Irradiated Products Research Articles

Nitrogen‐Nitrogen Bond Breaking in Irradiation Products of Hexanitrohexaazaisowurtzitane (CL‐20)

AbstractWhile the primary result of an interaction of ionizing radiation with an organic material is the ejection of electrons from molecular orbitals producing cations, the free electrons can further interact, yielding excited states; and, potentially, anions. In this work, we computed reaction barriers and energies for N−N bond breaking in the CL‐20 cation, anion, and excited state to investigate if CL‐20 degradation is accelerated after radiation exposure. We focused on N−N bond dissociation because it is the rate‐determining step in the thermal degradation of CL‐20. We found that N−N cleavage rapidly takes place in the CL‐20 cation and anion with greatly reduced reaction energies as compared to CL‐20. We also outlined a potential path for photodissociation of the N−N bond. While CL‐20 is kinetically stable, initial degradation occurs readily in its irradiation products. This is of importance for the performance of the explosive after high‐dose exposure and influences aging if CL‐20 is irradiated at a low dose over extended periods of time.

Cost-Effective Thermomechanical Processing of Nanostructured Ferritic Alloys: Microstructure and Mechanical Properties Investigation.

Nanostructured ferritic alloys (NFAs), such as oxide-dispersion strengthened (ODS) alloys, play a vital role in advanced fission and fusion reactors, offering superior properties when incorporating nanoparticles under irradiation. Despite their importance, the high cost of mass-producing NFAs through mechanical milling presents a challenge. This study delves into the microstructure-mechanical property correlations of three NFAs produced using a novel, cost-effective approach combining severe plastic deformation (SPD) with the continuous thermomechanical processing (CTMP) method. Analysis using scanning electron microscopy (SEM)-electron backscatter diffraction (EBSD) revealed nano-grain structures and phases, while scanning transmission electron microscopy (STEM)-energy dispersive X-ray spectroscopy (EDS) quantified the size and density of Ti-N, Y-O, and Cr-O fine particles. Atom probe tomography (APT) further confirmed the absence of finer Y-O particles and characterized the chemical composition of the particles, suggesting possible nitride dispersion strengthening. Correlation of microstructure and mechanical testing results revealed that CTMP alloys, despite having lower nanoparticle densities, exhibit strength and ductility comparable to mechanically milled ODS alloys, likely due to their fine grain structure. However, higher nanoparticle densities may be necessary to prevent cavity swelling under high-temperature irradiation and helium gas production. Further enhancements in uniform nanoparticle distribution and increased sink strength are recommended to mitigate cavity swelling, advancing their suitability for nuclear applications.

Alkylation of Complex Glycine Precursor (CGP) as a Prebiotic Route to 20 Proteinogenic Amino Acids Synthesis.

It is not known why the number of proteinogenic amino acids is limited to 20. Since Miller's experiment, many studies have shown that amino acids could have been generated under prebiotic conditions. However, the amino acid compositions obtained from simulated experiments and exogenous origins are different from those of life. We hypothesized that some simple precursor compounds generated by high-energy reactions were selectively combined by organic reactions to afford a limited number of amino acids. To this direction, we propose two scenarios. One is the reaction of HCN with each side-chain precursor (the aminomalononitrile scenario), and the other is alkylation of the "complex glycine precursor", which is the main product of proton irradiation of the primordial atmosphere (the new polyglycine scenario). Here, selective formation of the 20 amino acids is described focusing on the latter scenario. The structural features of proteinogenic amino acids can be described systematically. The scenario consists of three stages: a high-energy reaction stage (Gly, Ala, Asn, and Asp were established); an alkylation stage (Gln, Glu, Ser, Thr, Val, Ile, Leu, and Pro were generated in considerable amounts); and a peptide formation stage (Phe, Tyr, Trp, His, Lys, Arg, Cys, and Met were selected due to their structural advantages). This scenario is a part of the evolution of Garakuta World, in which many prebiotic materials are contained.

Radionuclide characterization and handling strategy of irradiated Fission Product Material (FPM) capsule waste from molybdenum-99 production

Abstract Irradiated FPM Capsule waste is one of the types of radioactive waste generated from Molybdenum-99 (99Mo) production. This 99Mo is a 99mTc parent radionuclide that is used for the diagnosis of human organ disorders. In its production, the capsule is used for the emplacement of uranium target for irradiation in the GA Siwabessy Reactor. Since the beginning of production until now, the irradiated FPM capsules waste are still being stored in the hot cells because no data on their characteristics and handling systems that are necessary for their treatment. However, long-term storage of the FPM capsules waste in the hot cells shall be avoided because it can disrupt the production process of 99Mo and pose radiation risk to workers. The objectives of this research are to characterize radionuclides composition in the FPM capsule waste and identify its appropriate handling system. The radionuclides characterization was carried out using ORIGEN 2.1 software whereas the selection of the handling system was based on the suitability or modification of the available facilities at Radioactive Waste Management Installation (RWMI)-BRIN. The characterization results show that up to a decay time of 50 years, an FPM capsule waste contains activation product radionuclides such as 55Fe, 59Ni, and 63Ni with a total specific activity of 7.11x106 Bq/g. Three FPM capsule waste handling systems were identified that can be implemented at the RWMI facility, namely by using a 350 -liter concrete shell and then storing in an interim storage for low and intermediate-level waste, using a 60-liter stainless-steel canister which is then stored in the interim storage pit for high-level waste, or by modifying the interim storage pit for high-level waste. Radionuclide characterization and appropriate handling systems are required for the safe management of irradiated FPM capsule waste. This FPM capsule waste management is important for human and environmental protection.

In vitro-irradiated cancer vaccine enhances anti-tumor efficacy of radiotherapy and PD-L1 blockade in a syngeneic murine breast cancer model

Background and PurposeLocal radiotherapy (RT) exerts immunostimulatory effects by inducing immunogenic cell death. However, it remains unknown whether in vitro–irradiated tumor cells can elicit anti-tumor responses and enhance the efficacy of local RT and immune checkpoint inhibitors when injected in vivo. Methods and MaterialsWe tested the “in vitro–irradiated cancer vaccine (ICV)”, wherein tumor cells killed by varying doses of irradiation and their supernatants are intravenously injected. We examined the efficacy of combining local RT (24 Gy in three fractions), PD-L1 blockade, and the ICV in a murine breast cancer model. The immune cell profiles were analyzed via flow cytometry and immunohistochemistry. The cytokine levels were measured by multiplex immunoassays. ResultsThe ICV significantly increased the effector memory phenotype and interferon-γ production capacity in splenic CD8+ T cells. The in vitro–irradiated products contained immune response-related molecules. When combined with local RT and PD-L1 blockade, the ICV significantly delayed the growth of irradiated and non-irradiated tumors. The triple combination therapy increased the proportions of CD8+ T cells and effector memory CD8+ T cells while decreasing the proportion of CTLA-4+ exhausted CD8+ T cells within tumor microenvironment. Additionally, plasma level of interferon-γ and proliferation of effector T cells in the spleen and tumor-draining lymph nodes were significantly increased by the triple combination therapy. ConclusionsThe ICV enhanced the therapeutic efficacy of local RT and PD-L1 blockade by augmenting anti-tumor immune responses. Our findings suggest a therapeutic potential of in vitro–irradiation products of tumor cells.

Microwave‐assisted synthesis of 1,4‐disubstituted 1,2,3‐triazole derivatives utilizing NiO/Cu2O nano‐photocatalyst

AbstractBACKGROUNDThe main characteristic features of nickel–copper‐catalyzed azide–alkyne click (Ni‐CuAAC) reactions for production of 1,2,3‐triazoles are regioselectivity and the reaction proceeding under mild conditions. The use of copper salts as catalysts often leads to challenges like contamination of the prepared triazoles. NiO/Cu2O nanocomposites (NCs) were utilized in Ni‐CuAAC reactions as heterogeneous nanocatalysts to achieve the production of some 1,4‐disubstituted 1,2,3‐triazoles in high chemical yields under microwave irradiation.RESULTSThe preparation of NiO/Cu2O NCs was performed through the coprecipitation of NiO nanoparticles on Cu2O surface. The prepared catalyst was used for catalyzing a reaction between benzoyl azides and phenylacetylene under optimized reaction conditions. The NiO/Cu2O NCs exhibited high catalytic activity compared to Cu2O nanoparticles. In addition, by utilizing ethanol–water as the solvent system under microwave irradiation, higher yields and efficient product separation were observed.CONCLUSIONThis study investigated the proficiency of NiO/Cu2O NCs as effective nanocatalysts for the selective synthesis of some 1,4‐disubstituted 1,2,3‐triazole derivatives. Employing heterogeneous nanoparticle catalysts, such as Cu2O and NiO/Cu2O, offers several advantages over homogeneous catalytic systems. These include easier catalyst separation and recovery, potential for catalyst reuse and the ability to fine‐tune the catalytic properties by modulating the nanoparticle composition and structure. © 2024 Society of Chemical Industry (SCI).

HYPSTAR: a hyperspectral pointable system for terrestrial and aquatic radiometry

Optical Earth observation satellites provide vast amounts of data on a daily basis. The top-of-atmosphere radiance measured by these satellites is usually converted to bottom-of-atmosphere radiance or reflectance which is then used for deriving numerous higher level products used for monitoring environmental conditions, climate change, stock of natural resources, etc. The increase of available remote sensing data impacts decision-making on both regional and global scales, and demands appropriate quality control and validation procedures. A HYperspectral Pointable System for Terrestrial and Aquatic Radiometry (HYPSTAR®) has been designed to provide automated, in-situ multiangular reflectance measurements of land and water targets. HYPSTAR-SR covers 380–1020 nm spectral range at 3 nm spectral resolution and is used at water sites. For land sites the HYPSTAR-XR variant is used with the spectral range extended to 1680 nm at 10 nm spectral resolution. The spectroradiometer has multiplexed radiance and irradiance entrances, an internal mechanical shutter, and an integrated imaging camera for capturing snapshots of the targets. The spectroradiometer is mounted on a two-axis pointing system with 360° range of free movement in both axes. The system also incorporates a stable light emitting diode as a light source, used for monitoring the stability of the radiometric calibration during the long-term unattended field deployment. Autonomous operation is managed by a host system which handles data acquisition, storage, and transmission to a central WATERHYPERNET or LANDHYPERNET server according to a pre-programmed schedule. The system is remotely accessible over the internet for configuration changes and software updates. The HYPSTAR systems have been deployed at 10 water and 11 land sites for different periods ranging from a few days to a few years. The data are automatically processed at the central servers by the HYPERNETS processor and the derived radiance, irradiance, and reflectance products with associated measurement uncertainties are distributed at the WATERHYPERNET and LANDHYPERNET data portals.

10 keV electron irradiation of methane ices at ocean world surface temperatures

The surface environmental conditions of many of the icy ocean worlds in the Solar System are outside of the thermal stability field of methane ice. However, mechanisms may exist that entrain or trap methane within water ice that arrives at the surface via plume eruptions or resurfacing events. At the surface, the ice grains may experience charged particle irradiation that could lead to the production of new complex hydrocarbons. We investigated the irradiation products of 12CH4 versus 13CH4, the temperature dependence of CH4 radiation processing and product stability, and the temperature stability of CH4 when mixed with H2O in a cryogenic vacuum environment. Significantly, methane ice experimentally encased in water ice was irradiated at 100 K in an ultra-high vacuum environment and produced similar radiation-formed secondary phases as pure methane ice irradiated at 20 K. The methane radiation products produced outside of the methane ice thermal stability field, while encased in a water ice film, were most notably 13CO2 and a candidate hydrocarbon feature. Evidence for complex hydrocarbons, such as C2H6, was observed during warming and sublimation of the sample.

GC/MS analyses, FTIR and quantum mechanics calculations of poly Vinyl Alcohol in neutral and irradiated state

The products obtained from a poly vinyl alcohol (PVA) at non-irradiated and irradiated state were identified. The analyses were carried out using Head Space (HS) – Gas Chromatography – Mass Spectrometry (HS-GC/MS) instruments. On the other hand, FTIR spectroscopy has been done to explain the functional groups present. Also, the quantum chemical calculations using DFT (Density Function Theory) method were used to confirm the fragmentation process of the GC/MS chromatogram and the mass spectra of non-irradiated and irradiated PVA products. The HS-GC/MS analysis exhibited that fourth according to namely: 2-Butene, 2-methyl- (MW = 70), Cyclohexene (MW = 82), Benzocyclopropene (MW = 90), and Benzene, 1,2,4-trimethyl (MW = 120) have been detected and identified according to its GC/MS chromatogram outcomes. The mass spectrum of each component has been recorded and confirms the molecular ion peak. The obtained results show that the peaks begin to develop as the irradiation dose increases, and that this proportion rises as the gamma dose increases. Furthermore, every component of the fragment appears in the GC/MS chromatogram at a higher relative intensity of Selected ion motoring (SIM) as gamma dosages increase for each molecule. An induced change in the band intensities has been observed in FTIR spectra, which indicates cleavage in the CH bond after irradiation. In both cases, it was found a significant difference between the fragmentation products of the PVA at non-irradiated and irradiated state. Density functional theory (DFT) provides theoretical confirmation of this for both irradiated and non-irradiated PVA states.

Implementation of a high dose routine dosimetry in a self-shielded irradiator

Introduction: Ionizing radiation is applied in various fields, and dosimetric control guarantees the quality and safety of products during the irradiation process. There is a need for dosimetric calibration procedures in industrial irradiation plants, specifically for self-shielded irradiation systems. Objective: To implement high dose dosimetry in the routine control of irradiated materials within a self-shielded irradiator. Methods: We worked with 32 dosimeters; we divided the dose range used into 8 points and used four RED Perspex dosimeters per point. We measured the specific absorbance for each dosimeter; plotted these values against dose and produced a third-degree polynomial fit as a calibration curve. Results: We obtained the calibration curve with an r2 of 0,9997. The uncertainties due to the dispersion of the dosimeters and the calibration curve were 1,39% and 0,22%, respectively, for a total uncertainty of 4,80%. This uncertainty includes dose determination with a factor coverage (k) equal to 2 for a 95% confidence interval. Conclusion: Perspex RED dosimeters can be used for routine control of irradiated products in a self-shielded irradiator system.

Impact of ultraviolet C treatment on sensory characteristics, amino acid profile, riboflavin content and toxicological activity of native whey

In the fight against fermentation-disrupting bacteriophages, UV-C irradiation is promising due to its capability of damaging nucleic acids and preventing organisms to replicate. The purpose of this study is to investigate the effect of this radiation on whey using three different devices (lab-/technical-scale, batch/continuous) and UV-C doses between 0.4 and 100 J mL−1. In vitro toxicity assays (Comet, WST-1, Ames) proved that irradiated whey does not exhibit any genotoxic, cytotoxic, or mutagenic activity and is presumed to be harmless to health. However, the irradiated product had an intense “cowish/stable-like/manure-like” off-flavor, which was identified as para-cresol by GC-MS-O. Riboflavin decay was observed as well as decreases in cystine and aromatic amino acids, whose degradation products are known to be odor-active. With our current data, we are not able to define a suitable process window or to recommend the application of this technology to treat whey.

How explain on-grid PV systems diffusion? Review and application in Brazil

This paper examines the remarkable growth of photovoltaic (PV) solar energy technology in Brazil, which stands out among the leading countries in photovoltaic installations. The recent implementation of Law 14300 on grid-connected PV systems has caused a stir in the Brazilian market, with investors anticipating installations to avoid reductions in benefits. This phenomenon, previously observed in Europe, instigates an understanding of the variables underlying the exponential growth of the Brazilian market. This study seeks to identify the predictors that explain the PV systems diffusion in Brazil, in two stages: a systematic review of the literature to map approaches and methods, followed by the construction of a database and the application of predictive models. The literature revealed 24 methods in six approaches, with 44 predictors. For Brazil, the database contains 90,129 instances, 22 predictors, and covers all 5570 municipalities. The results highlight the crucial importance of the electricity tariff as the main predictor, followed by irradiation and municipal Gross Domestic Product. Predictors such as the number of companies, minimum wage, HDI education, demographic density, and vehicle fleet prove to be relevant. In conclusion, the spatially explicit analysis highlights the complexity of the market, offering valuable implications for energy planners and stakeholders.

Irradiate the knowledge gap: Empowering residents for blood product selection at Albany Medical Center.

e23236 Background: Transfusion-associated graft versus host disease (ta-GvHD) poses risks for immunocompromised patients. Indications for irradiated blood products include hematological malignancies and bone marrow transplant cases. In instances of severe acute pancytopenia, the initial contact at the emergency room (ER) is typically a nurse, followed by the ER physician. Patients referred from the local private practice, New York Oncology and Hematology (NYOH) office to our local hospital, Albany Medical Center (AMC), often bring comprehensive paper charts, but those coming directly from home frequently lack necessary documents, relying on the medical teams' expertise to ensure appropriate blood product selection. We aim to improve understanding of transfusion products and their indications. Methods: An initial pre-survey questionnaire was sent to internal medicine residents. Of the 33 responses received, 87.9% were aware of the need for irradiated blood products in hematological malignancies, 66.6% knew it was not required for solid tumors, and only 57.6% knew about the need for CAR-T patients. Additionally, only 15.2% knew where to find information on selecting irradiated blood products at AMC. The analysis highlighted a significant knowledge gap in transfusing irradiated blood products for hematological and oncological malignancies. In response, a user-friendly educational resource was created and displayed in residents' conference rooms during inpatient rotations, with plans for intermittent educational sessions over the next months. A comprehensive educational initiative addressed this aspect of patient care within the inpatient service, distributing detailed materials and discussions with the internal medicine residents at AMC. The focus was on emphasizing the critical requirement for irradiated blood products in specific clinical scenarios, particularly when managing patients with hematological malignancies and other conditions where irradiated blood is medically indicated. Results: A follow-up survey, conducted four months after distributing educational material on medicine floors, included responses from 27 internal medicine residents. Notably, 100% and 88.9% were knowledgeable about the necessity of irradiated blood products in hematological malignancies and bone marrow transplant recipients, respectively. Additionally, 24 out of 27 residents were aware that irradiated products are unnecessary for solid tumor malignancies in adult patients. All residents knew where to find information on blood product selection at AMC, and 92.6% found the education material helpful. Conclusions: Improved knowledge among residents underscores our commitment to patient care. We aim to extend education on irradiated blood product necessity beyond our residency program. Our long-term vision is to broaden this critical knowledge across the healthcare community at AMC.

Contribution to dose control at the Moroccan Boukhalef ionization facility: Design by Monte Carlo simulation of a container for agricultural products irradiation

In facilities that manage sources of ionizing radiation, controlling the absorbed dose delivered to a target is of paramount importance. This factor is essential as it directly reflects the quality of irradiation within such facilities. The BOukhalef Ionization Station (SIBO), part of the Moroccan National Institute for Agronomic Research (INRA), presents an example of one among several applications of ionizing radiation worldwide. It houses a60Co gamma irradiator used for conducting scientific research in the field of agriculture. The objective of this work is to contribute to dose control at SIBO by designing a container for agricultural products irradiation. This Container will enable a more uniform distribution of absorbed dose within the irradiated products. In this study, the Monte Carlo simulation GATE (Geant4 Application for Tomographic Emission) code is employed to flexibly adjust the dimensions of the container, and to calculate the dose homogeneity factor in the irradiated products. By selecting a cylindrical container for the irradiated products, this study shows a significant enhancement in the homogeneity factor through the reduction of the cylinder's thickness (external radius minus internal radius) when transitioning from a solid cylinder to a hollow one. Indeed, the homogeneity factor improves significantly from 2.65 to 1.64 when transitioning from a solid cylinder with a radius of 20 cm and a height of 20 cm, to a hollow cylinder with a height of 10 cm, an internal radius of 20 cm, and an external radius of 28.3 cm.

Pre-Experimental Assessment of Uranyl Nitrate Solution Irradiation in Kartini Reactor Facilities

Medical radioisotope production using neutron irradiation via fission reaction requires a sufficient neutron source. The Kartini reactor has been proposed and studied to become a neutron source for radioisotope production under the Subcritical Assembly for 99Mo Production (SAMOP) project, which uses uranyl nitrate solution as the irradiation target. A full-scale experiment involving a liquid fission product is difficult to conduct and requires facility rearrangement to reduce the risk of contamination. Although a small-batch experiment is safer to perform, a pre-experimental assessment is necessary to address the practicality of production and the accompanying problems. The goals of this assessment are (1) to characterize the Kartini reactor irradiation facilities’ flux through experiment and Monte Carlo benchmark simulation, (2) to predict the irradiation product inventory in relation to the variation of uranium concentration and the measured flux, and (3) to predict the irradiated sample gamma spectrum reading using high-purity germanium detector simulation. The irradiation simulation uses natural uranium as a control parameter, which caused the irradiation inventory dominated by actinides from transmutation. The simulation also presents the possibility of instant small-batch 99Mo production using the measured Lazy Susan facilities’ flux from a neutronic perspective. The qualitative assessment of the predicted irradiation inventory and its spectrum reading from different sample concentrations are discussed along with the recommendation and possible action to improve the experiment or future production process.

α-D-2'-Deoxyadenosine, an irradiation product of canonical DNA and a component of anomeric nucleic acids: crystal structure, packing and Hirshfeld surface analysis.

α-D-2'-Deoxyribonucleosides are products of the γ-irradiation of DNA under oxygen-free conditions and are constituents of anomeric DNA. They are not found as natural building blocks of canonical DNA. Reports on their conformational properties are limited. Herein, the single-crystal X-ray structure of α-D-2'-deoxyadenosine (α-dA), C10H13N5O3, and its conformational parameters were determined. In the crystalline state, α-dA forms two conformers in the asymmetric unit which are connected by hydrogen bonds. The sugar moiety of each conformer is arranged in a `clamp'-like fashion with respect to the other conformer, forming hydrogen bonds to its nucleobase and sugar residue. For both conformers, a syn conformation of the nucleobase with respect to the sugar moiety was found. This is contrary to the anti conformation usually preferred by α-nucleosides. The sugar conformation of both conformers is C2'-endo, and the 5'-hydroxyl groups are in a +sc orientation, probably due to the hydrogen bonds formed by the conformers. The formation of the supramolecular assembly of α-dA is controlled by hydrogen bonding and stacking interactions, which was verified by a Hirshfeld and curvedness surface analysis. Chains of hydrogen-bonded nucleobases extend parallel to the b direction and are linked to equivalent chains by hydrogen bonds involving the sugar moieties to form a sheet. A comparison of the solid-state structures of the anomeric 2'-deoxyadenosines revealed significant differences of their conformational parameters.

Behaviour of small scale dispersed PV generation

The spread over of the small scale PhotoVoltaic plants requires a central production forecast. The regional meteorological information is not suitable for individual production calculation. We investigated the behaviour of the PV plants in different regions. We have also been looking for the relation between daily irradiation and energy production. We start from a basic assumption then we visualize the appropriate series of data and we calculate the correlation or other factors. Finally we confirm or neglect the initial idea. The geographical extent has significant effect on the daily cumulated production curve. The co-running of the daily power peak in a region is really strict but it has no correlation with the daily irradiation. The daily irradiation is proportional with the daily electricity production. The individual production forecast is not really viable that is why aggregation is necessary. The area of the whole country must be handled by regions.

Лазерне зміцнення інструментів та деталей обладнання ремонтних майстерень автомобільного транспорту в АПК

The purpose of this work is to study the effect of laser processing on the surface layers of alloys and to study their microstructure and features in order to improve their mechanical properties and increase the production resource of relevant tools and parts of equipment for repair shops of automobile transport in the agricultural sector. The effect of laser processing on the near-surface microstructure of alloys was studied. It is shown which steel will have the maximum hardness as a result of laser hardening among steels 40H13, 30H13 and 20H13. As a result of the change in the chemical composition, the levels of martensitic transformation points in the liquid state zones decrease, and a significant amount of residual austenite (40-60%), characterized by a dispersed structure, remains in them. This has a positive effect on the operational characteristics of irradiated products, especially when exposed to external shock loads. The optimal level of dissolution in R6M5, 9HS and HVG steels of initial carbides to obtain the maximum possible hardness during their laser processing was determined. The value of microhardness and heat resistance of bronze as a result of its laser hardening was investigated. Therefore, the influence of laser processing on the near-surface microstructure of alloys was investigated in order to improve their mechanical properties and increase the resource of production of appropriate tools and parts of automobile transport repair workshops equipment in the agricultural sector. It was determined that the maximum hardness is achieved in the case of hardening steel 40H13, since the carbon content in it is the highest compared to steels 30H13 and 20H13. Also, to obtain the maximum possible hardness during laser processing of R6M5 steel, it is enough to dissolve 30% of the original carbides and 60-70% for 9HS and HVG steels. Treatment of bronze by laser hardening made it possible to achieve values of microhardness up to 700 Hμ50, and heat resistance of the layer up to 350°С. The service life of products made of these laser-hardened alloys is increased by an average of 4-5 times compared to standard heat treatment.

Photochemical Transformations of Diverse Biologically Active Resveratrol Analogs in Batch and Flow Reactors.

Previous biological tests have shown that some resveratrol analogs exhibited significant antioxidative and cholinesterase inhibitory potential, as evidenced by lower IC50 values compared to the established standards, resveratrol and galantamine, respectively. Photochemical transformations were made in parallel on these compounds in the presence of porphyrin photocatalysts in batch and microreactor, showing the significant advantage of flow photochemistry concerning productivity, selectivity, and yields. In this research, the products of photocatalysis and direct irradiation (photolysis) of resveratrol analogs were compared to elucidate how the types and ratios of the products depend on the excitation energy, to reveal the effects of the substituent on the photoinduced reactions and to rationalize experimentally and computationally the nature and ratio of the obtained products. Thus, two main paths were computed in agreement with the experimental results: isomerization with the participation of triplet state intermediates to yield the experimentally detected cis-isomers and subsequent cyclization following a pathway not available for the trans-isomers. The investigation of five model compounds confirmed the advantages of the flow photoreactor in the photochemical reactions of heterocyclic resveratrol analogs.

MICROBIOLOGICAL QUALITY AND ACCEPTANCE OF GAMMA IRRADIATED FERMENTED MUSHROOM AND CABBAGE DURING STORAGE

For developing countries, safe shelf-stable foods without refrigeration would offer advantages. Gamma ray, an ionizing radiation is known to be a safe technology for treating food products in extending their shelf-life. Studies were carried out to overcome arisen problems of the safe shelf-stable food and to evaluate the suitability of irradiation in preserving local fermented mushrooms (Pekasam Cendawan) and local fermented cabbages. Generally, local fermented mushrooms can be kept in room temperature and under chilled condition only for one and three days respectively. Similarly, local fermented cabbages require chilled condition for storage to avoid the packages bloated upon displayed and storage. Fresh packed fermented products were obtained from local producers and irradiated at doses of 2.0 kGy, 5.0 kGy and 10 kGy, using 60Co gamma irradiation source at MINTec-Sinagama. The irradiated and non-irradiated samples were displayed at room temperature storage periods for 2 weeks, 1 month, 3 months and 6 months. Microbiological analysis was carried out to determine status of bacteria (Total Plate Count) and fungi counts. The results were expressed as colony forming units per gram (cfu/g). Colour changes of the products were recorded using Colorimeter (Minolta) for lightness (L), redness (a) and yellowness (b) values. Acceptability of the irradiated fermented products were determined through sensory evaluation by using 30 members (male and female) of untrained panellists. The fungal and microbial counts in both samples irradiated at 5 and 10 kGy were more lowered than samples irradiated at 2 kGy. After storage at 3 months, the fungal and microbial counts were increased in the both control samples of fermented mushrooms and cabbages but maintained low in both irradiated samples. The control samples of fermented mushrooms (not irradiated) were spoiled after displayed one day in room temperature and after chilled for 3 months. Both irradiated samples at 2 kGy and 5 kGy were more accepted in sensory evaluation especially the texture and taste and no significant changes (P<0.05) in lightness, redness, and redness of fermented cabbage samples during 3 months storage. However, fermented mushroom samples irradiated at 5 kGy become darker after 3 months storage. Irradiation reduced the bloatness in the packaged fermented cabbages by reducing the count of bacteria in the products. These results showed the ability gamma irradiation for decontamination of selected fermented food and reliable process for food storage in commercial industries.