Tolerable Limits Research Articles

A Single Camera Calibration-Free Approach For Dispersion Size Measurement Using Depth From Defocus

The Depth from Defocus (DFD) imaging technique is used to measure the size and number concentration of particles in dispersed two-phase flows, but until now it has primarily been applied to low concentration particle images. This study explores how the technique can be extended to handle overlapping images caused by neighboring particles, significantly broadening the application scope of the DFD technique and enabling measurements at higher particle number/volume concentrations. The processing algorithms are experimentally validated using a dedicated apparatus that can systematically vary particle size, shape, and degree of image overlap. Additionally, this study explores the use of Convolutional Neural Networks (CNN) for this task, comparing these results with those obtained using conventional analyses in terms of accuracy, tolerable concentration limits, and computational speed. This approach requires a large teaching dataset of images, which is only practical and feasible if the dataset can be synthetically generated. An image generation procedure for out-of-focus neighboring spherical particles, resulting in a known blurred image overlap, is therefore first developed. This procedure is validated using laboratory images with known particle size distribution, position, and image overlap before creating the teaching dataset. The trained processing scheme is then applied to both synthetic datasets and experimental data, allowing the evaluation of the technique’s limits in terms of image overlap and tolerable volume concentration, as a function of particle size distribution.

Elemental Composition and Health Risk Assessment of Deep-Sea Teleost's of the Levantine Basin.

The determination of metal(loid) (As, Fe, Al, Sr, Zn, Pb, Mn, Cu, Cr, and Cd) levels in the muscle tissue of 23 different deep-sea bony fish sampled off Mersin Bay (NE Levantine Basin) and the assessment of health risks for human consumption were aimed. Tissue metal(loid) concentrations were determined as dry weight and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The tissue metal(loid) concentrations (µg g dw) were converted to wet weight prior to health risk assessment calculations. Standard mathematical formulas were used to determine the health risk assessment. There was a statistically significant difference between the fish species in terms of tissue metal(loid) levels (p < 0.05). The highest metal(loid) level was found in C. sloani among other species. As and Fe had the highest and Cd the lowest tissue concentrations in the examined species (p < 0.05). The relationships between the metal(loid)s analyzed in the tissue were significant (p < 0.01;0.05). Fe had an antagonistic effect with Cd, while other metal(loid)s had a synergetic effect with each other. Risk assessment analyses were performed for the consumable species, and it was found that the estimated daily and weekly intakes were below the tolerable limits established by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). The target hazard quotient (THQ) values exceeded the threshold of 1 (THQ > 1) only for As. The target cancer risk (TCR) was below the tolerable limits (> 10-5) except for As, Cd, and Al.

Limited drought tolerance in the neotropical seasonally dry forest plants impairs future species richness.

Neotropical seasonal dry forest (NSDF) is one of the most threatened ecosystems according to global climate change predictions. Nonetheless, few studies have evaluated the global climate change impacts on diversity patterns of NSDF plants. The lack of whole biome-scale approaches restricts our understanding of global climate change consequences in the high beta-diverse NSDF. We analysed the impact of global climate change on species distribution ranges, species richness, and assemblage composition (beta diversity) for 1,178 NSDF species. We used five representative plant families (in terms of abundance, dominance, and endemism) within the NSDF: Cactaceae, Capparaceae, Fabaceae, Malvaceae, and Zygophyllaceae. We reconstructed potential species distributions in the present and future (2040-2080), considering an intermediate Shared Socioeconomic Pathway and two dispersal ability assumptions on the taxa. Using a resource use scores index, we related climate-induced range contractions with species' water stress tolerance. Even under a favourable dispersal scenario, species distribution and richness showed future significant declines across those sites where mean temperature and precipitation seasonality are expected to increase. Further, changes in species range distribution in the future correlated positively with potential use of resources in Fabaceae. Results suggest that biotic heterogenization will likely be the short-term outcome at biome scale under dispersal limitations. Nonetheless, by 2080, the prevailing effect under both dispersal assumptions will be homogenization, even within floristic nuclei. This information is critical for further defining new areas worth protecting and future planning of mitigation actions for both species and the whole biome.

Engineering psychrophilic polymerase for nanopore long-read sequencing.

Unveiling the potential application of psychrophilic polymerases as candidates for polymerase-nanopore long-read sequencing presents a departure from conventional choices such as thermophilic Bacillus stearothermophilus (Bst) renowned for its limitation in temperature and mesophilic Bacillus subtilis phage (phi29) polymerases for limitations in strong exonuclease activity and weak salt tolerance. Exploiting the PB-Bst fusion DNA polymerases from Psychrobacillus (PB) and Bacillus stearothermophilus (Bst), our structural and biochemical analysis reveal a remarkable enhancement in salt tolerance and a concurrent reduction in exonuclease activity, achieved through targeted substitution of a pivotal functional domain. The sulfolobus 7-kDa protein (Sso7d) emerges as a standout fusion domain, imparting significant improvements in PB-Bst processivity. Notably, this study elucidates additional functional sites regulating exonuclease activity (Asp43 and Glu45) and processivity using artificial nucleotides (Glu266, Gln283, Leu334, Glu335, Ser426, and Asp430). By disclosing the intricate dynamics in exonuclease activity, strand displacement, and artificial nucleotide-based processivity at specific functional sites, our findings not only advance the fundamental understanding of psychrophilic polymerases but also provide novel insights into polymerase engineering.

Morphological Characteristics and Drought Tolerance of the Diploid and Tetraploid Angelonia angustifolia

Angelonia (Angelonia angustifolia) is an important potted flowering plant or bedding plant widely used in tropical and subtropical regions. However, most Angelonia cultivars have relatively small flowers and demonstrate limited drought tolerance in root-restricted environments such as small containers. Polyploid plants often exhibit larger flowers and enhanced drought tolerance. In this study, Angelonia ‘Serena White’ seeds and ‘Serena Purple’ seedlings were treated with 0.1% and 0.2% colchicine to induce polyploid lines, respectively. The resulting tetraploids had larger pollen and flowers, along with thicker, greener leaves distinguished by serrated edges, longer stomata, and lower stomatal density compared with diploid ‘Serena White’ and ‘Serena Purple’ plants. Both diploid and tetraploid plants subjected to a 20% volumetric water content (VWC) treatment exhibited smaller leaves, higher SPAD-502 readings, and a decreased number of flowers compared with those subjected to 40% VWC treatment. Moreover, tetraploids had higher photosynthetic rates than diploids under both 20% and 40% VWC conditions. When grown in 0.8-L containers, tetraploid plants required fewer watering events and had thicker, erect stems with larger flowers than diploids, even under a 20% VWC treatment. Colchicine-induced polyploidization presents a promising method to potentially enhance drought tolerance in angelonia.

Heavy Metal Levels and Length-Weight Dynamics of Anodontia philippiana (Reeve, 1850) from Barobo and Hinatuan, Surigao del Sur, Philippines

Anodontia philippiana is among the commercially valuable edible clams found in Brgy. Wakat, Municipality of Barobo, and Brgy.Loyola, Municipality of Hinatuan, Surigao del Sur, Philippines. However, anthropogenic activities may pose a threat to the abundance and quality of this species. This study aimed to determine the levels of lead (Pb), nickel (Ni), chromium (Cr), and mercury (tHg) in both the sediments and flesh of A. philippiana using Atomic Absorption Spectrophotometry (AAS). Additionally, the length-weight relationship (LWR) of A. philippiana was assessed to determine the size structure of the species’ population. Among the heavy metals tested, only the concentration of Cr (59±0.38 ppm) in Hinatuan exceeded the prescribed tolerable limit of ≥50 ppm (FAO, 1993). Conversely, the heavy metal levels in the flesh of A. philippiana consistently remained below tolerable limits. Furthermore, A. philippiana from Barobo exhibited a positive allometry (B&gt;3), while those from Hinatuan showed a negative allometry (B&lt;3), suggesting the influence of environmental stressors on growth patterns. The LWR in A. philippiana exhibited significant differences (P&lt;0.001) between the two stations. Despite heavy metal concentrations in A. philippiana flesh and sediments were mostly below standard limits, the observed negative allometric growth pattern in Hinatuan indicates the presence of ecological stressors in the sediments. This study underscores the potential impact of heavy metals on the growth patterns of A. philippiana. It is recommended that regular monitoring of heavy metal concentrations be conducted in these areas. Further studies can provide better insights into morphometric patterns in A. philippiana and other commercially significant bivalves.

Rehydrated corn grain silage with wet brewery residue and different inoculants

The objective was to evaluate the effects of including different proportions of Wet Brewery Residue (WBR) using inoculants on rehydrated ground corn silage quality. The experiment was conducted in a completely randomized design in a 4 x 3 factorial scheme with four replications. Four combinations of WBR and ground corn were evaluated to achieve 45 (DM45), 50 (DM50), 55 (DM55), and 65% (DM65) of dry matter (DM) in the homogenized material before siling, and three types of inoculation: without inoculant, with L. plantarum + P. acidylactici (Homo) and with L. buchneri (L. B). Ensiling was done in experimental PVC silos (±4.0kg) and stored for 180 days. The variables obtained were analyzed by the analysis of variance and regression procedures (P&lt;0.05) using the R software. The percentage of real DM included in the treatments was 47%, 52%, 56%, and 66%. No impairment of the pH-reducing capacity of corn rehydrated with WBR was observed. Total dry matter losses were within the acceptable limit in silage with 52% DM (DM50), regardless of the type of inoculation. Gas losses were within the permissible limit only in the DM50 treatments with Homo inoculant and in the DM50 treatment without inoculation. Effluent losses were outside the tolerable limit in the treatment with 47% DM (DM45) in the presence of the inoculant LB. There was a significant interaction between the inoculant LB and the silages, with 47% (DM45) and 56% (DM55) DM for the Crude Protein (CP) levels. The ADF and NDF variables reduced linearly as a function of the increase in dry matter of the ensiled material, with a tendency for the lowest values to be found in treatments without inoculation. For all variables, an increase in energy levels (Non-Fibrous Carbohydrates, starch, Total Digestible Nutrients, and Net Energy gain) was observed with the increase in the DM content of the silage. It is concluded that silage with 52% DM (DM50) obtained the best results for fermentative losses. For bromatological and energetic characteristics, silage with 66% DM was the best, except for the CP variable, where 47% DM silage achieved superior results. In general, the addition of additives did not show any improvement in relation to treatments without inoculants.

Ultrawide Dynamic Sensing from Single‐Photon Counting to Linear Detection Using a Segmented Superconducting Nanowire

AbstractDespite their exceptional sensitivity, single photon detectors typically exhibit limited tolerance to strong light compared to conventional linear photodetectors. Consequently, a disparity arises between these two detector types, hindering the achievement of both high sensitivity and high dynamic range in sensing and imaging. To bridge this gap, a segmented architecture is implemented with a waveform‐variance readout scheme for extacting high‐flux photon informaiton.This approach gives an unprecedented ultra‐high dynamic range of 75 dB at a fixed bias current, where single photon counting mode and quasi‐linear photodetection mode coexist. High‐dynamic imaging, passive thermal imaging, and joint active and passive imaging are demonstrated, which validate the advantages of this dual‐mode detector. Such a versatile detector will offer enhanced flexibility, single‐photon sensitivity, as well as ultra‐wide dynamic range across various scientific and technical domains.

Plasmoid drift and first wall heat deposition during ITER H-mode dual-SPIs in JOREK simulations

The heat flux mitigation during the thermal quench (TQ) by the shattered pellet injection (SPI) is one of the major elements of disruption mitigation strategy for ITER. It’s efficiency greatly depends on the SPI and the target plasma parameters, and is ultimately characterised by the heat deposition on to the plasma facing components. To investigate such heat deposition, JOREK simulations of neon-mixed dual-SPIs into ITER baseline H-mode and a ‘degraded H-mode’ with and without good injector synchronization are performed with focus on the first wall heat flux and its energy impact. It is found that low neon fraction SPIs into the baseline H-mode plasmas exhibit strong major radial plasmoid drift as the fragments arrive at the pedestal, accompanied by edge stochasticity. Significant density expulsion and outgoing heat flux occurs as a result, reducing the mitigation efficiency. Such drift motion could be mitigated by injecting higher neon fraction pellets, or by considering the pre-disruption confinement degradation, thus improving the radiation fraction. The radiation heat flux is found to peak in the vicinity of the fragment injection location in the early injection phase, while it relaxes later on due to parallel impurity transport. The overall radiation asymmetry could be significantly mitigated by good synchronization. Time integration of the local heat flux is carried out to provide its energy impact for wall heat damage assessment. For the baseline H-mode case with full pellet injection, melting of the stainless steel armour of the diagnostic port could occur near the injection port, which is acceptable, without any melting of the first wall tungsten tiles. For the degraded H-mode cases with quarter-pellet SPIs, which have 1/4 total volume of a full pellet, the maximum energy impact approaches the tolerable limit of the stainless steel with un-synchronized SPIs, and stays well below such limit for the perfectly synchronized ones.

Functional group tolerant hydrogen borrowing C-alkylation

Hydrogen borrowing is an attractive and sustainable strategy for carbon–carbon bond formation that enables alcohols to be used as alkylating reagents in place of alkyl halides. However, despite intensive efforts, limited functional group tolerance is observed in this methodology, which we hypothesize is due to the high temperatures and harsh basic conditions often employed. Here we demonstrate that room temperature and functional group tolerant hydrogen borrowing can be achieved with a simple iridium catalyst in the presence of substoichiometric base without an excess of reagents. Achieving high yields necessitates the application of anaerobic conditions to counteract the oxygen sensitivity of the catalytic iridium hydride intermediate, which otherwise leads to catalyst degradation. Substrates containing heteroatoms capable of complexing the catalyst exhibit limited room temperature reactivity, but the application of moderately higher temperatures enables extension to a broad range of medicinally relevant nitrogen rich heterocycles. These newly developed conditions allow alcohols possessing functional groups that were previously incompatible with hydrogen borrowing reactions to be employed.

Insights into the physiology, biochemistry, and metabolic pathways of ethanol-resistant marine microalgae in phytoplankton

Over two decades have passed since genetically modified prokaryotic cyanobacteria became capable of photosynthetically producing bioethanol. However, the limitation of low ethanol tolerance has impeded bioethanol production. In this study, the findings revealed that eukaryotic marine microalgae exhibited higher tolerance to ethanol compared to freshwater microalgae through a comparison of the growth performance of algal species under ethanol-induced stress. Specifically, the marine microalga Chlorella sp. MEM17 (MEM17) demonstrated tolerance to ethanol concentrations up to 6.0 % (v/v). Additionally, the polysaccharide and unsaturated fatty acid contents of MEM17 were considerably higher compared to ethanol-untreated control groups under ethanol stress. In conjunction with the comparative metabolomics approach, the remodeling of glycerophospholipid metabolic pathways was observed, specifically the conversion of a fraction of the reduced glycerophospholipids into specific glycerophospholipids, thereby enhancing the hindrance of ethanol entry into cells. The up-regulation of amino acid-related metabolic pathways aimed to augment the relative content of specific metabolites, such as gamma-aminobutyric acid (GABA), with the objective of scavenging intracellular reactive oxygen species (ROS). Furthermore, bolstered properties of the cell wall potentially facilitated by the increased polysaccharide content of MEM17 further impeded the potential entry of ethanol into the cell, while excess polysaccharide assisted in scavenging intracellular ROS. This study represents the first discovery of a high-concentration ethanol-tolerant eukaryotic marine microalga and its key metabolic pathways, with potential as “marine photosynthetic cell factories” for bioethanol production.

Resistance of Lactobacillus fermentum InaCC B1295 Encapsulated in Microcrystalline Cellulose from Palm Leaf Waste to Acidic Conditions Across Various Temperatures and Storage Durations"

Lactobacillus fermentum InaCC B1295 is a probiotic bacterium with limited tolerance to acidic environments, bile fluids, and high temperatures, necessitating physical protection via microcrystalline cellulose (MCC) encapsulation derived from palm leaf waste. This study aimed to evaluate the resistance of encapsulated probiotic bacteria under acidic conditions at various temperatures and storage durations to identify the optimal storage temperature. A factorial complete randomized design (CRD) with two factors was employed: storage temperature (room temperature, 4°C, and -18°C) and storage time (0, 7, 14, 21, 28, 35, and 42 days). The results indicated that storage time and the interaction between storage time and temperature significantly affected the total lactic acid bacteria (LAB) count. However, temperature alone and its interaction with storage time did not significantly impact the percentage reduction in the number of encapsulated Lactobacillus fermentum InaCC B1295 at pH 2. Overall, encapsulated bacteria stored at various temperatures demonstrated comparable bacterial resistance..

Facile Generation of Heterotelechelic Poly(2‐Oxazoline)s Towards Accelerated Exploration of Poly(2‐Oxazoline)‐Based Nanomedicine

AbstractControlling the end‐groups of biocompatible polymers is crucial for enabling polymer‐based therapeutics and nanomedicine. Typically, end‐group diversification is a challenging and time‐consuming endeavor, especially for polymers prepared via ionic polymerization mechanisms with limited functional group tolerance. In this study, we present a facile end‐group diversification approach for poly(2‐oxazoline)s (POx), enabling quick and reliable production of heterotelechelic polymers to facilitate POxylation. The approach relies on the careful tuning of reaction parameters to establish differential reactivity of a pentafluorobenzyl initiator fragment and the living oxazolinium chain‐end, allowing the selective introduction of N‐, S‐, O‐nucleophiles via the termination of the polymerization, and a consecutive nucleophilic para‐fluoro substitution. The value of this approach for the accelerated development of nanomedicine is demonstrated through the synthesis of well‐defined lipid‐polymer conjugates and POx‐polypeptide block‐copolymers, which are well‐suited for drug and gene delivery. Furthermore, we investigated the application of a lipid‐POx conjugate for the formulation and delivery of mRNA‐loaded lipid nanoparticles for immunization against the SARS‐COV‐2 virus, underscoring the value of POx as a biocompatible polymer platform.

Facile Generation of Heterotelechelic Poly(2-Oxazoline)s Towards Accelerated Exploration of Poly(2-Oxazoline)-Based Nanomedicine.

Controlling the end-groups of biocompatible polymers is crucial for enabling polymer-based therapeutics and nanomedicine. Typically, end-group diversification is a challenging and time-consuming endeavor, especially for polymers prepared via ionic polymerization mechanisms with limited functional group tolerance. In this study, we present a facile end-group diversification approach for poly(2-oxazoline)s (POx), enabling quick and reliable production of heterotelechelic polymers to facilitate POxylation. The approach relies on the careful tuning of reaction parameters to establish differential reactivity of a pentafluorobenzyl initiator fragment and the living oxazolinium chain-end, allowing the selective introduction of N-, S-, O-nucleophiles via the termination of the polymerization, and a consecutive nucleophilic para-fluoro substitution. The value of this approach for the accelerated development of nanomedicine is demonstrated through the synthesis of well-defined lipid-polymer conjugates and POx-polypeptide block-copolymers, which are well-suited for drug and gene delivery. Furthermore, we investigated the application of a lipid-POx conjugate for the formulation and delivery of mRNA-loaded lipid nanoparticles for immunization against the SARS-COV-2 virus, underscoring the value of POx as a biocompatible polymer platform.

Assessment of the nutritional profiles and potentially toxic elements of wild and farmed freshwater fish in Cambodia

Climate change and pollution are threatening inland freshwater ecosystems which contribute to human well-being by providing food and incomes. To address this issue, aquaculture is expanding sometimes in intensive settings. We aimed to assess the nutritional and contaminant profiles of three fish species (Channa micropeltes, Pangasianodon hypophthalmus, Clarias microcephalus) from the wild ecosystem and caged culture in the Tonle Sap Lake. The mineral profile was assessed by ICP-MS and the overall nutritional quality was characterized by SAIN-LIM scores. Using data on fish consumption by pregnant women, we estimated the daily intakes of several potentially toxic elements. Overall, fish species had similar nutritional profiles, regardless of production method. Only lipid content was higher in caged systems. The production method had no influence on mineral profile and potentially toxic element contents except for mercury higher among wild Pangasianodon hypophthalmus (2.1 µg/100 g). With a consumption of 108 g of fish per day per woman, the median estimated daily intakes of potentially toxic elements were below the tolerable daily limits. However, three women who ate large quantities of fish had mercury intakes (30–32 µg/day) that exceeded the tolerable daily intake. When the rice consumption was taken into account, a high number of women had inorganic arsenic intakes (20–80 µg/day) exceeding the tolerable daily limits. This work is a contribution to the assessment of the risks of arsenic and mercury exposure for pregnant women in Cambodia integrating real food consumption data.

Comparative stress physiological analysis of aluminium stress tolerance of indigenous maize (Zea mays L.) cultivars of eastern Himalaya

Yield potential of maize having distinct genetic diversity in Eastern Himalayan Region (EHR) hill ecologies is often limited by Al toxicity caused due to soil acidity. Stress physiological analysis of local check exposed to 0–300 μM Al under sand culture revealed that 150 μM Al as critical and 200 μM Al as tolerable limit. Increase in Al from 0 to 300 μM reduced total chlorophyll, carotenoids by 74.8 % and 44.7 % respectively and enhanced anthocyanin by 35.3 % whereas LA, SLW and SL have reduced by 81.3%, 21.3 % and 47.8 % respectively. R/S ratio was 51.0 and 13.7 % higher at lower Al levels (50 μM and 100 μM) and photosynthetic, transpiration rate and TDM were 62.5 %, 42.9 % and 78.6 % lower at higher Al (300 μM) as compared to control. TRL, RSA, RDW and RV at higher Al (300 μM) were 92.6 %, 98.7 %, 78.7 and 97.5 % lower over control respectively. Root and shoot Al and PUpE at higher Al (300 μM) was 194.0, 69.2 and 830 % higher whereas PUE decreased to 88.5 % over control. Evaluation of 31 indigenous maize cultivars at 0, 150, and 250 μM Al in sand culture, alongside tolerance scoring and assessment, revealed that Megha-9, Megha-10, and MZM-19 exhibits high Al tolerance, Megha-1, MZM-22, and MZM-42 demonstrated moderate tolerance, whereas Uruapara, Sublgarh, and BRL Para were identified as Al-sensitive. Stress physiological parameters like SDW, TDM, TRL, SL and LA contributed 46.02 % of variability to PC1, whereas A, RV, RSA, anthocyanin and Chlorophyll_b, contributed 13.56 % of variability to PC2. Highest values of CMS, SL, LP, LA, TRL and anthocyanin were recorded in cluster I having sensitive cultivars while highest CMS, SL, LA, LP, TRL and RSA were found in cluster II having moderately tolerant cultivars and highest mean values for TRL, RSA, LP, LA, CMS and SL were recorded in cluster III having highly Al stress tolerant cultivars. The traits viz., A, RV, RSA, anthocyanin and Chlorophyll_b, total chlorophyll and TDM were emanated as physio-morphological for assessing Al toxicity stress tolerance in Maize with high divergence values. Tolerant cultivars showing 63.4 % and 22.4 % higher anthocyanin at 150 μM Al and 250 μM Al than moderately tolerant one in acid soil experiment with increased root Al, shoot Al, root P and shoot P by 42.6 %, 11 %, 95.1 % and 34 % respectively were emerged as promising for novel maize improvement under acid soils of EHR.

Fungal Isolation, Detection, and Quantification of Aflatoxins in Nuts Sold in the Lebanese Market

This study examines the prevalence of aflatoxin contamination in 160 nut samples, both shelled and unshelled (including pistachios, peanuts, and walnuts), from the Lebanese market, focusing on their fungal contamination and specific toxigenic strains. Aflatoxin B1 (AFB1), known for its potent carcinogenic and immunosuppressive properties, was detected in various samples. Moisture content analysis showed that unshelled nuts often exceeded maximum moisture limits more frequently than shelled nuts, with levels ranging from 1.9 to 9.5%. The predominant fungal genus identified through cultivation on potato dextrose agar (PDA) plates was Aspergillus. In total, 55% of samples were contaminated with A. flavus and 45% with A. niger. All toxigenic strains isolated were identified as Aspergillus flavus. The aflatoxins, particularly AFB1, were quantified using the enzyme-linked immunosorbent assay (ELISA) and reversed-phase high-performance liquid chromatography (HPLC), revealing contamination in 43.8% of the samples, with concentrations ranging from 0.4 to 25 µg/kg. Some samples notably exceeded the established maximum tolerable limits (MTLs) for AFB1, set between 2 and 8 µg/kg. Shelled pistachios showed the highest contamination rate at 52% and were the most frequent to surpass the MTL of 8 µg/kg for pistachios, whereas walnuts displayed the lowest contamination levels, with only 15.4% exceeding the MTL for aflatoxins.

Perencanaan Perawatan Mesin Injection Molding Dengan Menggunakan Metode Realibility Centered Maintenance PT. Bolde Makmur Indonedia

The instability of the economy and increasingly sharp competition in the industry requires a company to further enhance the efficiency of its operations. Treatment method that has been used is still corrective maintenance where engine maintenance activities undertaken to improve and enhance the condition of the engine so as to achieve the standards set at the level tersebut.Besarnya machine downtime which reaches up to 40% each month. Due to the growing number of downtime that occurs it will be increasingly detrimental to the productivity of a company. In this study used methods Realibility Centered Maintenance abbreviated to (RCM), which is to determine the optimal engine maintenance activities for the company. Reliability Centered Maintenance (RCM) is an approach that combines maintenance practices and strategies of preventive maintenance (PM) and corrective maintenance (cm) to maximize the life (life time) and the function of assets / systems / equipment at a minimal cost. Subjects studied machine is the machine Injection Molding, where the focus of engine components that will be examined as many as six parts: Barrel, Piston Injection, Toggle Clamping, Nozzle, Hydro Motor, Hopper. As for the category based on time (TD), the treatment provided in the form of component replacement schedule. Category finding damage (FF) recommended replacement components if the level of damage exceeds tolerable limits. Failure of components that include safety problem 13:33%, Outage System 80.00%, 6.67% Economic System. Of the total minimum downtime obtained Screw interval of 30 days, the crosshead link 11 days, Seal 13-day, 12-day screening. Downtime Screw impairment 37.21%, 41.15% crosshead link, Seal 24.56%, and 29.32% Screening

The potential effect of silver nanoparticles to inhibit microbial activity in orthodontic adhesive appliances: A literature review

Silver nanoparticles have been the focus of research in various areas of dentistry, including orthodontics. Orthodontic treatment requires a long period of time, so the brackets are in the oral cavity for a long time. This can potentially trigger the formation of white spot lesions because plaque sticks more easily to the surrounding enamel. Using silver nanoparticles mixed with orthodontic adhesives has been reported to increase antibacterial and antimicrobial characteristics. This literature review aims to investigate the effect of adding silver nanoparticles to orthodontic adhesive devices in inhibiting antimicrobial activity. This study method was carried out by searching the online electronic databases PubMed, Science Direct, and Google Scholar with the keywords "silver nanoparticles AND antimicrobial", "silver nanoparticles AND orthodontic adhesive", "silver nanoparticles AND composite resin", which is an original article published the year 2019- 2023. The results of research from 10 articles that met the inclusion criteria showed that orthodontic adhesives with silver nanoparticles effectively inhibited microbial activity, such as Streptococcus mutans (S.mutans), Lactobacillus acidophilus (L.acidophilus), Streptococcus sanguinis (S.sanguinis) and Candida albicans through increased release of Ag+ ions. Silver has been known to have effects, including producing minimal bacterial resistance compared to antibiotics. Even though it results in a decrease in the shear bond strength (SBS), the decrease level is still within clinically tolerable limits. It can be concluded that research needs to continue to be developed to obtain the right concentration and composition of the addition of silver nanoparticles so that an orthodontic adhesive material is obtained that is not only superior in its antibacterial properties but also in its mechanical properties.

Chemo-and regioselective aqueous phase, co-acid free nitration of aromatics using traditional and nontraditional activation methods.

Electrophilic aromatic nitrations are used for the preparation of a variety of synthetic products including dyes, agrochemicals, high energy materials, fine chemicals and pharmaceuticals. Traditional nitration methods use highly acidic and corrosive mixed acid systems which present a number of drawbacks. Aside from being hazardous and waste-producing, these methods also often result in poor yields, mostly due to low regioselectivity, and limited functional group tolerance. As a consequence, there is a need for effective and environmentally benign methods for electrophilic aromatic nitrations. In this work, the major aim was to develop reaction protocols that are more environmentally benign while also considering safety issues. The reactions were carried out in dilute aqueous nitric acid, and a broad range of experimental variables, such as acid concentration, temperature, time, and activation method, were investigated. Mesitylene and m-xylene were used as test substrates for the optimization. While the optimized reactions generally occurred at room temperature without any activation under additional solvent-free conditions, slight adjustments in acid concentration, stoichiometric equivalents, and volume were necessary for certain substrates, in addition to the activation. The substrate scope of the process was also investigated using both activated and deactivated aromatics. The concentration of the acid was lowered when possible to improve upon the safety of the process and avoid over-nitration. With some substrates we compared traditional and nontraditional activation methods such as ultrasonic irradiation, microwave and high pressure, respectively, to achieve satisfactory yields and improve upon the greenness of the reaction while maintaining short reaction times.