Residual Mass Research Articles

Upcycling waste phosphogypsum as an alternative filler for asphalt pavement

Mineral fillers are an essential component of asphalt concrete. Significant amounts of mineral fillers are used in constructing asphalt pavement. However, mineral fillers are an important non-renewable natural resource which needs to be preserved. In addition, the production of mineral fillers also consumes much energy and affects environment negatively. This study set out to explore the feasibility of upcycling waste phosphogypsum as an alternative filler for asphalt concrete. The phosphogypsum was first pretreated at 60, 160, and 800 °C, and the crystalline phase of phosphogypsum was evaluated by X-ray diffraction (XRD). Phosphogypsum with three crystalline phases and limestone powder were then mixed with base asphalt binders to prepare asphalt mastic at the filler-asphalt ratio of 1:1 at 150 °C. The chemical structural changes and thermal stability features of phosphogypsum asphalt mastic were analyzed using Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG). The viscoelasticity, high-temperature performance, and fatigue characteristics of different asphalt mastics were measured by frequency sweep, multiple stress creep and recovery (MSCR), and linear amplitude sweep (LAS), respectively. The results indicate that phosphogypsum had different crystalline phases after pretreatment at different temperatures. The addition of phosphogypsum as fillers in asphalt is mainly a physical hardening effect. The 600 °C residual mass ratio of asphalt mastic prepared from phosphogypsum pretreated at 60, 160, and 800 °C was 53.9%, 56.2%, and 58.6%. As the temperature increased, the different crystallized water states in phosphogypsum were decomposed. The replacement of mineral powder with phosphogypsum can improve the high-temperature properties of asphalt mastic and the percent recovery (R), while the nonrecoverable creep compliance (Jnr) was reduced. At the extremely high-temperature of 70 °C, the improvement of the high-temperature performance of phosphogypsum asphalt mastic is more evident than that of 46 °C. Furthermore, the addition of phosphogypsum also reduced the fatigue life of asphalt mastic. This study is expected to paving the road for the upcycling of waste phosphogypsum as an alternative filler in asphalt pavement.

Green and sustainable bio-synthesis of gold nanoparticles using Aspergillus Trinidadensis VM ST01: Heterogeneous catalyst for nitro reduction in water

In this study, a gold nanoparticles (GNPs) have been successfully fabricated by the bio reduction route using soil extract Aspergillus trinidadensis (VM ST01’ OL587588) fungi as a reducing and capping agent without any solvent interference. The GNPs were grown and stabilized by a two-step one-pot method, without any influence of chemical reactants. Characteristics of prepared GNPs were investigated using various microscopic and spectroscopic techniques. GNPs were roughly spherical in shape. Water dispersion study of GNPs has shown a stable dispersion in a broad range of 2–12 pH. The stirring and precursor salt concentration has influenced the kinetics involved in the fabrication process. Stoichiometric data has shown 3.5 × 1020 gold atoms per gram of biomass with diameters of around 35 nm, as determined with High-Resolution Transmission Electron Microscopy (HR-TEM). Zeta potential and Powder X-Ray Diffraction (P-XRD) studies have elucidated the crystalline nature of GNPs. Presence of participating functional groups were examined with Fourier Transform Infra-Red Spectroscopy (FT-IR). Synthesized GNPs were analyzed for surface morphology by Scanning Electron Microscope (SEM). The thermal stability of the lyophilized GNPs sample and capping of the particle were evaluated with Thermo-Gravimetric Analysis (TGA) and had a residual mass of 25% at 306 °C. The Aspergillus trinidadensis capped GNPs have been demonstrated as an efficient heterogeneous catalyst (AtGNHC) for the reduction of 4-Nitrophenol as a model substrate in water. An isolated yield (>95%) of the reduced product in 4 h has shown the effectiveness of the prepared catalyst.

Optimization of CNTs and SiO<sub>2</sub> for thermostability and mechanical properties of PF microcapsules: used for self-healing of closed wall cracks in goaf

Air leakage of closed wall in coal mine goaf would cause spontaneous combustion of remained coal. Most of measures to repair cracks are carried out after cracks are penetrated, which is not conducive to early prevention of spontaneous combustion. Repairing damage at the initial stage of cracking makes prevention effect to the best. Phenol-formaldehyde resin (PF) microcapsules embedded in closed wall to achieve self-healing of initial cracks, but the actual repair effect is often less than expected. PF microcapsules (PFM) of carbon nanotubes (CNTs) and silicon dioxide (SiO2) decorated shell for self-healing of closed wall cracks were prepared by in-situ polymerization. The effects of nanomaterials on morphology, chemical constitution, thermal performance and mechanical properties of PF microcapsules were characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and nanoindentation test. The test results indicated that nanomaterials were successfully introduced into the shell of PF microcapsules. The CNTs-SiO2@PF microcapsules were uniformly dispersed, the thermal decomposition was delayed, and the residual carbon was significantly increased, and the brittleness of PF microcapsules was significantly enhanced. The 0.2CNTs-SiO2@PF microcapsules (0.2CNTs-SiO2@PFM) had a uniform and full particle size, the initial decomposition temperature was 267.6 ℃, the residual mass was 41.3%, the maximum load on the capsule wall reached 94.79 mN, and the load dropped sharply after the capsule wall rupture. Finally, the self-healing mechanism of closed wall doped with microcapsules was discussed. The exploration of modified phenolic microcapsules provides a new idea for the repair of closed wall in goaf.

Mechanical and microstructural properties of MK-FA-GGBFS-based self-compacting geopolymer concrete composites

Self-compacting geopolymer concrete (SCGC) is an eco-efficient and sustainable concrete with a lower carbon footprint than conventional concrete. The combination and doping of composites present a challenge in investigating the mechanical and microstructural properties of SCGC. This experimental work investigated the effect of different dosing levels of metakaolin (MK), fly ash (FA), and ground granulated blast furnace slag (GGBFS) on the properties of SCGC composites from both macroscopic and microscopic aspects. The main objectives of this study are to determine the fresh properties of SCGC in the fresh state and its mechanical properties in the hardened state and to explain the reasons for the differentiation of macroscopic properties through mesoscopic and microscopic analyses. Results showed that both MK and GGBFS reduce the flowability of fresh geopolymer concrete, with MK having a greater negative effect than GGBFS, with maximum and minimum slump flows of 645 mm and 505 mm, respectively. With the increase of MK and GGBFS admixture, the compressive strength of SCGC continuously increased until reaching the maximum value of 51.76 MPa, which corresponded to maximum admixtures of 50% and 40% for MK and GGBFS, respectively. GGBFS had the greatest positive effect on the rapid development of the early mechanical properties of SCGC, with calcium oxide (CaO) playing a crucial role. The 3d/7d compressive strength of SCGC was 0.83/0.85 of 28d when the slag admixture reached 40%, respectively. Strength prediction models with excellent fit coefficients were developed, and the correlation coefficients for the three equations were 0.83, 0.98, and 0.99. A higher stress level of SCGC corresponds to a higher intensity and density of the acoustic emission signal. Thermal analysis results showed that the higher the CaO content in the SCGC specimen, the smaller the residual mass of the sample, i.e., the higher the number of gels and compressive strength. Scanning electron microscope images showed that a higher CaO content of SCGC corresponded to a denser matrix structure and better mechanical properties.

Effects of particle size on the pyrolysis of spruce and poplar: Thermogravimetric analyses, DAEM modelling, validation, and prediction of secondary charring

Particle size plays a crucial role in biomass pyrolysis mechanisms and their subsequent industrial uses. However, an applicable kinetic method that combines thermogravimetric data with distributed activation energy model (DAEM) adapted to the sample size is still missing. This work investigated pyrolysis kinetics of two wood species (spruce and poplar) with five particle shapes (powder, particle, 5-mm diameter cylinders with heights of 1 mm, 2 mm, and 4 mm) and one additional reaction condition (powder with lid). The experimental data were numerically simulated by two Gaussian + one exponential DAEM distributions. Thermogravimetric results evidenced a significant effect of particle geometry on char yields, which increased by 81% and 66%, from powder to 4-mm high cylinders, for spruce and poplar respectively. The increase in particle size and use of a crucible lid led to an increase of exothermic heat. Elemental analysis demonstrated a contradictory relation between carbonization and mass loss, which was explained by secondary charring. Synthetic indexes built from the kinetics parameters of the DAEM model clearly depicts the effect of particle sizes. The prediction ability of the model was checked by further experiments performed at different time-temperature patterns with several particle sizes. Finally, correlations between dimensionless residual mass (DRM) and element compositions allowed us to determine the composition of secondary charring, which consists mainly of carbon. The elemental composition of char can therefore be predicted using the difference of DAEM kinetics between fine powder and a given particle size.

Thermokinetic and Ballistic Property Studies of Azide‐Based Airbag Gas Generants with Dual Oxidizers (Sr(NO3)2 and KNO3)

Thermokinetic degradation studies of an airbag gas generant ternary mixture comprising NaN3, KNO3, and SrNO3 are carried out for the first time using simultaneous differential scanning calorimetry–thermogravimetric analysis. The results point toward the fact that the use of dual oxidizers has improved the reactivity of the azide‐based airbag gas generant mixture and reduced the amount of residual masses remaining after degradation to a minimal value of 2%. The activation energy of the mixture is also found to be increased to a maximum value of 249 kJ mol−1 which is better than the conventional airbag mixtures. The ballistic property studies done on the ternary mixture show that it can activate the airbag within 43.3 ms of crash which is very much an improved timeframe compared to the existing airbag mixtures. The study indicates that stoichiometric mixture containing NaN3/Sr(NO3)2/KNO3:75/12/13 by weight can be used as a potential airbag gas generant for automotive airbags. The blended mode methodology used in this research work combining the thermokinetic and ballistic property measurement can be effectively used to evaluate the performance parameters of airbag gas generants.

Self-cleansing velocity in upward three-phase steady pipe-flow

The solids transport and the conditions required to begin the transport of granular particles, or to avoid their deposition, in three-phase turbulent flows of mixtures of gas–liquid–solids, in upward inclined pipes, are complex phenomena whose governing equations and corresponding solutions can be approximated via experimental investigation and numerical computation. An experimental installation for establishing steady flow conditions of air–water-solids in an upward transparent acrylic pipe of 84 mm was built and prepared to allow the measurement of the transported flow rates of air, water, sand and fine gravel, with particle diameters between 0.425 and 7.20 mm. Two full set of experiments with water-solids, and air–water-solids, under comparable conditions, were performed in Laboratory, in order to analyse the influence of the gas phase. Three pipe angles between 30° and 58°, and four solid particle ranges with intermediate sizes forming a bed were tested. The average water superficial velocity demonstrates to be the most relevant variable for the solids transport beginning, and the presence of air has a positive influence, even without the mobilisation of the water flow rate increase due to air-lift pumping. A model relating a modified Shields parameter (Shmixc) with a modified Reynolds number of the particles (Remixc), both defined for the critical average flow rates of three-phase mixtures under steady flow, for which a residual mass of solid particles begins to be transported, is proposed. The resulting equation follows a power law of the generic type Shmixc = a Remixc−b, where a and b are positive constants experimentally obtained for the different angles of inclination of the upward pipe, with coefficients of determination well above 90%. The mathematical model proposed in this work allows the explicit computation of the self-cleansing velocity required for two-phase flows. The critical average air superficial velocity and subsequent average velocity of the mixture required for the solids transport in steady three-phase flows, when the average water superficial velocity is below the two-phase self-cleansing velocity, are computed using the proposed model by numerical iterative processes.

Experimental upscaling analyses for a surfactant-enhanced in-situ chemical oxidation (S-ISCO) remediation design

Surfactant-enhanced in-situ chemical oxidation (S-ISCO) is an emerging innovative remediation technology for the treatment of dense non-aqueous phase liquids (DNAPLs). S-ISCO combines the solubilization of contaminants by means of surfactants with the chemical oxidation by an oxidizing agent, thus, potentially increasing the efficiency of the state-of-the-art ISCO technique. Scientific investigations are needed to enable the technology transfer for potential field applications based on the development of a remediation design under well-defined boundary conditions.For this purpose, experimental upscaling analyses were performed using the special infrastructure of the research facility for subsurface remediation (VEGAS). Batch tests showed that oxidation of the selected surfactant E-Mulse 3® (EM3) by activated persulfate (Na-PS) reduced the solubilization of the model contaminants 1,4-DCB, naphthalene, and PCE. As a consequence, the processes of contaminant solubilization and degradation were temporally and spatially separated in the developed remediation design.A proof of concept was provided by performing an S-ISCO medium-scale experiment (100 cm length, 70 cm height, 12.5 cm width), with 1,2-DCB as model DNAPL contaminant to be treated. A groundwater circulation well (GCW) was used to inject a 60 g/L Na-PS solution and to effectively mix the reagents. Sampling of the experiment's outflow and the soil material after treatment showed that neither rebound effects nor residual mass loadings on the soil material could be detected after termination of the S-ISCO treatment.To further evaluate the S-ISCO remediation design under field-like conditions, a large-scale S-ISCO experiment was conducted (6 m length, 3 m height, 1 m width), allowing for an extensive sampling campaign to monitor relevant processes. An efficient contaminant removal from the former source zone could be reached by surfactant solubilization, decreasing contaminant levels from initially over 2000 mg/L 1,2-DCB to final concentrations below 5 mg/L 1,2-DCB. The heterogeneously distributed contaminant degradation, implemented by a three-filter GCW, was attributed to density-induced migration processes that impeded an optimal reaction zone. A density-dependent numerical transport could qualitatively match the observations. By comparing different simulation scenarios, an adapted operation of the GCW was established that provides for a more efficient distribution of the density-influenced oxidant injection.

Testicular Radiomics To Predict Pathology At Time of Postchemotherapy Retroperitoneal Lymph Node Dissection for Nonseminomatous Germ Cell Tumor

IntroductionTesticular germ cell tumors are the most common malignancy in young adult males. Patients with metastatic disease receive standard of care chemotherapy followed by retroperitoneal lymph node dissection for residual masses >1cm. However, there is a need for better preoperative tools to discern which patients will have persistent disease after chemotherapy given low rates of metastatic germ cell tumor after chemotherapy. The purpose of this study was to use radiomics to predict which patients would have viable germ cell tumor or teratoma after chemotherapy at time of retroperitoneal lymph node dissection. Patients and MethodsPatients with nonseminomatous germ cell tumor undergoing postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) between 2008 and 2019 were queried from our institutional database. Patients were included if prechemotherapy computed tomography (CT) scan and postchemotherapy imaging were available. Semiqualitative and quantitative features of residual masses and nodal regions of interest and radiomic feature extractions were performed by 2 board certified radiologists. Radiomic feature analysis was used to extract first order, shape, and second order statistics from each region of interest. Post-RPLND pathology was compared to the radiomic analysis using multiple t-tests. Results45 patients underwent PC-RPLND at our institution, with the majority (28 patients) having stage III disease. 24 (53%) patients had teratoma on RPLND pathology, while 2 (4%) had viable germ cell tumor. After chemotherapy, 78%, 53%, and 33% of patients had cystic regions, fat stranding, and local infiltration present on imaging. After radiomic analysis, first order statistics mean, median, 90th percentile, and root mean squares were significant. Strong correlations were observed between these 4 features;a lower signal was associated with positive pathology at RPND. ConclusionsTesticular radiomics is an emerging tool that may help predict persistent disease after chemotherapy.

Microwave Pyrolysis of Woody Biomass: Influence of Radiation Power on the Composition of Conversion Products

Biomass is a promising resource for the production of renewable energy, liquid fuels, and chemicals. Microwave pyrolysis is one of the directions of multifunctional conversion of raw materials. In the present work, the effect of microwave power on the characteristics of sawdust pyrolysis is studied. With an increase in power, the maximum yield of combustible gases increased, and a large proportion of the total pyrolysis time included the useful time for the release of gases. An increase in power affected the yield of individual gases non-linearly and on a different scale. The average yield of CO and CO2 remained practically unchanged when the microwave power was increased from 840 to 1760 W. However, with a further increase in power to 2200 W, there was a significant increase in the average yield of CO and CO2 (2.5 and 1.4 times, respectively). An increase in power by 2.6 times contributed to an increase in the average yield of CH4 by 5 times and H2 by 3.8 times. The increased power of microwaves contributed to the degassing of wood and intensification of secondary pyrolysis reactions, which resulted in a decrease in the mass of the solid residue by 5.3 times and a decrease in the liquid product yield by 2.7 times. A comprehensive analysis using MCDA showed that an increase in energy costs with an increase in microwave power is integrally compensated by an improvement in pyrolysis performance. So, when the power was varied from 840 W to 2200 W, the pyrolysis efficiency indicator increased by 1.3–2.2 times, considering the growth in energy consumption.

Kinetic study of mechanical and thermal properties and thermal degradation of PVC composites based on coal gasification fine slag

Coal gasification fine slag (CGFS) is a by-product of gasification process of gasification beds that pollutes the environment. To make the utilization of CGF more efficient, poly (vinyl chloride) (PVC)/CGFS composites were prepared via a melt blending process, and their mechanical and thermal properties were investigated. In order to dig deeper into the decomposition mechanism, the thermal degradation kinetics were systematically analyzed by drawing non-isothermal heat maps based on the Flynn-Wall-Ozawa, Friedman, and Kissinger model-free methods. According to the results, the properties of all tests vary significantly with CGFS content. In particular, at a the CGFS content of 20 phr, the tensile strength (tensile modulus) and flexural strength (flexural modulus) of CGFS-20 were 13.5% (47.8%) and 13.9% (41.6%) higher, respectively, than those of conventional CGFS-0 composites. However, the impact strength decreases with the increase of CGFS content. At the same time, the addition of CGFS suppresses the mass conversion rate and improves the thermal stability of PVC composites at high temperature, and the final residual mass reaches 31%, which is 12.7% higher than that of pure PVC. The kinetic analysis of thermal decomposition shows that CGFS promotes the initial degradation of the composites reduces the activation energy of the reaction, and at the same time endows them with higher thermal stability in the high-temperature phase.

Investigation of mechanical, thermal and water absorption behaviour of MWCNT’s with AL2O3 reinforced polymer composite

In this work, composite materials were developed using compression moulding method, which the composition of M2A1C (Epoxy + 2 wt % MWCNT +1 wt % Al2O3), M2A1.5C (Epoxy + 2 wt % MWCNT +1.5 wt % Al2O3) and M2A1C (Epoxy + 2 wt % MWCNT +2 wt % Al2O3). From the composition, M2A1.5C had improved the mechanical properties of 30%, 24% and 28% in tensile strength, flexural strength and impact strength, respectively, compared to the M2A1C. From the thermo-gravimetric examination, the critical change was happened during increasing of Al2O3, however, the M2A1.5C had a significant improvement within the residual mass and maximum temperature decomposition with compared to other composites. Hydrophobicity decreased in the M2A1C composition, due to the low density of the material in the composite. The study is exploring ways to improve the polymer-metal matrix hybrid composite materials to make them lighter and more affordable, as well as easier to use in light load applications.

Anthropometric and Physical Performance Characteristics of Swimmers

Introduction: The study of body measurements and proportions by anthropometry is important for the identification of young talents in swimming. Therefore, the aim of this study was to a) compare the physical performance profile of swimmers on land and in water and b) understand the relationship between anthropometric and physical performance tests. Methods: To this end, 31 anthropometric variables were determined in 6 male (n=3) and female (n=3) swimmers using the International Society for the Advancement of Kinanthropometry (ISAK) protocols and VO2max laboratory tests. Body fractionation (adipose, muscle, bone, residual, and skin tissue masses) was determined using the validated Kerr & Ross five-way fractionation model for body composition. Data analysis included the person correlation coefficient. Results: The swimming performance test was positively strongly correlated with body height, seat height, arm span, shoulder and pelvic width, and arm and leg length (p ≤ 0.001). In conclusion, these studies reveal some potential key anthropometric factors in the performance of active swimmers. These results support the view that while swimmers have unique anthropometric profiles, more successful swimmers tend to have greater arm spans. Conclusion: These results suggest that anthropometric characteristics are important in swimming performance. This study concluded that improvement in swimming performance is strongly related to anthropometric and kinanthropometric profiles.

Simulation-Optimization Modelling of Yield and Yield Components of Tomato Crop

This study simulate and optimize the yield and yield parameters of tomato using AquaCrop model and genetic algorthm (GA) respectively. The AquaCrop model was firstly calibrated using the data obtained from the field and was later used to simulate the observed yield, water productivity and biomass of tomato. The Root Mean Square Error (RMSE), Coefficient of Residual Mass (CRM) Normalized Root Mean Square Error (NRMSE) and Modelling efficiency (EF) were used to compare the observed and simulated values. The governing equation of AquaCrop simulation software was then optimized using the evolutionary optimization method of GA with MATLAB programming software. All the statistical indices except CRM used in comparing the simulated and observed values indicated good agreement. The CRM values of -0.11, -0.06 and -0.20 were obtained for the yield, biomass and water productivity of tomato which indicated a very slight over-estimation of the observed results by the AquaCrop model. The optimization algorithm terminated when the optimal values of yield and biomass were 4.496 〖ton ha〗^(-1) and 4.90 〖ton ha〗^(-1) respectively. The GA revealed that the yield and biomass of tomato can be increased by 57% and 23% respectively if the optimized parameters were either attained on the field experiment or used during simulation. Thus, the study ascertained that crop simulation models such as AquaCrop and optimization algorithms can be used to identify optimal parameters that if maintained on the field could improve the yield of crops such as tomato.

A novel P, N doped organic-inorganic hierarchical core-shell nanostructures: Reducing the fire risk of epoxy resin

The wide application of epoxy resin (EP) causes a great potential fire risk to humans and the environment. To effectively reduce the fire risk of EP, we designed a novel P, N-doped organic-inorganic hierarchical core-shell nanostructure (BN@PEI@UiO-66@PPA). Encouragingly, with only 2 wt% of BN@PEI@UiO-66@PPA, the peak heat release rate (PHRR) and total heat release (THR) were reduced by 47.2 % and 47.9 %, respectively, compared with those of pure EP, indicating a considerable enhancement in flame retardancy. The peak smoke release rate (PSPR), total smoke production (TSP), peak CO production rate (PCOPR), and peak CO2 production rate (PCO2PR) were significantly reduced by 46.0 %, 52.7 %, 72.1 %, and 75.1 %, respectively, compared with those of pure EP, indicating a significant reduction in fire toxicity. In addition, the mass of the char residue of BN@PEI@UiO-66@PPA/EP increased by 185.3 %, and the graphitization degree and thermal stability of the char were significantly improved. The results indicate that the various components in BN@PEI@UiO-66@PPA were functionally different and cross-assisted to form dense P-N-C char with high graphitization and high thermal stability, which effectively improved the fire safety of EP. This work provides a new reference for the construction of multi-component hierarchical structures to optimize their application in the field of fire safety of polymer composites.

Эколого-биологические и морфологические особенности возбудителя трихинеллёза в Кировской области и оптимизация мер борьбы

Trichinellosis is one of the most dangerous zoonosis. The analysis of different methods of prevention in helminthology indicates an increasing attention to such zoonotic diseases as trichinellosis in the World and Russia. Wild animals as a source of infection play the leading role in human infection. The task of present work is diagnostics, prevention of helminthozoonosis and improved monitoring and surveillance of the dissemination of trichinellosis. Practical application of expertise of meat and meat products from hunter’s trophies allows preventing infection of human and domestic animals with dangerous zoonosis. The article considers the influence of low temperatures, and the improvement of the fight against trichinosis in the northern territories. The index and shape of the capsule of trichinella in carnivores have differences. Apparently, these features are due to the peculiarities of parasite-host relationships and differences in the morphology of muscle tissue myosymplasts in various animals, and are species-specific for the host animals of trichinella. The conducted studies confirm the effectiveness of the combination of methods of compressor trichinoscopy and digestion in the artificial gastric juice for postmortem diagnosis of trichinosis of wild animals. When comparing these methods, it was found that the method of digestion in artificial gastric juice is more sensitive compared to compressor trichinoscopy, but it is less effective in detecting dead trichinella. New technologies for disinfection of carcasses and residual muscle mass after hides have been milled have also been developed for mechanical harvesting stations; for this, special refrigerating chambers and solutions of disinfectants have been proposed. Trichinella of the northern territories are more resistant to low temperatures, therefore, disinfection modes should be increased (both temperature and exposure time). So, for example, if pork is frozen at a temperature of -15 oC, and according to the recommendation of the International Commission on Trichinosis, it is necessary to keep the meat for at least 3–4 weeks, and carcasses of wild animals should be frozen for at least 3 weeks at a temperature of less than -20 oC.

Comparative physicochemical analysis of chitin quality of the two tagmata in the exoskeleton of the horseshoe crab Limulus polyphemus

Recently, chitin biopolymer has received much attention as a wide variety of biomedical application for this and its derivatives have been reported, in fact, the study of non-conventional species as alternative sources of them compounds has taken particular interest. Here, we present a comparative physicochemical survey of the two tagmata in the exoskeleton of the horseshoe crab Limulus polyphemus: the prosoma and the opisthosoma, collected in Yucatán, Mexico. The characterization included CHNSO analysis, FTIR, TGA, DSC, XRD, and SEM. The CHNSO analysis revealed that C is present in the highest proportion (∼45 %) and that chemical composition did not show significant differences (P < 0.05) between the two tagmata. FTIR spectra of two tagmata presented a wide characteristic band of the chitin between 3600 and 3000 cm−1, confirming the presence of this biopolymer in the exoskeleton studied. TGA and DTGA profiles resulted very similar for both tagmata being the residual mass at 650 °C of around 30 % for both samples; these values were associated to the presence of minerals. SEM micrographs showed a porous matrix with infinite large number of irregularly shaped particles. Results show that both tagmata are made up of chitin, and they seem to have a high mineral content.

Understanding of surface fouling of brackish water reverse osmosis spiral wound membrane using an integrated analysis of seawater quality and membrane autopsy

To understand the cause of the scale, an integrated analysis of the saline water quality and discarded reverse osmosis membranes was developed. Damaged areas on the membrane were excised and characterized by the Fujiwara test, infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. A spatula and sonication were used to remove scale. Thermodynamic modeling (PHREEQC) was used to predict scale formation at 75 bar, resulting in saturation index values for both mixed and pure compounds. Fujiwara's test revealed damage to the polyamide and organic fouling by polysaccharides, silica, and aromatics. Thermo-oxidative decomposition and residual masses of metal oxides and salts were observed. The microscopy detected incrustations in the membrane by analyzing compounds with silicon, oxygen, calcium, magnesium, aluminum, etc. The modeling indicated the low-solubility compounds of scale are aluminum silicates, clays, quartz, etc., identified experimentally. PHREEQC can model desalination to predict scale problems, allowing for early decision-making.

1853-PUB: Extrapancreatic Effects of GIP on Bone

Glucose-dependent insulinotropic polypeptide (GIP) exhibits extrapancreatic effects through the receptor for GIP (GIPR). In this study, we used Ni-Ti Closed Coil Spring (Ni-Ti) in GIPR-deficient mice (GIPRKO) and wild-type mice (WT) to investigate the effect of GIP on force-induced bone remodeling due to orthodontic tooth movement. It was investigated. Ni-Ti was attached between the maxillary bone and the maxillary left first molar (M1) of GIPRKO and WT, and mechanical load was applied by pulling the M1 in the mesial direction. Remaining amount and bone quality were measured. A histological examination of the maxilla was also performed. As a result, compared to WT, GIPRKO showed a significant increase in tooth movement distance and a significant decrease in residual alveolar bone mass. TRAP staining showed an increase in osteoclasts in GIPRKO compared to WT on the tooth moving side. We also found that GIPRKO reduced osteoblasts in the steady state and suppressed osteoblasts after tooth movement. These results suggest that GIPRK impairs bone remodeling through increased bone resorption due to mechanical load, and that GIP plays an important role in bone remodeling. Disclosure T.Yamauchi: None. S.Goto: None. K.Naruse: None. N.Nakamura: None. M.Miyabe: None. M.Ito: None. R.Hoshino: None. S.Kanada: None. T.Sekiya: None. T.Matsubara: None. K.Miyazawa: None.

TOI-908: A planet at the edge of the Neptune desert transiting a G-type star

Abstract We present the discovery of an exoplanet transiting TOI-908 (TIC-350153977) using data from TESS sectors 1, 12, 13, 27, 28 and 39. TOI-908 is a T = 10.7 mag G-dwarf (Teff = 5626 ± 61 K) solar-like star with a mass of 0.950 ± 0.010 M⊙ and a radius of 1.028 ± 0.030 R⊙. The planet, TOI-908 b, is a 3.18 ± 0.16 R⊕ planet in a 3.18 day orbit. Radial velocity measurements from HARPS reveal TOI-908 b has a mass of approximately 16.1 ± 4.1 M⊕, resulting in a bulk planetary density of $2.7^{+0.2}_{-0.4}$ g cm−3. TOI-908 b lies in a sparsely-populated region of parameter space known as the Neptune desert. The planet likely began its life as a sub-Saturn planet before it experienced significant photoevaporation due to X-rays and extreme ultraviolet radiation from its host star, and is likely to continue evaporating, losing a significant fraction of its residual envelope mass.