[Establishment and verification of invasion syndrome prediction model in patients with diabetes complicated with Klebsiella pneumoniae liver abscess].

Objective: To analyze the correlative factors of invasion syndrome in patients with diabetes complicated with Klebsiella pneumoniae liver abscess, and to construct and verify the online nomographic prediction model. Methods: A case control study. The clinical data of 213 diabetic patients with Klebsiella pneumoniae liver abscess admitted to the Third Affiliated Hospital of Soochow University from January 1, 2015 to December 31, 2021 were retrospectively analyzed. The patients were divided into the training set (149 cases) and the test set (64 cases) by stratified random sampling method at a ratio of 7∶3. Synthetic minority over-sampling technique(SMOTE) was used to process the imbalanced data, then Lasso regression was used to screen out the optimal feature variables in the training set and multivariate logistic regression model was used to construct the prediction model of invasion syndrome in patients with diabetes complicated with Klebsiella pneumoniae liver abscess, and verify it in the training set and test set. Receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis (DCA) were used to evaluate the prediction efficiency of the model, and the simple and online interactive dynamic web page column graph was constructed. Results: Among the 213 patients, 60 were males and 153 were females, aged of (61.4±12.0) years. A total of 25(11.74%) diabetic patients with Klebsiella pneumoniae liver abscess developed invasion syndrome, which were included in divided into invasive K.pneumoniae liver abscesses syndrome (IKPLAS) group, and the other 188 cases were in without invasive K.pneumoniae liver abscesses syndrome (NIKPLAS) group. SMOTE algorithm was used for oversampling processing, so that the ratio of positive and negative samples was 1∶1. In the oversampling training set, 5 main risk factors were screened based on Lasso regression, namely fasting blood glucose (λ=0.063), hemoglobin (λ=-0.042), blood urea nitrogen (λ=-0.050), abscess size (λ=-0.025) and sequential organ failure assessment (SOFA) score (λ=0.450), respectively. Multivariate logistic regression model showed that fasting blood glucose (OR=1.20, 95%CI: 0.98-1.48, P=0.006), hemoglobin (OR=0.90, 95%CI: 0.86-0.95, P<0.001), blood urea nitrogen (OR=1.22, 95%CI: 1.03-1.43, P=0.017), abscess diameter (OR=0.76, 95%CI: 0.61-0.94, P=0.010), SOFA score (OR=3.08, 95%CI: 2.18-4.36, P<0.001) were associated with invasion syndrome in patients with diabetes complicated with Klebsiella pneumoniae liver abscess. The area under the curve of ROC in the training set was 0.966 (95%CI: 0.943-0.989), the sensitivity was 90.5%, and the specificity was 91.3%. The area under the curve of the validation set ROC was 0.946 (95%CI: 0.902-0.991), with a sensitivity of 79.6% and a specificity of 88.9%. The calibration curves drawn in the training set and the test set fit well with the ideal curve. DCA showed that the neomorph prediction model had a good clinical net benefit when predicting the risk of IKPLAS in patients with diabetes complicated with Klebsiella pneumoniae liver abscess was 0.10-0.40. Conclusions: Fasting blood glucose, hemoglobin, urea nitrogen, abscess size and SOFA score are the related factors for invasion syndrome in patients with diabetes complicated with Klebsiella pneumoniae liver abscess. The constructed column graph can effectively predict the risk of invasion syndrome in patients with diabetes complicated with Klebsiae pneumoniae liver abscess.

[Study on the pharmacokinetics of bromadiolone in oral poisoning rabbits].

Objective: To investigate the variations of bromadiolone concentration in blood and its metabolism in rabbits after oral administration of bromadiolone, and to provide reference for the study of bromadiolone metabolism. Methods: Designed absolute alcohol (1 g/kg) reagent control group, high dose (0.3 mg/kg) and low dose group (0.05 mg/kg) , there were 6 rabbits in each group. Blood samples were collected from the rabbit central auricular artery at regular intervals as 1 h, 2 h, 4 h, 8 h, 12 h, 16 h, 24 h, 36 h, 48 h, 72 h, 168 h, 336 h, 504 h after oral administration. The samples were centrifuged within 1 h. Prothrombin time (PT) , activated partial thromboplastin time (APTT) and concentrations of bromadiolone in plasma were tested. Metabolic kinetics data was analyzed by DAS 3.0.2 software. Results: Bromadiolone had no significant effect on the body weight of the experimental rabbits during the experimental period (P>0.05) . PT and APTT were significantly abnormal in different dose groups, but for occurrence of exception, PT was earlier than APTT. The concentration of bromadiolone in plasma reached the peak value 12 h after gavage in both high-dose and low-dose groups. The absorption time of t(1/2Ka) in high-dose group was 4.34 h, the clearance time of t(1/2) was 81.52 h, the absorption time of t(1/2Ka) in low-dose group was 6.90 h, and the elimination time of t(1/2) was 56.38 h. The atrioventricular model of bromadidone was three compartment model in rabbits. Conclusion: Bromadiolone can be absorbed rapidly by oral administration, but its metabolism is slow. The change of bromadiolone in vivo accords with the three compartment model.

Establishing the mechanisms underpinning solids breakthrough in UASB configured anaerobic membrane bioreactors to mitigate fouling.

In this study, the mechanisms for solids breakthrough in upflow anaerobic sludge blanket (UASB) configured anaerobic membrane bioreactors (AnMBRs) have been described to establish design parameters to limit membrane fouling. As the sludge blanket develops, two periods can be identified: (i) an initial progressive enhancement in solids separation provided through sludge blanket clarification, via depth filtration, which sustains downstream membrane permeability; and (ii) sludge blanket destabilisation, which imposed solids breakthrough resulting in a loss in membrane permeability. The onset of sludge blanket destabilisation was identified earlier in the flocculent AnMBR, which was ascribed to an increased gas production, caused by hydrolysis within the sludge blanket at extended solids residence time. Whilst hydrolysis also induced higher gas productivity within the granular AnMBR, solids breakthrough was not evidently observed during this period, and was instead only observed as the sludge blanket approached the UASB overflow. However, solids breakthrough was observed earlier for both reactors when treating wastewater with lower temperatures. This was explained through characterisation of the settling velocity of discrete particles from the sludge blanket of both MBRs; solids washout was evidenced to be induced by the increase in fluid viscosity with a reduction in temperature, which lowered terminal particle settling velocity. Nevertheless, particle settling velocity was comparable for particles from both sludge blankets. We therefore propose that the enhanced stability imparted by the granular AnMBR is due to the higher inertial force of the dense granular sludge. From this study, we suggest that similarly low levels of membrane fouling can be achieved within flocculent AnMBR by managing solids retention time to constrain sludge bed height and excess hydrolysis, together with adopting an upflow velocity based on particle buoyancy at the lowest expected operating temperature.

Impact of static biocarriers on the microbial community, nitrogen removal and membrane fouling in submerged membrane bioreactor at different COD:N ratios.

The polyvinyl formal (PVFM) biocarrier addition in a membrane bioreactor (MBR) was evaluated at high and low carbon/nitrogen (C/N) ratio of 20.0 and 6.7. Results indicated that static biocarrier addition could enrich nitrification and denitrification bacteria, dominating by Tauera, Amaricoccus and Nitrosospira at the genus level and slightly improved the total nitrogen removal even at a low C/N ratio. The bulk sludge characteristics (such as bigger particle size, lower SMP, lower SMP P/C) were also significantly changed in the hybrid MBR (HMBR), leading to a more sustainable membrane operation. The biocarrier addition also reduced the relative abundance of Sphingobacterials_unclassified, Ohtaekwangia and Rhodocyclaceae_unclassified at the genus level, indicating less membrane fouling in the HMBR. Consequently, HMBR with static PVFM addition could partially overcome the drawback of low C/N ratio for total nitrogen removal and membrane fouling control, providing a more resilient MBR to the undesirable environment such as low C/N ratio.

Association between leukoaraiosis and cerebral blood flow territory alteration in asymptomatic internal carotid artery stenosis.

AIM: To test the hypothesis that leukoaraiosis (also known as white matter lesion) is associated with cerebral blood flow territory change as revealed by territorial arterial spin-labeling (TASL) magnetic resonance imaging (MRI) in patients with asymptomatic internal carotid artery stenosis (aICAS). MATERIALS AND METHODS: The institutional review board approved this study. Thirty-three patients with aICAS were included prospectively and divided into high-grade (ultrasonographic stenosis ≥70%, n=17) and low-grade (n=16) groups; 16 healthy subjects were also included. Cerebral flow territory was delineated for left ICA, right ICA, and vertebral arteries using TASL MRI and fuzzy clustering. Two licensed neuroradiologists independently and dichotomously rated the hemispherical asymmetry of flow territories. Flow territories were finalised by consensus, and when asymmetry was present, these were divided into normal and abnormal areas where the raters separately assessed leukoaraiosis based on fluid-attenuated inversion recovery images and the Fazekas scale. RESULTS: The inter-rater agreement in the evaluation of flow territory asymmetry with TASL imaging in conjunction with time-of-flight angiogram is substantial (Cohen's kappa=0.82). Multinomial logistic regression (reference group=healthy subjects) indicates that global leukoaraiosis is not a predictor of aICAS after controlling for age, whereas in high-grade patients, the deep white matter lesion is more severe in the area receiving collateral circulation than in the area with normal flow territory (Wilcoxon signed-rank test, p=0.03). CONCLUSION: TASL MRI is clinically feasible in aICAS and shows that more severe deep white matter lesions are associated with collateral circulation in high-grade patients.

Pre-operative serum albumin level substantially predicts post-operative morbidity and mortality among patients with colorectal cancer who undergo elective colectomy.

The quantitative relationship between serum albumin level and surgical outcomes has not been clearly established. This study included 3732 patients with colon cancer who underwent a potentially curative colectomy. Post-operative mortality and morbidity were analysed according to the patients' demographic data, pre-operative comorbidities, and tumour-related factors. Age, asthma, renal impairment, and albumin level were significantly associated with post-operative morbidity and mortality in the multivariate analyses. Logistic regression analysis revealed linear relationships of post-operative morbidity and mortality with albumin level. The morbidity and mortality rates decreased by 7.3% and 15.6%, respectively, for each 0.1 g/dL increase in albumin level. This finding remained significant in the hypoalbuminaemia subgroup but not in the normoalbuminaemia subgroup. That is, the morbidity and mortality rates significantly decreased by 8.7% and 17.7%, respectively (both P < 0.001), in the former group and decreased by 2.7% (P = 0.112) and 11.6% (P = 0.092), respectively, in the latter group. This study demonstrated that serum albumin level linearly predicted the post-operative morbidity and mortality among the colorectal cancer patients. Pre-operative serum albumin level may therefore be used as a continuous rather than a categorical marker of disease severity, especially among patients with hypoalbuminaemia.

[Blood cerebrospinal fluid barrier damage of rats induced by lead acetate or nano-lead exposure].

OBJECTIVE: To investigate the damage of blood-cerebrospinal fluid barrier (BCB) of rats induced by lead and nano-lead exposure in order to provide the basis for mechanism study of lead neurotoxicity. METHODS: 39 male rats were randomly divided into control group, lead acetate exposed group and nano-lead exposed group. Rats in lead acetate exposed group and nano-lead exposed group were given 20 mg/kg lead acetate or nano-lead by oral gavage and rats in control groups were given the same amount saline for 9 weeks.Morris maze was used to test the learning function, serum albumin and CSF albumin were determined by ELISA. Confocal laser scanning microscope was applied to detect ZO-1 and Occludin protein expression in choroid plexus, real time-PCR was used to test the expression of ZO-1 and Occludin mRNA expression. Pathological changes of choroid plexus cells were observed by the electron microscopy. RESULTS: Compared with the control group, the escape latency of rats in lead acetate or nano-lead exposure group were longer and times of across platform were less. The levels of CSF albumin and the CSF albumin index in lead acetate or nano-lead exposed rats were obviously higher, and the fluorescence intensity of ZO-1, Occludin as well as mRNA expressions were lower than those in control group(P<0.05). Compared with lead acetate exposed group, the levels of CSF albumin and the CSF albumin index in nano-lead exposure group were higher. The fluorescence intensity and mRNA expressions of ZO-1, Occludin in nano-lead exposure group were than those in lead acetate group(P<0.05). Electron microscopy revealed that lead acetate or nano-lead exposure could induce shorter microvillus of choroid plexus epithelial cells, mitochondrion destruction and partial disconnection in intracellular junctions between two adjacent epithelial cells. CONCLUSION: Lead acetate and nano-lead exposed can result in the blood-cerebrospinal fluid barrier damage, which may involve in the process of lead induced neurotoxicity. Meanwhile, nano-lead exposure can induced in more worse damage in terms of blood-results in blood-cerebrospinal fluid barrier function.

Molecular cloning, characterization, and expression analysis of a Broad-Complex homolog during development in the oriental river prawn Macrobrachium nipponense.

Broad-Complex (BR-C) is an early ecdysone-responsive gene encoding a family of zinc-finger transcription factors. In this study, we isolated the full-length cDNA of a BR-C homolog from the testes of the oriental river prawn (Macrobrachium nipponense), according to established expressed sequence tag information, using the rapid amplification of cDNA ends technique. The homolog was designated as MnBR-C. The full-length cDNA of MnBR-C contained a 1095-bp open reading frame encoding a precursor protein of 365 amino acid residues. Comparative and bioinformatic analyses revealed that MnBR-C exhibited a high degree of homology with BR-C proteins, and contained the BTB and Zf-H2C2-2 domains. Real-time quantitative polymerase chain reaction (qPCR) analysis revealed that the MnBR-C expression level varied significantly in the developing embryo, postembryonic larva, and adult tissue. Real-time qPCR showed that the MnBR-C gene was expressed in all of the tissues investigated, with the highest level of expression in the brain. In addition, MnBR-C was more abundantly expressed in the testes than in the ovaries.

Characterization of the male-specific lethal 3 gene in the oriental river prawn, Macrobrachium nipponense.

In this study, male-specific lethal 3 homolog (Mnmsl3) was cloned and characterized from the freshwater prawn Macrobrachium nipponense (Crustacea: Decapoda: Palaemonidae) by rapid amplification of cDNA ends. The deduced amino acid sequences of Mnmsl3 showed high-sequence homology to the insect Msl3 and contained a conserved chromatin organization modifier domain and an MORF4-related gene domain. Real-time quantitative reverse transcription-polymerase chain reaction showed that the Mnmsl3 gene was expressed in all the investigated tissues, with the highest level of expression in the testis. The expression level of Mnmsl3 between males and females was different in the gonad (testis or ovary), abdominal ganglion, and heart. The results revealed that the Mnmsl3 gene might play roles in regulating chromatin and in dosage compensation of M. nipponense. Real-time quantitative reverse transcription-polymerase chain reaction also revealed that Mnmsl3 mRNA expression was significantly increased in both 5 and 20 days post-larvae after metamorphosis, suggesting that Mnmsl3 plays complex and important roles in the early embryonic development and sex differentiation of M. nipponense.

Molecular cloning and expression analysis of female sterile homeotic gene (fsh) in the oriental river prawn Macrobrachium nipponense.

The gene female sterile homeotic (fsh) plays crucial roles in molecular function, including protein kinase activity and DNA binding, which are involved in biological processes such as terminal region determination and negative regulation of DNA-dependent transcription. Although fsh has been found in Drosophila melanogaster, little is known regarding its expression in crustaceans. In this study, a fsh gene homologue, designated as Mnfsh, was cloned and characterized from the testis of the oriental river prawn, Macrobrachium nipponense, by using EST analysis and the RACE approach for the first time. The full-length cDNA of Mnfsh was 2029 bp, consisting of a 5' UTR of 361 bp, a 3' UTR of 216 bp, and an ORF of 1452 bp encoding 484 amino acids. qRT-PCR analysis showed that the Mnfsh gene was expressed in the testis, ovary, muscle, heart, eyestalk, and abdominal ganglion, with the highest level of expression in the ovary and the lowest in the heart. qRT-PCR analyses showed that the expression levels of Mnfsh mRNA both significantly increased in the zoea stage, the VII larvae, and 1st day post-larvae after metamorphosis. In conclusion, the results of the present study indicate that Mnfsh is an arthropod fsh homologue and probably also plays important roles in embryogenesis, organogenesis, and morphological differentiation of M. nipponense.

Gene expression profile analysis of testis and ovary of oriental river prawn, Macrobrachium nipponense, reveals candidate reproduction-related genes.

This study utilized high-throughput RNA sequencing technology to identify reproduction- and development-related genes of Macrobrachium nipponense by analyzing gene expression profiles of testis and ovary. More than 20 million 1 x 51-bp reads were obtained by Illumina sequencing, generating more than 7.7 and 11.7 million clean reads in the testis and ovary library, respectively. As a result, 10,018 unitags were supposed to be differentially expressed genes (DEGs) between ovary and testis. Compared to the ovary library, 4563 (45.5%) of these DEGs exhibited at least 6-fold upregulated expression, while 5455 (54.5%) DEGs exhibited at least 2-fold downregulated expression in the testis. The Gene Ontology (GO) enrichment analysis showed that 113 GO terms had potential molecular functions in reproduction. The Kyoto Encyclopedia of Genes and Genomes results revealed that the most important pathways may be relevant to reproduction and included 7 pathways. Forty-two genes were identified as reproduction-, development-, and sex-related genes based on GO classification and sequence comparison with other publications, including male reproductive-related LIM protein, spermatogenesis-associated protein, gametocyte-specific factor 1, VASA-like protein, vitellogenin, sex-determining protein fem-1, and other potential candidates. These results will advance research in the field of molecular genetics in M. nipponense and offer a valuable resource for further research related to reproduction in crustaceans.

Identification of androgenic gland microRNA and their target genes to discover sex-related microRNA in the oriental river prawn, Macrobrachium nipponense.

The oriental river prawn, Macrobrachium nipponense, is an important aquaculture species in China. The androgenic gland produces hormones that play crucial roles in the differentiation of crustaceans to the male sex. MicroRNA (miRNA) post-transcriptionally regulates many protein-coding genes, influencing important biological and metabolic processes. However, currently, there is no published data identifying miRNA in M. nipponense. In this study, we identified novel miRNA in the androgenic gland of M. nipponense. Using the high-throughput Illumina Solexa system, 1077 miRNA were identified from small RNA libraries by aligning with the de novo androgenic gland transcriptome of M. nipponense (obtained from RNA-Seq) and the sequences in the miRBase21 database. A total of 8,248, 76,011, and 78,307 target genes were predicted in the EST and SRA sequences provided in the NCBI database, and the androgenic gland transcriptome of M. nipponense, respectively. Some potential sex-related miRNA were identified based on the function of the predicted target genes. The results of our study provide new information regarding the miRNA expression in M. nipponense, which could be the basis for further genetic studies on decapod crustaceans.

Proteomics comparison of the sera from multiple sclerosis patients and neuromyelitis optica patients.

This study aimed to identify the proteins that are differentially expressed in sera of multiple sclerosis (MS) patients, neuromyelitis optica (NMO) patients, and normal controls by using a two-dimensional gel electrophoresis (2-DE) assay. Serum samples were collected from the 3 groups, and total proteins were isolated and quantified by using the Bradford assay. The 2-DE and silver staining were carried out, and the Image Master 2D Platinum 5.0 software was used to analyze the images. Differentially expressed protein spots were removed from the gel and digested by enzymolysis and high-definition tandem mass spectrometry, and the MASCOT online software was applied to identify the proteins. Three differentially expressed proteins were identified: immunoglobulin (Ig) lambda chain, keratin 83, and haptoglobin (Hp2); the Ig lambda chain was only found in MS patients. The expression of keratin 83 was significantly elevated in the MS group compared to the normal control or NMO groups. The expression of Hp2 in the NMO group was elevated by more than 2-fold compared to the normal control or MS groups. In summary, a variety of proteins were found to be differentially expressed in the serum between MS, NMO, and normal subjects using 2-DE: Ig lambda, Hp2, and keratin 83 were identified as potential diagnostic markers or treatment targets for MS or NMO.

Genetic diversity analysis of oriental river prawn, Macrobrachium nipponense, in Yellow River using microsatellite marker.

To assess the genetic status of this species, the genetic diversity of wild Macrobrachium nipponense from seven geographic locations in the Yellow River basin were investigated using 20 polymorphic microsatellite DNA loci. The genetic diversity between populations was indicated by the mean number of alleles per locus and mean observed heterozygosity (H) and the expected H, which was arranged from 2 to 10, from 0.4705 to 0.5731, and from 0.5174 to 0.6146, respectively. Hardy-Weinberg equilibrium analysis indicated that a deficiency of heterozygotes existed in all seven populations. Both the F(ST) and AMOVA analyses showed that there is significant difference on population differentiation among populations. The UPGMA clustering tree demonstrated that their close relationship is consistent with their geographic proximity. The data suggest that this Yellow River population has a wide genetic base that is suitable for breeding.

Molecular cloning and expression analysis of two sex-lethal homolog genes during development in the oriental river prawn, Macrobrachium nipponense.

In this study, two Sxl gene homologs, designated as Mnsxl1 and Mnsxl2, were cloned and characterized from the freshwater prawn Macrobrachium nipponense by rapid amplification of cDNA ends. The deduced amino acid sequences of Mnsxl1 and Mnsxl2 showed high sequence homology to the insect Sxl and contained conserved domains in two RNA-binding motifs. Real-time quantitative reverse transcription-polymerase chain reaction (RT-QPCR) showed that the Mnsxl1 and Mnsxl2 genes were expressed in all investigated tissues, with the highest level of expression in the intestine and liver. RT-QPCR also revealed that Mnsxl1 and Mnsxl2 mRNAs expressions were both significantly increased at 5 and 20 days post-larvae after metamorphosis. Thus, the results of the present study imply that Mnsxl1 and Mnsxl2 play complex and important roles in the sex differentiation of M. nipponense.

The dependence of extracted current on discharge gas pressure in neutral beam ion sources on HL-2A tokamak.

The discharge gas pressure is a key factor to influence the extracted current of ion source. In this paper, the dependence of extracted current on discharge gas pressure was investigated in detail at different arc discharge currents. The discharge gas pressure with a very broad range (0.1 Pa-2.7 Pa) was scanned for the first time. It is turned out that, with the increasing of discharge gas pressure, the extracted current increases and the arc voltage decreases at different arc currents; however, when the discharge gas pressure exceeds a certain value, the extracted current decreases. For the same discharge gas pressure, the higher the arc current, the higher the arc voltage and the extracted current are. The arc efficiency was also calculated, and its dependence on gas pressure was almost the same with the dependence of extracted current on gas pressure, but at the same discharge gas pressure, the lower the arc current, the higher the arc efficiency is and the lower the extracted current is.

Serologic prevalence of Toxoplasma gondii in field mice, Microtus fortis, from Yuanjiang, Hunan Province, People's Republic of China.

Antibodies to Toxoplasma gondii were investigated in serum samples of field mice, Microtus fortis, from Yuanjiang, Hunan Province, People's Republic of China. The modified agglutination test (MAT) incorporating formalin-fixed whole tachyzoites and mercaptoethanol was used to determine antibodies. Antibodies to T. gondii (MAT > or = 1:20) were found in 36 (29%) of 124 trapped mice. The antibody titers of positive sera (percentage in parentheses) were 1:20 (8.9), 1:40 (3.2), 1:80 (3.2), 1:160 (1.6), 1:320 (1.6), 1:640 (1.6), 1:1,280 (1.6), 1: 2,560 (0.8), and > 1:2,560 (6.5). No antibody to T. gondii was found in 104 sera of laboratory-bred M. fortis infected with Schistosoma japonicum between 1 and 45 days after infection.

Changed cellular membrane lipid composition and lipid peroxidation of kidney in rats with chronic fluorosis.

An animal model of chronic fluorosis was produced by subjecting Wistar rats to high doses of fluoride in drinking water for a prolonged period. Phospholipid and neutral lipid contents in rat kidney were then analyzed by high-performance liquid chromatography (HPLC), and fatty acid compositions from individual phospholipids were measured by gas chromatography. Lipid peroxidation was detected by the thiobarbituric-acid-reactive substance assay. Results showed that the total phospholipid content significantly decreased in the kidney of the rats treated with high doses of fluoride and the main species influenced were phosphatidylethanolamine (PE) and phosphatidylcholine (PC). Decreased proportions of polyunsaturated fatty acids were observed in PE and PC in kidney of fluoride-treated animals compared to controls. No changes could be detected in the amounts of cholesterol and dolichol in kidneys between the rats treated with fluoride and controls. A significant decrease of ubiquinone in rat kidney was observed in the groups treated with excessive fluoride. High levels of lipid peroxidation were detected in kidney of the rats with fluorosis. It is plausible that the specific modification of lipid composition results from lipid peroxidation. The oxidative stress and modification of cellular membrane lipids may be involved in the pathogenesis of chronic fluorosis and provide a possible explanation for the gross system damage observed in the body, especially in soft tissues and organs.

Microporous segmented polyetherurethane vascular graft: I. Dependency of graft morphology and mechanical properties on compositions and fabrication conditions.

The influence of polyurethane compositions and fabrication conditions on the pore morphology and mechanical properties of microporous segmented polyetherurethane (SPEU) grafts, which were produced by the coagulation technique, were carefully investigated in this article. SPEU resins based on polytetramethylene oxide (PTMO) were synthesized by the solution polymerization method. Different types of coagulant were adapted to examine the feasibility of producing a microporous SPEU graft with good structural regularity. The experimental results indicate that a microporous SPEU graft with a uniform pore structure can be fabricated quite conveniently by using a proper concentration of water and ethanol mixed coagulant. Tensile tests demonstrated that the fabricated microporous SPEU grafts possess high mechanical strengths and satisfy the requirements as vessel replacements. The burst strength test also revealed that the SPEU graft can sustain extremely high internal pressure. Furthermore, a high compliant SPEU (high porosity) graft can be obtained by blending a proper amount of "soluble filler" (i.e., free PTMO polyol in this study) into the SPEU resin.