Effect of non-linear strain stiffening in eDAH and unjamming.

In cell clusters, the prominent factors at play encompass contractility-based enhanced tissue surface tension and cell unjamming transition. The former effect pertains to the boundary effect, while the latter constitutes a bulk effect. Both effects share outcomes of inducing significant elongation in cells. This elongation is so substantial that it surpasses the limits of linear elasticity, thereby giving rise to additional effects. To investigate these effects, we employ atomic force microscopy (AFM) to analyze how the mechanical properties of individual cells change under such considerable elongation. Our selection of cell lines includes MCF-10A, chosen for its pronounced demonstration of the extended differential adhesion hypothesis (eDAH), and MDA-MB-436, selected due to its manifestation of cell unjamming behavior. In the AFM analyses, we observe a common trend in both cases: as elongation increases, both cell lines exhibit strain stiffening. Notably, this effect is more prominent in MCF-10A compared to MDA-MB-436. Subsequently, we employ AFM on a dynamic range of 1-200 Hz to probe the mechanical characteristics of cell spheroids, focusing on both surface and bulk mechanics. Our findings align with the results from single cell investigations. Specifically, MCF-10A cells, characterized by strong contractile tissue tension, exhibit the greatest stiffness on their surface. Conversely, MDA-MB-436 cells, which experience significant elongation, showcase their highest stiffness within the bulk region. Consequently, the concept of single cell strain stiffening emerges as a crucial element in understanding the mechanics of multicellular spheroids (MCSs), even in the case of MDA-MB-436 cells, which are comparatively softer in nature.

Granular bacterial inoculant alters the rhizosphere microbiome and soil aggregate fractionation to affect phosphorus fractions and maize growth.

The constraint of phosphorus (P) fixation on crop production in alkaline calcareous soils can be alleviated by applying bioinoculants. However, the impact of bacterial inoculants on this process remains inadequately understood. Here, a field study was conducted to investigate the effect of a high-concentration, cost-effective, and slow-release granular bacterial inoculant (GBI) on maize (Zea mays L.) plant growth. Additionally, we explored the effects of GBI on rhizosphere soil aggregate physicochemical properties, rhizosphere soil P fraction, and microbial communities within aggregates. The outcomes showed a considerable improvement in plant growth and P uptake upon application of the GBI. The application of GBI significantly enhanced the AP, phoD gene abundance, alkaline phosphatase activity, inorganic P fractions, and organic P fractions in large macroaggregates. Furthermore, GBI impacted soil aggregate fractionation, leading to substantial alterations in the composition of fungal and bacterial communities. Notably, key microbial taxa involved in P-cycling, such as Saccharimonadales and Mortierella, exhibited enrichment in the rhizosphere soil of plants treated with GBI. Overall, our study provides valuable insight into the impact of GBI application on microbial distributions and P fractions within aggregates of alkaline calcareous soils, crucial for fostering healthy root development and optimal crop growth potential. Subsequent research endeavors should delve into exploring the effects of diverse GBIs and specific aggregate types on P fraction and community composition across various soil profiles.

First Report of Fusarium tricinctum Causing Root Rot on Chinese dwarf cherry (Cerasus humilis) in China.

Chinese dwarf cherry (Cerasus humilis) is a perennial small shrub indigenous to northern China, highly regarded for its calcium-rich fruit known as 'calcium fruit'. These fruits have a remarkable capacity to aid in human calcium absorption. Additionally, they contain beneficial flavonoids that hold promise for applications in the healthcare industry (Wang et al., 2018). In July 2020, a concerning development occurred on the farms in Jingtai County (37.48o N, 103.82o E), Baiyin City, Gansu Province in China. Approximately 20 to 30% of C. humilis at the full culture stage exhibited symptoms of root rot, including brownish leaves, rotten roots, and plant mortality, leading to a decrease of over 30% in calcium fruit yield. To identify the pathogen, the surface of symptomatic roots was sterilized with 3% NaOCl for 2 minutes, followed by 70% ethanol for 30 seconds, and rinsed three times with sterile water. Tissue sections (5×5mm) from the margin of the necrotic lesion were cut and cultured on potato dextrose agar (PDA) medium, and incubated for 7 days at 25℃. Five pure culture isolates were obtained from individual spores. Initially, the isolates exhibited abundant white aerial mycelia that turned light pink on the third day. Macroconidia were falciform, two to five septate, straight or slightly curved, and measuring 20.1 to 32.5×2.2 to 3.8 µm (n=50). Napiform microconidia were oval-ellipsoid, non-septate, and measuring 6.2 to 9.3×4.2 to 5.8 µm (n=50). Based on these morphological characteristics, the fungus was tentatively identified as Fusarium species (Leslie and Summerell, 2006). To confirm the identification, the internal transcribed spacer region (ITS) and the translation elongation factor (EF1α) of the isolate CH-2 were partially amplified and sequenced using the primers ITS1/ITS4 and EF2T/EF3 (Li et al., 2013, Yang et al., 2022). Upon comparison with the sequences in GenBank, 857 bp ITS sequence showed 100% homology to Fusarium tricinctum isolate QY3-1 (GenBank accessions no. MZ572963.1), and 665 bp EF1α sequence showed 99.7% homology to F. tricinctum strain TQC-C2 (GenBank accessions no. KF939493.1). The resulting sequences were deposited into GenBank with accession nos. OQ581576 and OQ848462 respectively. A maximum likelihood (ML) phylogenetic analysis based on combined partial ITS and EF1α data set was conducted via ML bootstrapping using MEGA 11. According to morphology and phylogenetic analysis, the isolate was identified as F. tricinctum (Wang et al., 2022). For a pathogenicity test, a pot experiment was conducted in a greenhouse with a temperature range of 20-27℃ and 60% relative humidity. Roots of C. humilis were immersed in a spore suspension (1×107 conidia/ml) of isolate F. tricinctum CH-2 for approximately 5 minutes. Subsequently the treated roots were planted in pots filled with sterilized field soil, while roots dipped in sterilized water were used as the control. The experiment considered of ten pots for the inoculation treatment and six pots for the control treatment. All pots were maintained in the greenhouse. After 15 days, it was observed that 80% of the inoculated plants displayed symptoms consistent with the field observations, indicating successful infection. In contrast, plants in the control treatment did not exhibit any symptoms. The same fungal pathogen as F. tricinctum CH-2 was reisolated from the diseased root tissue and confirmed through morphological and molecular assays, thereby satisfying Koch's postulates. This is the first documented report of F. tricinctum causing root rot in C. humilis in China. This disease has the potential to become one of the most significant diseases affecting C. humilis in China.

First Report of Fusarium solani and Fusarium oxysporum Causing Basal Stem Rot on Celery in China.

Celery (Apium graveolens L.) is an economically important vegetable crop in China. In recent years, celery has been widely planted in Yuzhong county, Gansu province. From 11 April to 24 May, 2019-2021, basal stem rot of celery was observed with incidences up to 15% in the Yuzhong region (35°49'N, 104°16'E, 1865 m a.s.l.), which caused serious economic losses to local farmers. Typical symptoms of the disease included wilting and darkening of the basal stem, leading to plant death. To identify the cause of the disease, small pieces (5mm×5mm) of the margin of asymptomatic and rotting basal stem tissues were sterilized with 70% ethanol for 30 s and 3% NaClO for 5 min, then placed on potato dextrose agar (PDA) plates, and incubated at 25℃ (Zhao et al. 2021). Twenty-seven single-conidium isolates with morphological characteristics similar to Fusarium spp. were obtained (Ma et al. 2022), which displayed two kinds of colony morphology. On PDA, seven isolates developed white, fluffy aerial mycelium and twenty isolates developed light pink abundant aerial mycelium. Isolate F5 and F55 from each distinct morphological group were cultured on PDA and synthetic low nutrient agar (SNA) for pathogenicity tests, morphological and molecular identification. The macroconidia (18.3 to 29.6 × 3.6 to 5.3 µm, n=50) with 1 to 2 septa and microconidia (7.5 to 11.6 × 2.6 to 3.5 µm, n=50) with 0 to 1 septum were observed in F5. For F55, the size of macroconidia was 14.2 to 19.5 × 3.3 to 4.2 µm (n = 50) with 1 to 2 septa; Microconidia were mostly 0 to 1 septum and measured 7.3 to 12.8 × 2.2 to 4.2 µm (n = 50). To confirm the identity of the isolates, the internal transcribed spacer region (ITS) and the translation elongation factor-1 alpha (TEF-1α) gene were amplified using primers ITS1/ITS4 and EF-1/EF-2 (Uwaremwe et al. 2020), respectively. The sequence similarities of isolate F5 (GenBank No. OL616048 and OP186480) and F55 (GenBank No. OL616049 and OP186481) with the corresponding sequences of F. solani (MT447508 and MN650097) and F. oxysporum (MG461555 and OQ632904) ranged from 99.22% to 100.00%, with matching base pairs of 531/532, 416/416, 511/515 and 394/395, respectively. The voucher samples were deposited in the sample center of Northwest Institute of Ecological Environment and Resources, Chinese Academy of Sciences. Morphological and molecular results confirmed the species of F5 and F55 as F. solani and F. oxysporum, respectively. A pathogenicity test was conducted under greenhouse conditions (19-31°C, avg. 26°C). Conidial suspension (105 spores/mL) of isolates F5 and F55 were poured onto the basal stems of healthy celery seedlings at the age of 1 month and mock-inoculated control treatments with sterile water. Ten plants were inoculated for each treatment. After 21 days, all plants inoculated with both fungal isolates developed symptoms similar to those observed in the field, whereas the mock-inoculated plants remained healthy. The pathogen was successfully reisolated from the inoculated symptomatic plants onto PDA medium and had morphology as described above, confirming Koch's postulates. F. solani and F. oxysporum have been reported to infect many plant species, including carrot (Zhang et al. 2014) and Angelica sinensis (Liu et al. 2022). To our knowledge, this is the first report that F. solani and F. oxysporum cause basal stem rot on celery in China. The identification of pathogens of the observed basal stem rot on celery provides a clear target for the prevention and management of this disease.

Six potential biomarkers in septic shock: a deep bioinformatics and prospective observational study.

Background: Septic shock occurs when sepsis is related to severe hypotension and leads to a remarkable high number of deaths. The early diagnosis of septic shock is essential to reduce mortality. High-quality biomarkers can be objectively measured and evaluated as indicators to accurately predict disease diagnosis. However, single-gene prediction efficiency is inadequate; therefore, we identified a risk-score model based on gene signature to elevate predictive efficiency. Methods: The gene expression profiles of GSE33118 and GSE26440 were downloaded from the Gene Expression Omnibus (GEO) database. These two datasets were merged, and the differentially expressed genes (DEGs) were identified using the limma package in R software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichments of DEGs were performed. Subsequently, Lasso regression and Boruta feature selection algorithm were combined to identify the hub genes of septic shock. GSE9692 was then subjected to weighted gene co-expression network analysis (WGCNA) to identify the septic shock-related gene modules. Subsequently, the genes within such modules that matched with septic shock-related DEGs were identified as the hub genes of septic shock. To further understand the function and signaling pathways of hub genes, we performed gene set variation analysis (GSVA) and then used the CIBERSORT tool to analyze the immune cell infiltration pattern of diseases. The diagnostic value of hub genes in septic shock was determined using receiver operating characteristic (ROC) analysis and verified using quantitative PCR (qPCR) and Western blotting in our hospital patients with septic shock. Results: A total of 975 DEGs in the GSE33118 and GSE26440 databases were obtained, of which 30 DEGs were remarkably upregulated. With the use of Lasso regression and Boruta feature selection algorithm, six hub genes (CD177, CLEC5A, CYSTM1, MCEMP1, MMP8, and RGL4) with expression differences in septic shock were screened as potential diagnostic markers for septic shock among the significant DEGs and were further validated in the GSE9692 dataset. WGCNA was used to identify the co-expression modules and module-trait correlation. Enrichment analysis showed significant enrichment in the reactive oxygen species pathway, hypoxia, phosphatidylinositol 3-kinases (PI3K)/Protein Kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling, nuclear factor-κß/tumor necrosis factor alpha (NF-κß/TNF-α), and interleukin-6 (IL-6)/Janus Kinase (JAK)/Signal Transducers and Activators of Transcription 3 (STAT3) signaling pathways. The receiver operating characteristic curve (ROC) of these signature genes was 0.938, 0.914, 0.939, 0.956, 0.932, and 0.914, respectively. In the immune cell infiltration analysis, the infiltration of M0 macrophages, activated mast cells, neutrophils, CD8 T cells, and naive B cells was more significant in the septic shock group. In addition, higher expression levels of CD177, CLEC5A, CYSTM1, MCEMP1, MMP8, and RGL4 messenger RNA (mRNA) were observed in peripheral blood mononuclear cells (PBMCs) isolated from septic shock patients than from healthy donors. Higher expression levels of CD177 and MMP8 proteins were also observed in the PBMCs isolated from septic shock patients than from control participants. Conclusions: CD177, CLEC5A, CYSTM1, MCEMP1, MMP8, and RGL4 were identified as hub genes, which were of considerable value in the early diagnosis of septic shock patients. These preliminary findings are of great significance for studying immune cell infiltration in the pathogenesis of septic shock, which should be further validated in clinical studies and basic studies.

Quantifying ecological and human health risks of heavy metals from different sources in farmland soils within a typical mining and smelting industrial area.

The quality of food crops and human health is threatened by heavy metals (HMs) accumulated in farmland soils for a long time. In this study, we selected 148 soil samples randomly from farmlands in a region featuring abandoned lead-zinc (Pb-Zn) mining activities with the aim to quantify the pollution risk and identify potential sources of heavy metals, based on a case in the southwestern of China. The median contents of metals, such as Pb, Zn, Cd, As, Cu and Cr, are above the background values for Chinese soils and prescribed pollution threshold guide values (GB15618-2018), except Hg and Ni. The farmland soils in sites surrounding areas with previous Pb-Zn mining and smelting activities were classified as seriously polluted. Pollution sources were evaluated using GIS-based geostatistical methods, multivariate statistical analyses and positive matrix factorization (PMF) modeling. Four sources were quantitatively apportioned, which were industrial sources such as mining and smelting (53.1%), agricultural practices (11.6%), natural source (21.6%) and other industrial sources such as electroplating (13.7%). The potential risks of contamination associated with the heavy metals were evaluated using several indices including the Nemerow, geoaccumulation (Igeo) and ecological risk (RI) indices. Based on the Igeo index, As and Pb were the most severe pollutants among all of those measured. With the combination of the potential ecological risk index (RI) and human health risk (HHR) assessment models, the ecological risk and HHR from different sources were analyzed quantitatively. Industrial activities such as mining and smelting were the greatest contributors to ecological risk, non-carcinogenic risk and carcinogenic risk, accounting for about 86.9%,73.9% and 81.9%, respectively. Additionally, the health risks of children were more serious relative to those of adults from the perspective of non-carcinogenic and carcinogenic risks.

Research advances of femtosecond laser-induced nanogratings for transparent materials.

Femtosecond laser-induced nanogratings generation inside transparent materials has been the focus of research in the field of femtosecond laser precision processing. Due to the advantages of optical birefringence phenomenon, periodicity, thermal stability, controllability of delay value and optical axis direction, and re-writability, nanogratings are widely used in research fields such as optical storage and optical devices. This mini-review explores the existing mechanism of femtosecond laser-induced formation of nanogratings and the progress of inducing nanogratings in different types of glass and sapphire crystals. It also describes the prospects of nanogratings for a wide range of applications in optical components and optical devices.

Electron beam treated injectable agarose/alginate beads prepared by electrospraying.

Granular hydrogels have evolved into an innovative technology for biomedicine. Unlike conventional hydrogels, granular hydrogels display dynamic properties like injectability and porosity, making them feasible for applications in 3D bioprinting and tissue engineering. High-energy electron irradiation combines sterilization and tuning of hydrogel properties without adding potentially cytotoxic chemicals. In this study, granular agarose/alginate hydrogels are prepared by electrospraying. Utilizing 10 MeV electron irradiation, the granular hydrogels are treated in a dose range of 0 kGy-30 kGy relevant for sterilization. Herein, a size reduction of the microparticles is observed. Mechanical properties of individual agarose/alginate beads are examined using AFM measurements revealing a gel softening attributed to radiation induced chain scission. Shear-thinning and self-healing characteristics of the entire granular hydrogel are studied employing rheology. Although viscoelasticity changes under irradiation, shear-thinning and self-healing prevails. These dynamic properties enable injection, which is demonstrated for 27 G needles. This study presents a mechanical characterization of high-energy electron irradiated granular agarose/alginate hydrogels that extends the diversity of available injectable hydrogels and provides a basis for biomedical applications of this scaffold.

Femtosecond Laser Processing Technology for Anti-Reflection Surfaces of Hard Materials.

The anti-reflection properties of hard material surfaces are of great significance in the fields of infrared imaging, optoelectronic devices, and aerospace. Femtosecond laser processing has drawn a lot of attentions in the field of optics as an innovative, efficient, and green micro-nano processing method. The anti-reflection surface prepared on hard materials by femtosecond laser processing technology has good anti-reflection properties under a broad spectrum with all angles, effectively suppresses reflection, and improves light transmittance/absorption. In this review, the recent advances on femtosecond laser processing of anti-reflection surfaces on hard materials are summarized. The principle of anti-reflection structure and the selection of anti-reflection materials in different applications are elaborated upon. Finally, the limitations and challenges of the current anti-reflection surface are discussed, and the future development trend of the anti-reflection surface are prospected.

Impact of disinfectants on the intestinal bacterial symbionts and immunity of silkworm (Bombyx mori L.).

The insect egg surface can serve as a vehicle for vertical symbiont transmission from the maternal parent to its offspring. Hypochlorite and formaldehyde are two common disinfectants used for insect egg surface sterilization. Here, we explored the intestinal microecology and immune response profile of the silkworm Bombyx mori strain Dazao after disinfectant exposure by using high-throughput sequencing technology and real-time PCR analysis. After egg surface sterilization, no significant difference (P > 0.05) in overall body weight was observed among the control, sodium hypochlorite, and formaldehyde groups. 16S rRNA metagenomic sequencing revealed that the main abundant intestinal bacteria were Enterococcus, Burkholderia, Phenylobacterium, Ralstonia, Chitinophaga, Bradyrhizobium, Herbaspirillum, and two unclassified Bacteroidetes species. Egg surface sterilization evidently altered the composition and abundance of intestinal microbiota but did not significantly change its alpha diversity. The dysbiosis of intestinal microbiota resulted in the perturbation of the immune response profile of the silkworm intestine. Our findings reveal that hypochlorite has a blocking effect on the symbiont transmission compared with formaldehyde. More importantly, egg surface sterilization exerts substantial effects on the ecophysiological traits of insects. The present study contributes to the scientific and reasonable application of disinfectants for insect egg surface sterilization during industrial silk production and laboratory-scale insect rearing.

Transcriptome analysis of the reproduction of silkworm (Bombyx mori) under dimethoate stress.

Dimethoate (DMT) is an organophosphorus pesticide which is widely used to prevent and control agricultural diseases and pests. But it also remains in crops and the environment, affecting other non-target organisms. Existing research mainly focuses on aquatic invertebrates, and research on terrestrial invertebrates is still relatively weak. This study selected the lepidopteran model insect silkworm (Bombyx mori) as the research object and revealed the influence of DMT on the reproduction of silkworms. This study used digital gene expression (DGE) and RT-qPCR analysis to compare gene expression changes in eggs laid by silkworms under the exposure of DMT (200 mg/L). A total of 320 differential genes were detected, of which 211 genes were up-regulated and 109 genes were down-regulated. The GO enrichment analysis bar graph shows those differential genes enriched in the BP's metabolic process, cellular process, CC's membrane part, cell, MF's catalytic activity, binding. KEGG enrichment analysis showed more differential genes enriched in signal transduction, endocrine system, cancers: Overview pathway. The results showed that the differential genes were mainly concentrated on promoting trehalase transporter genes, stress response-related genes, zinc finger protein genes, epidermal protein genes, and 5-HT pathway-related genes. The results of this study will provide important gene sequence information for insect toxicology studies, and also clarify the mechanism of influence of DMT on silkworm reproduction at the transcription level.

Ion-Doped Photonic Crystal Fiber Lasers.

Compared with conventional solid-state lasers, fiber lasers have the advantages of small size, simple cooling system, and good output beam quality, enabling them an extended service lifetime in industrialized environments. Periodically arranged photonic crystals have been the most important gain medium for high-power laser applications, which overcame the problems in fiber lasers such as small mode field, low degree of nonlinearity, and non-adjustable dispersion. In this mini-review, we summarize the recent advances of typical ion-doped photonic crystal fiber lasers doped, discuss the challenges, and provide an outlook on the future developments in ion-doped photonic crystal fiber lasers.

[Distribution Characteristics and Source Analysis of Polycyclic Aromatic Hydrocarbons in Salinized Farmland Soil from the Oil Mining Area of the Yellow River Delta].

Eighty-nine soil samples were collected from the Binzhou oil mining area of the Yellow River Delta (including 83 farmland soil samples and 6 soil samples from an oil extraction area). A total of 16 US-EPA priority polycyclic aromatic hydrocarbons (PAHs) were measured by gas chromatography-mass spectrometry (GC-MS). Principal component analysis (PCA) and positive matrix factorization (PMF) were employed to investigate potential source apportionment of PAHs in the farmland soil. The total PAH concentrations ranged from 31.5 µg·kg-1 to 1399.4 µg·kg-1 (dry weight) with an arithmetic mean concentration of 119.4 µg·kg-1. The characteristics of PAHs showed that 4- to 6-ring PAHs were slightly dominant in this study area, and most of the PAHs were significantly correlated (P<0.01), which indicates that the sources of the PAHs had some similarities in this sampling area. Source apportionment results derived from two different models were similar, indicating that the sources of PAHs were coal combustion, biomass combustion, fossil fuel combustion, and diesel combustion. The results of the PMF were more detailed, with the following four factors being identified:gasoline combustion (24.05%), diesel combustion (6.17%), low-temperature pyrolysis processes (60.67%), and coal combustion (9.11%).

Talin2 regulates invasion of human breast cancer MDA-MB-231 cells via alteration of the tumor microenvironment.

The talin proteins are a key component of the extracellular matrix-integrin-cytoskeleton system, and our previous study suggested that talin2 contributes to the tumor invasion and metastasis processes regulated by the tumor microenvironment. In the present study, the specific effects of talin2 on the invasive ability of breast cancer cells, as well as the underlying mechanism, were investigated by creating two MDA-MB-231 cell lines with stable talin2 knockdown by specific RNA interference. Initially, it was confirmed that the expression levels of talin2 in human breast cancer tissues were upregulated compared with in normal adjacent tissues. Subsequently, invasion and wound healing assays revealed that depletion of talin2 in MDA-MB-231 cells decreased their migratory and invasive abilities. Western blot analysis demonstrated that knockdown of talin2 in MDA-MB-231 cells caused marked downregulation of the tumor microenvironment markers hypoxia-inducible factor 1α, phosphorylated ribosomal protein S6 kinase, phosphorylated protein kinase B and phosphorylated mechanistic target of rapamycin. Furthermore, knockdown of talin2 decreased the basal contents of glucose and lactic acid in the breast cancer cell line. In conclusion, the findings of the present study demonstrated that talin2 knockdown may inhibit the invasive ability of human breast cancer MDA-MB-23l cells via alterations in the tumor microenvironment.

Talin2 regulates breast cancer cell migration and invasion by apoptosis.

Talin is a key component molecule of the extracellular matrix-integrin-cytoskeleton. It serves an important role in the activation of integrin, which, in turn, is known to mediate physiological and pathological processes, including cell adhesion, growth, tumorigenesis, and metastasis. In vertebrates, there are two Talin genes, Talin1 and Talin2. Talin1 is known to regulate focal adhesion dynamics, cell migration and cell invasion; however, the precise role of Talin2 in cancer remains unclear. In the present study, the functional role of Talin2 was examined in the MDA-MB-231 breast cancer cell line. Talin2 knockdown significantly inhibited growth, migratory capacity and invasiveness of MDA-MB-231 cells, and promoted apoptosis. The expression levels of Talin2 in breast cancer cells and in the peritumoral normal breast tissues were also determined by immunohistochemistry. Talin2 was identified to be overexpressed in breast cancer tissues compared with that in the peritumoral breast tissues. In addition, the knockdown of Talin2 by specific RNA interference markedly inhibited cell growth, and caused the downregulation of the apoptotic markers, cleaved Caspase-3 and phosphorylation of poly ADP-ribose polymerase. These findings demonstrate that Talin2 expression is upregulated in human breast cancer and that downregulation of Talin2 may serve as a useful therapeutic target in patients with breast cancer.

Thallium dispersal and contamination in surface sediments from South China and its source identification.

Thallium (Tl) is a non-essential element in humans and it is considered to be highly toxic. In this study, the contents, sources, and dispersal of Tl were investigated in surface sediments from a riverine system (the western Pearl River Basin, China), whose catchment has been contaminated by mining and roasting of Tl-bearing pyrite ores. The isotopic composition of Pb and total contents of Tl and other relevant metals (Pb, Zn, Cd, Co, and Ni) were measured in the pyrite ores, mining and roasting wastes, and the river sediments. Widespread contamination of Tl was observed in the sediments across the river, with the highest concentration of Tl (17.3 mg/kg) measured 4 km downstream from the pyrite industrial site. Application of a modified Institute for Reference Materials and Measurement (IRMM) sequential extraction scheme in representative sediments unveiled that 60-90% of Tl and Pb were present in the residual fraction of the sediments. The sediments contained generally lower (206)Pb/(207)Pb and higher (208)Pb/(206)Pb ratios compared with the natural Pb isotope signature (1.2008 and 2.0766 for (206)Pb/(207)Pb and (208)Pb/(206)Pb, respectively). These results suggested that a significant fraction of non-indigenous Pb could be attributed to the mining and roasting activities of pyrite ores, with low (206)Pb/(207)Pb (1.1539) and high (208)Pb/(206)Pb (2.1263). Results also showed that approximately 6-88% of Tl contamination in the sediments originated from the pyrite mining and roasting activities. This study highlights that Pb isotopic compositions could be used for quantitatively fingerprinting the sources of Tl contamination in sediments.

Thallium transformation and partitioning during Pb-Zn smelting and environmental implications.

Thallium (Tl) is a toxic and non-essential heavy metal. Raw Pb-Zn ores and solid smelting wastes from a large Pb-Zn smelting plant - a typical thallium (Tl) pollution source in South China, were investigated in terms of Tl distribution and fractionation. A modified IRMM (Institute for Reference Materials and Measurement, Europe) sequential extraction scheme was applied on the samples, in order to uncover the geochemical behavior and transformation of Tl during Pb-Zn smelting and to assess the potential environmental risk of Tl arising from this plant. Results showed that the Pb-Zn ore materials were relatively enriched with Tl (15.1-87.7 mg kg(-1)), while even higher accumulation existed in the electrostatic dust (3280-4050 mg kg(-1)) and acidic waste (13,300 mg kg(-1)). A comparison of Tl concentration and fraction distribution in different samples clearly demonstrated the significant role of the ore roasting in Tl transformation and mobilization, probably as a result of alteration/decomposition of related minerals followed by Tl release and subsequent deposition/co-precipitation on fine surface particles of the electrostatic dust and acidic waste. While only 10-30% of total Tl amounts was associated with the exchangeable/acid-extractable fraction of the Pb-Zn ore materials, up to 90% of total Tl was found in this fraction of the electrostatic dust and acidic waste. Taking into account the mobility and bioavailability of this fraction, these waste forms may pose significant environmental risk.

[Expression of matrix metalloproteinase-2, -9 and their inhibitor-1 in hypertrophic scars].

OBJECTIVE: To investigate the gene expression of matrix metalloproteinases (MMP-2, MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in proliferative and mature hypertrophic scars. METHODS: Total RNA from 8 normal skin samples and from 16 human hypertrophic scar samples of different maturing stage was respectively extracted, and then mRNA was isolated. The gene expressions of MMP-2, MMP-9 and TIMP-1 in these samples were examined with reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The gray scale ratio of MMP-2, MMP-9 and TIMP-1 transcription in normal skin were (3.8 +/- 0.7)%, (5.8 +/-4.4)%, (30.3 +/- 3.0)%, respectively, which were obviously higher than those in proliferative hypertrophic scar [(14 +/- 5)%, (18 +/- 5)%, (38 +/- 4)%, P < 0.05]. The expression of MMP-2 and MMP-9 genes in mature hypotrophic scar returned to normal level, but that of TIMP-1 remained high when compared with that of normal level (P < 0. 05). CONCLUSION: The increase in MMP-2, MMP-9 and TIMP-1 gene expression might be involved in the formation of hypertrophic scars, while the lowering of MMP-2 and MMP-9 gene expression might be associated with the maturation of hypertrophic scars.

[Isolation, culture and identification of adult epidermal stem cell].

OBJECTIVE: To explore and establish a new method of isolation, culture, and identification of adult epidermal stem cell in vitro for the provision of seed-cells in tissue engineering of skin. METHODS: Epidermis was obtained by digesting human foreskin with protease and it was dissociated into single cells with trypsin and ethylenediaminetetraacetic acid (EDTA). These single epidermis cells were inoculated onto human collagen IV coated flasks and cultured at 37 degrees C in a humidified atmosphere containing 5% CO(2). The nonadherent cells were rinsed off 10-15 minutes after inoculation. The adherent cells were observed under phase contrast microscope and electron microscope, and they were identified with immunocytochemical methods. Cell cycles of the adherent cells were determined with flow cytometry. RESULTS: With phase contrast microscope, the rapidly adherent cells were observed to form colonies 24 hours after inoculation. Immunocytochemistry showed the rapidly adherent cells were positive for beta1-integrin and keratin 19. Cell cycles showed that about 86.83% cells were in resting state/pre-DNA-synthetic gap (G0/G1 phase). Electron microscopy revealed that the rapidly adherent cells were immature. CONCLUSION: This study shows that adult epidermal stem cells could be isolated and cultured in vitro successfully.

[The effect of hyperoxic Ringer's solution on the rabbits with inhalation injury at early postburn stage].

OBJECTIVE: To investigate the effect of hyperoxic Ringer's solution on inhalation injury given at early postburn stage in rabbit. METHODS: Seventy-seven rabbits were randomly divided into four groups, i.e. A (normal control, n = 5, without injury), B (n = 24, with Ringer's solution infusion for 10 days after injury), C (n = 24, with hyperoxic Ringer's solution infusion for 10 days after injury) and D (n = 24, without treatment after injury) groups. The rabbits in B, C and D groups were observed on 1 post injury day (PID), 2 PID, 3 PID, 5 PID, 7 PID and 10 PID, with 4 in each time points. The vital signs and survival rate were observed and the blood gas analysis, the WBC and PMN in the peripheral blood, ratio of wet/dry weight (W/D) of the lung tissue, the MDA, SOD contents in the pulmonary tissue, and the pulmonary pathomorphology were determined by corresponding methods. RESULTS: The respiratory rate of the rabbits increased postburn, which was accompanied with gasping breath, flapping of nasal alae, frequent cough, and increased buccal and nasal secretion. Dry and wet rales were heard in the lungs after injury. The survival rate in D, B and C groups was 13.3%, 27.8% and 65.6%, respectively. Metabolic acidosis was identified in these groups by blood gas analysis. The indices of PaCO2, WBC, PMN, W/D, MDA in B, C and D groups were higher than those in A group in the order of D > B > C > A groups. While the pH, PaO2 value and SOD content in D group were lower than those in A group in the order of D < B < C < A groups (P < 0.05). Pathomorphological examination revealed that pulmonary volume increased after the injury with microscopic inflammatory changes in pulmonary tissue in B, C and D groups. While the extent and degree of injury in C group after the treatment of hyperoxic Ringer's solution were evidently less severe than those in other groups. CONCLUSION: Early administration of hyperoxic Ringer's solution during the early postburn stage could be beneficial to the management of inhalation injury.