Fanconi Anemia Complementary Group A (FANCA) Facilitates the Occurrence and Progression of Liver Hepatocellular Carcinoma.

BACKGROUND: Liver hepatocellular carcinoma (LIHC) is a serious liver disease worldwide, and its pathogenesis is complicated. AIMS: This study investigated the potential role of FANCA in the advancement and prognosis of LIHC. METHODS: Public databases, quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot (WB) and immunohistochemistry (IHC) were employed to measure FANCA expression between tumor and normal samples. The relationship between FANCA expression and prognosis of LIHC patients were examined. Functional enrichment of FANCA-related genes was performed. Furthermore, univariate and multivariate analyses were conducted to determine the independent prognosis value of FANCA in LIHC. Finally, influence of FANCA knockout on the proliferation, migration, and invasion of HepG2 cell was validated with cloning formation, CCK8, and Transwell assays. RESULTS: Expression analysis presented that FANCA had high expression level in LIHC tissues and cells. Receiver operating characteristic (ROC) curve analysis showed that FANCA was of great diagnosis value in LIHC. Clinicopathological analysis revealed that FANCA was significantly greater expressed in the advanced stage than in the early stage of LIHC. Univariate, multivariate, and Kaplan-Meier survival analysis confirmed that high expression of FANCA was strongly associated with poor survival of LIHC patients. In addition, high level of FANCA in LIHC showed a negative association with immunoinfiltrated B cells, T cells, and stromal scores. Moreover, Knockout of FANCA significantly inhibited HepG2 cell proliferative activity, migration, and invasion ability. CONCLUSIONS: Our data revealed that high level of FANCA was closely associated with LIHC malignant progression, suggesting its potential utility as a diagnostic, predictive indicator, and therapeutic target.

Focusing on the Abnormal Events of NPC1, NPC2, and NPC1L1 in Pan-Cancer and Further Constructing LUAD and KICH Prediction Models.

Cancer's high incidence and death rate jeopardize human health and life, and it has become a global public health issue. Some members of NPCs have been studied in a few cancers, but comprehensive and prognostic analysis is lacking in most cancers. In this study, we used the Cancer Genome Atlas (TCGA) data genomics and transcriptome technology to examine the differential expression and prognosis of NPCs in 33 cancer samples, as well as to investigate NPCs mutations and their effect on patient prognosis and to evaluate the methylation level of NPCs in cancer. The linked mechanisms and medication resistance were subsequently investigated in order to investigate prospective tumor therapy approaches. The relationships between NPCs and immune infiltration, immune cells, immunological regulatory substances, and immune pathways were also investigated. Finally, the LUAD and KICH prognostic prediction models were built using univariate and multivariate COX regression analysis. Additionally, the mRNA and protein levels of NPCs were also identified.

A Four Amino Acid Metabolism-Associated Genes (AMGs) Signature for Predicting Overall Survival Outcomes and Immunotherapeutic Efficacy in Hepatocellular Carcinoma.

Metabolites are important indicators of cancer and mutations in genes involved in amino acid metabolism may influence tumorigenesis. Immunotherapy is an effective cancer treatment option; however, its relationship with amino acid metabolism has not been reported. In this study, RNA-seq data for 371 liver cancer patients were acquired from TCGA and used as the training set. Data for 231 liver cancer patients were obtained from ICGC and used as the validation set to establish a gene signature for predicting liver cancer overall survival outcomes and immunotherapeutic responses. Four reliable groups based on 132 amino acid metabolism-related DEGs were obtained by consistent clustering of 371 HCC patients and a four-gene signature for prediction of liver cancer survival outcomes was developed. Our data show that in different clinical groups, the overall survival outcomes in the high-risk group were markedly low relative to the low-risk group. Univariate and multivariate analyses revealed that the characteristics of the 4-gene signature were independent prognostic factors for liver cancer. The ROC curve revealed that the risk characteristic is an efficient predictor for 1-, 2-, and 3-year HCC survival outcomes. The GSVA and KEGG pathway analyses revealed that high-risk score tumors were associated with all aspects of the degree of malignancy in liver cancer. There were more mutant genes and greater immune infiltrations in the high-risk groups. Assessment of the three immunotherapeutic cohorts established that low-risk score patients significantly benefited from immunotherapy. Then, we established a prognostic nomogram based on the TCGA cohort. In conclusion, the 4-gene signature is a reliable diagnostic marker and predictor for immunotherapeutic efficacy.

Exploring the diagnostic value, prognostic value, and biological functions of NPC gene family members in hepatocellular carcinoma based on a multi-omics analysis.

Liver cancer is a cunning malignancy with a high incidence and mortality rate among cancers worldwide. The NPC gene family members (NPCs: NPC1, NPC2, and NPC1L1) are closely linked to the development of multiple cancers, but their role in liver cancer remains unclear. As a result, we must investigate their functions in liver hepatocellular carcinoma (LIHC). NPCs were significantly differentially expressed between normal and LIHC tissues, with a high mutation frequency in LIHC. The ROC curve analysis revealed that NPC1/NPC2 had high diagnostic and prognostic values in LIHC. NPC1 expression was also found to be negatively correlated with its methylation level. The differentially expressed genes between high and low NPC1 expression groups in LIHC were mainly related to channel activity, transporter complexes, and plasma membrane adhesion molecules. Additionally, NPC1 expression was significantly associated with multiple immune cells and immunization checkpoints. It was hypothesized that a TUG1/SNHG4-miR-148a-3p-NPC1 regulatory axis is associated with hepatocarcinogenesis. Finally, the protein expression of NPC1 in LIHC tissues and paraneoplastic tissues was detected, and NPC1-knockdown HepG2 cells (NPC1KO) inhibited the proliferation, migration, and invasion. This study helped to identify new prognostic markers and potential immunotherapeutic targets for LIHC and revealed the molecular mechanisms underlying NPC1 regulation in LIHC. The NPCs play a key role in the prognosis and diagnosis of LIHC and may be an important indicator for LIHC prognosis and diagnosis; NPC1 might be a potential therapeutic target in LIHC.

Arginine methyltransferases PRMT2 and PRMT3 are essential for biosynthesis of plant-polysaccharide-degrading enzymes in Penicillium oxalicum.

Many filamentous fungi produce plant-polysaccharide-degrading enzymes (PPDE); however, the regulatory mechanism of this process is poorly understood. A Gal4-like transcription factor, CxrA, is essential for mycelial growth and PPDE production in Penicillium oxalicum. Its N-terminal region, CxrAΔ207-733 is required for the regulatory functions of whole CxrA, and contains a DNA-binding domain (CxrAΔ1-16&Δ59-733) and a methylated arginine (R) 94. Methylation of R94 is mediated by an arginine N-methyltransferase, PRMT2 and appears to induce dimerization of CxrAΔ1-60. Overexpression of prmt2 in P. oxalicum increases PPDE production by 41.4-95.1% during growth on Avicel, compared with the background strain Δku70;hphR+. Another arginine N-methyltransferase, PRMT3, appears to assist entry of CxrA into the nucleus, and interacts with CxrAΔ1-60 in vitro under Avicel induction. Deletion of prmt3 resulted in 67.0-149.7% enhanced PPDE production by P. oxalicum. These findings provide novel insights into the regulatory mechanism of fungal PPDE production.

Morphology and Microwave-Absorbing Performances of Rubber Blends with Multi-Walled Carbon Nanotubes and Molybdenum Disulfide.

This study details microwave-absorbing materials made of natural rubber/nitrile butadiene rubber (NR/NBR) blends with multi-walled carbon nanotubes (MWCNTs) and molybdenum disulfide (MoS2). The mechanical blending method and the influences of fabrication on the morphology and microwave-absorbing performance of resulting compounds were logically investigated. It was found that interfacial differences between the fillers and matrix promote the formation of MWCNTs and MoS2 networks in NR/NBR blends, thus improving microwave-absorbing performance. Compared with direct compounding, masterbatch-based two-step blending is more conducive to forming interpenetrating networks of MWCNTs/MoS2, endowing the resulting composite with better microwave attenuation capacity. Composites with MWCNTs in NR and MoS2 in NBR demonstrate the best microwave-absorbing performance, with a minimum reflection loss of -44.54 dB and an effective absorption bandwidth of 3.60 GHz. Exploring the relationship between morphology and electromagnetic loss behavior denotes that such improvement results from the selective distribution of dual fillers, inducing networking and multi-component-derived interfacial polarization enhancement.

Synthesis, characterization and potential applications for oxidized agarose.

The knowledge of agarose (AG) oxidation using periodate as oxidizer has not been systematically explored. This paper synthesized oxidized agarose (OAG) using solid-sate and solution reaction methods; the reaction mechanism and the properties of OAG samples were systematically evaluated. Chemical structure analysis disclosed that the aldehyde group and carboxyl group contents in all OAG samples are extremely low. Meanwhile, crystallinity, dynamic viscosity and molecular weight of OAG samples is lower than that of the original AG. Reaction temperature, time and sodium periodate dosage are inversely proportional to the decline of the gelling temperature (Tg) and melting temperature (Tm); and the Tg and Tm for the OAG sample obtained are even 19 °C and 22 °C lower than that of the original AG. The as-synthesized OAG samples all possess excellent cytocompatibility and blood compatibility; and can promote the proliferation and migration of fibroblast cells. Last but not least, the gel strength, hardness, cohesiveness, springiness and chewiness of the OAG gel can be effectively regulated via oxidation reaction. In conclusions, both solid and solution oxidation can regulate the physical properties of OAG and enlarge its potential applications in wound dressing, tissue engineering and food areas.

Molecular Dynamic and Dissipative Particle Dynamic Simulation on the Miscibility of NR/CR Blends.

Natural rubber (NR) exhibits good elasticity, flexural resistance, wear resistance, and excellent mechanical properties, and it has been widely used in aerospace, transportation, medical, and health fields. For NR, however, the resistance to thermal-oxidation and ozone aging is fairly poor. Although aging properties of NR can be significantly improved with the incorporation of chloroprene rubber (CR) according to some references, the miscibility between NR and CR, the morphologies of the binary blends, and so on are revealed ambiguously. In this work, molecular dynamics simulation (MD) and dissipative particle dynamics (DPD) simulation were carried out to predict the compatibility between natural rubber and chloroprene rubber in view of Flory-Huggins parameters. The morphologies of the blends were obtained with the use of the DPD method. The simulation results were furtherly examined by means of Fourier transform infrared spectroscopy (FT-IR) and dynamic mechanical analysis (DMA). It was found that the miscibility between NR and CR is poor. Nevertheless, the miscibility could be improved when the content of CR is 50% or 90%. In addition, spinodal decomposition with a critical temperature of 390 K would take place according to the phase diagram. Microphase structure such as spherical, lamellar, and bicontinuous phases can be found with different contents of CR in the blends with the results of morphologies analysis.

Natural Hollow Fiber-Derived Carbon Microtube with Broadband Microwave Attenuation Capacity.

Constructing hierarchical structures is indispensable to tuning the electromagnetic properties of carbon-based materials. Here, carbon microtubes with nanometer wall thickness and micrometer diameter were fabricated by a feasible approach with economical and sustainable kapok fiber. The carbonized kapok fiber (CKF) exhibits microscale pores from the inherent porous templates as well as pyrolysis-induced nanopores inside the wall, affording the hierarchical carbon microtube with excellent microwave absorbing performance over broad frequency. Particularly, CKF-650 exhibits an optimized reflection loss (RL) of −62.46 dB (10.32 GHz, 2.2 mm), while CKF-600 demonstrates an effective absorption bandwidth (RL < −10 dB) of 6.80 GHz (11.20−18.00 GHz, 2.8 mm). Moreover, more than 90% of the incident electromagnetic wave ranging from 2.88 GHz to 18.00 GHz can be dissipated by simply controlling the carbonization temperature of KF and/or the thickness of the carbon-microtube-based absorber. These encouraging findings provide a facile alternative route to fabricate microwave absorbers with broadband attenuation capacity by utilizing sustainable biomass.

Influence of Clones on Relationship between Natural Rubber and Size of Rubber Particles in Latex.

IAN873, Dongfang93114 and Reyan73397, created through vegetative propagation for their high yield and excellent cold resistance, are major clones planted in China. In this work, latexes with rubber particles of the same size from these clones are separated from fresh natural rubber latex, and corresponding rubber films are prepared from each latex. The structure and components of each film are measured. This indicates that the characteristics of the rubbers obtained from latexes with similar particle sizes show some resembling trends among different clones, while for specific samples, those characteristics vary depending on the clone. The molecular weight is generally highest in IAN873 and lowest in Reyan73397. Rubber chains in small rubber particles are longer, and large rubber particles show a wider molecular weight distribution. The gel content of every sample from Reyan73397 is lower than the other two clones. The nitrogen content increases with the size of rubber particles in all clones. The ester content of small rubber particles in IAN873 and Reyan73397 is almost zero. Large rubber particles have more branching points formed via esters. This study provides a new perspective on the influence of clones on the relationship between characteristics of natural rubber and the size of rubber particles in natural rubber latex.

Sustainable Kapok Fiber-Derived Carbon Microtube as Broadband Microwave Absorbing Material.

The design of hierarchical structures from biomass has become one of the hottest subjects in the field of microwave absorption due to its low cost, vast availability and sustainability. A kapok-fiber-derived carbon microtube was prepared by facile carbonization, and the relation between the structure and properties of the carbonized kapok fiber (CKF) was systematically investigated. The hollow tubular structures afford the resulting CKF composites with excellent microwave-absorbing performance. The sample with a 30 wt.% loading of CKF in paraffin demonstrates the strongest microwave attenuation capacity, with a minimum reflection loss of -49.46 dB at 16.48 GHz and 2.3 mm, and an optimized effective absorption bandwidth of 7.12 GHz (10.64-17.76 GHz, 2.3 mm) that covers 34% of the X-band and 96% of the Ku-band. Further, more than 90% of the incident electromagnetic wave in the frequency from 4.48 GHz to 18.00 GHz can be attenuated via tuning the thickness of the CKF-based absorber. This study outlines a foundation for the development of lightweight and sustainable microwave absorbers with a high absorption capacity and broad effective absorption bandwidth.

Mechanically Robust Dual-Crosslinking Elastomer Enabled by a Facile Self-Crosslinking Approach.

We propose a simple but rapid strategy to fabricate self-crosslinked dual-crosslinking elastomers (SCDCEs) with high mechanical properties. The SCDCEs are synthesized through one-pot copolymerization of Butyl acrylate (BA), acrylic amide (AM), and 3-Methacryloxypropyltrimethoxysilane (MEMO). Both the amino group on AM and the methoxy group on MEMO can be self-crosslinked after polymerization to form a dual-network crosslink consisting of hydrogen bonds crosslink and Si-O-Si covalent bonds crosslink. The SCDC endow optimal elastomer with high mechanical properties (the tensile strength is 6MPa and elongation at break is 490%) as the hydrogen bonds crosslink can serve as sacrificial construction to dissipate stress energy, while covalent crosslinking networks can ensure the elasticity and strength of the material. These two networks also contribute to the recoverability of the elastomers, leading them to recover their original shape and mechanical properties after being subjected to deformation in a short time.

Effect of Nonisoprene Degradation and Naturally Occurring Network during Maturation on the Properties of Natural Rubber.

It well-known that the superior performance of natural rubber (NR) compared to its synthetic counterpart mainly derives from nonisoprene components and naturally occurring network, which varies during the progress of the maturation and thereby results in technically graded rubber with different properties. However, identifying the roles of these two factors in the forming of excellent performance of NR is still a challenge as they change simultaneously during the maturation process. Here, influences of naturally occurring networking and nonisoprene degradation on the components, structures and properties of NR were systematically investigated by tailored treatments of maturation. It was found that the maturation-induced formation of natural network structure contributes to the increase in initial plastic value, Mooney viscosity and gel content for un-crosslinked NR, while the decomposition of nonisoprene components plays a dominant role in improving the mechanical properties of vulcanized NR. Stress-strain curve and Mooney-Rivlin analysis demonstrate that the biodegradation of the nonisoprene components significantly boost the vulcanization process, which significantly increases the number of chemical cross-link networks and effective cross-link density of the material, greatly improving the mechanical properties of NR vulcanizates. This resulted in the tensile strength of TSR 10CV being able to reach 22.6 MPa, which is significantly improved compared to 15.8 MPa of TSR 3CV. Evidenced by tubular model fitting, the increase in chemical cross-linking points effectively reduces the movable radius of the molecular chain under dynamic loading, making the molecular chain more difficult to move, which suppresses the entropy change under dynamic loading and consequently endows NR excellent dynamic mechanical properties. This resulted in a significant decrease in the temperature rising of TSR 10CV to 3.3 °C, while the temperature rising of TSR 3CV was still as high as 14.5 °C. As a minor factor, the naturally occurring network improves the mechanical properties of vulcanizates in the form of sacrificial bonds.

Biodegradable Natural Rubber Based on Novel Double Dynamic Covalent Cross-Linking.

In this paper, biodegradable epoxidized natural rubber containing cyclic carbonate groups (CNR) was prepared by the reaction between epoxidized natural rubber (ENR) and carbon dioxide. Dynamic disulfide bonds and a boronic ester structure were successfully constructed and then the cross-linking network was formed by the thermally initiated "click" reaction between thiol groups of the cross-linker and the residual epoxy groups of ENR. As a result of the exquisite double dynamic covalent structure, the material exhibits high self-healing efficiency. Moreover, by virtue of the cyclic carbonate structure of the CNR, the natural rubber was confirmed to be biodegradable according to the biodegradable measurement. To the best of our knowledge, natural rubber with biodegradable and self-healing characteristics was obtained for the first time.

Analysis of the Expression and Prognostic Value of MSH2 in Pan-Cancer Based on Bioinformatics.

BACKGROUND: MutS homolog 2 (MSH2), with the function of identifying mismatches and participating in DNA repair, is the "housekeeping gene" in the mismatch repair (MMR) system. MSH2 deficiency has been reported to enhance cancer susceptibility for the association of hereditary nonpolyposis colorectal cancer. However, the expression and prognostic significance of MSH2 have not been studied from the perspective of pan-cancer. METHODS: The GTEx database was used to analyze the expression of MSH2 in normal tissues. The TCGA database was used to analyze the differential expression of MSH2 in pan-cancers. The prognostic value of MSH2 in pan-cancer was assessed using Cox regression and Kaplan-Meier analysis. Spearman correlations were used to measure the relationship between the expression level of MSH2 in pan-cancer and the level of immune infiltration, tumor mutational burden (TMB), and microsatellite instability (MSI). RESULTS: MSH2 is highly expressed in most type of cancers and significantly correlated with prognosis. In COAD, KIRC, LIHC, and SKCM, the expression of MSH2 was significantly positively correlated with the abundance of B cells, CD4+ T cells, CD8+ T cells, dendritic cells, macrophages, and neutrophils. In THCA, MSH2 expression correlated with CD8+T Cell showed a significant negative correlation. MSH2 had significantly negative correlations with stromal score and immune score in a variety of cancers and significantly correlated with TMB and MSI of a variety of tumors. CONCLUSIONS: MSH2 may play an important role in the occurrence, development, and immune infiltration of cancer. MSH2 can emerge as a potential biomarker for cancer diagnosis and prognosis.

G protein γ subunit modulates expression of plant-biomass-degrading enzyme genes and mycelial-development-related genes in Penicillium oxalicum.

Heterotrimeric-G-protein-mediated signaling pathways modulate the expression of the essential genes in many fundamental cellular processes in fungi at the transcription level. However, these processes remain unclear in Penicillium oxalicum. In this study, we generated knockout and knockout-complemented strains of gng-1 (POX07071) encoding the Gγ protein and found that GNG-1 modulated the expression of genes encoding plant-biomass-degrading enzymes (PBDEs) and sporulation-related activators. Interestingly, GNG-1 affected expression of the cxrB that encodes a known transcription factor required for the expression of major cellulase and xylanase genes. Constitutive overexpression of cxrB in ∆gng-1 circumvented the dependence of PBDE production on GNG-1. Further evidence indicated that CxrB indirectly regulated the transcription levels of key amylase genes by controlling the expression of the regulatory gene amyR. These data extended the diversity of Gγ protein functions and provided new insight into the signal transduction and regulation of PBDE gene expression in filamentous fungi. KEY POINTS: • GNG-1 modulates the expression of PBDE genes and sporulation-related genes. • GNG-1 controls expression of the key regulatory gene cxrB. • Overexpression of cxrB circumvents dependence of PBDE production on GNG-1.

Anions effect construction of 1D naphthalene diimide supramolecular chains by π interactions and fluorescence detect iodide anion.

Five diverse 1D supramolecular chains, {[4-pmntd]}n(1), {H2[4-pmntd]•2Br-}n(2), {H2[4-pmntd]•2NO3-}n(3), {H2[4-pmntd]•2ClO4-}n(4), {H2[4-pmntd]•2BF4-}n(5), (where 4-pmntd was N,N'-bis (4-pyridylmethyl)naphthalene diimide) were synthesized and characterized by X-ray single-crystal structure analysis, IR spectroscopy, elemental analyses, thermogravimetric analyses, fluorescence detection. The anions effect construction of their 1D chain structural diversity through different π interactions. Compound 1 through the adjacent pyridine rings parallel π∙∙∙π interactions formed 1D linear chain structure. Compound 2 through Br- anion∙∙∙π interactions and halogenbond interactions formed 1D zigzag chain structure. Compound 3 through lone pair∙∙∙π interactions of naphthalene diimide and the adjacent carboxyl group formed 1D stairway chain structure. Compound 4 through ClO4- anion∙∙∙π interactions formed 1D ribbon chain structure. Compound 5 through parallel π∙∙∙π interactions of the adjacent naphthalene diimide planes and pyridine rings formed 1D ladder chain structure. The five compounds' fluorescence properties and thermal stabilities were investigated. The compound 2 solution could fluorescence detection for iodide anion via fluorescence quenching.

PoxCbh, a novel CENPB-type HTH domain protein, regulates cellulase and xylanase gene expression in Penicillium oxalicum.

The essential transcription factor PoxCxrA is required for cellulase and xylanase gene expression in the filamentous fungus Penicillium oxalicum that is potentially applied in biotechnological industry as a result of the existence of the integrated cellulolytic and xylolytic system. However, the regulatory mechanism of cellulase and xylanase gene expression specifically associated with PoxCxrA regulation in fungi is poorly understood. In this study, the novel regulator PoxCbh (POX06865), containing a centromere protein B-type helix-turn-helix domain, was identified through screening for the PoxCxrA regulon under Avicel induction and genetic analysis. The mutant ∆PoxCbh showed significant reduction in cellulase and xylanase production, ranging from 28.4% to 59.8%. Furthermore, PoxCbh was found to directly regulate the expression of important cellulase and xylanase genes, as well as the known regulatory genes PoxNsdD and POX02484, and its expression was directly controlled by PoxCxrA. The PoxCbh-binding DNA sequence in the promoter region of the cellobiohydrolase 1 gene cbh1 was identified. These results expand our understanding of the diverse roles of centromere protein B-like protein, the regulatory network of cellulase and xylanase gene expression, and regulatory mechanisms in fungi.

Involvement of phospholipase PLA2 in production of cellulase and xylanase by Penicillium oxalicum.

Phospholipases play vital roles in immune and inflammatory responses in mammals and plants; however, knowledge of phospholipase functions in fungi is limited. In this study, we investigated the effects of deleting predicted phospholipase genes on cellulase and xylanase production, and morphological phenotype, in Penicillium oxalicum. Individual deletion of nine of the ten predicted phospholipase genes resulted in alteration of cellulase and xylanase production, and the morphological phenotypes, to various degrees. The mutant ∆POX07277 lost 22.5 to 82.8% of cellulase (i.e., filter paper cellulase, carboxymethylcellulase, and p-nitrophenyl-ß-cellobiosidase) and xylanase production, whereas p-nitrophenyl-ß-glucopyranosidase production increased by 5.8-127.8 fold. POX07277 (P. oxalicum gene No. 07277) was predicted to encode phospholipase A2 and was found to negatively affect the sporulation of P. oxalicum. Comparative transcriptomic and quantitative reverse transcription-PCR analysis indicated that POX07277 dynamically affected the expression of cellulase and xylanase genes and the regulatory genes for fungal sporulation, under micro-crystalline cellulose induction. POX07277 was required for the expression of the known regulatory gene PoxCxrB (cellulolytic and xylanolytic regulator B in P. oxalicum), which is involved in cellulase and xylanase gene expression in P. oxalicum. Conversely, POX07277 expression was regulated by PoxCxrB. These findings will aid the understanding of phospholipase functions and provide novel insights into the mechanism of fungal cellulase and xylanase gene expression. KEY POINTS : • The roles of phospholipases were investigated in Penicillium oxalicum. • POX07277 (PLA2) is required for the expression of cellulase and xylanase genes. • PoxCxrB dynamically regulated POX07277 expression.

Preparation and Characterization of Ultra-Fine Oil Palm Ash Powder by Ultrasonication and Alkaline Treatment for Its Evaluation as Reinforcing Filler in Natural Rubber.

Ultra-fine oil palm ash (OPA) particles were successfully prepared using ultrasonication along with optimal chemical deagglomeration. The influence of chemical treatment by sodium hydroxide (NaOH) solution on the OPA particles was found to be an important factor in enhancing deagglomeration efficiency. The average particle size of the original OPA (41.651 µm) decreased remarkably more than 130 times (0.318 µm) with an obvious increase of Brunauer-Emmet-Teller (BET) surface area after treating the OPA with 3M NaOH, followed by ultrasonication for 30 min. The changes in particle size and surface morphology were investigated using transmission electron microscopy and scanning electron microscopy. Moreover, the chemical functional groups of the untreated and treated OPA showed different patterns of infrared spectra by the presence of sodium carbonate species owing to the effect of NaOH treatment. The incorporation of both untreated and treated OPA in natural rubber by increasing their loading can improve cure characteristics (i.e., reducing optimum cure time and increasing torques) and cure kinetic parameters (i.e., increasing the rate of cure and reducing activation energy). Nevertheless, the strength, degree of reinforcement, and thermal stability of treated OPA as well as wettability between treated OPA particles and NR were greater than that resulting from the untreated OPA.