs during plastic deformation. A digital image correlation (DIC) technique was used to measure the surface strain field of both micro- and macro-samples, to calculate the plastic strain ratio, through-thickness strain, and to point out possible inhomogeneities in the plastic behavior of the TWB weld beads. The TWB joint exhibited a significant formability of the fusion zone and of the TWIP heat affected zone, whereas it was rather limited at the TRIP side. Locally, an uneven plastic behavior within the fusion zone was observed, with a variable plastic strain ratio (i.e., thinning) in both axial and transverse direction. The other regions of the weld, instead, deformed more homogeneously. Preliminary considerations about the numerical modeling of TWIP/TRIP TWBs and their prospective use in sheet forming operations have been outlined.
Display omitted
•Graphene oxide were used as nanoplatelets into UV-curable epoxy resin.•Cationic UV–curing was performed for the different formulations.•A clear enhancement of the water vapor ...transmission rate was measured for composites coatings.
In this paper we investigated the improvement of water-vapor barrier properties of an UV-cured epoxy film containing graphite oxide nanoplatelets. Graphene platelets were successfully dispersed in the epoxy resin and cured by UV-irradiation. Good performances in increasing water vapor barrier properties at a very low filler loading are obtained: the permeability decreased of about 40% with a 0.5wt.% of GOx and of about 60% with a 1.0wt.% of GOx. These good results are attributed to a homogeneous filler dispersion, as clearly shown by TEM microscopy.
An important aspect of safety and quality in healthcare is the implementation of infection prevention and control guidelines. However, little is known regarding the strength of evidence on which ...recommendations for such guidelines are based. This study aimed to describe the strength of recommendations of infection prevention and control guidelines published in the last 10 years. For this review, the websites of government and professional organizations for national and international infection prevention and control clinical guidelines were purposively searched. The search was limited to publications between January 2009 and April 2019, and those with a formal grading system were used to determine the strength of the evidence underpinning the recommendations. Recommendations from guidelines were categorized into 21 infection control categories. A descriptive synthesis of the data was undertaken.
A total of 31 guidelines comprising 1855 recommendations were included. Guidelines were mainly developed in the USA (N = 11, 35.5%) and Canada (N = 9, 29.0%). Most guidelines used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach (N = 6, 19.4%. The majority of the guidelines contained recommendations categorized under the themes of devices (N = 316, 16.9%) and transmission-based precautions (N = 315, 16.8%). Most recommendations (N = 769, 41.5%) were graded as using evidence from descriptive studies, expert opinion and low-quality evidence.
There are a vast number of infection prevention and control guidelines developed by national and international government or professional organizations, many without a strong evidence base. This presents multiple research opportunities that should prioritize common prevention activities that currently have a low evidence base.
PDF
