Primary Precursor Research Articles

Increased Toxicity toward Mammalian Cells in the Periodate Oxidation Process of Wastewater: The Overlooked Formation of Noniodinated but Nitrogenous Byproducts.

Periodate (PI) shows promising potential as an oxidant for wastewater treatment; however, its impact on the toxicity of wastewater remains unknown. Here, we found that with 100 μM PI addition, the cytotoxicity of wastewater increased from 4.8 to 7.6 mg-Phenol/L to 9.5 to 12.8 mg-Phenol/L, and genotoxicity increased from 0.3 to 0.9 μg-4-NQO/L. Interestingly, hypoiodous acid (HOI) was not detected during the reaction, and there was no observed increase in the concentration of total organic iodine (TOI). CHON components in dissolved organic matter changed most obviously in PI oxidation, which might serve as primary precursors for toxic byproducts. Cytotoxicity of typical nitrogen-containing precursors of tryptophan, lysine, phenylalanine, and tyrosine after PI oxidation increased from not detected to 14.7, 2.4, 4.1, and 3.2 mg-Phenol/L, respectively. Here, four nonhalogenated aromatic nitrogenous byproducts (N-DBPs) of 3-hydroxyquinoline, 4-hydroxyquinoline, benzopyridine, and benzopyrrole were confirmed using standards, and four byproducts such as 2-formylbenzonitrile were tentatively proposed. The cytotoxicity of the four confirmed byproducts was comparable to those known N-DBPs such as nitrosamines, suggesting attention should be given to these nonhalogenated but nitrogenous byproducts. The four confirmed byproducts were detected in two PI-treated wastewater samples with concentrations of 0.8, 0.98, 0.52, and 0.0038, and 18.28, 1.50, 0.57, and 0.0074 μg/L, respectively, with contributions less than 1.5% to the overall cytotoxicity. Further investigations are warranted to elucidate the primary drivers of toxicity in PI-treated wastewater.

Transition metal ions-chelated COFs derived bifunctional oxygen catalysts for rechargeable Zn-air batteries

Improving energy conversion efficiency and battery cycle stability is an essential goal in energy conversion and storage, while a critical factor in achieving this goal is the design of effective bifunctional catalysts. The covalent organic framework is a new type of high molecular material that can be employed as an ideal template for quantitative chelate metal ions to synthesize highly efficient bifunctional catalysts with high dispersion metal active sites. In this work, the Fe2Ni1/NiFe2O4@NCG bifunctional catalysts are constructed by employing metal-chelated COFs and MA/GO mixture as primary precursors combined with a high-temperature pyrolysis strategy. COFs and MA serve as chelators and spacers to improve the dispersion of metal nanoparticles. The Fe2Ni1/NiFe2O4@NCG composite exhibits a large BET surface area and hierarchical structure with plentiful nanoparticles on the carbon layers. HRTEM proves the coexistence of FeNi and NiFe2O4. The optimal Fe2Ni1/NiFe2O4@NCG-800 composite shows satisfactory catalytic O2 performance, providing a half-wave potential of 0.857 V for ORR and an overpotential of 244 mV for OER. Meanwhile, DFT calculations prove that electron redistribution occurs at the interface between FeNi and NiFe2O4 after combination. The Fe2Ni1/NiFe2O4@NCG-based liquid and solid-state ZABs perform very well, exhibiting large specific capacities (796 mAh·g−1 for aqueous ZAB; 742 mAh·g−1 for solid-state ZAB) and stable charge-discharge cycle performance (300 h for aqueous ZAB; 180 h for solid-state ZAB).

Evidences of the structures controlling the unrest in Campi Flegrei, Italy; Joint interpretation of ambient noise and local earthquake tomography

Campi Flegrei is one of the largest active calderas exhibiting several episodes of unrest since historical times. These episodes are characterized by numerous earthquakes and significant soil uplifts, often reaching several centimeters or even meters within each cycle. Seismicity in this region rises substantial concern, as it is a primary precursor to potential volcanic eruptions. Additionally, the intense urbanization of the area amplifies the seismic and volcanic risk increasing the population concern. The last unrest phase began in 2006 and is still ongoing. It is accompanied by a large number of earthquakes mainly concentrated beneath the Solfatara-Pisciarelli system, accompanied by the increment of gas emission in Pisciarelli and significant variations in geochemical and geophysical parameters.In this study we present two classes of seismic models generated using passive methods employing earthquakes recorded from 2005 to November 2023 and continuous ambient noise recorded at 20 stations between 2012 and 2021. These models reveal the existence of high P-wave velocity bodies within the caldera: one onshore, located between the port of Pozzuoli and Solfatara, and another offshore, located a few kilometers south of Pozzuoli. The body beneath Pozzuoli and Solfatara lies at 3.0 km deep, exhibiting high Vp/Vs ratios suggesting it is rich in fluids and possibly contributing to the current unrest. Ambient noise tomography shows that both anomalous bodies are linked to the structures at the edge of the resurgence block forming the central part of the coast of the Pozzuoli Gulf, which is responsible for the uplift of the marine terraces. These findings suggest that the peripheral structures may influence the upward fluid migration, playing a role in the sustaining the ongoing unrest.

Source apportionment of ultrafine particles in urban Europe

There is a body of evidence that ultrafine particles (UFP, those with diameters ≤ 100 nm) might have significant impacts on health. Accordingly, identifying sources of UFP is essential to develop abatement policies. This study focuses on urban Europe, and aims at identifying sources and quantifying their contributions to particle number size distribution (PNSD) using receptor modelling (Positive Matrix Factorization, PMF), and evaluating long-term trends of these source contributions using the non-parametric Theil-Sen’s method. Datasets evaluated include 14 urban background (UB), 5 traffic (TR), 4 suburban background (SUB), and 1 regional background (RB) sites, covering 18 European and 1 USA cities, over the period, when available, from 2009 to 2019. Ten factors were identified (4 road traffic factors, photonucleation, urban background, domestic heating, 2 regional factors and long-distance transport), with road traffic being the primary contributor at all UB and TR sites (56–95 %), and photonucleation being also significant in many cities. The trends analyses showed a notable decrease in traffic-related UFP ambient concentrations, with statistically significant decreasing trends for the total traffic-related factors of −5.40 and −2.15 % yr−1 for the TR and UB sites, respectively. This abatement is most probably due to the implementation of European emissions standards, particularly after the introduction of diesel particle filters (DPFs) in 2011. However, DPFs do not retain nucleated particles generated during the dilution of diesel exhaust semi-volatile organic compounds (SVOCs). Trends in photonucleation were more diverse, influenced by a reduction in the condensation sink potential facilitating new particle formation (NPF) or by a decrease in the emissions of UFP precursors. The decrease of primary PM emissions and precursors of UFP also contributed to the reduction of urban and regional background sources.

Factors affecting the different growth rates of PM2.5：Evidence from composition variation, formation mechanisms, and importance analysis of water-soluble inorganic ions with case study in northern China

PM2.5 affects air quality, therefore, understanding the mechanism of PM2.5 growth is essential to figure out mitigation measures. Hourly real-time concentrations of water-soluble inorganic ions (WSIIs), including anions and cations, in fine particulate matter (PM2.5) were measured in Baoji, northwest China. During the winter monitoring period, the concentrations of PM2.5 and most WSIIs exhibited similar trends. Mass proportions of SNA [i.e., sulfate (SO42−), nitrate (NO3−), ammonium (NH4+)] in PM2.5 gradually increased with air deterioration, while equivalent ratios of anions to cations also increased. The heterogeneous aqueous reactions and/or gas-phase homogeneous reactions promoted the formation of secondary inorganics, especially during the haze events. Rapid transformations of primary gaseous precursors to secondary pollutants could lead to the substantial formation of SO42− and NO3−. In terms of particle growth rate, the mass proportions of SNA in PM2.5 decreased from General Growth (GG) to Explosive Growth (EG) events. Furthermore, the particle growth rates did not coincide with the pollution levels, while it occurred most frequently during the Transition Period, instead of the Polluted Period. The diurnal variation of SNA at different PM2.5 growth rates has been discussed. The results of the Random Forest (RF) model showed that RH was an important factor for EG of PM2.5, while low RH was a reliable reason for the relatively low mass proportion of SNA. The results of this study could advance our understanding of particle growth and provide scientific evidence to support the establishment of unique air quality control measures under different pollution scenarios in Fenwei Plain, China.

Who transitions to bipolar disorder? A comparison of major depressive disorder, anxiety, and ADHD

BackgroundDiagnostic delays in Bipolar Disorder (BD) are common and can contribute to worse outcomes. While most studies focus on depression as a primary precursor, both anxiety and attention deficit disorders are also frequent initial diagnoses. In the current study, we utilized a large, diverse electronic health record (EHR) dataset to quantify the rates and correlates of conversion to BD from these major precursor diagnoses. MethodsOur study analyzed a comprehensive ten-year EHR dataset from Johns Hopkins Medicine, a diverse urban medical center, to assess and compare the rates and correlates of conversion to BD from Major Depressive Disorder (MDD), anxiety disorders, and ADHD. Risk factors for transition were assessed as time-varying variables in proportional hazards models. ResultsOf the 21,341 patients initially included, 1232 later transitioned to a diagnosis of BD. Adjusted-one-year conversion rates for patients with MDD, anxiety disorders, and ADHD were 4.2 %, 3.4 %, and 4.0 %, respectively, with ten-year rates at 11.4 %, 9.4 %, and 10.9 %, respectively. Age (19–29 years), treatment setting (emergency and inpatient), and psychotropic medications were associated with conversion to BD across all precursor diagnoses. Severe and psychotic forms of MDD were among the strongest risk factors for transitioning to BD. Although transition rates were lower in children, risk factors were similar, with the exception of ADHD, which showed a stronger association with BD conversion in adults. ConclusionsThe highest risk of transitioning to BD was observed in patients initially diagnosed with MDD, though significant risk was also noted in those with initial diagnoses of anxiety disorders and adult ADHD.

Astrocyte-derived factors regulate CNS myelination.

The role that astrocytes play in central nervous system (CNS) myelination is poorly understood. We investigated the contribution of astrocyte-derived factors to myelination and revealed a substantial overlap in the secretomes of human and rat astrocytes. Using in vitro myelinating co-cultures of primary retinal ganglion cells and cortical oligodendrocyte precursor cells, we discovered that factors secreted by resting astrocytes, but not reactive astrocytes, facilitated myelination. Soluble brevican emerged as a new enhancer of developmental myelination in vivo, CNS and its absence was linked to remyelination deficits following an immune-mediated damage in an EAE mouse model. The observed reduction of brevican expression in reactive astrocytes and human MS lesions suggested a potential link to the compromised remyelination characteristic of neurodegenerative diseases. Our findings suggested brevican's role in myelination may be mediated through interactions with binding partners such as contactin-1 and tenascin-R. Proteomic analysis of resting versus reactive astrocytes highlighted a shift in protein expression profiles, pinpointing candidates that either facilitate or impede CNS repair, suggesting that depending on their reactivity state, astrocytes play a dual role during myelination.

The impact of toroidal mode coupling on high-density discharges in J-TEXT

Density limit has long been a widely studied issue influencing the operating range of tokamaks. The rapid growth of the m/n = 2/1 (where m and n are poloidal and toroidal mode numbers, respectively) tearing mode is generally regarded as a primary precursor to the density limit disruption. In this experiment, the coupling of the m/n = 1/1 mode and the m/n = 2/1 mode in high-density plasma was observed. During a sawtooth cycle, the frequencies of the two modes gradually converge until they become equal. After that, toroidal coupling occurs between the 1/1 and 2/1 modes, resulting in a mutually fixed phase relationship. With the occurrence of toroidal coupling, the 2/1 mode is stabilized. Prior to the disruption, the cessation of the 1/1 and 2/1 mode coupling, along with the rapid growth in the amplitude of the 2/1 mode, can be observed. Additionally, under the same parameters, comparing discharges with or without the 1/1 mode, it is found that the presence of the 1/1 mode leads to higher plasma density and temperature parameters.

Global Temperature Dependency of Biogenic HCHO Columns Observed From Space: Interpretation of TROPOMI Results Using GEOS‐Chem Model

AbstractTemperature is the principal driver of global atmospheric formaldehyde (HCHO) and its primary oxidation precursor biogenic volatile organic compounds (BVOCs). We revisit such a temperature (T‐) dependency globally, leveraging TROPOMI HCHO column data. We find substantial variations in the T‐dependency of biogenic HCHO across plant functional types (PFTs), with the highest over Broadleaf Evergreen Tropical Trees (doubling every 6.0 K ± 4.1 K) and lowest over Arctic C3 Grass (doubling every 30.8 K ± 9.6 K). The GEOS‐Chem model interprets HCHO columns' T‐dependency at the PFT level (r = 0.87), with a 16% discrepancy on average. The discrepancy can be explained by BVOC emissions T‐dependency for Broadleaf Evergreen Tropical Trees and Warm C4 Grass and can be attributed to the insensitivity of HCHO columns to BVOC emissions for other PFTs. Our findings underscore a potentially magnified variation of BVOC emissions by GEOS‐Chem and MEGAN therein, particularly in regions experiencing greater temperature variations.

Manifesting the hidden pollutants: Quantifying emissions and environmental impact of petroleum refinery on PM2.5

This research thoroughly examined the emissions of primary fine particle and precursors of secondary particles (VOCs, SO2 and NOx) originating from the petroleum refinery operation. The central aim was to quantify the emission factors of fine particulate matter and analyze their spatial dispersion and source contributions, in order to evaluate their environmental impacts.The VOCs emission measurement appeared that the wastewater treatment plant unit was the most significant source of VOCs emissions, with pentane, cyclopentane, and propane being the dominant VOCs species released. The study employed the secondary organic aerosol potential (SOAP), sulfur oxidation ratio (SOR), and nitrogen oxidation ratio (NOR) methodologies to calculate the emissions of secondary PM2.5. The combustion stacks were the principal contributor to secondary PM2.5 emissions, with SO2 being the predominant secondary PM2.5 precursor species contributing to fine particulate matter, accounting for 82.5% of the total secondary PM2.5 emissions. The overall emission factor for the refinery was determined to be 0.31 g secondary PM2.5 per kg of refined crude oil. Furthermore, the analysis indicated that the combustion stacks were the primary contributors to PM2.5 concentrations at all receptor sites, accounting for 64.4%–80.8% of the total contribution, followed by the wastewater treatment unit and storage tanks. The study underscored the importance of focusing on secondary PM2.5 precursor emissions to effectively reduce emissions and environmental concentrations of PM2.5, highlighting the potential for more effective management and mitigation strategies targeting these precursors.

Synthesis of eco-friendly CaCO3@Zn-Al MMO core-shell nanoflowers photocatalyst using bio–eggshell waste for improved photocatalytic degradation of RhB under visible light irradiation

In this study, a type-I heterojunction was synthesized based on eggshell waste doped mixed metal oxide (ES@ZnAl MMO) for the degradation of RhB dye under visible light irradiation. The ES@ZnAl MMO core-shell was synthesized using waste eggshell and layered double hydroxide (LDH) as primary precursors. After their mechanochemical assembly and thermal treatment, CaCO3 was formed in both calcite and vaterite forms, alongside mixed metal oxides derived from the LDH (ZnO and Al2O3). The formation of a heterojunction between the semiconductors results in an improved activation of sites, a decrease in bandgap energy from 5.72 to 3.44 eV, and an increase in degradation capacity. The elemental composition, morphology, structural, and optical properties of the ES@ZnAl MMO nanocomposite were analyzed using various techniques. The optimal ES@ZnAl MMO photocatalyst demonstrated superior performance, reaching over 98% of RhB dye degradation under optimal conditions, outperforming pure ZnAl LDH, ZnAl MMO, and ES. After five run cycles, the ES@ZnAl MMO heterojunction still maintained a high photocatalytic performance for RhB dye (99%). Furthermore, it displayed high performance in degrading various other pollutants, including OG, IC, MB, and 2.4-DP, with degradation efficiencies of 97%, 99%, 99%, and 87%, respectively. This economically advantageous heterojunction showed its importance in environmental remediation, presenting a promising solution for addressing diverse pollution challenges.

OPDA signaling channels resource (e-) allocations from photosynthetic ETC to plastid cysteine biosynthesis in defense activations.

A primary precursor of jasmonates 12-oxo-phytodienoic acid (OPDA) is an autonomous hormone signal that activates and fine-tunes plant defense responses, as well as growth and development. However, the architecture of its signaling circuits remains largely elusive. Here we describe that OPDA signaling drives photosynthetic reductant powers toward the plastid sulfur assimilations, incorporating sulfide into cysteine. Under stressed states, OPDA -accumulated in the chloroplasts- binds and promotes cyclophilin 20-3, an OPDA receptor, to transfer electrons from thioredoxin F2, an electron carrier in the photosynthesis reaction, to serine acetyltransferase 1 (SAT1). The charge carrier (H+, e-) then splits dimeric SAT1 trimers in half to signal the recruitment of dimeric O-acetylserine(thiol)lyase B, forming a hetero-oligomeric cysteine synthase complex (CSC). The CSC formation and its metabolic products (esp., glutathione) then coordinate redox-resolved retrograde signaling from the chloroplasts to the nucleus in adjusting OPDA-responsive gene expressions such as GLUTAREDOXIN 480 and CYTOCHROME P450, and actuating defense responses against various ecological constraints such as salinity and excess oxidants, as well as mechanical wounding. We thus conclude that OPDA signaling regulates a unique metabolic switch in channeling light input into outputs that fuel/shape a multitude of physiological processes, optimizing plant growth fitness and survival capacity under a range of environmental stress cues.

Hydrodeoxygenation of Glycerol to Propene Over Molybdenum and Niobium Phosphate Catalysts

AbstractIn single‐step conversion of glycerol to propene, the intricate catalytic pathways with molybdenum and niobium catalysts remain elusive. While these catalysts can effectively accelerate the hydrogenolytic cleavage of the glycerol CO bonds, resulting in a high selectivity to propene, the routes have not been thoroughly studied. This study explores the reaction routes and the role hydrogen plays in determining the product distribution. The hydrodeoxygenation (HDO) of glycerol was investigated using various glycerol purities in both batch and continuous reaction modes. Remarkably, Mo(PO4)x and Nb(PO4)x demonstrated catalytic performance with raw glycerol, indicating that impurities had no detrimental effect on the catalyst's activity. In batch mode, a propene selectivity of 53% was achieved over Mo(PO4)x as the catalyst, highlighting the catalyst's stability under these conditions. In continuous operation, the highest product selectivity to propene (12%) was observed at low temperatures (573 K), while more C2 to C6 alkanes were formed at increased temperatures (623 and 673 K). Whereas a hydrogen atmosphere promotes formation of 2‐propenol, as primary precursor to propene, an inert atmosphere leads to increased formation of propanal and dissociation products. Our work has elucidated new routes to upcycle biorenewable glycerol to propene over Mo(PO4)x and Nb(PO4)x catalysts.

Comparative Evaluation of Aminoguanidine, Semicarbazide and Thiosemicarbazide Treatment for Methylglyoxal-Induced Neurological Toxicity in Experimental Models

Background: Advanced glycation end products (AGEs) are complex compounds that play a critical role in neurological disorders, including the pathogenesis of Alzheimer's disease. Methylglyoxal (MG) is recognized as the primary precursor of AGEs. Methylglyoxal is produced endogenously and also introduced through dietary exposures. Objectives: This study aimed to investigate and compare the effects of aminoguanidine (AG), semicarbazide (SC), and thiosemicarbazide (TSC) on MG-induced neurological toxicity in rats. Methods: Male Wistar rats were exposed orally to MG, MG + AG, MG + SC, and MG + TSC for 70 days. Neurobehavioral, biochemical, and histopathological changes were evaluated. Results: The findings indicated that oral administration of MG for 70 days resulted in memory impairment and increased anxiety in neurobehavioral tests. Additionally, MG elevated protein carbonylation in brain tissues. Semicarbazide was found to prevent MG-induced memory problems, while both SC and AG reduced carbonyl content in brain tissues. Aminoguanidine and TSC were effective in alleviating anxiety induced by MG exposure. Histopathological analysis revealed that MG caused cell damage and neuronal necrosis in the hippocampus, particularly in the cornu ammonis 1 and 3 (CA1 and CA3) and AG, SC, and TSC improved neuronal survival specifically in the CA1 and DG areas. Conclusions: The data suggest that SC, AG, and TSC may offer neuroprotective effects against MG-induced neurobehavioral toxicity. Further studies are required to explore the mechanisms of action of these compounds.

Microplastics stress alters microorganism community structure and reduces the production of biogenic dimethylated sulfur compounds

AbstractDimethylsulfoniopropionate (DMSP) is a plentiful organic sulfur metabolite and the primary precursor for dimethyl sulfide (DMS), which plays a crucial role in global sulfur cycling, the formation of clouds, and cooling the warming earth. The origin and fate of DMSP are intricately linked to marine microorganisms, making the variation of the microorganism community crucial for DMSP dynamics. Nonetheless, the impact of pervasive marine microplastics on microorganisms and processes related to DMSP synthesis and degradation remains insufficiently investigated. To bridge this gap, a 14‐d deck‐based microcosm experiment was conducted, revealing that microplastics significantly altered the composition of microorganism communities and dramatically inhibited the release of DMS and DMSP. Furthermore, multivariate analysis demonstrated that the variations both in environmental variables and microorganism communities caused by microplastics were forcing factors in reducing DMS and DMSP release. In addition, the predicted function of the bacterial community showed a significant reduction in the presence of dddP and dmdA genes when exposed to microplastics, which directly disrupted both the demethylation and cleavage pathways of DMSP. These results indicate that the release of DMS and DMSP in marine ecosystems can be significantly affected by microplastics through influencing microorganisms. Thus, it is imperative to conduct research on controlling the synthesis and degradation of DMSP in the ocean, particularly in response to these environmental pollution issues. Such research can help discern new patterns from specific phenomena and identify crucial processes.

Elemene as a binding stabilizer of microRNA-145-5p suppresses the growth of non-small cell lung cancer

Elemene is widely recognized as an effective anti-cancer compound and is routinely administered in Chinese clinical settings for the management of several solid tumors, including non-small cell lung cancer (NSCLC). However, its detailed molecular mechanism has not been adequately demonstrated. In this research, it was demonstrated that elemene effectively curtailed NSCLC growth in the patient-derived xenograft (PDX) model. Mechanistically, employing high-throughput screening techniques and subsequent biochemical validations such as microscale thermophoresis (MST), microRNA-145-5p (miR-145-5p) was pinpointed as a critical target through which elemene exerts its anti-tumor effects. Interestingly, elemene serves as a binding stabilizer for miR-145-5p, demonstrating a strong binding affinity (KD = 0.39 ± 0.17 μg/mL) and preventing its degradation both in vitro and in vivo, while not interfering with the synthesis of the primary microRNA transcripts (pri-miRNAs) and precursor miRNAs (pre-miRNAs). The stabilization of miR-145-5p by elemene resulted in an increased level of this miRNA, subsequently suppressing NSCLC progression through the miR-145-5p/mitogen-activated protein kinase kinase kinase 3 (MAP3K3)/nuclear factor kappaB (NF-κB) pathway. Our findings provide a new perspective on revealing the interaction patterns between clinical anti-tumor drugs and miRNAs.

Expounding the application of nano and micro silica as a complementary additive in metakaolin phosphate geopolymer for ceramic applications—micro and nanoscale structural investigation

Metakaolin phosphate geopolymers comprising poly-phospho-siloxo units are known for their structural performance, additionally advancing their microstructure with the transformation of crystalline berlinite phases at elevated temperatures. The intrinsic reaction of Al of metakaolin in the acid exploited, but the reaction of secondary silica phases is limitedly known. Metakaolin as a primary precursor (M) with the addition of 2% and 5% of nano silica (MS2 and MS5) and micro silica (MM2 and MM5) cast using 8-M phosphoric acid was cured at 80 °C. To enhance the utilization of geopolymer in any high-temperature applications, the structural transformations were studied after heating to various temperatures (200, 400, 600 and 800 °C) by XRD, Raman, TGA-DTA, SEM, XPS, FTIR and MAS-NMR. Sample M attained a strength of 46.2 MPa enhanced to 63.6 MPa in MS5 and 54.2 MPa in MM5. This can be ascribed from the transformation of Si–O–Al–O–Si into Si–O–Al–O–P from Raman bands. Comparing the chemical shift of Al (IV) to control, micro silica addition shifts the signal to a lower field (53 to 50 ppm) related to the increase of the number of Al-connected Si to give a tougher network. Nanoindentation is visualized from hardness and elasticity, and the corresponding values are 1.4 to 2.1 GPa and 0.8 to 1.4 GPa for loads ranging from 20 to 100 mN in silica-reinforced samples that are much higher than M. The micro and macro hardness is due to the reinforcement of quartz in micro silica around the gel. TGA-DTA showed that the reduction of mass loss is as high as 25.4% in control whereas 17.2% in MS5 and 15.8% in the MM5. Further, shrinkage rate in MS5 and MM5 was as low as − 1.1% and − 0.8% throughout the temperature range from 25 to 1000 °C and thus provides the way of use of nano and micro form of silica for better thermal resistance.Graphical

Structural and transport properties of newly synthesized ZSM-5 sourcing silica from coconut shell ash

ZSM-5 is a crucial catalyst in industrial chemistry and petrochemical processing, distinguished by its unique structural and chemical properties. The cost of its production is heavily influenced by the expense of silica-alumina sources, which are the primary precursors for the formation of the zeolitic network. This study introduces a pioneering approach to synthesize the valuable zeolite ZSM-5 using waste coconut shell ash (CSA), a readily available and cost-effective alternative natural source of silica. High-purity amorphous silicon dioxide (SiO2) was successfully extracted from discarded coconut shells, as confirmed by X-ray diffraction (XRD) analysis, providing an eco-friendly approach to the production of this valuable material. The optimal preparation conditions for ZSM-5 were found to be 150 °C and 60 h, yielding the ZSM-5 zeolite from extracted silica. The XRD pattern revealed the presence of a pure crystalline MFI phase in the ZSM-5, and the FTIR findings corroborated its pentasil structure. Microscopic images (SEM and TEM) confirmed that the zeolite was polycrystalline, with agglomerated rod-shaped particles. The WDXRF data revealed a low SiO2/Al2O3 ratio of 17.84. Electrical characterization showed that the dielectric constant decreased with increasing frequency. Complex impedance spectroscopy enabled the distinction between grain and grain boundary contributions to total resistance, and the electric modulus indicated a hopping conduction mechanism. This study demonstrated the potential of a new ZSM-5 using CSA as the source of silica for various catalytic applications.

ThymoSpheres culture: A model to study human polyclonal unconventional T cells.

In vitro cultures remain crucial for studying the fundamental mechanisms of human T-cell development. Here, we introduce a novel in vitro cultivation system based on ThymoSpheres (TS): dense spheroids consisting of DLL4-expressing stromal cells and human hematopoietic precursor cells, in the absence of thymic epithelial cells. These spheroids are subsequently cultured at the air-liquid interphase. TS generate large numbers of mature T cells, are easy to manipulate, scalable, and can be repeatably sampled to monitor T-cell differentiation. The mature T cells generated from primary human hematopoietic precursor cells were extensively characterized using single-cell RNA and combined T-cell receptor (TCR) sequencing. These predominantly CD8α T cells exhibit transcriptional and TCR CDR3 characteristics similar to the recently described human polyclonal αβ unconventional T cell (UTC) lineage. This includes the expression of hallmark genes associated with agonist selection, such as IKZF2 (Helios), and the expression of various natural killer receptors. The TCR repertoire of these UTCs is polyclonal and enriched for CDR3-associated autoreactive features and early rearrangements of the TCR-α chain. In conclusion, TS cultures offer an intriguing platform to study the development of this human polyclonal UTC lineage and its inducing selection mechanisms.

Prevalence of colorectal polyps in patients undergoing colonoscopy in Sulaimaniyah gastroenterology center: a retrospective study

Background & objectives: Colorectal cancers are believed to develop primarily through an adenoma-carcinoma sequence, with adenomatous polyps beginning as the primary precursor lesions. Thus, this study aimed to assess the prevalence of colorectal polyps with their characteristics and relation to age/gender and to aid in establishing a screening program to detect polyps and colorectal cancer in the early stages. Methods: In this retrospective study, the data of 2698 patients who underwent colonoscopy in Sulaimani Gastroenterology Center, Sulaimaniyah, Iraq, for various complaints and asymptomatic patients from January 2019 to February 2021 were studied regarding colorectal polyps. Patients sociodemographic data (age, gender, and residency), presented symptoms, surveillance rate for colon cancer and polyps, and disease follow-up were studied. Briefly, patients were given bowel preparation solutions the day before the colonoscopy, and the process was performed under conscious sedation. Results: The mean±SD age of patients was 52.0±17.59 years, and most were females (55.1%)(p=0.000) and from urban areas (62.12%) (p?0.05). Among the studied patients, 14.3% were diagnosed with polyps, of which 17.1% were males and 12.1% were females. The high prevalence rate was found in patients aged >60 years (23.8%), followed by 50-60 years (17.71%), and then 40-49 years (13.07%). Conclusion: Colorectal polyp was common among patients undergoing colonoscopy for several gastrointestinal symptoms, especially after the age of forty.