Airtight Chamber Research Articles

Insight into physiological and biochemical markers against formaldehyde stress in spider plant (Chlorophytum comosum L.).

Formaldehyde is a prominent volatile organic compound and also considered as an indoor air pollutant. Chlorophytum comosum, an indoor plant, has been reported to metabolize indoor formaldehyde. But the phytotoxic effects of formaldehyde, being a pollutant, on C. comosum are not well explored. Furthermore, C. comosum responses that can be considered as markers at the physiological and biochemical level against formaldehyde stress are not yet investigated. Therefore, the current research study was aimed to evaluate such potential markers against formaldehyde in C. comosum. Briefly, C. comosum was exposed to 5-, 10-, and 20-ppm formaldehyde doses in an airtight glass chamber. Plant samples were then taken to analyze morpho-anatomical, physiological, and biochemical responses after short (2, 4, and 6h), medium (12 and 24h), and extended durations (48 and 96h) for each tested dose. Application of 10 and 20ppm formaldehyde doses leads to a significant incline in enzymatic antioxidants. Formaldehyde concentration of 10ppm leads to a maximum increase in catalase (30.30 U/mg of protein), guaiacol peroxidase (135.64 U/mg of protein), and superoxide dismutase (44.76 U/mg of protein) compared to their respective controls. A significant change is also observed in non-enzymatic parameters, including total phenolic content, which ranged from 3.62mg GAE/g (control) to 10.51mg GAE/g, total antioxidants vary from 27.37% (control) to 85.05% in 20ppm formaldehyde, respectively. However, formaldehyde application negatively affected the physiological responses of C. comosum by reducing its photosynthetic rate, transpiration rate, and stomatal conductance. Additionally, extended exposure of C. comosum to 10- and 20-ppm formaldehyde doses leads to visible leaf damage. Principal component analysis indicated that enzymatic parameters including SOD, CAT, and GPX and non-enzymatic parameters including MDA, TPC, TFC, TAOs, carotenoids, TSS, and intercellular CO2 contributed the most to the total variance. Thus, these parameters have potential to serve as physiological and biochemical markers in C. comosum against formaldehyde stress.

Suppression of B-type natriuretic peptide gene expression in cardiomyocytes under anoxic conditions

Several cell biology studies have focused on the effects of hypoxic environments on cardiomyocytes. However, the effect of anoxic conditions on cardiomyocytes remains largely unexplored. In the present study, we investigated the direct effects of anoxia on B-type natriuretic peptide (BNP) gene expression in cardiomyocytes. Neonatal rat cardiomyocytes (NRCMs) were exposed to anoxia using an airtight chamber saturated with 95% N2/5% CO2. BNP mRNA levels in NRCM were substantially reduced after more than 8hours of anoxia exposure, whereas after reoxygenation, BNP gene expression levels recovered in a time-dependent manner and significantly increased after 24hours of reoxygenation. BNP mRNA levels suppressed under anoxic conditions were significantly increased by aldosterone-induced activation of sodium-proton exchanger 1 (NHE1), which was cancelled by an NHE1 inhibitor, suggesting that anoxia reduces BNP gene expression, at least in part, in an NHE1-dependent manner. In summary, we found that BNP gene expression in cardiomyocytes decreases under anoxic conditions, in contrast to previous research findings that BNP expression increases under hypoxic conditions. These findings reveal a new insight that, within a single heart tissue in various cardiovascular diseases, such as myocardial infarction, the biological responses of cardiomyocytes are fundamentally different in regions of anoxia and hypoxia.

Use of Melinex film for flat embedding tissue sections in LR White.

Tissue slices can undergo distortions during processing into resin for light and electron microscopy as a result of differential shrinkage of the various tissue components, and this may necessitate removal of a considerable amount of material from the final resin-embedded tissue block to ensure production of complete sections of the sample. To mitigate this problem, a number of techniques have been devised that ensure the sample is held flat during the final curing/polymerisation of the resin. For embedding in acrylic resins, oxygen must be excluded as it inhibits polymerisation, and methods devised for epoxy resin embedding are generally unsuitable. The method describes the preparation and use of air-tight flat-embedding chambers prepared from Melinex film and provides an inexpensive, technically simpler, and versatile alternative to chambers formed from either Thermanox coverslips or Aclar films that have previously been advocated for such purposes. Lay description: Tissue slices can undergo distortions during processing into resin for light and electron microscopy as a result of differential shrinkage of the various tissue components. Such distortions may necessitate removal of a considerable amount of material to ensure production of complete sections of the sample. For embedding in acrylic resins, oxygen must be excluded as it inhibits polymerisation, and methods devised for epoxy resin flat-embedding are generally unsuitable. Air-tight flat-embedding chambers prepared from either Thermanox coverslips, or a combination of PTFE-coated glass slides, polycarbonate film gaskets, and Aclar film have been advocated for such purposes. Thermanox coverslips are expensive and limited in size to 22mm × 60mm, and the alternative method is technically complicated. Melinex film is commercially available as 210mm × 297mm sheets and is approximately 1/20th the price of Thermanox and less than half the price of Aclar film. The method describes the preparation and use of embedding chambers made from Melinex film, glass slides and double-sided adhesive tape as a technically simpler, inexpensive and versatile alternative to both Thermanox coverslips and the Aclar film method.

Noble Dome: A Novel Air-Free Transfer System For Battery Research with Electron Microscopy

"Noble Dome: A Novel Air-Free Transfer System" introduces an innovative solution for loading air-sensitive samples into SEM/FIB instruments. Traditional loading methods expose samples to atmosphere during transfer, hindering investigations of reactive materials. The presented prototype, Noble Dome, directly attaches to the SEM/FIB, enabling sample transfer in an oxygen-free environment. The device's design and operational process are outlined, including airtight chambers, gas introduction, and modified venting systems. Experimental results demonstrate Noble Dome's effectiveness in preserving sample integrity. Compared to existing solutions, which often pose limitations, Noble Dome offers a practical approach for various research needs.Imaging and micromanipulation techniques such as Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB) can reveal critical information about the microstructure and composition of materials. To utilize these techniques, a sample must be loaded into the chamber of the instrument which is then pumped down to low vacuum conditions. In the process of removing a sample from its packaging and mounting it on the SEM/FIB stage, the sample is briefly exposed to atmosphere. This is problematic for researchers who are interested in investigating air sensitive samples or samples for which atmospheric contamination would detract from the investigation. This set of samples includes metals commonly used as battery materials such as lithium and sodium, which are highly reactive with elements in the air such as moisture or oxygen.We present a prototype for a glove box load lock that addresses this problem directly. This device attaches directly onto the side of a SEM/FIB and allows researchers to remove a sample from packaging and transfer it directly on the stage via an accessory port of the SEM/FIB in an oxygen-free environment and then pump the tool down to vacuum without any atmospheric exposure in the process, eliminating the use of an intermediary shuttle from a separate glove box. We call this device Noble Dome.In order to test Noble Dome’s ability to protect samples from atmosphere, we imaged and collected EDS spectra on the same location of a lithium metal sample in a pristine state, after sitting in Noble Dome for 30 minutes, and after sitting in atmosphere for 30 minutes.We note that there was very little change in the surface topography and oxygen counts between the sample in its pristine state and the sample after sitting in Noble Dome for 30 minutes. However, there is a marked increase in surface oxidation and topography after the sample sat in atmosphere for 30 minutes.Lithium-ion batteries are increasingly prolific in the landscape of modern technology. In order to improve the energy density, life cycle and safety of lithium-ion batteries, researchers require significant amounts of materials characterization pre-assembly, post-assembly and after several charge/discharge cycles. Electron microscopy is crucial for effective materials characterization, which necessitates a solution for loading samples into the vacuum chamber of the microscope without exposing these reactive samples to air.Other solutions currently on the market for loading air sensitive samples into a SEM/FIB involve manipulating the sample in a glove box which is separate from the instrument, loading the sample into an inert gas transfer shuttle which is closed by remote control, removing the shuttle from the glovebox, loading the shuttle into the SEM/FIB, and then opening the sample again via remote control. These solutions are not ideal because they're very expensive, have a variety of limitations on sample size, stage travel, and signal strength, and are high tech solutions prone to costly malfunction. These drawbacks highlight the demand for a more practical and efficient approach.The presented prototype, Noble Dome, addresses the challenge of loading air-sensitive samples into SEM/FIB instruments with a practical and innovative approach. The device eliminates the need for an intermediary glove box and inert gas transfer shuttle, allowing direct sample transfer onto the stage in an oxygen-free environment. The results demonstrate Noble Dome's efficacy in preserving sample integrity by minimizing atmospheric exposure, as evidenced by the minimal changes observed in surface topography and composition compared to samples exposed to atmosphere. Noble Dome enables research on reactive samples, used to pursue a carbon-free future. Figure 1

An ethically guided preclinical device for phenotyping H2 production in laboratory rodents.

Dihydrogen (H2) is produced endogenously by the intestinal microbiota through the fermentation of diet carbohydrates. Over the past few years, numerous studies have demonstrated the significant therapeutic potential of H2 in various pathophysiological contexts, making the characterization of its production in laboratory species of major preclinical importance. This study proposes an innovative solution to accurately monitor H2 production in free-moving rodents while respecting animal welfare standards. The developed device consisted of a wire rodent cage placed inside an airtight chamber in which the air quality was maintained, and the H2 concentration was continuously analyzed. After the airtightness and efficiency of the systems used to control and maintain air quality in the chamber were checked, tests were carried out on rats and mice with different metabolic phenotypes, over 12 min to 1-h experiments and repeatedly. H2 production rates (HPR) were obtained using an easy calculation algorithm based on a first-order moving average. HPR in hyperphagic Zucker rats was found to be twice as high as in control Wistar rats, respectively, 2.64 and 1.27 nmol.s-1 per animal. In addition, the ingestion of inulin, a dietary fiber, stimulated H2 production in mice. HPRs were 0.46 nmol.s-1 for animals under control diet and 1.99 nmol.s-1 for animals under inulin diet. The proposed device coupled with our algorithm enables fine analysis of the metabolic phenotype of laboratory rats or mice with regard to their endogenous H2 production.

Optimization of Matrix Components for Improved Catalytic Activities of Cellulase Immobilized on Biochar-Chitosan Beads

Bioethanol is a renewable energy that is gaining popularity globally. It’s biochemical production requires the use of enzyme, especially cellulase. Cellulase is an enzyme that catalyzes the degradation of cellulose and related polysaccharides which finds applications in food, textiles, detergents, biofuels etc. However, the worldwide use of cellulase is limited by its relatively high production costs and low biological activity. This study was design to locally produce biochar-chitosan beads at optimized conditions to immobilize cellulase for improved thermal and storage stability as well as ensure reusability of the enzyme so as to improve biological activity and avoid the continuous production of free cellulase thereby reducing the production cost. Biochar was produced by pyrolyzing sugarcane bagasse in a local airtight chamber for 1 hour. Beads were formed from different ratios of biochar and chitosan in varying concentrations of calcium chloride solution as generated by design expert software version 13. The beads were dried in an oven at 50 0C for 24 hours and functionalized in 25% glutaraldehyde (GDA). The beads were loaded with enzyme (10.06 µmole/min/mL) at room temperature (27 ± 3 oC). Enzyme activity, thermal stability, storage stability and reusability tests were carried out according to standard procedures. The half-life and activation energy were also evaluated. The result showed that the optimum activity of the loaded enzyme (2.63 µmole/min/mL) was obtained when 2.46 g of porous biochar was mixed with 2.48 g chitosan in 5 % Calcium chloride aqueous solution. The immobilized enzyme was able to maintain thermal stability between 30 oC and 70 oC while the activity for free enzyme started declining after 50 oC. Also, the activation energy for immobilized cellulase enzyme (23.17 KJ/mol) was lower than the activation energy (55.146 KJ/mol) for free cellulase. The half-life, when stored at ambient Temperature (27 ± 3 oC), for free enzyme was 0.4 days while the half-life for immobilized enzyme was 3.59 days. Therefore, cellulase immobilized on support locally produced at optimal conditions had improved catalytic properties when compared to the free enzyme. Hence, more indigenous materials and practices may be employed for a cost effective and cheaper industrial processes.

An Individual Barrier Enclosure Actively Removing Aerosols for Airborne Isolation: A Vacuum Tent.

Aerosol barrier enclosure systems have been designed to prevent airborne contamination, but their safety has been questioned. A vacuum tent was designed with active continuous suctioning to minimize risks of aerosol dispersion. We tested its efficacy, risk of rebreathing, and usability on a bench, in healthy volunteers, and in an ergonomic clinical assessment study. First, a manikin with airway connected to a breathing simulator was placed inside the vacuum tent to generate active breathing, cough, and CO2 production; high-flow nasal cannula (HFNC) was applied in the manikin's nares. Negative pressure was applied in the vacuum tent's apex port using wall suction. Fluorescent microparticles were aerosolized in the vacuum tent for qualitative assessment. To quantify particles inside and around vacuum tent (aerosol retention), an airtight aerosol chamber with aerosolized latex microparticles was used. The vacuum tent was tested on healthy volunteers breathing with and without HFNC. Last, its usability was assessed in 5 subjects by 5 different anesthesiologists for delivery of full anesthesia, including intubation and extubation. The vacuum tent was adjusted until no leak was visualized using fluorescent particles. The efficacy in retaining microparticles was confirmed quantitatively. CO2 accumulation inside the vacuum tent showed an inverse correlation with the suction flow in all conditions (normal breathing and HFNC 30 or 60 L/min) in bench and healthy volunteers. Particle removal efficacy and safe breathing conditions (CO2, temperature) were reached when suctioning was at least 60 L/min or 20 L/min > HFNC flow. Five subjects were successfully intubated and anesthetized without ergonomic difficulties and with minimal interference with workflow and an excellent overall assessment by the anesthesiologists. The vacuum tent effectively minimized aerosol dispersion. Its continuous suction system set at a high suction flow was crucial to avoid the spread of aerosol particles and CO2 rebreathing.

Study on the test accuracy of the high-air-volume purifier under different test chamber volumes

Due to the increasing local purification demand of public spaces during production processes, high-air-volume purifiers (HAVPs) with flow rates >800 m3/h have been increasingly applied in commercial and industrial spaces. Compared with clean air standards in the United States, Europe and other countries, relevant HAVP detection guidelines have not been standardized in most countries, and only Chinese and South Korean standards consider scaling HAVP test chambers. There remains a lack of theoretical and experimental HAVP detection studies. In this study, the airtight test chamber decay method was used, and the chamber size was increased by a ratio of 1:2:3 based on the original volume (30 m3). The effect of the test chamber volume on the HAVP accuracy was evaluated considering the amount of valid data, pollutant uniformity, and air cleaner position. Based on the results, the clean air delivery rate (CADR) deviation varied between 1.4% and 35.7% under the effect of the test chamber volume. The test accuracy was higher for the 60 m3 test chamber, which is more suitable for HAVP testing. A new index based on the CADR–test chamber volume relationship was proposed, revealing that the air cleaner performance can be accurately measured when the equivalent clean air volume ventilation rate varies between 9 and 22 L/h. The upper HAVP detection limit should be considered in standard supplementation. The HAVP flow rate classification in Chinese standards should be refined. The results provide a reference for rapid selection of the appropriate test chamber volume for air cleaners with different flow rates, which facilitates HAVP application in industrial and commercial spaces.

Determining Formaldehyde Phytoremediation Efficacy of Selected Ornamental Plants

In the recent past, deterioration of indoor air quality has become a serious concern due to the increased energy efficiency and reduced air exchange rate inside urban buildings. Volatile organic compounds (VOCs) are a major category of indoor air pollutants that can lead to adverse health outcomes such as headaches, allergies and asthma in those exposed for prolonged periods. Formaldehyde, the VOC used in the present study is a common contaminant of indoor air which originates from particle board, plywood, paper products, certain adhesives, tobacco smoke and other sources. The use of plants for the mitigation of indoor air pollution is viewed as a cost effective and eco-friendly method with untapped potential. The main objective of the present study was to determine the formaldehyde removal efficacy of selected plant species while investigating the mechanisms used by these plants in the removal process. The selected plant species were Zamioculcas zamiifolia, Hedera helix, Dracaena sanderiana and Ficus sp. Plants of the same age were used with three replicates from each species. Phytoremediation potential was assessed by exposing the plants for 24 hours to gaseous formaldehyde (2.0 μL L-1) in air tight chambers made of Plexiglass (an inert material for VOCs) with dimensions of 0.9 m height×0.58 m length×0.55 m width. Formaldehyde removal was measured using GC-MS and the result was expressed as removal percentages. Several leaf anatomical characters (cuticle thickness, epidermal thickness and mesophyll layer thickness), stomatal characters (stomatal density, stomatal index, guard cell length and potential conductance index) and physiological characters (stomatal conductance and photosynthetic rate) were measured to study the possible mechanisms involved in the formaldehyde removal process. The data were subjected to ANOVA and Pearson correlation test. According to the results obtained, Ficus sp. had the highest formaldehyde removal percentage (92.80%) while Hedera helix had the lowest (56.86%). The study further showed that stomatal density and stomatal conductance play a major role in formaldehyde removal by these plants while cuticle and epidermal thickness act as hindrances to this process. This conclusion was further confirmed by Pearson‘s correlation values in correlation analysis. The current study was carried out for 24 hours of exposure and it would be of interest to explore, the long term behavior of the plants through further studies. Overall, the results justify future studies on a cross-section of diverse plant species for formaldehyde removal efficiency to determine species with superior removal efficiencies for a better phytoremediation process. 
 Keywords: Phytoremediation, VOCs, Formaldehyde, GC-MS technology

In situ neutron imaging of lithium-ion batteries during heating to thermal runaway

Lithium-ion batteries (LIBs) have become essential components that power most current technologies, such as smartphones and electric vehicles, thus making various safety evaluations necessary to ensure their safe use. Among these evaluations, heating tests remain the most prominent source of safety issues. However, information on the phenomena occurring inside batteries during heating has remained inaccessible. In this study, we demonstrate the first in situ neutron imaging method to observe the internal structural deformation of LIBs during heating. We developed an airtight aluminium chamber specially designed to prevent radioactive contamination during in situ neutron imaging. We successfully observed the liquid electrolyte fluctuation inside a battery sample and the deformation of the protective plastic film upon heating up to thermal runaway. Hence, this work provides the foundation for future investigations of the internal changes induced in batteries during heating tests and experiments.

Additively Manufactured Porous Filling Pneumatic Network Actuator

This research project investigated the additive manufacturing of pneumatic actuators based on the principle of droplet dosing using an Arburg Freeformer 300-3X 3D printer. The developed structure consists of a porous inner filling and a dense, airtight chamber. By selectively varying the filling densities of the porous inner filling, different membrane deflections of the actuator were achieved. By linking the actuators, a pneumatic network actuator was developed that could be used in endorobotics. To describe the membrane deflection of an additively manufactured pneumatic actuator, a mathematical model was developed that takes into account the influence of additive manufacturing and porous filling. Using a dedicated test rig, the predicted behavior of the pneumatic actuators was shown to be qualitatively consistent. In addition, a pneumatic network actuator (PneuNet) with a diameter of 17 mm and a height of 76 mm, consisting of nine chambers with different filling densities, could be bent through 82° under a pressure of 8 bar. Our study shows that the variation of filling densities during production leads to different membrane deflections. The mathematical model developed provides satisfactory predictions, although the influence of additive manufacturing needs to be determined experimentally. Post-processing is still a necessary step to realize the full bending potential of these actuators, although challenges regarding air-tightness remain. Future research approaches include studying the deflection behavior of the chambers in multiple directions, investigating alternative materials, and optimizing the printing process to improve mechanical properties and reliability.

Investigation of euthanasia techniques in four species of cockroaches

While cockroaches are commonly exhibited in zoos and museums, studied in research laboratories, and even kept as pets, scientifically based guidelines for their euthanasia are lacking. This study assessed euthanasia techniques in four species of cockroaches (Dubia (Blaptica dubia), red runner (Shelfordella lateralis), Madagascar hissing (Gromphadorhina portentosa), and giant cave (Blaberus giganteus)). In an initial pilot study, two hundred fifty adult Dubia cockroaches were exposed in groups of ten to a cotton ball soaked with 2 mL of isoflurane in a 1 L air-tight chamber. Thirty minutes beyond loss of any individual movement, groups were exposed to one of the following secondary treatments: freezing at −18 °C or −80 °C from 0.25 to 24 hours; immersion in 10% neutral buffered formalin, 70% isopropyl alcohol, or reverse osmosis water for 0.25 or 0.5 hours; or intracoelomic injection of potassium chloride (456 mEq/kg) or pentobarbital-based euthanasia solution (3.9 g/kg). A control group remained in the air-tight isoflurane chamber for 24 hours. Following all treatments, cockroaches were monitored for an additional 24 hours for spontaneous movement. Irreversible loss of movement was considered synonymous with irreversible loss of consciousness (death). Across all species, isoflurane anesthesia followed by either 70% isopropyl alcohol immersion for 0.25 or 0.5 hours or isoflurane exposure for 24 hours resulted in euthanasia in 100% of cockroaches. This study is the first evaluation of American Veterinary Medical Association-recommended euthanasia protocols in cockroaches.

Biological nitrogen fixation in rice paddy soils is driven by multiple edaphic factors and available phosphorus is the greatest contributor

Biological nitrogen fixation (BNF) is important for sustainable rice cultivation. Various edaphic factors have been individually evaluated for their effects on BNF in paddy soils. However, no single factor could fully explain the different soil outcomes. Paddy BNF is more likely to be simultaneously influenced to various degrees by combinations of several factors; however, the relative importance of the interaction of multiple edaphic factors on the regulation of BNF in rice soils is still unclear. Twenty-seven paddy soil samples with different soil properties were collected from major cropping areas in southwest and northeast China. Rice was transplanted into pots of these soils and grown in a 15N2 enriched airtight chamber. Estimation of BNF was based on measurements of 15N enrichment in the different soils and rice plants at the end of a 77-d incubation period. BNF amounts ranged from 0.66 to 12.3 kg ha−1. BNF had a significant positive relationship with available phosphorus (AP) and significant quadratic relationships with available molybdenum (AMo) and total soil nitrogen (TN). AP explained 42% of the observed variation in BNF, TN explained 17%, and AMo explained 13%. The specific interaction between the soil cation exchange capacity (CEC) and available soil N (ASN, as determined by rice N uptake) accounted for 28% of the variation. BNF was reduced when AP was < 14 mg kg−1, AMo < 0.09 mg kg−1, or when TN was > 3.2 g kg−1. These results provide valuable benchmarks that could be used to guide farmers in managing their soils to improve the potential contribution of paddy BNF to soil fertility.

Calibration of Sensor Network for Outdoor Measurement of PM2.5 on High Wood-Heating Smoke in Temuco City

In order to ascertain the spatial and temporal changes in the air quality in Temuco City, Chile, we created and installed a network of inexpensive sensors to detect PM2.5 particulate matter. The 21 measurement points deployed were based on a low-cost Sensiron SPS30 sensor, complemented with temperature and humidity sensors, an Esp32 microcontroller card with LoRa and WiFi wireless communication interface, and a solar charging unit. The units were calibrated using an airtight combustion chamber with a Grimm 11-E as a reference unit. The calibration procedure fits the parameters of a calibration model to map the raw low-cost particle-material measurements into reliable calibrated values. The measurements showed that the concentrations of fine particulate material recorded in Temuco present a high temporal and spatial variability. In critical contamination episodes, pollution reaches values as high as 354 µg/m3, and at the same time, it reaches 50 µg/m3 in other parts of the city. The contamination episodes show a similar trend around the city, and the peaks are in the time interval from 07:00 PM to 1:00 AM. In the winter, this time of day coincides with when families are usually home and there are low temperatures outside.

Infrared Spectroscopy to Assess Manufacturing Procedures of Bone Artefacts from the Chalcolithic Settlement of Vila Nova de São Pedro (Portugal)

Vibrational spectroscopy was applied to study cylindrical engraved bone boxes from the Chalcolithic settlement of Vila Nova de São Pedro (VNSP, Azambuja, Portugal) which has the largest and richest artefact assemblage of Copper Age Western Iberia. The objectives were to reconstitute manufacturing techniques, determine the role of pyrotechnology in the production of cylindrical engraved bone boxes and assess oxygen conditions during burning. Four fragments of cylindrical engraved bone “boxes” from VNSP were used in this research. Anaerobic experimental burn conditions were recreated by using a home-made steel airtight chamber under vacuum. Human bone fragments were burnt at 400–1000 °C for 120–211 min. Fourier-transform infrared spectroscopy analyses were performed on bone powder samples. The resulting spectra and chemometric indices were used as a reference to establish comparisons with the archaeological artefacts. None of these presented spectral features compatible with anaerobic burning. Therefore, aerobic burns were used to achieve the whitish look and were most probably used to attain the darker shade displayed by the artefacts. Artefact manufacturing appears to have relied on bone cutting, bone engraving and maybe polishing, followed by heat treatment. The population from VNSP appears to have been highly specialized in the use of fire to work different raw materials.

A mechanistic study on the CO2 activation over Pd-containing MCM-22 zeolite based on DRIFT analysis: Impact of counter cations in the zeolite framework

Zeolites have been playing an important role in the field of so-called “Carbon dioxide Capture, Utilization, and Storage (CCUS)”. Catalytic activation of CO2 over zeolite-based catalysts has been extensively investigated, while many issues remain unsolved. In this study, the MWW-type zeolites impregnated with the Pd nanoparticles were used as the catalysts for CO2 activation. Furthermore, various amounts of charge balance cations (Na+ and H+) were added to the Pd-MWW with the intention of improving CO2 adsorption capacity. A fixed-bed reactor equipped with the Mass Spectrometer for effluent gas analysis was used to evaluate the steady-state conversion of the CO2 activation on these as-prepared catalysts from 50 to 650 °C. The compositions of the effluent gases and their associated quantities were monitored for each test. Finally, two infrared techniques (steady-state and dynamic measurements) were applied to identify the spectroscopic evidence of the heterogeneous catalysis reaction. In the first technique, the amount of chemisorbed CO2 was quantified by the infrared transmitted intensity across the samples from the vacuum to various levels of CO2 pressure at ambient temperature. The second technique investigates the hydrogenation mechanisms of adsorbates by the time-resolved FTIR with an in-situ diffusive reflectance airtight chamber. Both methods facilitated the infrared spectra of surface-adsorbed species during the hydrogenation. In combination with the temperature-programmed CO2 activation tests, this research prompted to reveal the kinetic mechanisms of CO2 activation.

Measuring O2 Consumption in Drosophila Melanogaster using Coulometric Microrespirometry.

Coulometric microrespirometry is a straightforward, inexpensive method for measuring the O2 consumption of small organisms while maintaining a stable environment. A coulometric microrespirometer consists of an airtight chamber in which O2 is consumed and the CO2 produced by the organism is removed by an absorbent medium. The resulting pressure decrease triggers electrolytic O2 production, and the amount of O2 produced is measured by recording the amount of charge used to generate it. In the present study, the method has been adapted to Drosophila melanogaster tested in small groups, with the sensitivity of the apparatus and the environmental conditions optimized for high stability. The amount of O2 consumed by wildtype flies in this apparatus is consistent with that measured by previous studies. Mass-specific O2 consumption by CASK mutants, which are smaller and known to be less active, was not different from congenic controls. However, the small size of CASK mutants resulted in a significant reduction in O2 consumption on a per-fly basis. Therefore, the microrespirometer is capable of measuring O2 consumption in D. melanogaster, can distinguish modest differences between genotypes, and adds a versatile tool for measuring metabolic rates.

Performance validation of a non-photocatalytic air purifier built by reactive adsorbent against a commercial UV-based air purifier

A portable non-photocatalytic air purifier (AP) was built by modifying a honeycomb-type ceramic (HC) filter through immobilization of a reactive adsorbent (i.e., manganese dioxide (MnO2 (1 wt%))-Universitetet i Oslo (UiO)-66-amine (NH2): namely, M-U6N). This non-photocatalytic AP system was examined for the removal of gaseous formaldehyde (FA) at room temperature (RT) in a 17 L airtight chamber. The kinetic reaction rates (RW, μmol h−1 g−1) of AP (M-U6N), when measured at 10%, 50%, 90%, and 100% of its removal, were 631, 433, 191, and 114, respectively. This non-photocatalytic AP system fully mineralized FA to CO2 and H2O through the Mars–van Krevelen (MvK) mechanism with a significantly higher (i.e., 1.6–3.3 times) kinetic reaction rate (RF, μmol h−1 filter−1) than that of its UV-based AP counterpart. As such, based on our experimental performance validation, the non-photocatalytic AP system developed in this work was demonstrated to be superior to the commercial photocatalytic AP system in the treatment of gaseous FA. The findings of this study offer practical guidelines for the fabrication of cost-effective non-photocatalytic AP systems.

Evaluating the antioxidative defense response of selected indoor plants against benzene and formaldehyde.

Volatile organic compounds (VOCs) such as formaldehyde and benzene are among the key contributors to indoor air pollution. The current situation of environmental pollution is alarming, especially indoor air pollution is becoming a challenge as affecting plants and humans. VOCs are known to adversely affect indoor plants by causing necrosis and chlorosis. In order to withstand these organic pollutants, plants are naturally equipped with an antioxidative defense system. The current research study aimed to evaluate the combined effect of formaldehyde and benzene on the antioxidative response of selected indoor C3 plants including Chlorophytum comosum, Dracaena mysore, and Ficus longifolia. After the combined application of different levels (0, 0; 2, 2; 2, 4; 4, 2; and 4, 4ppm) of benzene and formaldehyde respectively, in an airtight glass chamber, the enzymatic and non-enzymatic antioxidants were analyzed. Analysis of total phenolics showed a significant increase (10.72mg GAE/g) in F. longifolia; C. comosum (9.20mg GAE/g); and D. mysore (8.74mg GAE/g) compared to their respective controls as 3.76, 5.39, and 6.07mg GAE/g. Total flavonoids (724µg/g) were reported in control plants of F. longifolia which were increased to 1545.72µg/g from 724µg/g (in control) followed by 322.66µg/g in D. mysore (control having 167.11µg/g). Total carotenoid content also increased in D. mysore (0.67mg/g) followed by C. comosum (0.63mg/g) in response to increasing the combined dose compared to their control plants having 0.62 and 0.24mg/g content. The highest proline content was exhibited by D. mysore (3.66μg/g) as compared to its respective control plant (1.54μg/g) under a 4ppm dose of benzene and formaldehyde. A significant increase in enzymatic antioxidants including total antioxidants (87.89%), catalase (59.21 U/mg of protein), and guaiacol peroxidase (52.16 U/mg of protein) was observed in the D. mysore plant under a combined dose of benzene (2ppm) and formaldehyde (4ppm) with respect to their controls. Although experimental indoor plants have been reported to metabolize indoor pollutants, the current findings indicate that the combined application of benzene and formaldehyde is also affecting the physiology of indoor plants as well.

Geometric Feature Mining for the Residual Oxygen Measurement of Pharmaceutical Glass Vials on a Filling Production Line

Oxygen invasion into pharmaceutical glass vials directly affects the quality of medicine, and noncontact inversion of the residual oxygen concentration can effectively determine whether the encapsulated medicine is qualified. Different from studies in an airtight chamber, it is impractical to build a linear inversion model of an open-path optical environment, but this scenario is inevitable for the online residual oxygen measurement of glass-bottled sterile preparations. In this paper, the novel concept of a harmonic characteristic triangle (HCT) is proposed. Then, four groups of available geometric features are discovered in unstable 2^nd harmonic signals, and the optimal features are selected after a quantitative evaluation of their discriminative abilities. Based on the HCT concept, 2-D, 3-D and 4-D nonlinear models are constructed for residual oxygen concentration inversion. Experimental results prove that the proposed multidimensional nonlinear models achieved better oxygen inversion effects, with at least a 20&#x0025; accuracy increase over traditional models.