Magnetic Tunability via Control of Crystallinity and Size in Polycrystalline Iron Oxide Nanoparticles.

Iron oxide nanoparticles (IONPs) are widely used for biomedical applications due to their unique magnetic properties and biocompatibility. However, the controlled synthesis of IONPs with tunable particle sizes and crystallite/grain sizes to achieve desired magnetic functionalities across single-domain and multi-domain size ranges remains an important challenge. Here, a facile synthetic method is used to produce iron oxide nanospheres (IONSs) with controllable size and crystallinity for magnetic tunability.

Efficacy and safety of Aviron Rapid® in adolescents and children with viral acute upper respiratory tract infection: a multi-center, randomized, double blind, placebo-controlled clinical trial.

Acute upper respiratory tract infections (AURTIs) are associated with a significant burden on society attributed to medical care and loss of productivity. Novel therapies that are able to shorten disease duration, while providing symptom relief and being well tolerated, are an unmet medical need.

Idealizing Tauc Plot for Accurate Bandgap Determination of Semiconductor with Ultraviolet-Visible Spectroscopy: A Case Study for Cubic Boron Arsenide.

The Tauc plot is widely used to determine the bandgap of semiconductors, but the actual plot often exhibits significant baseline absorption below the expected bandgap, leading to bandgap discrepancies from two different extrapolations. In this work, we first discuss the origin of baseline absorption and show that both extrapolation methods can produce significant errors by simulating Tauc plots with varying levels of baseline absorption. We then propose and experimentally verify a new method that idealizes the absorption spectrum by removing its baseline before constructing the Tauc plot.

Photoluminescence and Raman Spectra of One-Dimensional Lead-free Perovskite CsCuI Single-Crystal Wires.

Lead-free highly luminescent CsCuI perovskite has attracted much attention recently, but agreements on basic optical properties have remained unsettled. By correlating X-ray diffraction with the photoluminescence (PL) of CsCuI single-crystal wires, we first show that blue PL at 420 nm originates from CuI. We then exclude defect states as a source for the broadband emission centered at 570 nm from the lack of defect absorption, PL under sub-bandgap photoexcitation, observations of a linear dependence of PL intensity on excitation laser power, and a strong spectral blueshift under mild hydrostatic pressure.

Precrystallization solute assemblies and crystal symmetry.

Solution crystallization is a part of the synthesis of materials ranging from geological and biological minerals to pharmaceuticals, fine chemicals, and advanced electronic components. Attempts to predict the structure, growth rates and properties of emerging crystals have been frustrated, in part, by the poor understanding of the correlations between the oligomeric state of the solute, the growth unit, and the crystal symmetry. To explore how a solute monomer or oligomer is selected as the unit that incorporates into kinks and how crystal symmetry impacts this selection, we combine scanning probe microscopy, optical spectroscopy, and all-atom molecular simulations using as examples two organic materials, olanzapine (OZPN) and etioporphyrin I (EtpI).

Integration of Highly Luminescent Lead Halide Perovskite Nanocrystals on Transparent Lead Halide Nanowire Waveguides through Morphological Transformation and Spontaneous Growth in Water.

The integration of highly luminescent CsPbBr quantum dots on nanowire waveguides has enormous potential applications in nanophotonics, optical sensing, and quantum communications. On the other hand, CsPb Br nanowires have also attracted a lot of attention due to their unique water stability and controversial luminescent property. Here, the growth of CsPbBr nanocrystals on CsPb Br nanowires is reported first by simply immersing CsPbBr powder into pure water, CsPbBr  X (X = Cl, I) nanocrystals on CsPb Br  X nanowires are then synthesized for tunable light sources.

Special Conditions in Venous Thrombembolism - Case Series.

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a preventable cause of in-hospital death, and one of the most prevalent vascular diseases. There is a lack of knowledge with regards to contemporary presentation, management, and outcomes of patients with VTE. Many clinically important subgroups (including the elderly, those with recent bleeding, renal insufficiency, disseminated malignancy or pregnant patients) have been under-represented in randomized clinical trials.

New Way to Synthesize Robust and Porous NiFe Layered Double Hydroxide for Efficient Electrocatalytic Oxygen Evolution.

Traditional catalysts are usually synthesized by sputtering, electrochemical deposition, or hydrothermal methods, and they also need to be combined with substrates to obtain the working electrodes. Here we introduce a new route to produce an efficient catalyst for oxygen evolution reaction (OER) that is made by ball milling and sintering. By using Se as a grinding aid, the bulk electrode NiFeSe is obtained with high porosity and robust mechanical strength after sintering.

Extrinsic Green Photoluminescence from the Edges of 2D Cesium Lead Halides.

Since the first report of the green emission of 2D all-inorganic CsPb Br , its bandgap and photoluminescence (PL) origin have generated intense debate and remained controversial. After the discovery that PL centers occupy only specific morphological structures in CsPb Br , a two-step highly sensitive and noninvasive optical technique is employed to resolve the controversy. Same-spot Raman-PL as a static property-structure probe reveals that CsPbBr nanocrystals are contributing to the green emission of CsPb Br ; pressure-dependent Raman-PL with a diamond anvil cell as a dynamic probe further rules out point defects such as Br vacancies as an alternative mechanism.

Origin of Luminescent Centers and Edge States in Low-Dimensional Lead Halide Perovskites: Controversies, Challenges and Instructive Approaches.

With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects, the defect-tolerant electronic and optical properties of lead halide perovskites have made them appealing materials for high-efficiency, low-cost, solar cells and light-emitting devices. As such, recent observations of apparently deep-level and highly luminescent states in low-dimensional perovskites have attracted enormous attention as well as intensive debates. The observed green emission in 2D CsPbBr and 0D CsPbBr poses an enigma over whether it is originated from intrinsic point defects or simply from highly luminescent CsPbBr nanocrystals embedded in the otherwise transparent wide band gap semiconductors.

Phonon fingerprints of CsPbBr.

CsPbBr is a stable, water-resistant, material derived from CsPbBr perovskite and featuring two-dimensional Pb-Br framework separated by Cs layers. Both compounds can coexist at nanolength scale, which often produces conflicting optical spectroscopy results. We present a complete set of polarized Raman spectra of nonluminescent CsPbBr single crystals that reveals the symmetry and frequency of nondegenerate Raman active phonons accessible from the basal (0 0 1) plane.

HRTEM low dose: the unfold of the morphed graphene, from amorphous carbon to morphed graphenes.

We present experimental evidence under low-dose conditions transmission electron microscopy for the unfolding of the evolving changes in carbon soot during mechanical milling. The milled soot shows evolving changes as a function of the milling severity or time. Those changes are responsible for the transformation from amorphous carbon to graphenes, graphitic carbon, and highly ordered structures such as morphed graphenes, namely Rh6 and Rh6-II.

Chemical vapor deposition of thin crystals of layered semiconductor SnS2 for fast photodetection application.

Layered two-dimensional (2D) semiconductors, such as MoS(2) and SnS(2), have been receiving intensive attention due to their technological importance for the next-generation electronic/photonic applications. We report a novel approach to the controlled synthesis of thin crystal arrays of SnS(2) at predefined locations on chip by chemical vapor deposition with seed engineering and have demonstrated their application as fast photodetectors with photocurrent response time ∼ 5 μs. This opens a pathway for the large-scale production of layered 2D semiconductor devices, important for applications in integrated nanoelectronic/photonic systems.

Four-fold Raman enhancement of 2D band in twisted bilayer graphene: evidence for a doubly degenerate Dirac band and quantum interference.

We report the observation of a strong 2D band Raman in twisted bilayer graphene (tBLG) with large rotation angles under 638 nm and 532 nm visible laser excitations. The 2D band Raman intensity increased four-fold as opposed to the two-fold increase observed in single-layer graphene. The same tBLG samples also exhibited rotation-dependent G-line resonances and folded phonons under 364 nm UV laser excitation.

Validation of nomograms predicting lymph node involvement in patients with prostate cancer undergoing extended pelvic lymph node dissection.

Our aim was to validate Briganti's nomograms predicting the probability of lymph node involvement (LNI) in prostate cancer (PCa). Clinicopathological data of 256 PCa patients who underwent extended pelvic lymph node dissection (ePLND) and radical prostatectomy (RP) were obtained from two Bulgarian institutions. Predicted probabilities of LNI were assessed using Briganti's nomograms based on ePLND.

Radical Prostatectomy as a First-Line Treatment in Patients with Initial PSA >20 ng/mL.

Initial PSA >20 ng/mL is generally considered an adverse prognostic feature in prostate cancer (PCa). Our goals were to estimate the impact of radical prostatectomy (RP) on biochemical recurrence- (BCR-) free and cancer-specific survival (CSS) rates of PCa patients with PSA >20 ng/mL, and to identify patients with favorable oncological outcome. Using 20 ng/mL as a cut-point value, 205 PCa patients, who underwent RP, were stratified into two groups.

AB-stacked multilayer graphene synthesized via chemical vapor deposition: a characterization by hot carrier transport.

We report the synthesis of AB-stacked multilayer graphene via ambient pressure chemical vapor deposition on Cu foils and demonstrate a method to construct suspended multilayer graphene devices. In four-terminal geometry, such devices were characterized by hot carrier transport at temperatures down to 240 mK and in magnetic fields up to 14 T. The differential conductance (dI/dV) shows a characteristic dip at longitudinal voltage bias V = 0 at low temperatures, indicating the presence of hot electron effect due to a weak electron-phonon coupling.

Validation of pre- and postoperative nomograms used to predict the pathological stage and prostate cancer recurrence after radical prostatectomy: a multi-institutional study.

Purpose: To validate the preoperative and postoperative predictive tables of Johns Hopkins hospital, Baltimore, Maryland (JHH) and the prostate nomograms of Memorial Sloan Kettering Cancer Center, New York (MSKCC), most commonly used to predict the pathological tumor stage and postoperative freedom from recurrence, in a mixed cohort of Bulgarian prostate cancer patients.

Methods: Clinical and laboratory data of 282 prostate cancer patients, who underwent radical prostatectomy, were supplied from three different institutions in Bulgaria. Preoperative prostate specific antigen (PSA) values, clinical stage, biopsy Gleason score and the pathological features of the radical prostatectomy specimens were collected from each center and evaluated.

Parallel and orthogonal E-field alignment of single-walled carbon nanotubes by ac dielectrophoresis.

We designed planar electrodes, for dielectrophoretic manipulation of single-walled carbon nanotubes (SWNTs), built as metal-oxide-semiconductor nanogap capacitors with common substrate and oxide thicknesses of 17 and 150 nm. Such design generates high electric fields (10(9) V m(-1)) and also the fringing field is curved due to the conducting substrate, unlike fields generated by conventionally used planar electrodes. Scanning electron microscopy images showed SWNTs aligned parallel and perpendicular to the electrodes.

Thermal mismatch strains in sidewall functionalized carbon nanotube/polystyrene nanocomposites.

We present an unusual temperature dependence of thermal strains in 4-(10-hydroxy)decyl benzoate (HDB) modified SWNTPS (SWNT-single wall carbon nanotube, PS-polystyrene) nanocomposites. The strain transfer from the matrix to nanotubes in these nanocomposites, inferred from the frequency change of the Raman active tangential modes of the nanotubes, is enhanced strongly below 300 K, whereas it is vanishingly small at higher temperatures. The increased strain transfer is suggestive of reinforcement of the HDB-SWNTPS nanocomposites at low temperatures.

A parametric study of single-wall carbon nanotube growth by laser ablation.

Results of a parametric study of carbon nanotube production by the double-pulse laser oven process are presented. The effect of various operating parameters on the production of single-wall carbon nanotubes (SWCNTs) is estimated by characterizing the nanotube material using analytical techniques, including scanning electron microscopy, transmission electron microscopy, thermo gravimetric analysis and Raman spectroscopy. The study included changing the sequence of the laser pulses, laser energy, pulse separation, type of buffer gas used, operating pressure, flow rate, inner tube diameter, as well as its material, and oven temperature.