Unified modeling of photothermal and photochemical damage.

Correlating damage outcomes to a retinal laser exposure is critical for diagnosis and choosing appropriate treatment modalities. Therefore, it is important to understand the causal relationships between laser parameters, such as wavelength, power density, and length of exposure, and any resulting injury. Differentiating photothermal from photochemical processes in an in vitro retinal model using cultured retinal pigment epithelial cells would be a first step in achieving this goal. The first-order rate constant of Arrhenius has been used for decades to approximate cellular thermal damage. A modification of this equation, called the damage integral (Ω), has been used extensively to predict the accumulation of laser damage from photothermal inactivation of critical cellular proteins. Damage from photochemical processes is less well studied and most models have not been verified because they require quantification of one or more uncharacterized chemical species. Additionally, few reports on photochemical damage report temperature history, measured or simulated. We used simulated threshold temperatures from a previous in vitro study to distinguish between photothermal and photochemical processes. Assuming purely photochemical processes also inactivate critical cellular proteins, we report the use of a photothermal Ω and a photochemical Ω that work in tandem to indicate overall damage accumulation. The combined damage integral (ΩCDI) applies a mathematical switch designed to describe photochemical damage relative to wavelength and rate of photon delivery. Although only tested in an in vitro model, this approach may transition to predict damage at the mammalian retina.

Thermal Profiles in Water Injection Wells: Reduction in the Systematic Error of Flow Measurements during the Transient Regime.

This article presents an analytical solution for calculating the flow rate in water injection wells based on the established thermal profile along the tubing. The intent is to minimize the intrinsic systematic error of classic quasi-static methodologies, which assume that all thermal transience on well completion has passed. When these techniques are applied during the initial hours of injection well operation, it can result in errors higher than 20%. To solve this limitation, the first law of thermodynamics was used to define a mathematical model and a thermal profile was established in the injection fluid, captured by using distributed temperature systems (DTSs) installed inside the tubing. The geothermal profile was also established naturally by a thermal source in the earth to determine the thermal gradient. A computational simulation of the injection well was developed to validate the mathematical solution. The simulation intended to generate the fluid's thermal profile, for which data were not available for the desired time period. As a result, at the cost of greater complexity, the systematic error dropped to values below 1% in the first two hours of well operation, as seen throughout this document. The code was developed in Phyton, version 1.7.0., from Anaconda Navigator.

Factors influencing bactericidal efficacy using atmospheric cold plasma (ACP) against Escherichia coli in wheat flour.

This study aimed to evaluate operating factors that influence the bactericidal efficacy of atmospheric cold plasma (ACP) using wheat flour contaminated with Escherichia coli. It also investigated how non-optimized operating factors of ACP could affect wheat flour properties. Five operating factors (container volume, flour weight, shaking RPM, treatment time, and gas flow rate) were evaluated for the bactericidal effect of ACP using the Box-Behnken design. In addition, thermal and pasting properties were measured to assess the effect of non-optimized ACP operating conditions on wheat flour quality. ACP operating factors (volume of the container, shaking RPM, and treatment time) had significant effects on reducing E. coli in wheat flour (p < 0.05). The bactericidal effect also depended on the distance and contact area between the plasma jet and sample. The temperature at the flour surface increased (max. 70 ℃) when ACP treatment didn't provide sufficient space and optimized duration. Thermal, pasting, and gelling properties of ACP treated-wheat flour in a 10 mL container increased significantly compared to untreated wheat flour. Large amounts of samples, long processing time, and insufficient space contributed to overheating which leads to denaturation or change of the wheat flour properties. The present study proposed important data for industrial sterilization of wheat flour using ACP.

Transcutaneous Pulsed RF Energy Transfer Mitigates Tissue Heating in High Power Demand Implanted Device Applications: In Vivo and In Silico Models Results.

This article presents the development of a power loss emulation (PLE) system device to study and find ways of mitigating skin tissue heating effects in transcutaneous energy transmission systems (TETS) for existing and next generation left ventricular assist devices (LVADs). Skin thermal profile measurements were made using the PLE system prototype and also separately with a TETS in a porcine model. Subsequent data analysis and separate computer modelling studies permit understanding of the contribution of tissue blood perfusion towards cooling of the subcutaneous tissue around the electromagnetic coupling area. A 2-channel PLE system prototype and a 2-channel TETS prototype were implemented for this study. The heating effects resulting from power transmission inefficiency were investigated under varying conditions of power delivery levels for an implanted device. In the part of the study using the PLE setup, the implanted heating element was placed subcutaneously 6-8 mm below the body surface of in vivo porcine model skin. Two operating modes of transmission coupling power losses were emulated: (a) conventional continuous transmission, and (b) using our proposed pulsed transmission waveform protocols. Experimental skin tissue thermal profiles were studied for various levels of LVAD power. The heating coefficient was estimated from the porcine model measurements (an in vivo living model and a euthanised cadaver model without blood circulation at the end of the experiment). An in silico model to support data interpretation provided reliable experimental and numerical methods for effective wireless transdermal LVAD energization advanced solutions. In the separate second part of the study conducted with a separate set of pigs, a two-channel inductively coupled RF driving system implemented wireless power transfer (WPT) to a resistive LVAD model (50 Ω) to explore continuous versus pulsed RF transmission modes. The RF-transmission pulse duration ranged from 30 ms to 480 ms, and the idle time (no-transmission) from 5 s to 120 s. The results revealed that blood perfusion plays an important cooling role in reducing thermal tissue damage from TETS applications. In addition, the results analysis of the in vivo, cadaver (R1Sp2) model, and in silico studies confirmed that the tissue heating effect was significantly lower in the living model versus the cadaver model due to the presence of blood perfusion cooling effects.

Sustainable Production of Novel Oleogels Valorizing Microbial Oil Rich in Carotenoids Derived from Spent Coffee Grounds.

Sustainable food systems that employ renewable resources without competition with the food chain are drivers for the bioeconomy era. This study reports the valorization of microwave-pretreated spent coffee grounds (SCGs) to produce oleogels rich in bioactive compounds. Microbial oil rich in carotenoids (MOC) was produced under batch fermentation of Rhodosporidium toruloides using SCG enzymatic hydrolysates. Candelilla wax (CLW) could structure MOC and sunflower oil at a 3.3-fold lower concentration than that of carnauba wax (CBW). MOC-based oleogels with 10% CBW and 3% CLW showed an elastic-dominant and gel-like structure (tan δ ≪ 1), providing gelation and oil binding capacity (>95%). Dendritic structures of CBW-based oleogels and evenly distributed rod-like crystals of CLW-based ones were observed via polarized light microscopy. MOC-based oleogels exhibited similar Fourier-transform infrared spectroscopy spectra. X-ray diffractograms of oleogels were distinguished by the oil type that presented ß'-type polymorphism. MOC-based oleogels could be applied in confectionary products and spreads as substitutes for trans fatty acids, reformulating fat-containing food products.

Cold arousal - A mechanism used by hibernating bats to reduce the energetic costs of disturbance.

During the season of hibernation, temperate bats alternate between prolonged bouts of torpor with reduced body temperature and short arousals with a return to normothermy. Hibernating bats are sensitive to non-tactile stimuli and arouse following changes in microclimatic conditions or disturbance from other bats, potential predators, or humans. Here, we used temperature data loggers to register the skin temperature of 38 Myotis myotis bats over two winters (between January and March), during which regular visits were made to the hibernaculum. Two kinds of arousal were observed, normothermic (Tsk > 25 °C) and cold (Tsk < 15 °C). Although bats responded to the presence of a researcher by arousals of both kinds, cold arousals were more frequent (63.8%). We found that mass loss was not affected by the number of disturbances, however it was in positive relationship with the mass at the beginning of the observation and differed between sex and age categories. Furthermore normothermic bats crawling among cluster-mates initiated arousal cascades, which mainly consisted of cold arousals. We failed to detect any effect of age or sex on the number of arousals initiated by normothermic individuals. Warming by only a few degrees requires less energy than a normothermic arousal and we propose it is sufficient to activate the sensory system in order to assess the relevance of external stimuli. Our results indicate that cold arousals reflect a physiological and behavioural adaptation aimed at avoiding the energetic costs of disturbance that can lead to depletion of fat reserves.

pH-Stat Titration: A Rapid Assay for Enzymatic Degradability of Bio-Based Polymers.

Bio-based polymers have been suggested as one possible opportunity to counteract the progressive accumulation of microplastics in the environments. The gradual substitution of conventional plastics by bio-based polymers bears a variety of novel materials. The application of bioplastics is determined by their stability and bio-degradability, respectively. With the increasing implementation of bio-based plastics, there is also a demand for rapid and non-elaborate methods to determine their bio-degradability. Here, we propose an improved pH Stat titration assay optimized for bio-based polymers under environmental conditions and controlled temperature. Exemplarily, suspensions of poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) microparticles were incubated with proteolytic and lipolytic enzymes. The rate of hydrolysis, as determined by counter-titration with a diluted base (NaOH), was recorded for two hours. PLA was hydrolyzed by proteolytic enzymes but not by lipase. PBS, in contrast, showed higher hydrolysis rates with lipase than with proteases. The thermal profile of PLA hydrolysis by protease showed an exponential increase from 4 to 30 °C with a temperature quotient Q10 of 5.6. The activation energy was 110 kJ·mol-1. pH-Stat titration proved to be a rapid, sensitive, and reliable procedure supplementing established methods of determining the bio-degradability of polymers under environmental conditions.

Insights into real industrial wastewater treatment by Fenton's oxidation in gas bubbling reactors.

In the present study, bubbling reactors (BRs) were chosen to design a new procedure for real industrial wastewater (WW) treatment by Fenton's oxidation. The process was carried out in BRs under batch mode for the treatment of a WW with a high organic load (chemical oxygen demand (COD) above 7000 mgO2/L), being the efficient mixing of the liquid phase ensured by the gas bubbling. The parameters that influenced the WW treatment (i.e., H2O2 and Fe2+ concentration, and initial pH) were optimized in a smaller BR (0.5 L volumetric capacity); the maximum oxidation efficiency (dissolved organic carbon (DOC) removal = 52% and COD removal = 83% after 60 min) was reached under the following conditions: Qair = 1.0 L/min (measured at room temperature and atmospheric pressure), [H2O2] = 22.5 g/L, [Fe2+] = 0.75 g/L, and pH = 4.6 - original WW pH. It was not detected any significant effect in the process efficiency of the air flow rate and gas phase composition (i.e., N2, and air), but when the process was performed with continuous O2 bubbling an increase in the DOC removal (from 43% to 53%) was observed after 5 min of oxidation. Even so, the high costs discourage the use of pure oxygen streams in real WWTPs. To understand the dynamics of the process, the continuous air bubbling was compared to another mixing mode (mechanical stirring), and similar mineralization was achieved, proving the feasibility of Fenton's process in a BR. In addition, the gas bubbling proved to be more efficient in terms of heat dissipation during the treatment, decreasing temperature profiles along the oxidation of heavily charged real effluents. An effective scale-up with a bubble column reactor with a higher volumetric capacity by a factor of almost one order of magnitude was also proved, providing similar mineralization. The final effluent was non-toxic and more biodegradable.

Chemical Composition, Oxidative Stability, and Antioxidant Activity of Allium ampeloprasum L. (Wild Leek) Seed Oil.

Allium ampeloprasum L., commonly known as wild leek, is an edible vegetable that has been cultivated for centuries. However, no detailed studies have been undertaken to valorize A. ampeloprasum seed oil. This study aims to evaluate the physicochemical properties, chemical composition, and antioxidant activity of A. ampeloprasum seed oil. The seed oil content was found to be 18.20%. Gas chromatographymass spectrometry (GC-MS) showed that linoleic acid (71.65%) was the dominant acid, followed by oleic acid (14.11%) and palmitic acid (7.11%). A. ampeloprasum seed oil exhibited an oxidative stability of 5.22 h. Moreover, γ- and δ-tocotrienols were the major tocols present (79.56 and 52.08 mg/100 g oil, respectively). The total flavonoid content (16.64 µg CE /g oil) and total phenolic content (62.96 µg GAE /g oil) of the seed oil were also determined. The antioxidant capacity of the oil, as evaluated using the ABTS assay (136.30 µM TEAC/g oil), was found to be significant. These findings indicate that A. ampeloprasum seeds can be regarded as a new source of edible oil having health benefits and nutritional properties.

Fat properties and antinutrient content of rambutan (Nephelium lappaceum L.) seed during solid-state fermentation of rambutan fruit.

Rambutan seed is usually discarded during fruit processing. However, the seed contains a considerable amount of crude fat. Hence, the objective of this study was to investigate the fat properties and antinutrient content of the seed during fermentation of rambutan fruit. Results showed that the crude fat content of the seed reduced by 22% while its free fatty acid content increased by 4.3 folds after 10 days of fermentation. Arachidic acid was selectively reduced and was replaced by linoleic acid from the seventh day of fermentation onwards. Only 14.5% of triacylglycerol remained in the seed fat at the end of fermentation. The complete melting temperature, crystallization onset temperature and solid fat index at 37 °C of the fermented seed fat were higher than that of non-fermented seed fat. The saponin and tannin contents of the seed were reduced by 67% and 47%, respectively, after fermentation.

Spatio-temporal behavior of brightness temperature in Tel-Aviv and its application to air temperature monitoring.

This study applies remote sensing technology to assess and examine the spatial and temporal Brightness Temperature (BT) profile in the city of Tel-Aviv, Israel over the last 30 years using Landsat imagery. The location of warmest and coldest zones are constant over the studied period. Distinct diurnal and temporal BT behavior divide the city into four different segments. As an example of future application, we applied mixed regression models with daily random slopes to correlate Landsat BT data with monitored air temperature (Tair) measurements using 14 images for 1989-2014. Our preliminary results show a good model performance with R(2) = 0.81. Furthermore, based on the model's results, we analyzed the spatial profile of Tair within the study domain for representative days.

Daily oscillations of skin temperature in military personnel using thermography.

INTRODUCTION: The human body makes many physiological adjustments throughout the day, including adjustments to body temperature. The purpose of this study was to determine oscillations in the skin temperature (Tsk-1-Tsk-25) at 25 body regions of interest (ROIs) over 1 day using infrared thermography. METHODS: Tsk values of 31 male (age 22.9±3.0 years) Brazilian Air Force members were evaluated from five thermograms collected at 7, 11, 15, 19 and 23 h (Tsk7,11,15,19,23) by a Fluke imager. We applied one-way analysis of variance for repeated measures for the different times of the day and Tukey's post hoc test to determine significant Tsk differences between ROIs (α=0.05), and the cosinor analysis was used to determine the midline estimating statistic of rhythm, amplitude and acrophase of Tsk during the 24 h period. RESULTS: The anterior hands showed the greatest Tsk variations throughout the day. In the lower limbs, scapula, abdomen, chest and lower back, Tsk-11, Tsk-15, Tsk-19 and Tsk-23 were significantly different (p<0.05) from Tsk-7. The lowest Tsk values were obtained in the early morning, with increases in the afternoon and levelling after 15:00. CONCLUSIONS: The Tsk at all ROIs and the averaged Tsk showed oscillations throughout the day, with the lowest values in the early morning (07:00). Temperature fluctuations depended on the specific ROI, with thermal stabilisation in some regions in the afternoon and a central upward trend throughout the day in the hands.

A simplified laser treatment planning system: proof of concept.

INTRODUCTION: The physician using a laser in medicine should have treatment planning software available that will help him or her to better understand the full effects of the laser radiation on the patient, similar to that of a radiation oncologist. Combining this software with imaging scans from the patient, treatments can be optimized for individual patients. METHODS: Using off-the-shelf computers and software, we put together a simple system that is able to calculate thermal profiles from laser irradiation using an algorithm that runs in real time on a laptop computer with commercial software. The tissues used in these studies are simulated. We use realistic parameters and add some random blood vessels to the simulated tissue. RESULTS: We demonstrate in the simulations the temperature profile in tissue after laser irradiation. We can see build up of temperature in tissue irradiated with multiple pulses at 2 Hz repetition rate. The simulations show how the volume of the tissue is important in calculating thermal relaxation times. We also show how temperature relaxes away from small volumes in a short time and longer durations are needed for larger volumes of tissue. DISCUSSION: The importance of understanding how a laser interacts fully with the tissue will allow the surgeon to better determine when a laser is appropriate and which laser is optimal for a patient. The results show how these calculations can be made in a simplified fashion. Ultimately, it would be convenient to combine such software with imaging systems for careful laser treatment planning.