A pre-time-zero spatiotemporal microscopy technique for the ultrasensitive determination of the thermal diffusivity of thin films.

Diffusion is one of the most ubiquitous transport phenomena in nature. Experimentally, it can be tracked by following point spreading in space and time. Here, we introduce a spatiotemporal pump-probe microscopy technique that exploits the residual spatial temperature profile obtained through the transient reflectivity when probe pulses arrive before pump pulses. This corresponds to an effective pump-probe time delay of 13 ns, determined by the repetition rate of our laser system (76 MHz). This pre-time-zero technique enables probing the diffusion of long-lived excitations created by previous pump pulses with nanometer accuracy and is particularly powerful for following in-plane heat diffusion in thin films. The particular advantage of this technique is that it enables quantifying thermal transport without requiring any material input parameters or strong heating. We demonstrate the direct determination of the thermal diffusivities of films with a thickness of around 15 nm, consisting of the layered materials MoSe2 (0.18 cm2/s), WSe2 (0.20 cm2/s), MoS2 (0.35 cm2/s), and WS2 (0.59 cm2/s). This technique paves the way for observing nanoscale thermal transport phenomena and tracking diffusion of a broad range of species.

Unraveling Heat Transport and Dissipation in Suspended MoSe2 from Bulk to Monolayer.

Understanding heat flow in layered transition metal dichalcogenide (TMD) crystals is crucial for applications exploiting these materials. Despite significant efforts, several basic thermal transport properties of TMDs are currently not well understood, in particular how transport is affected by material thickness and the material's environment. This combined experimental-theoretical study establishes a unifying physical picture of the intrinsic lattice thermal conductivity of the representative TMD MoSe2 . Thermal conductivity measurements using Raman thermometry on a large set of clean, crystalline, suspended crystals with systematically varied thickness are combined with ab initio simulations with phonons at finite temperature. The results show that phonon dispersions and lifetimes change strongly with thickness, yet the thinnest TMD films exhibit an in-plane thermal conductivity that is only marginally smaller than that of bulk crystals. This is the result of compensating phonon contributions, in particular heat-carrying modes around ≈0.1 THz in (sub)nanometer thin films, with a surprisingly long mean free path of several micrometers. This behavior arises directly from the layered nature of the material. Furthermore, out-of-plane heat dissipation to air molecules is remarkably efficient, in particular for the thinnest crystals, increasing the apparent thermal conductivity of monolayer MoSe2 by an order of magnitude. These results are crucial for the design of (flexible) TMD-based (opto-)electronic applications.

Finite Element Simulation Tests of the Structural Strength of the Molding Module for Burger Production from Vegetable Outgrades.

The aim of the study was to assess the stresses of the structural materials of the forming module in the process of burger production from vegetable outgrades. The simulation research object was a virtual CAD 3D model of a device used for forming multi-vegetable products. Strength tests were performed on the computational model by applying the finite element method. The following were analyzed in the model: the forces exerted by the mixture of vegetables on the side walls of the tank and the dosing unit; the force from the servomotor resulting from the horizontal thickening of the vegetable mixture; the force from the servomotor resulting from the vertical mixing of the vegetable mixture; the force from the die assembly actuator; the force caused by punching the actuator from the die assembly. For evaluating the structure in the scope of the study, it was assumed that safely reduced stresses should be taken into account, with a safety factor equal to 1.1 of the yield strength of the parent material from which the structure was made (steel 1.4301 (304) with a yield stress Re0.2 of 230 MPa). For welds, safely reduced stresses should be taken into account, with a safety factor equal to 1.4 of the yield strength (Re0.2 of 230 MPa). Strength analyses confirmed that the permissible stress levels were not exceeded in the molding module.

Oxidative Stress and Hemostatic Parameters in Patients With Nephrolithiasis Before and After Ureteroscopic Lithotripsy.

PURPOSE: In patients with nephrolithiasis, oxidative stress, especially lipid peroxidation is observed. Moreover, various invasive methods [including extracorporeal shock wave lithotripsy (ESWL)] for treatment of nephrolithiasis may induce not only the oxidative stress, but they may modulate hemostasis. The study was aimed to evaluate the oxidative damages of lipids and proteins in patients with nephrolithiasis (before and after ureteroscopic lithotripsy - URSL). The aim of the present study was also determine selected parameters of hemostasis in these patients. METHODS: 56 patients with nephrolithiasis and 49 healthy participants were included: 30 men and 26 women (for patient group); 27 men and 22 women (for healthy group). We measured the level of selected typical two biomarkers of oxidative modification of lipids [such as the production of thiobarbituric acid reactive substances (TBARS) and isoprostane concentration (8-isoPGF2α)] and two biomarkers of oxidative damages of proteins (carbonylation and the level of thiol groups) in patients with nephrolithiasis (before and after URSL). The following parameters of hemostasis were measured: blood platelet count, the level of fibrinogen and D-dimer, and coagulation times (the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) of plasma). RESULTS: Different levels of plasma lipid peroxidation were observed in patients with nephrolithiasis before URSL and after URSL. However, no such difference in the level of oxidative damage to plasma proteins was observed. In addition, the tested hemostasis parameters were not influenced by the presence of nephrolithiasis, nor by treatment with URSL. CONCLUSION: We suggest URSL does not induce the oxidative modifications of plasma proteins and does not change hemostatic parameters in patients with nephrolithiasis.

The lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy.

AIM: To evaluate the level of lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy (ESWL). MATERIALS & METHODS: Isoprostane concentration (8-isoPGF2α) was measured in urine, and thiobarbituric acid reactive substance production in serum and erythrocytes. In addition, the concentrations of selected compounds (uric acid, glucose and creatinine) were measured in serum. RESULTS: The patients (before and after ESWL) demonstrated significantly higher levels of two different biomarkers of lipid peroxidation compared with the control group. A correlation was identified between increased amounts of uric acid and biomarkers of lipid peroxidation in patients with nephrolithiasis, both before and after ESWL. CONCLUSION: Uric acid may be associated with lipid peroxidation in patients with nephrolithiasis.

Transverse Kerker Scattering for Angstrom Localization of Nanoparticles.

Angstrom precision localization of a single nanoantenna is a crucial step towards advanced nanometrology, medicine, and biophysics. Here, we show that single nanoantenna displacements down to few angstroms can be resolved with sub-angstrom precision using an all-optical method. We utilize the tranverse Kerker scattering scheme where a carefully structured light beam excites a combination of multipolar modes inside a dielectric nanoantenna, which then, upon interference, scatters directionally into the far field. We spectrally tune our scheme such that it is most sensitive to the change in directional scattering per nanoantenna displacement. Finally, we experimentally show that antenna displacement down to 3 Å is resolvable with a localization precision of 0.6 Å.

Chiroptical response of a single plasmonic nanohelix.

We investigate the chiroptical response of a single plasmonic nanohelix interacting with a weakly focused circularly polarized Gaussian beam. The optical scattering at the fundamental resonance is characterized experimentally and numerically. The angularly resolved scattering of the excited nanohelix is verified experimentally and it validates the numerical results. We employ a multipole decomposition analysis to study the fundamental and first higher-order resonance of the nanohelix, explaining their chiral properties in terms of the formation of chiral dipoles.

Evaluation of hemostasis parameters and the role of the oxidative damage to plasma proteins in the modulation of hemostasis in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy.

PURPOSE: Extracorporeal shock wave lithotripsy (ESWL) is a commonly-used method in urology, which may modulate hemostasis and may induce lipid peroxidation in patients with nephrolithiasis. However, previous studies only examine changes occurring in patients 30-240 min after ESWL. The main aim of the present study was to determine whether oxidative stress may modulate the hemostatic activity of plasma in patients with nephrolithiasis before ESWL and the day after treatment ESWL. This will be performed by measuring selected parameters of hemostasis in these patients, both before ESWL and the following day, and assessing the level of oxidative damage to plasma proteins in these patients by measuring two biomarkers. METHODS: Twelve patients with nephrolithiasis and 10 healthy participants were included. The following parameters of hemostasis were measured: the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) of plasma, the level of fibrinogen, the level of D-dimer and blood platelet count. In addition, two selected biomarkers of oxidative stress were measured: protein carbonylation level and the number of protein thiol groups. RESULTS: No difference was observed between patients with nephrolithiasis before and after ESWL and healthy controls with regard to PT, TT or APTT. Fibrinogen concentration and blood platelet count were lower in the nephrolithiasis patients in the period after ESWL than before ESWL. The nephrolithiasis patients demonstrated elevated D-dimer concentration after ESWL. However, although oxidative damage was observed in the plasma proteins in the nephrolithiasis patients, this was not influenced by ESWL. CONCLUSION: Oxidative stress may induce changes of hemostasis in patients with nephrolithiasis, both before and after ESWL. In addition, changes of hemostasis parameters such as fibrinogen, blood platelet count and D-dimer level can be observed in these patients, especially after ESWL, and this may suggest that ESWL modulates hemostasis. By having a better understanding of the influence of ESWL on hemostasis, this could lead to modifying patient care for those patients at increased risk of bleeding.

Chiral optical response of planar and symmetric nanotrimers enabled by heteromaterial selection.

Chirality is an intriguing property of certain molecules, materials or artificial nanostructures, which allows them to interact with the spin angular momentum of the impinging light field. Due to their chiral geometry, they can distinguish between left- and right-hand circular polarization states or convert them into each other. Here we introduce an approach towards optical chirality, which is observed in individual two-dimensional and geometrically mirror-symmetric nanostructures. In this scheme, the chiral optical response is induced by the chosen heterogeneous material composition of a particle assembly and the corresponding resonance behaviour of the constituents it is built from, which breaks the symmetry of the system. As a proof of principle, we investigate such a structure composed of individual silicon and gold nanoparticles both experimentally, as well as numerically. Our proposed concept constitutes an approach for designing two-dimensional chiral media tailored at the nanoscale, allowing for high tunability of their optical response.

Polarization-controlled directional scattering for nanoscopic position sensing.

Controlling the propagation and coupling of light to sub-wavelength antennas is a crucial prerequisite for many nanoscale optical devices. Recently, the main focus of attention has been directed towards high-refractive-index materials such as silicon as an integral part of the antenna design. This development is motivated by the rich spectral properties of individual high-refractive-index nanoparticles. Here we take advantage of the interference of their magnetic and electric resonances to achieve strong lateral directionality. For controlled excitation of a spherical silicon nanoantenna, we use tightly focused radially polarized light. The resultant directional emission depends on the antenna's position relative to the focus. This approach finds application as a novel position sensing technique, which might be implemented in modern nanometrology and super-resolution microscopy set-ups. We demonstrate in a proof-of-concept experiment that a lateral resolution in the Ångström regime can be achieved.

AmyLoad: website dedicated to amyloidogenic protein fragments.

UNLABELLED: Analyses of amyloidogenic sequence fragments are essential in studies of neurodegenerative diseases. However, there is no one internet dataset that collects all the sequences that have been investigated for their amyloidogenicity. Therefore, we have created the AmyLoad website which collects the amyloidogenic sequences from all major sources. The website allows for filtration of the fragments and provides detailed information about each of them. Registered users can both personalize their work with the website and submit their own sequences into the database. To maintain database reliability, submitted sequences are reviewed before making them available to the public. Finally, we re-implemented several amyloidogenic sequence predictors, thus the AmyLoad website can be used as a sequence analysis tool. We encourage researchers working on amyloid proteins to contribute to our service. AVAILABILITY AND IMPLEMENTATION: The AmyLoad website is freely available at http://comprec-lin.iiar.pwr.edu.pl/amyload/. CONTACT: malgorzata.kotulska@pwr.edu.pl.

Characteristics of protein residue-residue contacts and their application in contact prediction.

Contact sites between amino acids characterize important structural features of a protein. We investigated characteristics of contact sites in a representative set of proteins and their relations between protein class or topology. For this purpose, we used a non-redundant set of 5872 protein domains, identically categorized by CATH and SCOP databases. The proteins represented alpha, beta, and alpha+beta classes. Contact maps of protein structures were obtained for a selected set of physical distances in the main backbone and separations in protein sequences. For each set a dependency between contact degree and distance parameters was quantified. We indicated residues forming contact sites most frequently and unique amino acid pairs which created contact sites most often within each structural class. Contact characteristics of specific topologies were compared to the characteristics of their protein classes showing protein groups with a distinguished contact characteristic. We showed that our results could be used to improve the performance of recent top contact predictor - direct coupling analysis. Our work provides values of contact site propensities that can be involved in bioinformatic databases.

Prediction of bladder cancer based on urinary content of MGEA5 and OGT mRNA level.

BACKGROUND: The mRNA expression of genes coding enzymes involved in O-GlcNAcylation were analyzed in urine obtained from 176 bladder cancer (BC) patients and 143 healthy persons. METHODS: MGEA5 and OGT expression was measured by a real-time PCR assay. RESULTS: OGT expression was not detected in urine of healthy persons but it was found in 51.7% of BC samples. Positive expression of MGEA5 was found in urine of both healthy persons (47.1%) and BC patients (52.3%). Poorly differentiated BC (grade III) showed significantly lower MGEA5 expression than grade I tumors. Contrary, OGT transcript level was significantly higher in grade II and III in comparison to grade I BC. Moreover, there was significant difference in OGT expression between early bladder cancers and invasive or advanced bladder cancers. CONCLUSIONS: These results suggest that analysis of urinary content of MGEA5 and OGT may be useful for bladder cancer diagnostics.