Tin Diselenide (SnSe2) Van der Waals Semiconductor: Surface Chemical Reactivity,Ambient Stability,Chemical and Optical Sensors

Tin diselenide (SnSe₂) is a layered semiconductor with broad application capabilities in the fields of energy storage, photocatalysis, and photodetection. Here, we correlate the physicochemical properties of this van der Waals semiconductor to sensing applications for detecting chemical species (chemosensors) and millimeter waves (terahertz photodetectors) by combining experiments of high-resolution electron energy loss spectroscopy and X-ray photoelectron spectroscopy with density functional theory. The response of the pristine, defective, and oxidized SnSe₂ surface towards H₂, H₂O, H₂S, NH₃, and NO₂ analytes was investigated. Furthermore, the effects of the thickness were assessed for monolayer, bilayer, and bulk samples of SnSe₂. The formation of a sub-nanometric SnO₂ skin over the SnSe₂ surface (self-assembled SnO₂/SnSe₂ heterostructure) corresponds to a strong adsorption of all analytes. The formation of non-covalent bonds between SnO₂ and analytes corresponds to an increase of the magnitude of the transferred charge. The theoretical model nicely fits experimental data on gas response to analytes, validating the SnO₂/SnSe₂ heterostructure as a suitable playground for sensing of noxious gases, with sensitivities of 0.43, 2.13, 0.11, 1.06 [ppm]⁻¹ for H₂, H₂S, NH₃, and NO_2, respectively. The corresponding limit of detection is 5 ppm, 10 ppb, 250 ppb, and 400 ppb for H₂, H₂S, NH₃, and NO_2, respectively. Furthermore, SnSe₂-based sensors are also suitable for fast large-area imaging applications at room temperature for millimeter waves in the THz range.     

HDAC and MAPK/ERK Inhibitors Cooperate To Reduce Viability and Stemness in Medulloblastoma

Journal of Molecular Neuroscience - Medulloblastoma (MB), which originates from embryonic neural stem cells (NSCs) or neural precursors in the developing cerebellum, is the most common malignant...     

Three-Dimensional Nanoscale Morphological Surface Analysis of Polymeric Particles Containing Allium sativum Essential Oil

Biodegradable particles were developed using poly-ε-caprolactone and gelatin carriers containing different concentrations of Allium sativum essential oil (EO) (360 µg/mL, 420 µg/mL, and 460 µg/mL). Atomic force microscopy was useful to evaluate the particles’ surface based on morphological parameters. The particles’ size varied from 150 nm to 300 nm. The diameter was related to the increase of the particles’ height as a function of the EO concentration, influencing the roughness of the surface core values (from 20 to 30 nm) and surface irregularity. The spatial parameters Str (texture aspect ratio) and Std (texture direction) revealed low spatial frequency components. The hybrid parameters Sdq (root mean square gradient) and Sdr (interfacial area ratio) also increased as a function of the EO concentration, revealing fewer flat particles. On the other hand, the functional parameters (inverse areal material ratio and peak extreme height) suggested differences in surface irregularities. Higher concentrations of EO resulted in greater microtexture asperity on the particles’ surface, as well as sharper peaks. The nanoscale morphological surface analysis allowed the determination of the most appropriate concentration of encapsulated EO, influencing statistical surface parameters.     

Psoriasis Following Bariatric Surgery: Clinical Evolution and Impact on Quality of Life on 10 patients

Psoriasis is a chronic systemic disease with important skin manifestations, affecting 2 % of the population. It is more frequent and severe in obese patients, and both have been associated with a higher cardiovascular risk. Recent studies suggest that weight loss may improve psoriasis and metabolic comorbidities in obese patients. We reviewed our prospective electronic database for all patients with psoriasis who underwent bariatric surgery between 2008 and 2011. We assessed surgical complications, weight progression, and psoriasis-related outcomes. The Dermatology Life Quality Index was used retrospectively to assess quality of life (QoL) before and after the operation. Ten patients were included; body mass index was 38.8 ± 5.2 kg/m(2). Pre-surgical treatment for psoriasis was topical (50 %) and systemic (40 %). Eight patients underwent laparoscopic Roux-en-Y gastric bypass and two underwent laparoscopic sleeve gastrectomy. At follow-up, the mean percent excess weight loss 1, 6, and 12 months after surgery was 45 %, 80 %, and 88 %, respectively. Comorbidity resolution was 75 % for diabetes mellitus, 100 % for insulin resistance, and 57 % for hypertension. Related to psoriasis, 70 % of the patients stayed in remission 6 months after surgery and three of the four patients who were previously medicated with systemic drugs discontinued medication. The impact of psoriasis on QoL improved from 14.9 ± 6.8 before surgery to 5 ± 6.3 after surgery (p = 0.005). Bariatric surgery for positive metabolic, skin, and quality of life results should be considered as a useful adjuvant therapy for obese patients with psoriasis.