Optimal Exposure Time Research Articles

Analysis of Extracellular Vesicles Lysing using Surface Acoustic Wave Resonator

The integration of a Y-channel microfluidic system with an annular SAW device developed using MEMS technology has built an efficient platform for mixing and lysing of extracellular vesicles. The travelling SAW used in this study operating at a frequency of 50 MHz is capable of generating surface acoustic waves stream on a liquid sample inside a Y-chamber. At a height of 80µm the PDMS chamber and a liquid sample flow rate of 10µl/min can produce a mixing method that is able to generate gas bubbles that cause the occurrence of microcavities which are the agents of the extracellular vesicle lysing mechanism. This method of rupturing extracellular vesicles through cavitation techniques results in cell rupture through a combination of shear force and pressure changes without destroying proteins and nucleic acids. The Bradford assay is used to observe the increased presence of proteins resulting from the rupture of extracellular vesicles after exposure to acoustic waves. Based on the results, it can be concluded that the most optimal SAW exposure time and power is at 20dBM and 60 seconds. Through this test it can also be observed that a longer exposure period will generate heat which results in the degradation of the proteins that come out of the extracellular vesicles. It can be concluded that the results of this study prove that mechanical method of integrating an annular -SAW device and a Y-channel PDMS microfluidic chamber for micro-mixing, the analysis of biological cells and lysing mechanism can be achieved more effectively compared to conventional methods.

Effect of saponification-based treatment of palm kernel shell aggregates on the mechanical properties of palm kernel shell aggregates concrete

This paper presents a method of treatment of Palm Kernel Shell (PKS) aggregates to remove the oil that inhibits the development of strength in PKS concrete. 13 treatments from 2 to 20 g/L concentration of solutions of potassium hydroxide were used to induce a saponification reaction with the oil present on the PKS surface. The oil is entirely removable, but the highly concentrated solution damages the aggregates’ surface. The optimum concentration to remove the oil was 10 g/L for an optimum exposure time of 12 h without affecting the PKS aggregates’ integrity and the PKS concrete’s mechanical properties. Compressive strength and a splitting tensile strength at 28 days of 20 MPa and 1.2 MPa were achieved without admixture.

Simulation of heat transfer, mass transfer and tissue damage in magnetic nanoparticle hyperthermia with blood vessels

Numerical simulation of magnetic nanoparticle hyperthermia for cancer treatment has been investigated in this study. The presented simulation did account for the effects of fluid flow, mass flow, and heat transfer during the MNP hyperthermia. The tumor was assumed to be a porous slab, 30% of which had been necrosed previously, with two capillaries, where magnetic nanoparticles were added into the bloodstream and distributed in the tumor by blood flow through capillaries. Fluid flow, mass transfer by capillaries, and interstitial tissues have been coupled in this study. Furthermore, tumor tissue damage has been calculated using a thermal damage indicator. The goal of this research is to find an optimum injection duration and exposure time in order to maximize hyperthermia treatment effectiveness using the BOBYQA optimization method. At the end of the 1-h time hyperthermia treatment, most of the non-necrotic tissue of the tumor were damaged. Moreover, the fraction of damaged tissue increased to more than 90% in some parts of the tumor. Results of this study indicate that MNP hyperthermia with the proposed setup can effectively damage the tumor in just one session, making it more susceptible to complementary therapies such as radiotherapy or chemotherapy.

Effectiveness of image optimization in digital intraoral radiographic systems

<h3>Objective</h3> To evaluate the effectiveness of image optimization in digital intraoral radiographic systems. <h3>Study Design</h3> Radiographic images from seven size 2 intraoral sensors (Carestream 6200, Dexis Platinum, Gendex GXS700, LEDTuxedo, Planmeca ProSensor HD, Sirona Schick 33, and XDR Radiology) were optimized in accordance with ANSI/ADA Standard 1094 Quality Assurance for Digital Intra-Oral Radiographic Systems to investigate the benefits of image optimization. The Dental Digital Quality Assurance (DDQA) phantom provided reference objects for assessment of dynamic range, spatial resolution, and contrast perceptibility. Images were analyzed with NIH ImageJ to objectively assess dynamic range and spatial resolution. Contrast perceptibility was subjectively scored based on the visibility of individual wells in two rows of the DDQA phantom. All radiographic images were acquired with the same DC x-ray source (Planmeca ProX) using the sensor's native software on a Gigabyte Laptop Model P34 with a display calibrated using the SMPTE monitor test pattern. To simulate clinically relevant scenarios, a second phantom of an endodontically prepared molar tooth was fabricated, consisting of a #6 K endodontic file placed to the apex of the palatal root of a maxillary molar. File position was confirmed using a scanning electronic microscope and then fixed in place within the root canal. The instrumented tooth was stabilized in acrylic to simulate soft tissue and bone absorption. Three exposures of the endodontic phantom were made using each sensor: one at the optimal exposure time and two at exposure settings one increment above and below. ImageJ was used to measure the distance from the file tip to the radiographic apex. <h3>Results</h3> While optimal exposure parameters varied among sensors, in all cases, the measured distance from the endodontic file to the apex was superior on images acquired at optimum exposure rather than radiographic images acquired with exposures just one increment higher or lower than the optimal parameters. <h3>Conclusion</h3> Optimization of radiographic images using the approach specified in ANSI/ADA Standard1094 enhances clinical diagnostic accuracy. <b>Statement of Ethical Review</b> Ethical Review or exemption was not warranted for this study

Applying ADA/ANSI Standard 1094: Impact of image adjustments and display device on subjective assessments

<h3>Objective</h3> To examine operator and device factors that impact subjective assessment of digital radiographic image quality. <h3>Study design</h3> The DDQA phantom was used to generate images to assess spatial resolution, contrast perceptibility, and latitude. The phantom was imaged using an XDR size 2 sensor with a Gendex Expert DC intraoral x-ray source (65 kVp, 7.5mA) at 8 exposure times. Five observers analyzed the images in the native XDR software. Observers were allowed to adjust brightness and contrast to facilitate visualization. Images were analyzed in two environments: a diagnostic radiology reading room with lowered ambient lighting and a Dell Ultrasharp monitor, and an intraoral radiographic room with bright ambient light (450 lux) and an HP EliteOne Computer. The optimum exposure, defined as the lowest exposure that provided the highest feature visualization, was recorded. <h3>Results</h3> In the radiology reading environment, observers were able to discern the full latitude of grayscales at all exposure times. The mean optimal exposure was 0.25s for discerning contrast wells and 0.32s for discerning spatial resolution. Scoring the same images in the intraoral radiography room environment yielded identical results. All observers were able to discern the full image latitude, and the identified optimal exposures were unchanged (0.25s for contrast wells and 0.32s for spatial resolution). <h3>Conclusions</h3> We demonstrate that establishing optimal exposure using the DDQA phantom is reliable, with minimal individual variation. Image adjustments cannot compensate for decreased information. Interestingly, room lighting conditions and display device did not change observer assessments of image quality and optimal exposure times when the observers were allowed to manually adjust brightness and contrast of the presented image. This further validates image quality-guided approaches to establish optimal exposure times in dental clinic settings. In ongoing studies, we will study different display models and ambient lighting settings that are more typical of chair-side settings. <b>Statement of Ethical Review</b> Ethical Review or exemption was not warranted for this study

3D printing of gadolinium oxide structure neutron absorber

The exceptional proprieties of gadolinium oxide (Gd2O3) enable wide applications as sensitized fluorescent material, optical additive, and especially neutron absorber material for nuclear industry or nuclear medicine. Herein, to address the challenge of manufacturing custom-designed Gd2O3 structures, we propose a new approach to fabricating the Gd2O3 structure by vat photopolymerization 3D printing. The preparation of printing feedstock, photo-curing parameters and post-processing were investigated thoughtfully. It was found that the printing feedstock was a typical non-Newtonian fluid. The optimal machine light intensity and exposure time were 6 (∼977 μW/cm2) and 3 s, respectively. After being sintered at 1600 °C for 2 h, the resulting sample reached a density of 58%, a bending stress of 40 MPa, and a flexural elastic modulus of and 20.219 GPa. The successful manufacturing of pure Gd2O3 was further evidenced by the SEM results and XRD pattern. The phase transition of Gd2O3 from cubic to monoclinic occurred around 1400 °C, leading to significant densification. Finally, a green mesh structure with a length of 10 cm was prepared, demonstrating the practical application potential in the neutron absorption and shielding.

Activation of R‐BAPB polyimide with cold plasma dielectric barrier discharge for improvement of cell‐material interaction

AbstractSurface modification of films of the laboratory R‐BAPB polyimide based on 1,3‐bis(3,3′,4,4′‐dicarboxyphenoxy)benzene (dianhydride R) and 4,4′‐bis(4‐aminophenoxy)biphenyl (diamine BAPB) was performed using a dielectric barrier discharge (DBD) with the aim of increasing proliferative activity of human fibroblasts on these films. The optimal duration of the DBD plasma treatment that provided the highest fibroblast proliferative activity was established. The surface roughness value of the film treated for this optimal period of time was equal to 47.5 ± 4.7 nm, and its surface free energy was 70 mJ/m2. It was demonstrated that the DBD plasma treatment to an increase in the concentrations of CO and CN bonds on the surface of R‐BAPB polyimide films, which enhanced proliferative activity of fibroblasts. The optimal DBD exposure time was 3 minutes.

Corneal stromal dehydration and optimal stromal exposure time during corneal refractive surgery measured using a three-dimensional optical profiler.

To quantitatively analyze human corneal stromal dehydration and estimate proper corneal stromal exposure time during corneal refractive surgery. The central thickness changes over time in 34 pieces of human corneal tissue were measured using a white light interferometer. The corneal stromal tissue was obtained by femtosecond laser small incision lenticule extraction. The thickness-time dehydration fitting curves were drawn, and the determination coefficient R2 was calculated. The differences in the fitting curve equation coefficients were compared between the thin and thick lenticule groups. The optimal stromal exposure time was calculated under various conditions, including different optical zones and allowable refractive errors. A water loss variation model was successfully established. Linear and quadratic fitting curves were drawn, and the determination coefficient R2 values were significantly close to 1. The average values of R2 for quadratic curves and linear phases 1, 2, and 3 were 0.998 ± 0.002, 0.995 ± 0.007, 0.996 ± 0.003, and 0.984 ± 0.035, respectively. The optimal stromal exposure time varied under different optical zones and allowable diopter error conditions. Taking the allowable error of 0.50 D and the optical zone size of 6.5mm as an example, the optimal time was approximately 24s. The dehydration rate of the human corneal stroma is nonlinear, and the quadratic stromal thickness-time dehydration fitting curve is more in line with the actual water loss trend. The length of the stroma exposure time may affect the postoperative refractive accuracy after corneal refractive surgery.

Innovative digital solution supporting sun protection and vitamin D synthesis by using satellite-based monitoring of solar radiation.

Public health campaigns advise minimising UV radiation (UVR)exposure to prevent skin cancer and precancer,e.g. actinic keratosis (AK). A 3-day clinical field study, in Brazil, was performed to evaluate the mobile app Sun4Health® by siHealth Ltd. The app performs real-time monitoring of both erythemal and vitamin D-effective solar radiation doses using satellite data, enabling personalised recommendations on optimal sun exposure time and sunscreen use. When coupled to a wearable device, the app also provides body-site specific recommendations ("3D" version). 59 healthy volunteers were randomised into 3 groups, each given a different app providing: (1) ultraviolet indexonly (control app), (2) personalised recommendations and sun overexposure alerts (Sun4Health® app), (3) as (2) but connected via Bluetooth to a wearable device to monitor sun exposure in 3D (Sun4Health®-3D app). Participants were offered sunscreens (SPF 30 and 50) to use at their discretion. Erythema, quantified by reflectance spectroscopy, was assessed daily in the mornings and evenings on six body sites. Serum vitamin D (25(OH)D3) was measured before and after the study. Mean increase of erythema (Mexameter® units ± SD) of all exposed body sites combined over 3days showed 55.76 ± 47.47 for group 1, 40.27 ± 37.91 for group 2 and 37.12 ± 30.69 for group 3 (p < 0.05 for all groups). Mean increase of serum 25(OH)D3 (nmol/l ± SD) showed 1.32 ± 36.49 for group 1, 6.38 ± 21.19 for group 2 and 18.68 ± 35.45 for group 3 (p > 0.05 for all groups). The results show that the Sun4Health® app is safe to use and can modify behaviour to reduce skin erythema (sunburn) yet not decreasing vitamin D status.

Automatic optimal camera exposure time control for digital image correlation

We present a method that can automatically determine the optimal camera exposure time for high-quality deformation measurement with digital image correlation (DIC) techniques. The proposed method needs to capture a series of surface images of a test sample at its reference state with different camera exposure times. The relationship between the mean intensity gradients (MIGs) and average grayscales of these images reveals that the best quality (i.e. maximum MIG) of a speckled sample surface always corresponds to a certain average grayscale. Thus, the proposed method can serve two purposes in DIC practice. First, at the initial state, the camera exposure time can be adjusted automatically to obtain a reference image with the best speckle pattern quality. Second, by adjusting the camera exposure time to make the average grayscale of an image close to the predetermined optimal value, the proposed method can adaptively output high-quality deformed images with an almost constant speckle pattern quality, regardless of serious ambient light variations. Experimental results demonstrated that the proposed method can automatically obtain stable and high-quality speckle pattern images, thus delivering better DIC measurement compared with regular DIC techniques using a fixed camera exposure time. Because the present automatic camera exposure time control method allows a nonprofessional operator to consistently obtain high-quality speckle pattern images that warrant high-accuracy DIC measurements, it is therefore suggested that the present method should be used as a routine practice in practical DIC applications.

A new PMA-qPCR method for rapid and accurate detection of viable bacteria and spores of marine-derived Bacillus velezensis B-9987

Marine-derived Bacillus velezensis B-9987 is an important biocontrol bacterium with a broad-spectrum antibacterial effect. The traditional plate counting method is widely used for quantitative detection of viable bacteria and spores but has some disadvantages such as being laborious and time-consuming (at least 24–48 h). This study aimed to develop a new PMA-qPCR method for rapid and accurate detection of viable bacteria and spores of B-9987. The specific primers were designed for qPCR amplification based on the conserved region of the bmmA gene (encoding a malonyl CoA-ACP transacylase) of B-9987. According to the characteristic that propidium monoazide (PMA) dye can distinguish viable and dead bacteria, the optimal PMA concentration of 10 μg/ml and optimal exposure time of 10 min were achieved under PMA treatment conditions. The B-9987 spores' genomic DNA was successfully extracted after the spore coat was removed and spore germination was induced. The quantification limits of the PMA-qPCR method were determined for viable B-9987 bacteria, spores in pure culture, and spores in marine Bacillus wettable powder (marine Bacillus WP) and were 1.5 × 103 CFU/ml, 6.5 × 102 CFU/ml, and 103 CFU/ml, respectively. Compared with the qPCR method, the PMA-qPCR method could sensitively detect viable bacteria in the viable/dead bacterial mixture. In this study, the developed PMA-qPCR method was found to have excellent sensitivity and specificity in the context of a pure culture of B-9987 strain, which could accurately and rapidly detect viable B-9987 bacteria within 3–4 h and viable B-9987 spores in marine Bacillus WP within 4–6 h.

Abstract 3914: Antibodies: The key to spatial mass spectrometry success

Abstract As multiplex immunofluorescent assays continue to be used more frequently than ever, their success almost exclusively relies on the quality and performance of the antibodies used. One of the most popular methods, imaging mass cytometry (IMC), primarily differs from traditional methods in that it uses 1) metal labels rather than fluorescent tags and 2) allows for the addition of all primary antibodies at one time rather than sequentially. Success in IMC, however, can be hindered by loss of antibody activity, poor optimization, or insufficient testing post-conjugation. The aim of this study was to assess whether thoroughly analyzing antibody activity before and after metal conjugation could serve as a predictor for success in IMC.Carrier-free antibodies (Bethyl Laboratories, Inc.) were conjugated using Fluidigm’s Maxpar® X8 Antibody Labelling Kits. Metal-antibody pairings were designated based on the protein’s expression level. Post-conjugation activity testing was performed on tissue microarrays using both citrate and tris HIER methods. Initial DAB testing was done first to observe any loss of signal, followed by IF testing using Dylight-conjugated secondary antibodies, to determine exposure time limitations. Initial testing concentration for each target was based off the validated working concentration provided on the data sheet for each antibody. If a loss of activity was observed, further IF testing was performed to recover activity via titration experiments. Optimal exposure times were obtained for each sample using the Vectra Polaris imaging system. The conjugates were then assessed in IMC using Fluidigm’s Hyperion System.A set of 60 antibodies were evaluated with 30% showing decreased activity post-conjugation, ranging from a minor reduction of signal to complete loss. Exposure times taken from each target were determined to be a valid predictor of success in IMC. A sliding scale showed that targets with &amp;lt;200ms exposure times would be successful while those with &amp;gt;300ms failed. Furthermore, several antibodies that showed a complete loss of signal post-conjugation were able to recover that signal via an increase in antibody concentration.The utilization of pre- and post-conjugation activity tests on metal-conjugated antibodies provides key insights on imaging mass cytometry outcomes. Exposure times from IF serve as one of the most crucial predictors for success. Additionally, the use of increased concentration gradients for first-pass “failed” antibodies can often recover any loss of activity. This loss of activity wastes time and money if not identified prior to use in imaging mass cytometry experiments. Building this sort of assessment into early IMC experiment planning can yield a streamlined approach to testing and evaluating potential IMC targets. Citation Format: Danielle Fails, Michael Spencer. Antibodies: The key to spatial mass spectrometry success [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3914.

Extraction of Metals from Polluted Soils by Bioleaching in Relation to Environmental Risk Assessment.

Environmental pollution has particular implications for the whole geosystem and increases the global risk to human and ecological health. In this regard, investigations were carried out on soil samples to perform the quality status assessment by determining: pH, texture, structure and metal concentration, as well as carrying out an assessment of anthropogenic activity by determining pollution indices: Cf (contamination factor), Cd (degree of contamination), PLI (pollution load index), Er (ecological risk index) and PERI (potential ecological risk index). Analyses on soil samples showed high concentrations of metals (Cu: 113–2996 mg kg−1; Pb: 665–5466 mg kg−1; Cr: 40–187 mg kg−1; Ni: 221–1708 mg kg−1). The metal extraction experiments were carried out by bioleaching using Thiobacillus ferrooxidans, microorganisms at different amounts of bioleaching solution (20 mL and 40 mL 9K medium) and a stirring time of up to 12 h. The results on the degree of contamination, pollution loading index PLI (2.03–57.23) and potential ecological risk index PERI (165–2298) indicate that the soils in the studied area have a very high degree of pollution. The decontamination procedure by bioleaching showed a decrease, but at the end of the test (12 h), the followed indices indicate high values, suggesting that bioleaching should continue. The depollution yield after 12 h of treatment is, however, encouraging: Cu 29–76%, Pb: 10–32%, Cr: 39–72% and Ni 44–68%. The use of yield–time correlation equations allows the identification of the optimal exposure time on the bioleaching extraction process to obtain optimal results. The aim of the research is to determine the soil quality, soil environmental risk, extraction of metals from polluted soils by bioleaching and to identify influencing factors in achieving high remediation yields.

An Improved Method for Quantification of Viable Fusarium Cells in Infected Soil Products by Propidium Monoazide Coupled with Real-Time PCR.

Fusarium is a soil-borne pathogen that causes root rot disease in cucumber. To date, quantitative real-time PCR (qPCR) is a common tool to detect the content of Fusarium in soil. However, qPCR cannot distinguish between viable and nonviable cells. The aim of this study was to develop a detection technique to pretreat tissue fluid with propidium monoazide (PMA) followed by extract DNA, and then to quantify viable Fusarium cells in contaminated soil. In this work, the specific primer pair F8-1/F8-2 was designed based on the translation elongation factor (EF) gene and a PMA-qPCR assay was established to amplify and quantify soils of viable Fusarium cells. The PMA pretreatment test was optimized, which indicated that the optimal PMA concentration and light exposure time were 50 mmol L−1 and 15 min, respectively. The lowest limit of viable cells in suspension detected and soil by PMA-qPCR were 82 spore mL−1 and 91.24 spore g−1, respectively. For naturally contaminated soil, viable Fusarium cells were detected in eight of the 18 samples, and the Fusarium amount ranged from 104 to 106 spore g−1. In conclusion, the PMA-qPCR method has the characteristics of high sensitivity, efficiency, and time saving, which could support nursery plants to avoid Fusarium infection and agro-industry losses.

Applications of Laser-Induced Fluorescence in Medicine

Fluorescence is the most sensitive spectroscopic method of analysis and fluorescence methods. However, classical analysis requires sampling. There are new needs for real-time analyses of biological materials, without the need for sampling. This article presents examples of proprietary applications of laser-induced fluorescence (LIF) in medicine with such methods. A classic example is the analysis of photosensitizers using the photodynamic treatment method (PDT). The level and kinetics of accumulation and excretion of sensitizers in the body are examined, as well as the optimal exposure time after the application of compounds. The LIF method is also used to analyze endogenous fluorophores; it has been used to detect neoplasms, e.g., lung cancer or gynecological and dermatological diseases. Furthermore, it is used for the diagnosis of early stages of tooth decay or detection of fungi. The article will present the construction of sensors based on the LIF method—fiber laser spectrometers and investigated fluorescence spectra in individual applications. Examples of fluorescence imaging, e.g., dermatological, and dental diagnostics and measuring systems will be presented. The advantage of the method is it has greater sensitivity and easily detects lesions early compared to the methods used in observing the material in reflected light.

Ozone Efficiency on Two Coleopteran Insect Pests and Its Effect on Quality and Germination of Barley.

Simple SummaryRhyzopertha dominica (Fabricius) and Tribolium castaneum (Herbst) are notorious global pests, destroying various stored grains, including barley, wheat, oats, maize, and rice. Ozone (O3) is a promising fumigant to control pests in stored grain since it can safely and rapidly auto-decompose without leaving residues, however, relatively few studies have focused on the toxicity of O3 on stored grain pests in stored barley. In this study we not only explored the susceptibility of all life stages of R. dominica and T. castaneum in barley seeds to different durations of gaseous O3, but also investigated the effect of O3 on germination ability, seedling growth, and quality of barley. O3 was effective against all life stages of two species in barley under sufficient exposure times without negative impacts affecting the commercial quality of barley. However, the germination ability and seedling growth were adversely impacted at longer O3 exposure times. Thus, it is imperative to select an optimal O3 exposure time to achieve the desired functional outcome, such as malting, animal feeding, and human consumption.Ozone (O3) is a potential fumigant to control pests in stored grain since it can safely and rapidly auto-decompose without leaving residues. In this study, the efficacy of O3 on all life stages of Rhyzopertha dominica (Fabricius) and Tribolium castaneum (Herbst) in barley and the physiological effects on barley and its quality were investigated. Complete control of all life stages of pests was obtained at 700 ppm for 1440 min of ozone exposure without negatively impacting the contents of soluble protein, moisture content, seed colour, hardness, and the weight of thousand barley seeds. The eggs and pupae of these two insects were the more tolerant stages than their larvae and adults. Prolonged exposure times (40 to 1440 min) and mortality assessment intervals (1, 2, and 7 days) increased O3 efficacy due to the reaction characteristics and delayed toxicity. Aging barley seeds appeared to be more sensitive to prolonged ozone duration than new seeds. A total of 20 and 40 min could promote germination rate, and longer O3 exposure (1440 min) was unfavourable for germination and seedling growth. Thus, it is imperative to select an optimal O3 exposure time to transfer ozone into quality contributors of final products and achieve the desired functional outcomes.

Digital light processing of β-tricalcium phosphate bioceramic scaffolds with controllable porous structures for patient specific craniomaxillofacial bone reconstruction

β-TCP scaffolds with four representative pore configurations are prepared for using digital light processing (DLP)-based additive manufacturing. The process optimization, pore design, mechanical properties, and microstructure of the fabricated scaffolds are investigated. The optimal slurry solid content, exposure intensity, slice thickness, and exposure time were found to be 60 wt%, 10 mW/cm2, 25 μm, and 4 s, respectively. The DLP-formed β-TCP bone scaffolds showed 3D interconnected and multilevel pores, achieving porosities of 49%–89% and strut diameters of 200–1000 μm. The primary pore size exceeded 100 μm, and the secondary pore size was less than 10 μm. The porosity significantly affected the mechanical properties of the scaffolds, whereas the pore configuration exerted a minor influence. The prepared scaffolds with a pore configuration of triply periodic minimal surface behaved the best mechanical properties. The compressive strength and elastic modulus of the scaffolds reached 20–30 MPa and 2–4 GPa, respectively. Based on patient’s medical imaging data, large-volume β-TCP scaffolds (∽70 × 40 × 15 mm and 40 × 40 × 4 mm, after sintering) with controlled biomimicking porous structures and anatomical shapes were successfully designed and fabricated by DLP for repair of massively damaged mandible and cranial defects.

Research on the thermal impact on steel structures of tanks in case of fire

The article investigates the behavior of steel structures of tanks under the thermal impact from fire in the tank farm. Critical fracture temperatures of steel structures are described, the study and analysis of the behavior of steel metal (structure) of the tank under heat exposure and cooling with water. The experiments carried out during cooling will allow to choose the optimal time of exposure and surface-active substances that ensure the improvement of wetting.

Cryopreservation OfPyramimonas Mucifera

BACKGROUND:It is important to appreciate microalgal diversity, better understand their ecosystem functioning and therefore implement conservation measures. The National Biodiversity Act of South Africa has a marine and coastal component which promotes such investigations.OBJECTIVE:To develop a cryostorage method for the marine unicellular algal speciesPyramimonas mucifera.MATERIALS AND METHODS:Cell viability, measured by propidium iodide, was used to determine both optimal exposure time to 10 % DMSO and survival following thawing of cryopreserved cells. Cryopreservation was achieved by a two-step cooling method.RESULTS &amp; DISCUSSION:A 30-min DMSO exposure was selected forP. mucifera, as cells following such treatment retained cell shape and integrity. Although density was significantly reduced after cryopreservation, the surviving cells were capable of returning to viability levels equal to those of the untreated control (&gt;90%).CONCLUSION:Cultures ofP. muciferacan be successfully cryopreserved and propidium iodide provides a useful indication of culture vitality.

Research on 3D printing process and properties of diamond–resin composites based on digital light processing

Additive manufacture of diamond tools has rarely been investigated to date. In this study, ultraviolet (UV) curable diamond–resin slurries with diamond contents from 6.25 to 25 vol% have been prepared to produce diamond-resin composites via 3D printing using digital light processing. The rheological properties and cure behavior of UV-curable slurries were examined. The results demonstrated that all slurries exhibited typical shear-thinning behavior, and the viscosity of each corresponding slurry noticeably increased as the diamond content increased from 0 to 25 vol%. Regarding the cure behavior, the cure depth and cure width of the slurries were increased and decreased by increasing the exposure time and solid loading, respectively. The mechanical and thermal properties of printed specimens were then characterized. The flexural strength of specimens decreased from 40 to 23.9 MPa with increase in the diamond contents from 0 to 18.75 vol% and appeared to plateau above 18.75vol% of diamond loading. Although the flexural strength increased with increase in the exposure time from 2 to 10 s, the optimal exposure time was 4 s. The geometric accuracy gradually decreased, and specimen deformation occurred when the exposure time exceeded 4 s. Results of the thermogravimetric analysis indicated that the addition of diamond to the slurry improve the specimens thermal stability.