Changes In Internal Structure Research Articles

Incidence of Temporomandibular Disorders in Patients in a University Hospital Setting

Disorders (TMD) is one of the most common pain disorders. TMD is defined as a heterogeneous group of psychological disorders, commonly characterized by pain, difficulty in chewing or both. It is one of the commonest problems affecting common people. This is also one of the most common disorder due to its varied vague signs and symptoms, which makes the common dentist to diagnose wrongly, which ultimately led to wrong treatment. The etiology of disorders is complex, the foremost normally cited factors are emotional tension, interference, genetics, teeth loss, postural deviation, dysfunction, internal and external changes in TMJ structure, either alone or both The disorders of TMJ, muscles and associated structure sometimes occur throughout childhood and adolescence, however with less intensity than in the adult population. Throughout adolescence, TMJ presents with mild or moderate signs and symptoms. So a study of this disorder is needed to create awareness among general dentist. This study aims to evaluate the incidence of disorders in patients reported to Saveetha Dental College. A total of 77 patients who underwent treatment for TMD were included in this study. The study was conducted at Saveetha Dental College. Data were collected from patients dental records. All the data were recorded and analyzed statistically using SPSS software. From the analysis, females were more prevalent than the male population. The most common treatment undergone by patients diagnosed with disorders is . Females are shown more prevalent than Male. A detailed examination should be done for better diagnosis and prognosis.

Fetal thymus in the middle and late trimesters: Morphometry and development using post-mortem 3.0T MRI.

The present study aimed to investigate the anatomical microstructure, features and signals of the fetal thymus by 3.0T FS-T2 weighted turbo spin echo sequences, which could provide imaging evidence for the evaluation of early-stage development of fetal thymus. In addition, the T2-weighted three-dimensional (3D) sequences and the 3D processing may contribute to the establishment of reference ranges for the fetal thymus. A total of 64 specimens obtained from the fetuses of 16-39 weeks of gestational age (GA) were scanned by 3.0T MRI. Morphological changes and quantitative measurements of the fetal thymus were assessed, including the anteroposterior diameter, width, height, surface area and volume. The shape of fetal thymus varied and the majority were X-shaped, with a narrow top and wide bottom. Morphology measurements demonstrated gradual growth with increasing GA. There were high linear correlations between width, height, surface area and volume and GA. No significant differences were observed between the sexes. Post-mortem 3.0T MRI clearly demonstrated changes in external contours and internal structure with GA. The images and data obtained reflect normal development of the fetal thymus and enrich the imaging data of fetal morphometry.

Fracture Parameters of Alkali-Activated Aluminosilicate Composites with Ceramic Precursor

This paper deals with selected alkali-activated aluminosilicate composites with a ceramic precursor in terms of their characterization using mechanical fracture parameters. Three composites were studied. They were manufactured using brick powder as a precursor and an alkaline activator with a dimensionless silicate modulus of Ms = 1.0, 1.2 and 1.4. The test specimens were nominally 40 × 40 × 160 mm in size and had a central edge notch with a depth of 1/3 of the specimen’s height. At least 6 specimens made of each composite were tested at the age of 28 days. The specimens were subjected to three-point bending tests, during which diagrams showing force vs. deflection at midspan (F–d diagrams) and force vs. crack mouth opening displacement (F–CMOD diagrams) were recorded. After the processing of these diagrams, values were determined for the static modulus of elasticity, effective fracture toughness (including its initiation component from the analysis of the first part of the F–CMOD diagrams), effective toughness and specific fracture energy using the effective crack model, Work-of-Fracture method, and Double-K fracture model. After the fracture experiments had been performed, compressive strength values were determined for informational purposes from one part of each specimen that remained after testing. In order to obtain visual information about the internal structure of the composites before and after the mechanical testing, the selected specimen was examined via X-ray microtomography. Tomographic measurements and image processing were performed for the qualitative and quantitative evaluation of internal structural changes with an emphasis on the calculation of porosimetry parameters as well as the visualization of the fracture process zone. The fractal dimension of the fracture surface and fracture process zone was determined. The porosity and microstructure images of selected samples taken from specimens were assessed.

Investigation of the Maturity Changes of Cherry Tomato Using Magnetic Resonance Imaging

The maturity of tomato fruit is normally characterized by external color, and it is often difficult to know when fruit have achieved commercial maturity or become over-mature. The internal structure of tomato fruit changes during development and this study investigates the utility of nondestructive measurement of tomato fruit structure as a function of maturity using magnetic resonance imaging (MRI). The objective of this work is to use analysis of internal tomato fruit structural measurements to characterize maturity. Intact cherry tomato fruit were harvested at six different maturity stages. At each stage of maturity, the internal structure of the fruit was measured using a series of two-dimensional (2D) magnetic resonance (MR) images. Qualitative and quantitative image analyses were performed to correlate internal fruit structure with maturity. Internal structural changes observed in the pericarp region of the tomato fruit are highly correlated with fruit maturity. MR image information combined with classical analysis techniques provides a more complete understanding of structure and physicochemical changes in tomato fruit during maturation. This study demonstrates that MRI is a useful analytical tool to characterize internal changes in agricultural produce as the produce matures. This technique can be applied to almost any agricultural produce to monitor internal physical changes due to external impact, maturity stage, variation in climate, storage time, and condition, or other factors impacting quality.

The effect of structural changes on the compressive strength of LVL

Laminated veneer lumber (LVL) is an important engineered wood product. Internal structural changes have a substantial influence on the mechanical performance of LVL. To investigate the relationship between the internal structural changes and the compressive strength, poplar LVL layering is manufactured by taking into account the veneer lathe checks, namely lathe checks both facing inwards (TLLT), lathe checks both oriented outwards (LTTL) and lathe checks in one layer facing outwards (LTLT). Macroscopic compressive strength of the samples is measured using a universal testing machine. Microscopic internal structural changes are periodically recorded with X-ray CT when the samples are compressed using a load cell. The results show that the compressive strength of LTLT is significantly higher than that of LTTL and TLLT types of LVL. During the compression test, density increase in the samples is non-homogenous. There is a minor increase in density of the glue line, while this is larger in regions with a low density. Density increase is mainly induced by collapse of large vessels. However, the presence of phenol formaldehyde resin can enhance the resistance of vessels against collapse. Structural changes, i.e., vessels collapse and collapse propagation, are likely to occur in locally heterogeneous regions. Propagation of collapsed vessels is more frequently observed in regions where large vessels are contiguous.

Structural and thermal properties of the amaranth starch granule obtained by high-impact wet milling

Abstract In this study, amaranth starch was extracted by high-impact wet milling and its structural and thermal properties and the effect of NaOH and SDS concentrations on extraction yield were evaluated. The best condition was 55 g of starch/100 g of amaranth, with a decrease from 2.5 to 3.5 kJ/g using different milling energies. The decrease in the protein content of the starch granule is due to an effect of the interaction between surfactant and alkali, preventing the destruction of granules. All starches presented a degree of crystallinity between 21 and 28%. The internal structural changes of the starch granule were monitored by attenuated total reflectance - Fourier-transform infrared (ATR-FTIR) in the region of 990 to 1060 cm−1. Spectra showed significant differences between the peaks at 1032 and 1005 cm−1, corresponding to the crystalline/amorphous region of the starch structure. Changes in viscosity profiles were observed between 0.302 and 1.163 Pa s.

Aging Effect on Structure, Hardness, Roughness Behavior and Bacterial Adhesion on Silver- Palladium Dental Alloy

Aging in normal saliva for different interval times make a change in internal structure (Formed phases and started base line) of Sliver- Palladium (Ag-Pd) dental alloy. Also aging in saliva for one, two and three weeks decreased Vickers hardness value, calculated maximum shear stress (τm) and roughness parameters for Sliver- Palladium alloy. Microbiological studies show the Candida spp. stuck on Sliver- Palladium alloy surface and their growth dependent on aging times.

THE SEMANTIC ORGANIZATION OF DIPLOMATIC TERMS

This article provides a brief description of semantic processes such as expansion, contraction or specialization of meanings. Nowadays there is no common understanding and continuity of main semantic categories known in the field of linguistics. It is known such categories as sign (symbol), concept, meaning, types of linguistic meanings, absolute and relative semantic content and others are included in that.The main thing in terminology process is word meaning, and it is determined by main featuresof term concept. As a result of semantic development of ancient words and changes in internal semantic structure the new nominative semewill be defined. Language is directly related to processes of differentiation and integration. These processes are characterized by semantic interpretation of language signs in understanding and communication. The diplomatic terms are formed according to general rules of word formation striving for individuality and stylistic neutrality. The meaning of complex term does not derive from individual meaning of its components. The component function is equal to function of phonemes in single-root terms particularly in distinctive form. The article was prepared on the basis of written sources and literature.

Correlative acoustic time-of-flight spectroscopy and X-ray imaging to investigate gas-induced delamination in lithium-ion pouch cells during thermal runaway

It remains difficult to detect internal mechanical deformation and gas-induced degradation in lithium-ion batteries, especially outside specialized diagnostics laboratories. In this work, we demonstrate that electrochemical acoustic time-of-flight (EA-ToF) spectroscopy can be used as an insightful and field-deployable diagnostic/prognostic technique to sense the onset of failure. A 210 mAh commercial lithium-ion cell undergoing thermal abuse testing is probed with in situ and operando EA-ToF spectroscopy, together with simultaneous fractional thermal runaway calorimetry (FTRC) and synchrotron X-ray imaging. The combination of X-ray imaging and EA-ToF analysis provides new understanding into the through-plane mechanical deformation in lithium-ion batteries through direct visualisation and the acoustic ToF response. Internal structural changes, such as gas-induced delamination, are identified using EA-ToF spectroscopy due to variations in the attenuation and signal peak shifts. This is corroborated using X-ray imaging, demonstrating EA-ToF spectroscopy as a promising technique for detecting onset of battery failure.

SARS-CoV-2 Risk Management in Clinical Psychiatry: A Few Considerations on How to Deal With an Unrivaled Threat.

The pandemic spread of the corona virus SARS-CoV-2 has even-handedly shattered national and international health systems and economies almost in an instant. As numbers of infections and COVID-19–related deaths rise from day to day, fears and uncertainties on how to deal with this unknown threat are extremely present both for individuals and societies as a whole. In this manuscript, we aim to exemplarily describe the bullet points concerning (a) the internal risk management, (b) the organizational and structural changes, and (c) the communicational strategies applied in a Psychiatric University Hospital in the Southern part of Germany. The authors are well aware about the fact that almost none of these considerations may be considered as evidence-based at the moment. However, the authors trust that these reflections and experiences may be useful as an orientation for similar risk constellations in other afflicted countries due to the temporal delay of the pandemic course.

Influence of Screw Centrifugal Inducer on Internal Flow Structure of Vortex Pump

Abstract Installing an inducer upstream of the main impeller is an effective approach for improving the performances of a centrifugal pump. In order to study the influence of inducer on the internal flow characteristics and evolution of vortex pump, the numerical simulation and experimental test of the 150WX-200-20 vortex pump have been done by the principle of computational fluid dynamics, to acquire performance and internal flow structure change of the vortex pump with inducer and without inducer. Based on these, the energy conversion of vortex pump is combined with the changes of the through-flow and circulating-flow of the internal flow structure. Through analyzing the influence of inducer on it, the energy conversion characteristic of vortex pump is revealed. The results show that adding the inducer can guarantee the power capacity of the vortex pump and improve the anticavitation performance, so as to improve the pump head and flows. Equipped with suitable for transporting solid liquid two phase flow of the screw centrifugal inducer, it can effectively weaken the existence of circulating-flow and significantly improve the flow situation in the impeller field. Adding inducer can weaken axial force of vortex pump and enhance stability of pump. And under the condition of no clogging, the conclusions are of great significance for improving the power capacity and fluid energy conversion of the vortex pump. In addition, it is a good method to weaken the axial force of the pump and enhance the stability of the pump system by adding the inducer.

Changes in mechanical properties, surface morphology, structure, and composition of Invisalign material in the oral environment

The mechanical properties of Invisalign material have rarely been explored because of the inaccessibility of the patent-protected raw material. The purpose of this study was to systematically evaluate the Invisalign thermoformed aligner material before and after clinical application, including mechanical properties, surface morphology, internal structure, and chemical composition changes. Twenty sets of "as-received" (0-week) and retrieved (2-week; worn for 2weeks, 20±2hours per day) Invisalign aligners were randomly collected from 4 different patients. Tensile tests, stress relaxation, and creep tests were carried out with a dynamic mechanical analyzer to characterize the changes in the mechanical properties of this material, Fourier transform infrared spectroscopy was used to capture the molecular changes on the surface of these aligners, scanning electron microscopy and transmission electron microscopy were used to observe the changes in surface morphology and internal structure, and scanning transmission electron microscopy-energy dispersive x-ray analysis was used to detect any changes in the chemical composition of this material before and after clinical application. The elastic modulus of 0-week and 2-week samples were 842±63MPa and 806±19MPa, respectively, with no significant difference. In addition, the relative stress after stress relaxation of 2hours was 19.89±2.25% and 15.91±6.04% for 0-week and 2-week groups, respectively, with no significant difference. Scanning electron microscopy observations showed voids and signs of delamination on the surface of the 2-week samples, and scanning transmission electron microscopy-energy dispersive x-ray analysis indicated the possible release of trace elements during clinical use, such as aluminum. Results of Fourier transform infrared spectroscopy analysis, and transmission electron microscopy observations were quite stable, indicating that the molecular structure on the surface and the internal structure of this material were relatively stable under the oral environment. The surface morphology showed some defects after the clinical use of 2weeks; however, there was no significant difference in mechanical properties. Trace elements may release out during clinical use and may pose a specific danger to allergic patients.

Effect of Elevated PEM Fuel Cell Operating Temperature (120°C and 140°C) and Membrane Thickness on Proton Conductivity for Combat Vehicle Use

Energy required from ground vehicles in the United States (U.S.) Army is increasing due to the need for increased capabilities and mission duties required for an ever changing combat environment. These additional capabilities include silent watch (long term mounted surveillance), advanced radios/jamming devices/sensors, directed energy weapons, exportable power supporting stationary applications, and vehicle-to-grid connectivity. Increasing the combat vehicle energy output, while still fitting into the limited space inside each vehicle, requires an energy source that is compact, power dense and energy efficient. PEM Fuel Cells (PEMFCs) meet those requirements for primary and/or auxiliary power generators placed in vehicles for short or long-term mission roles. While PEMFCs provide a potential solution for the U.S. Army’s vehicle energy requirements, there still exists a number of critical areas which need to be resolved before integration into combat vehicles is realized. These issues include: 1. Stack degradation from thermal-cycling and stack sealing loss, 2. Electrocatalyst degradation and 3. Cell membrane thermal degradation. In addition, specifically for the U.S. Army, vehicles significantly restrict heat rejection (due to low air flow from ballistic grills) to the PEMFC system in addition to vehicles operating in locations with elevated ambient temperatures, which can increase the stack operating temperature up to 140°C. Since cooling requirements for PEMFCs are typically engineered for operating temperatures closer to 65°C, these elevated stack temperatures could result in thermal degradation of the cell membrane.Since the cell membrane is a vital component for stack operation, membrane material formulations have been developed with increased chemical and thermal degradation resistances. One such membrane material is Nafion, which starts to thermally decompose around 300°C. Even when the operating temperature is lower than the decomposition temperature, a small percentage of the Nafion membrane potentially could degrade as temperatures reach between 120°C and 140°C which could change the performance of the PEMFC through changes in proton transport resistance. Another possible method of reducing membrane thermal degradation would be engineering cells with thicker membranes, where the added mass could withstand the increased temperature for longer periods of time. These potential changes to the Nafion membrane at elevated temperatures (120°C and 140°C) using different membrane thicknesses, when compared to stack operation at 65°C, were investigated in this study.Pristine Nafion membranes (Nafion 115, 117 and 1110) were used in the following analysis and were heated at 65°C, 120°C and 140°C, for 2, 8 and 24hrs at each temperature. The membranes all had similar polymer formulations with thicknesses of 127, 183 and 254μm, respectively. All three polymers were heated for 2, 8 and 24hrs in 16MΩ water at 65°C, 120°C and 140°C and were characterized to determine the impact of elevated temperatures and material thickness on proton conductivity and structural changes to each material. Figure 1a shows the calculated proton conductivities, from raw EIS data, at 65°C, 120°C and 140°C for all three membranes heated for 2, 8 and 24hrs. Results from heating at 120°C showed all three membranes had increased conductivities between 14% and 30% after 24hrs, compared to the 65°C results, and were statistically similar to each other. While large variations in the conductivities occurred, the majority of the 120°C measurement standard deviations did not overlap with the 65°C results. Results from heating at 140°C showed the three membranes had increased their conductivities by different amounts, depending on membrane thickness. Nafion 115 had been statistically increased by 30% compared to 115 heated at 65°C for 24hrs, while the 117 and 1110 had returned to a statistically similar value as the 65°C 24hr results.Figures 1b,c,d show internal structural changes to the vibrational modes for each membrane material using FTIR characterization, which support the changes in proton conductivities reported in Figure 1a. All three membranes, after 24hrs at 65°C, showed near identical scans. All three membrane materials, after heating at 120°C and 140°C, showed changes to the vibrational modes observed for the 65°C results and produced additional vibrations modes not originally present. These conductivity and FTIR results show heating Nafion, even at elevated temperatures, was sufficient to dynamically change its operating performance over time. Altering the membrane thickness did not mitigate performance changes over time however, with even the thicker membranes being less stable with time. Based on these results, an alternative approach or material should be used if operating the PEM fuel cell at or above 100°C. Figure 1

CHARACTERISATION OF THERMAL-LOADED CEMENT-BASED COMPOSITES BY COMBINED TIME-LAPSE TOMOGRAPHY AND THE FOUR-POINT BENDING TEST

Quasi-brittle materials like cement-based composites, rocks, and bricks are subjected to a number of environmental loadings throughout the life cycle of buildings. For instance, fluctuation of the ambient temperature (climatic cycles or fire) causing a variety of physical and chemical transitions resulting in structural changes and affecting the mechanical properties. In this work a special mixture containing glass spheres and Portland cement was evaluated by a combination of four-point bending and time-lapse X-ray computed tomography to verify the feasibility of this novel combined method.The effect of temperature on the behavior of investigated material in terms of sphericity of the present glass spheres and the way of crack propagation under load together with its influence to mechanical fracture parameters was studied. The described methodology was used especially to be able to monitor these changes throughout the loading process, as the characterization of the fracture surface using conventional optical methods is possible only after the complete fracture of the specimen and total damage of used material results in loosening of the matrix and filler to such an extent, that the results of these methods may be very distorted. It has been proven that the developed method can be used to characterize the internal structural changes in building materials and thus contribute to the understanding of the fracture processes during mechanical loading. Up to 600°C the glass spheres stay spherical and the crack is propagating through the interfacial transition zone, while at higher temperatures the glass loses its shape and the newly formed pores cause also cracks within the inclusions. The relationship between compressive strength and the maximum loading temperature was confirmed.

In situ observation of δ phase suppression by lattice strain in all-inorganic perovskite solar cells

Abstract The phase control and ordered crystal growth play a crucial role in the efficiency and stability of all-inorganic perovskite solar cells (PSCs). However, the innate dynamics of crystal growth driving the stable phase and high performance are unknown. Here, we for the first time unraveled that the degree of lattice strain is responsible for the suppression of the δ phase growth by in situ Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS) technique. We shadow the internal crystal structural changes in real time and successfully decoupled crystal growth dynamics under different substrate temperatures. The symmetrical crystal lattice and vertical substrate growth were finally achieved. This finding provides insights on the inorganic perovskite crystal growth and has significant benefit for high performing all-inorganic PSCs.

Quantitative study of meso-damage process on concrete by CT technology and improved differential box counting method

Abstract To study the change of concrete internal structure before and after stress, the meso-mechanical experiment of concrete was conducted using CT technology and a portable dynamic loading device. And CT images of the concrete internal structure change under uniaxial compression condition were obtained. For establishing the relationship between the micro-structure and macro-mechanics of concrete, an improved differential box counting (IDBC) method was proposed to calculate the fractal dimension of the CT images, which could describe the entire damage process of concrete. By comparing the fractal dimension calculated by the two methods, it can be seen that the fitting error of the fractal dimension obtained by the IDBC method is reduced by nearly 50% compared with that obtained by the DBC method. Afterward, the damage variable expression was established on the basis of the fractal dimension. The research results indicated that the damage variable established in this research can describe the damage process of concrete well. That is, the damage variable equaled to 0 during the first scan, and before reaching the peak stress, the damage variable showed a trend of increasing first and then decreasing. After the concrete specimen has completely fractured, the damage variable reached a maximum of one. Furthermore, through extracting the area of CT image cracks region at different stress stages, the relationship between the area of cracks region and the stress was studied. It appeared that the CT technology and fractal theory are promising methods to analyze the evolution of the concrete damage process under static uniaxial compression.

Study on stress-strain-resistivity and microscopic mechanism of red mud waste modified by desulphurization gypsum-fly ash under drying-wetting cycles

In order to investigate characteristics of red mud waste modified by desulfurization gypsum-fly ash, an unconfined compressive strength test and a synchronous resistivity test of solidified soil under different contents, curing time and dry-wet cycles were carried out. Moreover, the internal structure change, reaction mechanism, and the hydration characteristics of desulfurization gypsum-fly ash soil were analyzed by XRD and SEM tests. The results show that under the 77% red mud content, the unconfined compressive strength increases with the increase of age. The stress-strain-resistivity curves of the same amount in red mud at different ages are basically consistent with each other. Under different contents, in the first three-stage, stress increases with strain, and the resistivity decreases with increasing strain. In the local deformation stage, the stress decreases rapidly with the increase of strain, and the resistivity keeps decreasing until the specimen is completely destroyed. When the water content is lower, the resistivity is greater. Also, with the increase of number drying-wetting cycles, the strength of the sample mixture is gradually weakened from 1.34 MPa of one drying-wetting cycle to 0.8 MPa of nine drying-wetting cycle. The corresponding resistivity with one drying-wetting cycle continues decreasing slowly about 0.5%, and this trend of decreasing is gradually weakened. When the drying-wetting cycle is more than 5, the resistivity will increase with the increasing of the drying-wetting cycles. The microstructures of red mud waste modified by desulfurization gypsum-fly ash soil were examined by SEM analysis after a different number of dry-wet cycles. The SEM analysis has shown that the sample mixture was initially compacted with homogenous particles, because of the amorphous gel C-S-H and kotoite silicatian which are basically responsible for strength development. With the increases in drying-wetting cycle numbers, there are obvious changes in the characteristics and the structure of the mixture sample, whereas the porosity of the structure of the sample also increases, while the density and the unconfined compressive strength of the structure of the sample decreases. This paper aims to provide an important theoretical application of the comprehensive utilization of red mud as a road base material.

Solar-induced chlorophyll fluorescence and short-term photosynthetic response to drought.

Drought is among the most damaging climate extremes, potentially causing significant decline in ecosystem functioning and services at the regional to global scale, thus monitoring of drought events is critically important. Solar-induced chlorophyll fluorescence (SIF) has been found to strongly correlate with gross primary production on the global scale. Recent advances in the remote sensing of SIF allow for large-scale, real-time estimation of photosynthesis using this relationship. However, several studies have used SIF to quantify the impact of drought with mixed results, and the leaf-level mechanisms linking SIF and photosynthesis are unclear, particularly how the relationship may change under drought. We conducted a drought experiment with 2-yr old Populus deltoides. We measured leaf-level gas exchange, SIF, and pulse amplitude modulated (PAM) fluorescence before and during the 1-month drought. We found clear responses of net photosynthesis and stomatal conductance to water stress, however, SIF showed a smaller response to drought. Net photosynthesis (Anet ) and conductance dropped 94% and 95% on average over the drought, while SIF values only decreased slightly (21%). Electron transport rate dropped 64% when compared to the control over the last week of drought, but the electron transport chain did not completely shut down as Anet approached zero. Additionally, SIF yield (SIFy ) was positively correlated with steady-state fluorescence (Fs ) and negatively correlated with non-photochemical quenching (NPQ; R2 =0.77). Both Fs and SIFy , after normalization by the minimum fluorescence from a dark-adapted sample (Fo ), showed a more pronounced drought response, although the results suggest the response is complicated by several factors. Leaf-level experiments can elucidate mechanisms behind large-scale remote sensing observations of ecosystem functioning. The value of SIF as an accurate estimator of photosynthesis may decrease during mild stress events of short duration, especially when the response is primarily stomatal and not fully coupled with the light reactions of photosynthesis. We discuss potential factors affecting the weak SIF response to drought, including upregulation of NPQ, change in internal leaf structure and chlorophyll concentration, and photorespiration. The results suggest that SIF is mainly controlled by the light reactions of photosynthesis, which operate on different timescales than the stomatal response.

Shape-Memory-Recovery Characteristics of Microcellular Foamed Thermoplastic Polyurethane.

We investigated the shape-recovery characteristics of thermoplastic polyurethane (TPU) with a microcellular foaming process (MCP). Additionally, we investigated the correlation between changes in the microstructure and the shape-recovery characteristics of the polymers. TPU was selected as the base material, and the shape-recovery characteristics were confirmed using a universal testing machine, by manufacturing dog-bone-type injection-molded specimens. TPUs are reticular polymers with both soft and hard segments. In this study, we investigated the shape-memory mechanism of foamed polymers by maximizing the shape-memory properties of these polymers through a physical foaming process. Toward this end, TPU specimens were prepared by varying the gas pressure, foaming temperature, and type of foaming gas in the batch MCP. The effects of internal structural changes were investigated. These experimental variables affected the microstructure and shape-recovery characteristics of the foamed polymer. The generated cell density changed, which affected the shape-recovery characteristics. In general, a higher cell density corresponded to a higher shape-recovery ratio.

Raman profile alterations of irradiated human nasopharyngeal cancer cells detected with laser tweezer Raman spectroscopy.

Radiotherapy has been widely used for nasopharyngeal carcinoma (NPC) treatment, which causes DNA damage and alterations of macromolecules of cancer cells. However, the Raman profile alterations of irradiated NPC cells remain unclear. In the present study, we used laser tweezers Raman spectroscopy (LTRS) to monitor internal structural changes and chemical modifications in NPC cells after exposure at a clinical dose (2.3 Gy) to X-ray irradiation (IR) at a single-cell level. Two types of NPC cell lines, CNE2 (EBV-negative cell line) and C666-1 (EBV-positive cell line), were used. The Raman spectra of cells before and after radiation treatment were recorded by LTRS. The analysis of spectral differences indicated that the IR caused Raman profile alterations of intracellular proteins, DNA base and lipids. Moreover, by using the multivariate statistical analysis including principal component analysis (PCA) and linear discriminant analysis (LDA) algorithm, an accuracy of 90.0% for classification between CNE2 cells before and after IR could be achieved, which was 10% better than that of C666-1 cells. The results demonstrated that CNE2 cells were more sensitive to IR in comparison to C666-1 cells, providing useful information for creating a treatment strategy in clinical practice. This exploratory study suggested that LTRS combined with multivariate statistical analysis would be a novel and effective tool for evaluating the radiotherapeutic effect on tumor cells, and for detection of the corresponding alterations at the molecular level.