Pseudo Elevation of TSH and ACTH Caused by Heterophilic Antibodies: a Case Report and Literature Review.

BACKGROUND: TSH and ACTH are crucial hormones for diagnosing thyroid and adrenal diseases, and incorrect test reports can cause significant harm to patients. METHODS: The TSH and ACTH levels on the testing system of our laboratory were measured using "sandwich" assays. The patient had heterophilic antibodies in their body, causing a false increase in TSH and ACTH levels. RESULTS: TSH on the Abbott platform was 59.7 µIU/mL and on the Roche platform it was 4.33 µIU/mL. After pretreatment with HBR it was 3.95 µIU/mL; ACTH on the SIEMENS platform was 263.5 pg/mL, on the Abbott platform it was 47.6 pg/mL. After pretreatment with HBR it was 36.5 pg/mL. CONCLUSIONS: The patient's serum contains heterophilic antibodies, which interfere with the TSH and ACTH tested by this method.

A Pseudo Elevation of CEA Caused by Epidemic Hemorrhagic Fever.

BACKGROUND: Heterophilic antibodies (HA) are one of the main substances that interfere with immunology, especially chemiluminescence immunoassay. Non-specific binding, labeling antibodies, bridging to capture antibodies, or labeling antigens can interfere with the detection process, leading to serious discrepancies between the measured results and clinical manifestations, and even delaying clinical diagnosis and treatment. METHODS: This paper is a case of epidemic hemorrhagic fever causing pseudo CEA elevation caused by heterophagy induced antibodies in the body. RESULTS: The patient's CEA detected on the ABBOTT detection platform was 51.1 ng/mL, and on the ROCHE detection platforms it was 4.66 ng/mL, and treated by PEG precipitation it was 45.2 ng/mL, after diluting the sample the CEA was 50.2 ng/mL, meanwhile the patient's platelets were 96 x 109/L and serum creatinine was 188.4 µmol/L, epidemic hemorrhagic fever IgM antibody was positive. CONCLUSIONS: When the test results do not match clinical symptoms, further confirmation is required through additional testing. Patients who use mouse monoclonal antibody preparations for diagnosis or treatment may have human anti-mouse antibodies in their serum, and the test results may falsely increase or decrease.

Knowledge, attitudes, and practices of gouty arthritis in the general population aged > 30.

BACKGROUND: A knowledge of gouty arthritis could help in the primary prevention of the disease development and lead to an early diagnosis if it occurs. This study investigated the knowledge, attitudes, and practices (KAP) toward gouty arthritis in the general population > 30 years old. METHODS: This web-based cross-sectional study was conducted among the general population > 30 years old between January and March 2023 in Chengdu, Sichuan. The questionnaire was designed by the investigators based on the available guidelines (Cronbach's α = 0.846). A score above 70% indicated good knowledge, a positive attitude, and proactive practice. Multivariable and structural equation modeling (SEM) analyses were performed to analyze the factors influencing KAP. RESULTS: A total of 537 questionnaires were included. The knowledge, attitudes, and practices scores were 13.12 ± 6.41, 25.28 ± 3.97, and 45.25 ± 5.77, respectively. Female (OR = 0.47, 95%CI: 0.31-0.71, P < 0.001), suburban living (OR = 0.18, 95%CI: 0.04-0.78, P = 0.022), heads of institution/organization and professional and technical staff (OR = 2.04, 95%CI: 1.23-3.39, P = 0.006), and an income of < 2,000 yuan (OR = 0.35, 95%CI: 0.14-0.85, P = 0.021) were independently associated with knowledge. Female (OR = 2.17, 95%CI: 1.43-3.30, P < 0.001), age (OR = 1.03, 95%CI: 1.01-1.05, P = 0.001), college and above education (OR = 2.26, 95%CI: 1.16-4.41, P = 0.017), an income of 5,000-10,000 yuan (OR = 2.05, 95%CI: 1.27-3.31, P = 0.003), and an income of > 10,000 yuan (OR = 2.07, 95%CI: 1.12-3.81, P = 0.020) were independently associated with attitudes. Attitude (OR = 1.31, 95%CI: 1.23-1.40, P < 0.001), female (OR = 1.62, 95%CI: 1.01-2.58, P = 0.044), and age (OR = 1.02, 95%CI: 1.00-1.04, P = 0.016) were independently associated with practices. The structural equation modeling analysis showed that knowledge directly influenced attitude (ß=-0.10, P < 0.001) and indirectly influenced practice (ß=-0.07, P < 0.001), and attitude directly influenced practice (ß = 0.68, P < 0.001). CONCLUSION: The general population over 30 years old had inadequate knowledge, unfavorable attitudes, and less proactive practices toward gouty arthritis. Targeted interventions should focus on enhancing knowledge about gout and promoting positive attitudes toward its management.

Genome-Wide Identification, Characterization, and Expression Analysis of the BES1 Family Genes under Abiotic Stresses in Phoebe bournei.

The BRI1 EMS suppressor 1(BES1) transcription factor is a crucial regulator in the signaling pathway of Brassinosteroid (BR) and plays an important role in plant growth and response to abiotic stress. Although the identification and functional validation of BES1 genes have been extensively explored in various plant species, the understanding of their role in woody plants-particularly the endangered species Phoebe bournei (Hemsl.) Yang-remains limited. In this study, we identified nine members of the BES1 gene family in the genome of P. bournei; these nine members were unevenly distributed across four chromosomes. In our further evolutionary analysis of PbBES1, we discovered that PbBES1 can be divided into three subfamilies (Class I, Class II, and Class IV) based on the evolutionary tree constructed with Arabidopsis thaliana, Oryza sativa, and Solanum lycopersicum. Each subfamily contains 2-5 PbBES1 genes. There were nine pairs of homologous BES1 genes in the synteny analysis of PbBES1 and AtBES1. Three segmental replication events and one pair of tandem duplication events were present among the PbBES1 family members. Additionally, we conducted promoter cis-acting element analysis and discovered that PbBES1 contains binding sites for plant growth and development, cell cycle regulation, and response to abiotic stress. PbBES1.2 is highly expressed in root bark, stem bark, root xylem, and stem xylem. PbBES1.3 was expressed in five tissues. Moreover, we examined the expression profiles of five representative PbBES1 genes under heat and drought stress. These experiments preliminarily verified their responsiveness and functional roles in mediating responses to abiotic stress. This study provides important clues to elucidate the functional characteristics of the BES1 gene family, and at the same time provides new insights and valuable information for the regulation of resistance in P. bournei.

TAGAP activates Th17 cell differentiation by promoting RhoA and NLRP3 to accelerate rheumatoid arthritis development.

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that can give rise to joint swelling and inflammation, potentially affecting the entire body, closely linked to the state of T cells. The T-cell activation Rho GTPase activating protein (TAGAP) is associated with many autoimmune diseases including RA and is directly linked to the differentiation of Th17 cells. The present study intends to investigate the influence of TAGAP on the RA progression and its mechanism to empower new treatments for RA. A collagen-induced-arthritis (CIA) rat model was constructed, as well as the extraction of CD4+ T cells. RT-qPCR, H&E staining and safranin O/fast green staining revealed that TAGAP interference reduced TAGAP production in the ankle joint of CIA rats, and joint inflammation and swelling were alleviated, which reveals that TAGAP interference reduces synovial inflammation and cartilage erosion in the rat ankle joint. Expression of inflammatory factors (TNF-α, IL-1ß, and IL-17) revealed that TAGAP interference suppressed the inflammatory response. Expression of pro-inflammatory cytokines, matrix-degrading enzymes, and anti-inflammatory cytokines at the mRNA level was detected by RT-qPCR and revealed that TAGAP interference contributed to the remission of RA. Mechanistically, TAGAP interference caused a significant decrease in the levels of RhoA and NLRP3. Assessment of Th17/Treg levels by flow cytometry revealed that TAGAP promotes Th17 cells differentiation and inhibits Treg cells differentiation in vitro and in vivo. In conclusion, TAGAP interference may decrease the differentiation of Th17 cells by suppressing the expression of RhoA and NLRP3 to slow down the RA progression.

Metagenomics reveals the effects of glyphosate on soil microbial communities and functional profiles of C and P cycling in the competitive vegetation control process of Chinese fir plantation.

Although considerable efforts have been devoted to investigate the behavior of glyphosate on microbiome in various environment, knowledge about the soil microbial community and functional profile in weeds control process of the Chinese fir plantation are limited. In this study, shotgun metagenomic sequencing was used to determine the abundance and diversity of microbial communities and functional genes after foliar application of glyphosate for 1, 2, 3 and 4 months in a Chinese fir plantation. The results showed that glyphosate increased the copy numbers (qPCR) of 16S rRNA gene for 16.9%, improved the bacterial diversity (Shannon index) and complexity of bacterial co-occurrence network, and changed the abundances of some bacterial and fungal taxa, but had no effects on ITS gene copy numbers, fungal Shannon index, and bacterial and fungal communities (PCoA). Glyphosate application significantly decreased the amount of microbial function potentials involved in organic P mineralization for 10.7%, chitin degradation for 13.1%, and CAZy gene families with an exception of PL for 11.5% at the first month, while did not affect the profile of microbial genes response to P and C cycling in longer term. In addition, glyphosate reduced the contents of soil TOC, DOC and NH4+-H for 17.6%, 52.3% and 44.6% respectively, and decreased the starch, soluble sugar, Zn and Fe of Chinese fir leaves for 20.6%, 19.8%, 32.8% and 48.4% respectively. Mantle test, Spearman's correlation, and PLS-PM model revealed the connections among soil properties, tree nutrients, bacterial and fungal communities, and microbial function potentials were influenced by glyphosate. While our findings need to be validated in other filed and mechanistic studies, they may indicate that the foliar application of glyphosate has a potential effect on Chinese fir seedlings, and this effect may contribute to the changes of the bacterial community and soil properties including AN, DON and NH4+-H.

IRF2 inhibits ZIKV replication by promoting FAM111A expression to enhance the host restriction effect of RFC3.

BACKGROUND: Although interferon regulatory factor 2 (IRF2) was reported to stimulate virus replication by suppressing the type I interferon signaling pathway, because cell cycle arrest was found to promote viral replication, IRF2-regulated replication fork factor (FAM111A and RFC3) might be able to affect ZIKV replication. In this study, we aimed to investigate the function of IRF2, FAM111A and RFC3 to ZIKV replication and underlying mechanism. METHODS: siIRF2, siFAM111A, siRFC3 and pIRF2 in ZIKV-infected A549, 2FTGH and U5A cells were used to explore the mechanism of IRF2 to inhibit ZIKV replication. In addition, their expression was analyzed by RT-qPCR and western blots, respectively. RESULTS: In this study, we found IRF2 expression was increased in ZIKV-infected A549 cells and IRF2 inhibited ZIKV replication independent of type I IFN signaling pathway. IRF2 could activate FAM111A expression and then enhanced the host restriction effect of RFC3 to inhibit replication of ZIKV. CONCLUSIONS: We speculated the type I interferon signaling pathway might not play a leading role in regulating ZIKV replication in IRF2-silenced cells. We found IRF2 was able to upregulate FAM111A expression and thus enhance the host restriction effect of RFC3 on ZIKV.

High-Mobility Group Box 1 (HMGB1) Promotes Angiogenesis and Tumor Migration by Regulating Hypoxia-Inducible Factor 1 (HIF-1α) Expression via the Phosphatidylinositol 3-Kinase (PI3K)/AKT Signaling Pathway in Breast Cancer Cells.

BACKGROUND High-mobility group box 1 (HMGB1) is an essential contributor towards initiation and progression of many kinds of cancers. Nevertheless, our understanding of the molecular etiology of HMGB1-modulated vasculogenesis, as well as invasion, of breast cancer is poor. This study explored HMGB1 expression in breast cancer and its role in the development and spread of malignancy. MATERIAL AND METHODS We enrolled 15 patients with breast cancer who received primary surgery at the Department of Thyroid and Breast Surgery in our hospital. HMGB1 was recorded and analyzed. RESULTS Our investigation successfully proves that HMGB1 is upregulated in breast cancer tissues in comparison to the surrounding non-malignant tissues. HMGB1 enhanced vessel formation in breast cancer tissues by regulating hypoxia-inducible factor 1 (HIF-1alpha), which in turn upregulates the expression of VEGF. Furthermore, HMGB1-mediated upregulation of HIF-1alpha relies on its ability to stimulate the phosphatidylinositol 3-kinase (PI3K) pathway to reinforce AKT subunit phosphorylation. HMGB1 overexpression reinforces the vasculogenesis in malignancies not only in vivo but also in vitro. Additionally, shRNA knockdown of HMGB1 prohibited the vessel-forming and invasive capabilities, downregulated VEGF and HIF-1alpha, and suppressed AKT phosphorylation in breast cancer cells. Most importantly, PI3K/AKT axis suppression eliminated the effect of HMGB1-modulated vascularization and invasion in breast cancer cells. CONCLUSIONS Our research indicates that HMGB1 serves as a crucial regulator of malignant cell-modulated vessel formation and is involved in the development of malignancy. Our findings indicate that HMGB1 is a promising target for breast cancer treatment.

Impact of Tag Single Nucleotide Polymorphisms (SNPs) in CCL11 Gene on Risk of Subtypes of Ischemic Stroke in Xinjiang Han Populations.

BACKGROUND CCL11 is an important inflammatory cytokine associated with inflammation-related diseases such as atherosclerosis and stroke. The aim of this study was to investigate the relationship between CCL11 gene polymorphism with subtypes of ischemic stroke in Xinjiang Han populations. MATERIAL AND METHODS The improved multiple ligase detection reaction (iMLDR) method was used to analyze the genotypes of 6 tag SNPs in the CCL11 gene (rs1129844, rs17809012, rs1860183, rs1860184, rs4795898, and rs4795895) in a case-control study of 406 lacunar stroke patients, 214 large-artery atherosclerotic (LAA) stroke patients, and 425 controls. RESULTS We found the GG genotype of rs4795895 was significantly associated with increased risk of lacunar stroke (adjusted OR=1.676, 95%CI=1.117-2.515), and the GA genotype of rs17809012 was associated with a significant increase in risk of LAA stroke (adjusted OR=1.337, 95%CI=1.127-1.585). Hypertension stratification analyses showed that the GA genotype of rs17809012 was significantly associated with LAA stroke in the hypertensive group (adjusted OR=1.274, 95%CI=1.015-1.601). In the non-hypertensive group, the GA genotype of rs17809012 was significantly associated with LAA stroke (adjusted OR=1.361, 95%CI=1.041-1.780). The GG genotype of rs4795895 (adjusted OR=1.147, 95%CI=1.115-4.134) and the TT genotype of rs1860184 were significantly associated with lacunar stroke (adjusted OR=2.440, 95%CI=1.550-3.840). CONCLUSIONS This study demonstrates that the CCL11 gene could play an important role in the pathogenesis of lacunar stroke and LAA stroke in the Han population of China.

The roles of surface structure, oxygen defects, and hydration in the adsorption of CO(2) on low-index ZnGa(2)O(4) surfaces: a first-principles investigation.

The effects of the surface atomic and electronic structures, oxygen defects, and hydration on CO2 adsorption on ZnGa2O4(100), (110), and (111) surfaces were studied using density functional theory (DFT) slab calculations. For the perfect (100) surface, the most stable adsorption state involved the Zn-O-Ga bridge site, with an adsorption energy of 0.16 eV. In the case of the (110) and (111) surfaces, the strongest binding occurred on the Zn-O bridge sites, with much lower adsorption energies of -0.22 eV and -0.35 eV, respectively. In addition, the perfect surfaces showed CO2 activation ability, but dissociation adsorption could not proceed. The oxygen vacancies on these three surfaces (1) made the metal sites beside them carry less positive charge and further reduced the adsorption energies on these metal sites, and (2) created efficient adsorption sites that allowed even dissociative adsorption. The most favorable molecular and dissociative adsorption states both involved the O3c vacancy site of the (100) surface, and these two processes were spontaneous with adsorption energies of 0.74 eV and 0.80 eV, respectively. When H2O molecules are present on the perfect and defective surfaces, the generation of hydrogen bonds between H2O and CO2 would slightly enhance the stability of adsorption (except for that on the surface), making them energetically favorable. However, the co-adsorption of H2O could also increase the energy barriers for the decomposition reactions on the defective surfaces, making them kinetically unfavorable. Furthermore, the oxygen vacancy defects showed good activity for H2O adsorption and decomposition, as well. Thus, when both H2O and CO2 were present in the adsorption system, H2O would compete with CO2 for the oxygen vacancy sites and further decrease the amount of CO2 adsorption and decomposition. These findings have important implications for the decomposition of CO2 on the ZnGa2O4 surfaces and can provide theoretical guidance for chemists to efficiently synthesize ZnGa2O4 catalysts.

Effects of species mixing on maximum size-density relationships in Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.)-dominated mixed forests converted from even-aged pure stands.

Introduction: Density management is a key silvicultural tool in management programs that enhances compositional and structural diversity and hence forest growth during the conversion of even-aged pure stands into mixed forests. Methods: To determine the optimum stand density, a model of maximum size-density relationships was employed to explore the relationship of the self-thinning trajectory with growth, species mixing, latitude, and site conditions during the transition of even-aged pure Chinese fir stands to Chinese fir-dominated mixed forests using stochastic frontier analysis. Data were obtained from a total of 591 permanent plots located in Fujian, Jiangxi, Zhejiang, and Anhui provinces in southern China. Results: The results showed that (1) the slope of the maximum size-density relationship of Chinese fir-dominated mixed forests increased and plateaued over time; (2) the slope of the maximum size-density relationship of Chinese fir-dominated mixed forests did not deviate from Reineke's assumed universal slope of -1.605; and (3) mixing proportion had a positive effect on maximum size-density relationships, and latitude and site conditions had the opposite effect on maximum size-density relationships. Conclusions: Our findings will provide valuable guidance for the forest management of areas in which even-aged pure stands are being converted to mixed forests (i.e., when broadleaved tree species are planted after thinning to improve overall stand density and promote stand growth).

Infection with multi­drug resistant organisms in patients with limb fractures: Analysis of risk factors and pathogens.

Infection with multi-drug resistant organisms (MDROs) has emerged as a global problem in medical institutions. Overuse of antibiotics is the main cause of drug resistance. Notably, the incidence of infection with MDROs increases in patients with limb fractures who have undergone invasive surgery. The present study aimed to analyze the risk factors for postoperative MDROs infection in a cohort of patients with limb fractures. A retrospective study was performed on the data of patients with fractures between January 2020 and August 2022. Postoperative surgical site infection occurred in 114 patients in total, of which 47 were infected with MDROs. Univariate logistic regression analysis and multivariate binary logistic regression were used to confirm the associations between independent risk factors and MDRO infection. A total of 155 bacteria were collected from patients with MDROs infection and patients with non-MDROs infection, of which 66.5% were gram-positive bacteria and 33.5% were gram-negative. Staphylococcus aureus accounted for 26.5% of the 155 pathogens. MDROs, such as methicillin-resistant S. aureus and extended-spectrum ß-lactamases-positive gram-negative bacillus, were detected after antibiotic treatment. Univariate analysis indicated that the number of antibiotics administered, being bedridden, repeat infection, operative time and repeated operation were different in the two groups. In addition, univariate logistic analysis indicated that being bedridden (OR, 3.98; P=0.001), administration of >2 antibiotics (OR, 2.42; P=0.026), an operative time of >3 h (OR, 3.37; P=0.003), repeated infection (OR, 3.08; P=0.009) and repetition of procedures (OR, 2.25; P=0.039) were individual risk factors for MDRO infection. Multivariate analysis showed that being bedridden (OR, 2.66; P=0.037), repeated infection (OR, 4.00; P=0.005) and an operative time of >3 h (OR, 2.28; P=0.023) were risk factors of MDRO infection. In conclusion, constrained antibiotic use, shortened operative time and increased activity duration can effectively prevent surgical-site infection with MDROs in patients with fractures.

Colonization of root endophytic fungus Serendipita indica improves drought tolerance of Pinus taeda seedlings by regulating metabolome and proteome.

Pinus taeda is an important forest tree species for plantations because of its rapid growth and high yield of oleoresins. Although P. taeda plantations distribute in warm and wet southern China, drought, sometime serious and long time, often occurs in the region. To explore drought tolerance of P. taeda and usage of beneficial microorganisms, P. taeda seedlings were planted in pots and were inoculated with root endophytic fungus Serendipita indica and finally were treated with drought stress for 53 d. Metabolome and proteome of their needles were analyzed. The results showed that S. indica inoculation of P. taeda seedlings under drought stress caused great changes in levels of some metabolites in their needles, especially some flavonoids and organic acids. Among them, the levels of eriocitrin, trans-aconitic acid, vitamin C, uric acid, alpha-ketoglutaric acid, vitamin A, stachydrine, coumalic acid, itaconic acid, calceolarioside B, 2-oxoglutaric acid, and citric acid were upregulated more than three times in inoculated seedlings under drought stress, compared to those of non-inoculated seedlings under drought stress. KEGG analysis showed that some pathways were enriched in inoculated seedlings under drought stress, such as flavonoid biosynthesis, ascorbate and aldarate metabolism, C5-branched dibasic acid metabolism. Proteome analysis revealed some specific differential proteins. Two proteins, namely, H9X056 and H9VDW5, only appeared in the needles of inoculated seedlings under drought stress. The protein H9VNE7 was upregulated more than 11.0 times as that of non-inoculated seedlings under drought stress. In addition, S. indica inoculation increased enrichment of water deficient-inducible proteins (such as LP3-1, LP3-2, LP3-3, and dehydrins) and those involved in ribosomal structures (such as A0A385JF23). Meanwhile, under drought stress, the inoculation caused great changes in biosynthesis and metabolism pathways, mainly including phenylpropanoid biosynthesis, cutin, suberine and wax biosynthesis, and 2-oxocarboxylic acid metabolism. In addition, there were positive relationships between accumulation of some metabolites and enrichment of proteins in P. taeda under drought stress. Altogether, our results showed great changes in metabolome and proteome in inoculated seedlings under drought stress and provided a guideline to further study functions of metabolites and proteins, especially those related to drought stress.

A theoretical study of water adsorption and decomposition on low-index spinel ZnGa2O4 surfaces: correlation between surface structure and photocatalytic properties.

Water adsorption and decomposition on stoichiometrically perfect and oxygen vacancy containing ZnGa2O4 (100), (110), and (111) surfaces were investigated through periodic density functional theory (DFT) calculations. The results demonstrated that water adsorption and decomposition are surface-structure-sensitive processes. On a stoichiometrically perfect surface, the most stable molecular adsorption that could take place involved the generation of hydrogen bonds. For dissociative adsorption, the adsorption energy of the (111) surface was more than 4 times the energies of the other two surfaces, indicating it to be the best surface for water decomposition. A detailed comparison of these three surfaces showed that the primary reason for this observation was the special electronic state of the (111) surface. When water dissociated on the (111) surface, the special Ga3c-4s and 4p hybridization states at the Fermi level had an obvious downshift to the lower energies. This large energy gain greatly promoted the dissociation of water. Because the generation of O(3c) vacancy defects on the (100) and (110) surfaces could increase the stability of the dissociative adsorption states with few changes to the energy barrier, this type of defect would make the decomposition of water molecules more favorable. However, for the (111) surface, the generation of vacancy defects could decrease the stability of the dissociative adsorption states and significantly increase their energy barriers. Therefore, the decomposition of water molecules on the oxygen vacancy defective (111) surface would be less favorable than the perfect (111) surface. These findings on the decomposition of H2O on the ZnGa2O4 surfaces can be used toward the synthesis of water-splitting catalysts.

Novel insights on genes and pathways involved in Pinus elliottii response to resinosis.

Pinus elliottii, an important coniferous timber species, has recently become one of the most popular sources of resin in China. Resinosis is a common disease that may negatively affect pine tree growth and production. In this study, we used single-molecule real-time sequencing and Illumina RNA sequencing to generate an accurate transcriptome for P. elliottii. The transcriptome included 90,026 transcripts, 5160 long non-coding RNAs and 7710 transcription factors. We then analyzed RNA-sequencing, small RNA-sequencing and degradome data to identify genes, miRNAs and key miRNA-target pairs involved in response to resinosis in P. elliottii. We identified 1305 genes and 1151 miRNAs exhibiting significant differential expression in response to resinosis. According to the degradome sequencing analysis, 318 differentially expressed transcripts were targets of 14 differentially expressed miRNAs. Our study has provided resources for further functional characterization of genes and miRNAs involved in resinosis in P. elliottii, which should aid the future disease-resistance breeding of this species.

Research progress on productivity of mixed forest.

One of the effective ways to improve the productivity of mixed forests is enhancing resource use efficiency based on the biological characteristics of afforestation tree species. Resource use efficiency is affected by tree species interactions and environmental conditions through applying appropriate cultivation patterns. In this study, we evaluated two estimating methods for the productivity of mixed forest, analyzed the internal mechanism of interspecific tree competition and complementary effects on mixed forest productivity, clarified external factors of growth space and habitat factors control over productivity of mixed forest, discussed the effects of tree species composition, stand density and site quality on productivity, and illustrated the productivity trajectory during the development of mixed forests. Finally, based on the knowledge of the internal mechanism and habitat factors affecting the formation of mixed forest productivity, we focused on the key scientific issues that urgently need to be solved in the construction of the current mixed forests cultivation patterns, and put forward future research directions, including improving the productivity estimation system, establishing long-term mixed forest observation field, enhancing the research on the comprehensive effect of various cultivation measures, and reinforcing research of the growth and development dynamics in mixed forests.

Study on the effects of stand density management of Chinese fir plantation in Northern China.

The aim of this study was to clarify the mechanism by which thinning alters stand structure and affects forest productivity by characterizing changes in stand quantitative maturity age, stand diameter distribution, structural heterogeneity, and forest productivity of Chinese fir plantations at different thinning times and intensities. Our findings provide insights into how the density of stands could be modified to enhance the yield and timber quality of Chinese fir plantations. The significance of differences in individual tree volume, stand volume, and timber merchantable volume was determined using one-way analysis of variance and post hoc Duncan tests. The stand quantitative maturity age was obtained using the Richards equation. The quantitative relationship between stand structure and productivity was determined using a generalized linear mixed model. We found that (1) the quantitative maturity age of Chinese fir plantations increased with thinning intensity, and the quantitative maturity age was much greater under commercial thinning than under pre-commercial thinning. (2) Individual tree volume and the proportion of medium-sized and large-sized timber merchantable volume increased with stand thinning intensity. Thinning promoted increases in stand diameter. pre-commercially thinned stands were dominated by medium-diameter trees when the quantitative maturity age was reached, whereas commercially thinned stands were dominated by large-diameter trees. The living trees volume will decrease immediately after thinning, and then it will gradually increase with the age of the stand. When the stand volume included both living trees volume and thinned volume, thinned stands increased stand volume compared with unthinned stands. In pre-commercial thinning stands, the greater the intensity of thinning, the greater the increase in stand volume, and the opposite was true for commercial thinning. (3) Thinning also reduced heterogeneity in stand structure, which was lower after commercial thinning than after pre-commercial thinning. The productivity of pre-commercially thinned stands increased with thinning intensity, whereas that of commercially thinned stands decreased with thinning intensity. (4) The structural heterogeneity of pre-commercially and commercially thinned stands was negatively and positively correlated with forest productivity, respectively. In the Chinese fir plantations in the hilly terrain of the northern Chinese fir production area, when pre-commercial thinning was performed in the ninth year to a residual density of 1750 trees per hectare, the stand quantitative maturity age was reached in year 30, medium-sized timber accounted for 75.2% of all trees, and the stand volume was 667.9 m3 per hectare. This thinning strategy is favorable for producing medium-sized Chinese fir timber. When commercial thinning was performed in year 23, the optimal residual density was 400 trees per hectare. When the stand quantitative maturity age was reached in year 31, large-sized timber accounted for 76.6% of all trees, and the stand volume was 574.5 m3 per hectare. This thinning strategy is favorable for producing large-sized Chinese fir timber.

Synergistic effects in La/N codoped TiO2 anatase (101) surface correlated with enhanced visible-light photocatalytic activity.

The interaction between implanted La, substitutional N, and an oxygen vacancy at TiO(2) anatase (101) surface has been investigated by means of first-principles density function theory calculations to investigate the origin of enhanced visible-light photocatalytic activity of La/N-codoped anatase observed in experiments. Our calculations suggest that both the adsorptive and substitutional La-doped TiO(2) anatase (101) surfaces are probably defective configurations in experiments. The h-Cave-adsorbed La doping decreases the formation energy for the substitutional N implantation and vice versa, while the charge compensation effects do not take effect between the adsorptive La and substitutional N dopants, resulting in some partially occupied states in the band gap acting as traps of the photoexcited electrons. The Ti(5c)-substituted La doping decreases the energy required for the substitutional N implantation, and the substitutional La and N codoping promotes the formation of an oxygen vacancy, which migrates from the O(sb-3c) site at the inner layer toward the surface O(b) site. For the substitutional La/N-codoped (Ti(5c)_O(3c-down)) surface, the charge compensation between the substitutional La and substitutional N leads to the formation of two isolated occupied N(s)-O π* impurity levels in the gap, while the excitation energy from the higher impurity level to the CBM decreases by about 0.89 eV. After further considering an oxygen vacancy on the Ti(5c)_O(3c-down) surface, the two electrons on the double donor levels (O(b) vacancy) passivate the same amount of holes on the acceptor levels (substitutional La and N), forming the acceptor-donor-acceptor compensation pair, which provides a reasonable mechanism for the enhanced visible-light photocatalytic activity of La/N codoped TiO(2) anatase. This knowledge may aid the further design and construction of new effective visible-light photocatalysts.

Surface dependence of CO2 adsorption on Zn2GeO4.

An understanding of the interaction between Zn(2)GeO(4) and the CO(2) molecule is vital for developing its role in the photocatalytic reduction of CO(2). In this study, we present the structure and energetics of CO(2) adsorbed onto the stoichiometric perfectly and the oxygen vacancy defect of Zn(2)GeO(4) (010) and (001) surfaces using density functional theory slab calculations. The major finding is that the surface structure of the Zn(2)GeO(4) is important for CO(2) adsorption and activation, i.e., the interaction of CO(2) with Zn(2)GeO(4) surfaces is structure-dependent. The ability of CO(2) adsorption on (001) is higher than that of CO(2) adsorption on (010). For the (010) surface, the active sites O(2c)···Ge(3c) and Ge(3c)-O(3c) interact with the CO(2) molecule leading to a bidentate carbonate species. The presence of Ge(3c)-O(2c)···Ge(3c) bonds on the (001) surface strengthens the interaction of CO(2) with the (001) surface, and results in a bridged carbonate-like species. Furthermore, a comparison of the calculated adsorption energies of CO(2) adsorption on perfect and defective Zn(2)GeO(4) (010) and (001) surfaces shows that CO(2) has the strongest adsorption near a surface oxygen vacancy site, with an adsorption energy -1.05 to -2.17 eV, stronger than adsorption of CO(2) on perfect Zn(2)GeO(4) surfaces (E(ads) = -0.91 to -1.12 eV) or adsorption of CO(2) on a surface oxygen defect site (E(ads) = -0.24 to -0.95 eV). Additionally, for the defective Zn(2)GeO(4) surfaces, the oxygen vacancies are the active sites. CO(2) that adsorbs directly at the Vo site can be dissociated into CO and O and the Vo defect can be healed by the oxygen atom released during the dissociation process. On further analysis of the dissociative adsorption mechanism of CO(2) on the surface oxygen defect site, we concluded that dissociative adsorption of CO(2) favors the stepwise dissociation mechanism and the dissociation process can be described as CO(2) + Vo → CO(2)(δ-)/Vo → CO(adsorbed) + O(surface). This result has an important implication for understanding the photoreduction of CO(2) by using Zn(2)GeO(4) nanoribbons.

Theoretical insight into the structural stability of KZnB3O6 polymorphs with different BO(x) polyhedral networks.

In general, the presence of shared edges of polyhedra for high-valence low-coordinated small cations is rarely seen except under extreme conditions such as high pressure. However, the ambient-pressure synthesis of KZnB(3)O(6) built of edge-sharing BO(4) tetrahedra is contrary to this. By investigating the molecular dynamics, lattice dynamics, and electronic properties via density functional theory, we studied the origin of the phase stability of the edge-sharing (es) and "corner-sharing (cs)" KZnB(3)O(6). Lattice dynamics results show that there are no phonon anomalies that could lead to the instability of es-KZnB(3)O(6), which is consistent with molecular dynamics analysis. For "cs-KZnB(3)O(6)", a soft mode at the G point in the phonon dispersion is identified that reflects the dynamic instability with respect to small distortions. Eigenvector analysis of the soft mode of "cs-KZnB(3)O(6)" indicates that the instability comes from the linkage of ZnO(5) polyhedra rather than BO(x) polyhedra. Electronic property calculation indicates that the edge-sharing BO(4) polyhedra connected by the longest B-O σ bonds provide a solid framework for es-KZnB(3)O(6). In the case of "cs-KZnB(3)O(6)", the overlong Zn-O bond possesses the smallest covalent nature and the least orbital overlap among the bonds in a ZnO(5) polyhedron, and these two features of the electronic structure reduce the stability of "cs-KZnB(3)O(6)" compared to es-KZnB(3)O(6). The electronic property calculation further confirms the results obtained from lattice dynamics analysis.