The impact of continuous and intermittent ketogenic diets on cognitive behavior, motor function, and blood lipids in TgF344-AD rats.

Studies suggest that ketogenic diets (KD) may improve memory in mouse models of aging and Alzheimer's disease (AD). This study determined whether a continuous or intermittent KD (IKD) enhanced cognitive behavior in the TgF344-AD rat model of AD. At 6 months-old, TgF344-AD and wild-type (WT) littermates were placed on a control (CD), KD, or IKD (morning CD and afternoon KD) provided as two meals per day for 2 or 6 months. Cognitive and motor behavior and circulating ß-hydroxybutyrate (BHB), AD biomarkers and blood lipids were assessed. Animals on a KD diet had elevated circulating BHB, with IKD levels intermediate to CD and KD. TgF344-AD rats displayed impaired spatial learning memory in the Barnes maze at 8 and 12 months of age and impaired motor coordination at 12 months of age. Neither KD nor IKD improved performance compared to CD. At 12 months of age, TgF344-AD animals had elevated blood lipids. IKD reduced lipids to WT levels with KD further reducing cholesterol below WT levels. This study shows that at 8 or 12 months of age, KD or IKD intervention did not improve measures of cognitive or motor behavior in TgF344-AD rats; however, both IKD and KD positively impacted circulating lipids.

[Smeglutide inhibits high glucose-induced proliferation of myocardial fibroblasts by downregulating TGFß/Smad3 signaling].

OBJECTIVE: To investigate the effect of semaglutide on high glucose-induced proliferation of cardiac fibroblasts (CFs) and explore its possible mechanism. METHODS: Primary mouse CFs, identified by detecting vimentin expression, were stimulated with 25 mmol/L and treated with 5-20 nmol/L semaglutide, and the cell proliferation was examined with CKK-8 assay for concentration screening.Cultured CFs exposed to high glucose (25 mmol/L) were treated with 5 nmol/L semaglutide, and the changes in cell cycle were detected using Cell Cycle Staining Kit; The mRNA expressions of α-smooth muscle actin (α-SMA), transforming growth factor-ß1(TGF-ß1) and Smad3 were detected using RT-qPCR, and the levels of type Ⅰ collagen (CoLⅠ) and type Ⅲ collagen (CoLIII) in the cell cultures were determined with ELISA. RESULTS: Compared with the control cells, the CFs cultured in high glucose exhibited significantly enhanced proliferative activity (P<0.05) with increased percentage of S-phase cells.Semagutide treatment obviously inhibited high glucose-induced proliferation of the CFs (P<0.05) and reduced the percentage of S-phase cells.High glucose stimulation significantly increased the mRNA expressions of α-SMA, CoL Ⅰ and CoLIII in the cells (P<0.01), which were effectively lowered by semaglutide treatment (P<0.01).The expressions of TGF-ß1 and Smad3 were significantly increased in high glucose-stimulated CFs (P<0.01) and were lowered by semaglutide treatment (P<0.01). CONCLUSION: Semaglutide can inhibit high glucose-induced proliferation and collagen synthesis in mouse CFs possibly by downregulating the TGFß/Smad3 signaling pathway.

[Prospects of use of research results for drugs with anitihypoxic and antioxidative properties in neuroprotective treatment strategies (Opinion of the Council of Experts dated 26 March 2022)]. / Perspektiva ispol'zovaniya rezul'tatov issledovaniya preparatov s anitigipoksantnymi i antioksidantnymi svoistvami v neiroprotektivnoi strategii lecheniya (Zaklyuchenie soveta ekspertov ot 26 marta 2022 g.).

Cerebrovascular diseases are one of the main causes of death and permanent disability. Effective and timely neuroprotective therapy can reduce the burden of cerebrovascular disease. The possibilities of neuroprotection as a method of prevention and medical rehabilitation of acute and chronic cerebrovascular diseases are addressed.

[Epidural block associated with improved long-term survival after surgery for colorectal cancer: A retrospective cohort study with propensity score matching].

OBJECTIVE: To investigate the effect of epidural anesthesia on the long-term prognosis of patients after selective colorectal cancer resection surgery. METHODS: This was a retrospective cohort study and approved by local institution review board. Patients who underwent selective colorectal cancer resection surgery from August 2011 to December 2012 in Peking University First Hospital were enrolled. The patients were divided into general anesthesia (GA) group and combined epidural-general anesthesia (EGA) group according to anesthesia type. Primary outcome was patient's long-term survival status. Secondary outcome included the overall incidence of in-hospital complications and length of postoperative in-hospital stay. Propensity score was used to match cases between the two groups based on the probability of receiving EGA. Survival was analyzed by Kaplan-Meier analysis and compared by Log-rank test between the two groups. Multivariate Cox regression analysis was used to investigate the relationship between epidural anesthesia and other variables with long-term survival status. RESULTS: A total of 264 patients were entered into final analysis, including 166 cases in GA group and 98 cases in EGA group. Mean age of the patients was (63.3±12.1) years and mean survival time was 47.2 (95%CI 45.7-48.7) months. Before the propensity score match, the mortality in EGA group was 16.9% (28/166) and 9.2% (9/98) in GA group. But comparison between the two groups had no statistical significance (P=0.091). After the propensity score match, 87 paired cases were matched and analyzed. The risk of long-term mortality in EGA group was lower than that of GA group by Kaplan-Meier analysis (5.7% vs.16.1%, HR=0.344, 95%CI 0.124-0.955, P=0.041). Mean survival time of EGA group was longer than that of GA group (50.3 months vs. 42.9 months, P=0.032). Multivariate Cox regression ana-lysis showed that EGA, in comparison with GA, was related with lower risk of long-term mortality (HR=0.326, 95%CI 0.117-0.909, P=0.032). Age (HR=1.042, 95%CI 1.001-1.085, P=0.046) and preoperative lymph node metastasis (HR=2.924, 95%CI 1.162-7.356, P=0.023) were also related with increased risk of long-term mortality. CONCLUSION: Present study found that perioperative use of epidural anesthesia and analgesia was associated with improvement of the patient's long-term survival. Well-designed studies are needed to verify this hypothesis.

[Clinical characteristics of patients with multiple myeloma harboring 6q deletion].

Objective: To study the clinical and cytogenetic characteristics of patients with multiple myeloma harboring 6q deletion, with the aim to determine the impact of 6q deletion on survival. Methods: This study included the retrospective analysis of 382 newly diagnosed patients with multiple myeloma in our hospital from 2014 to 2017 and compared the clinical and cytogenetic characteristics between patients with and without 6q deletion. The log-rank test and the Cox proportional hazards regression model were used to analyze prognostic factors for progression-free survival (PFS) and overall survival (OS) . Results: Compared to those without 6q, the patients with 6q deletion were older (median age, 63 vs 58 years, P=0.039) , had higher incidence of t (4; 14) (30.4% vs 16.4% , P=0.020) , and higher proportion of complex karyotypes (22.2% vs 5.3% , P=0.001) . Univariate survival analysis using the log-rank test revealed that 6q deletion was associated with shorter PFS. However, by the Cox multivariate proportional hazards regression model, 6q deletion was not an independent prognostic factor and its effect on survival was affected by age, t (4; 14) , and other risk factors. Conclusions: 6q deletion was common in elderly patients with multiple myeloma and was often accompanied by t (4;14) and complex karyotypes. However, 6q deletion was not an independent prognostic factor for multiple myeloma.

Encapsulation of bacterial cells in cytoprotective ZIF-90 crystals as living composites.

Exploiting metal-organic frameworks (MOFs) as selectively permeable shelters for encapsulating engineered cells to form hybrid living materials has attracted increasing attention in recent years. Optimizing the synthesis process to improve encapsulation efficiency (EE) is critical for further technological development and applications. Here, using ZIF-90 and genetically engineered Escherichia coli (E. coli) as a demo, we fabricated E. coli@ZIF-90 living composites in which E. coli cells were encapsulated in ZIF-90 crystals. We illustrated that ZIF-90 could serve as a protective porous cage for cells to shield against toxic bactericides including benzaldehyde, cinnamaldehyde, and kanamycin. Notably, the E. coli cells remained alive and could self-reproduce after removing the ZIF-90 crystal cages in ethylenediaminetetraacetic acid, suggesting a feasible route for protecting and prolonging the lifespan of bacterial cells. Moreover, an aqueous multiple-step deposition approach was developed to improve EE of the E. coli@ZIF-90 composites: the EE increased to 61.9 ± 5.2%, in contrast with the efficiency of the traditional method (21.3 ± 4.4%) prepared with PBS buffer. In short, we develop a simple yet viable strategy to manufacture MOF-based living hybrid materials that promise new applications across diverse fields.

The mRNA Distribution of Cancer Stem Cell Marker CD90/Thy-1 Is Comparable in Hepatocellular Carcinoma of Eastern and Western Populations.

Epidemiology of hepatocellular carcinoma (HCC) showed a correlation between incidence and geographical-relevant risk factors. This study aims to compare the distributions of cancer stem cells (CSC) in two distant populations in Asia and Europe. We analyzed 52 and 43 selected HCC patients undergoing hepatectomy in Ho Chi Minh City (Vietnam) and Trieste (Italy). Each patient sample consisted of HCC, peri-HCC, and non-tumoral (distal) tissue. Demographic data were recorded together with clinical findings. The protocol for the collection of tissue samples and RNA was standardized in both laboratories and gene expression analysis was performed in a single laboratory with identical PCR conditions. Baseline data showed comparable laboratory findings between the two cohorts. mRNA distribution showed a comparable pattern of all CSC markers analyzed with the expression of CD90 progressively increasing from distal and peri-HCC to be highest in HCC (p < 0.001), confirmed by immunofluorescence data. CD90 mRNA distribution was related to HBV-related HCC and a tumor diameter less than 5 cm. Patients with high tumoral CD90 mRNA had a shorter time (p < 0.05) to tumor recurrence compared to patients with lower CD90. This comparative study showed that CD90 mRNA expressions are comparable between Eastern and Western HCC cases.

Has-miR-17 increases the malignancy of gastric lymphoma by HSP60/TNFR2 pathway.

The purpose of this study was to investigate the expression and mechanism of miR-17 in gastric lym-phoma. miR-17mimics, miR-17 inhibitors and negative controls were transfected into human gastric lymphoma cell line cyp6d. The proliferation, invasion and apoptosis of cyp6d cells were detected by CCK-8, Transwell and TUNEL methods, respectively. The expression and clinicopathological features of miR-17 in gastric lymphoma were analyzed by real-time quantitative PCR. The target gene of miR-17 was predicted by targetscan 7.2, and the expression of miR-17 related protein was detected by Western blot. The results showed that the expression of miR-17 in gastric lymphoma was significantly higher than that in normal tissues (P < 0.05), which was closely related to lymph node metastasis, tumor size and distant metastasis (P < 0.05). The high expression of miR-17 significantly promoted the proliferation and invasion of cyp6d cells and inhibited apoptosis (P < 0.05). The high expression of miR-17 can regu¬late the expression of HSP60 and TNFR2. It has been found that miR-17 can promote the development of gastric lymphoma by regulating HSP60/TNFR2 pathway, which is a potential molecular target for the diagnosis and treatment of gastric lymphoma.

Differential capacity of CD90+ cells in autophagy activation following chemotherapy in hepatocellular carcinoma.

INTRODUCTION AND OBJECTIVES: Analysis of cancer biomarkers is an important tool in developing targeted-therapy and in modulating chemoresistance. Here, we analyze the relevance of CD90, a marker of cancer stem cells (CSC) in hepatocellular carcinoma (HCC) and its correlation with autophagy. MATERIALS AND METHODS: For in vivo study, 86 specimens were collected from 43 patients undergoing liver resections. In each patient, HCC nodule (HCC) and surrounding non-tumor (SNT) were collected. For in vitro study, HCC cells JHH6 subpopulations expressing CD90+ and CD90- were isolated using magnetic-sorter and confirmed by flow-cytometry. Upon doxorubicin treatment, autophagy turn-over was analyzed by RTqPCR for mRNA expression, Western blot for protein expression, and autophagosome staining for autophagy-flux. Cytotoxicity test was performed by MTT assay. Gene and protein analysis were performed in clinical samples together with immunohistostaining. RESULTS: CD90 mRNA expression was higher in HCC than in SNT for 8-fold (p < 0.001). LC3-II protein was up-regulated in the HCC in comparison with the SNT (p < 0.05). In vitro model showed that CD90+ and CD90- cells had diverse expressions of autophagy-related genes. Upon doxorubicin treatment, autophagy was activated in both cells by increasing LC3-II protein expression, autophagic vacuoles, and dysregulation of autophagy-related mRNAs. A differential autophagic capacity was noticed between two subpopulations and it was correlated with cellular toxicity assay. CONCLUSIONS: We demonstrated the relevance of differential autophagy capacity of CD90+ cells in HCC. Autophagy was involved in cancer-defense mechanism against doxorubicin. Cancer promoting function of autophagy in CD90+ cells was also related to cancer environment.

On the mechanical behavior of austenitic stainless steel with nano/ultrafine grains and comparison with micrometer austenitic grains counterpart and their biological functions.

Conventional coarse-grained (CG) biomedical austenitic stainless steel with grain size in the micrometer range was subjected to a novel phase reversion concept involving severe cold deformation, followed by annealing, when the cold deformed martensite reverts to austenite with grain size in the nanometer/ultrafine (NG/UFG) regime (~200-400 nm). The mechanical behavior of CG and NG/UFG steels was studied via load-controlled and displacement-controlled experiments using a nanoindentation technique with the aim to simulate micromotion. The plastic zone associated with the indentation-induced deformed region was characterized by post-mortem electron microscopy of the deformed region to elucidate the deformation mechanism. Nanoscale twinning was the deformation mechanism in steel with grain size in the NG/UFG regime, and contributed to the ductility of high strength steel. In contrast, strain-induced martensite contributed to the ductility of low strength CG steel with micrometer grain size. Interestingly, besides the differences in the mechanical behavior, the biological functions of the two steels were remarkably different. Higher cell attachment, proliferation and higher expression level of prominent proteins, fibronection, actin and vinculin were favored by a surface with grain size in the nanometer regime and was in striking contrast with the surface with micrometer grain size. This behavior is attributed to the differences in the fraction of grain boundaries that are high energy two-dimensional defects. The study advances our understanding of the mechanical behavior of biomaterials and their cellular functions.

Genome-wide association study reveals candidate genes associated with body measurement traits in Chinese Wagyu beef cattle.

We performed a genome-wide association study to identify candidate genes for body measurement traits in 463 Wagyu beef cattle typed with the Illumina Bovine HD 770K SNP array. At the genome-wide level, we detected 18, five and one SNPs associated with hip height, body height and body length respectively. In total, these SNPs are within or near 11 genes, six of which (PENK, XKR4, IMPAD1, PLAG1, CCND2 and SNTG1) have been reported previously and five of which (CSMD3, LAP3, SYN3, FAM19A5 and TIMP3) are novel candidate genes that we found to be associated with body measurement traits. Further exploration of these candidate genes will facilitate genetic improvement in Chinese Wagyu beef cattle.

Evaluation of bee venom as a novel feed additive in fast-growing broilers.

1. The present study was designed to evaluate purified bee venom (BV) as an alternative to antibiotics in broiler chickens. The experimental treatment diets were formulated by adding BV into a maize-soybean meal-based diet to give 0, 10, 50, 100, and 500 µg BV per kg of diet. 2. Dietary BV quadratically improved (P < 0.05) feed conversion ratio and increased body weight gain at 1-21 d as level in diet increased. Higher BV levels lowered relative weight of spleen (linear and quadratic, P < 0.05), bursa of Fabricius (quadratic, P < 0.05), and liver (linear and quadratic, P < 0.05) at 21 d of age. Relative breast meat yields were increased quadratically at 21 d and linearly at 35 d with supplementation levels. Dietary BV increased (linear and quadratic, P < 0.05) lightness (L*) value for meat at 21 d, decreased (linear, P < 0.05) ileal villus height and narrowed (quadratic, P < 0.05) width. 3. Dietary BV inclusion linearly increased the concentration of secretory immunoglobulin A (sIgA) on ileal mucosa at 21 d and decreased (quadratic, P < 0.05) nitric oxide contents in serum samples at 21 d and 35 d. Total short-chain fatty acids (SCFA) in caecal digesta were reduced with increasing venom in diets at 21 d of age. None of the serum parameters except for creatinine was affected by dietary BV. 4. It was concluded that dietary BV exhibited wide range of in vivo biological properties in broiler chickens and could be incorporated into feed to promote growth and animal health.

Effects of fumonisin B1 and mycotoxin binders on growth performance, tibia characteristics, gut physiology, and stress indicators in broiler chickens raised in different stocking densities.

The present study was carried out to investigate the effects of stocking density, fumonisin B1 (FB), and mycotoxin binder (TB) on growth performance, bone quality, physiological stress indicators, and gut health in broiler chickens. Day-old Ross 308 male broiler chicks (n = 1,440/experiment) were randomly allocated to 72 floor pens in a 3 × 2 × 2 factorial arrangement, using 3 stocking densities (12.5 birds/m2 [HSD], 10 birds/m2 [MSD], or 7.5 birds/m2 [LSD]), 2 levels of purified FB (0 or 10 ppm), and 2 levels of TB (0 or 0.2%). Each treatment had 6 replicates (n = 6/treatment) and experiments lasted 34 days. All data were analyzed using 3-way ANOVA with stocking density level, FB, and TB as main factors. Body weight gain and feed intake were lower (P < 0.05) in broilers kept at HSD and MSD compared to LSD-housed counterparts. Birds fed an FB-contaminated diet exhibited a higher feed-to-gain ratio compared with those fed an FB-free diet (P < 0.05). None of the treatments affected intestinal morphology or ileal secretory immunoglobulin A levels. Stocking density affected tibia breaking strength (P < 0.05), which was lower in chickens housed at HSD compared with LSD-housed chickens. The heterophil/lymphocyte ratio (H/L ratio) was elevated (P < 0.05) in HSD and MSD groups compared with the LSD group. Serum nitric oxide (NO) levels were elevated (P < 0.05) in chickens fed the FB-contaminated diet compared with the control diet-fed counterparts. Significant interaction (P < 0.05) between FB and TB on serum NO levels was noted. In summary, increasing stocking density lowered growth performance and bone quality, but increased the H/L ratio. Dietary TB did not affect FB-induced increases in the feed-to-gain ratio. No interaction was observed between stocking density and FB for the measured variables.

Modified Mediterranean Diet for Enrichment of Short Chain Fatty Acids: Potential Adjunctive Therapeutic to Target Immune and Metabolic Dysfunction in Schizophrenia?

Growing interest in gut and digestive processes and their potential link to brain and peripheral based inflammation or biobehavioral phenotypes has led to an increasing number of basic and translational scientific reports focused on the role of gut microbiota within the context of neuropsychiatric disorders. However, the effect of dietary modification on specific gut metabolites, in association with immune, metabolic, and psychopathological functioning in schizophrenia spectrum disorders has not been well characterized. The short chain fatty acids (SCFA) acetate, butyrate, and propionate, major metabolites derived from fermentation of dietary fibers by gut microbes, interact with multiple immune and metabolic pathways. The specific pathways that SCFA are thought to target, are dysregulated in cardiovascular disease, type II diabetes, and systemic inflammation. Most notably, these disorders are consistently linked to an attenuated lifespan in schizophrenia. Although, unhealthy dietary intake patterns and increased prevalence of immune and metabolic dysfunction has been observed in people with schizophrenia; dietary interventions have not been well utilized to target immune or metabolic illness. Prior schizophrenia patient trials primarily focused on the effects of gluten free diets. Findings from these studies indicate that a diet avoiding gluten benefits a limited subset of patients, individuals with celiac disease or non-celiac gluten sensitivity. Therefore, alternative dietary and nutritional modifications such as high-fiber, Mediterranean style, diets that enrich the production of SCFA, while being associated with a minimal likelihood of adverse events, may improve immune and cardiovascular outcomes linked to premature mortality in schizophrenia. With a growing literature demonstrating that SCFA can cross the blood brain barrier and target key inflammatory and metabolic pathways, this article highlights enriching dietary intake for SCFA as a potential adjunctive therapy for people with schizophrenia.

[Influence of leptin receptor gene K109R polymorphism on the risk of nonalcoholic fatty liver disease and its interaction with PNPLA3 I148M polymorphism].

OBJECTIVE: To investigate the influence of leptin receptor (LEPR) gene K109R polymorphism on the risk of nonalcoholic fatty liver disease (NAFLD) and its interaction with PNPLA3 I148M polymorphism in the Han Chinese population in Qingdao, China. METHODS: Blood samples were collected from 296 NAFLD patients and 321 healthy controls, and the genotypes of these patients were determined by PCR and genotyping. Related statistical analyses were performed to compare genotypes, alleles, and clinical data between the two groups. Generalized multifactor dimensionality reduction (GMDR) was used to investigate the interaction between LEPR K109R and PNPLA3 I148M genes. RESULTS: The distribution of LEPR K109R genotypes and alleles showed no significant differences between the NAFLD group and the control group (P > 0.05). PNPLA3 I148M gene polymorphisms were closely associated with the risk of NAFLD, and the risk of NAFLD in G mutant gene carriers was 2.07 times that in patients who did not carry this gene (OR = 2.07, 95% CI 1.423-3.013, P < 0.001). The joint action of LEPR K109R and PNPLA3 I148M significantly increased the risk of NAFL (OR = 3.393, 95% CI 1.856-6.201, P < 0.001). CONCLUSION: In the Han Chinese population in Qingdao, LEPR K109R gene polymorphism is not associated with the risk of NAFLD, but its interaction with PNPLA3 I148M polymorphism can significantly increase the risk of NAFLD.

The Use of Fermented Soybean Meals during Early Phase Affects Subsequent Growth and Physiological Response in Broiler Chicks.

The objectives of this experiment was to evaluate the subsequent growth and organ weights, blood profiles and cecal microbiota of broiler chicks fed pre-starter diets containing fermented soybean meal products during early phase. A total of nine hundred 1-d-old chicks were randomly assigned into six groups with six replicates of 25 chicks each. The chicks were fed control pre-starter diet with dehulled soybean meal (SBM) or one of five experimental diets containing fermented SBM products (Bacillus fermented SBM [BF-SBM], yeast by product and Bacillus fermented SBM [YBF-SBM]; Lactobacillus fermented SBM 1 [LF-SBM 1]; Lactobacillus fermented SBM 2 [LF-SBM 2]) or soy protein concentrate (SPC) for 7 d after hatching, followed by 4 wk feeding of commercial diets without fermented SBMs or SPC. The fermented SBMs and SPC were substituted at the expense of dehulled SBM at 3% level on fresh weight basis. The body weight (BW) during the starter period was not affected by dietary treatments, but BW at 14 d onwards was significantly higher (p<0.05) in chicks that had been fed BF-SBM and YBF-SBM during the early phase compared with the control group. The feed intake during grower and finisher phases was not affected (p>0.05) by dietary treatments. During total rearing period, the daily weight gains in six groups were 52.0 (control), 57.7 (BF-SBM), 58.5 (YBF-SBM), 52.0 (LF-SBM 1), 56.7 (LF-SBM 2), and 53.3 g/d (SPC), respectively. The daily weight gain in chicks fed diet containing BF-SBM, YBF-SBM, and LF-SBM 2 were significantly higher values (p<0.001) than that of the control group. Chicks fed BF-SBM, YBF-SBM, and LF-SBM 2 had significantly lower (p<0.01) feed conversion ratio compared with the control group. There were no significant differences in the relative weight of various organs and blood profiles among groups. Cecal microbiota was altered by dietary treatments. At 35 d, chicks fed on the pre-starter diets containing BF-SBM and YBF-SBM had significantly increased (p<0.001) lactic acid bacteria, but lowered Coli-form bacteria in cecal contents compared with those fed the control diet. The number of Bacillus spp. was higher (p<0.001) in all groups except for LF-SBM 1 compared with control diet-fed chicks. At 7 d, jejunal villi were significantly lengthened (p<0.001) in chicks fed the fermented SBMs vs control diet. Collectively, the results indicate that feeding of fermented SBMs during early phase are beneficial to the subsequent growth performance in broiler chicks. BF-SBM and YBF-SBM showed superior overall growth performance as compared with unfermented SBM and SPC.

Effects of Dietary Calcium Levels on Productive Performance, Eggshell Quality and Overall Calcium Status in Aged Laying Hens.

This study was conducted to investigate the effects of diets with varying levels of calcium on egg production, shell quality and overall calcium status in aged laying hens. A total of five hundred 70-wk-old Hy-Line Brown layers were divided five groups and fed one of the five experimental diets with 3.5%, 3.8%, 4.1%, 4.4%, or 4.7% Ca, for 10 weeks. There were no significant differences in feed intake, egg production and egg weight among groups. The cracked eggs were linearly reduced as dietary Ca levels increased to 4.7% (p<0.01). A significant linear improvement for eggshell strength and thickness were determined with increasing dietary Ca levels (p<0.01). The contents of serum Ca and phosphorus were not affected by dietary Ca levels. With increase in dietary Ca levels, the tibial breaking strength slightly increased. There were no significant differences in the tibial contents of ash, Ca and phosphorus among groups. In conclusion, eggshell quality, as measured by appearance, strength and thickness of eggshell, were influenced by dietary Ca content as expected (p<0.05). These results suggested that aged laying hens require relatively higher level of Ca than required levels from current Korean feeding standards for poultry.

Contact fatigue of human enamel: Experiments, mechanisms and modeling.

Cyclic contact between natural tooth structure and engineered ceramics is increasingly common. Fatigue of the enamel due to cyclic contact is rarely considered. The objectives of this investigation were to evaluate the fatigue behavior of human enamel by cyclic contact, and to assess the extent of damage over clinically relevant conditions. Cyclic contact experiments were conducted using the crowns of caries-free molars obtained from young donors. The cuspal locations were polished flat and subjected to cyclic contact with a spherical indenter of alumina at 2Hz. The progression of damage was monitored through the evolution in contact displacement, changes in the contact hysteresis and characteristics of the fracture pattern. The contact fatigue life diagram exhibited a decrease in cycles to failure with increasing cyclic load magnitude. Two distinct trends were identified, which corresponded to the development and propagation of a combination of cylindrical and radial cracks. Under contact loads of less than 400N, enamel rod decussation resisted the growth of subsurface cracks. However, at greater loads the damage progressed rapidly and accelerated fatigue failure. Overall, cyclic contact between ceramic appliances and natural tooth structure causes fatigue of the enamel. The extent of damage is dependent on the magnitude of cyclic stress and the ability of the decussation to arrest the fatigue damage.

Multiplex Quantitative PCR Assays for the Detection and Quantification of the Six Major Non-O157 Escherichia coli Serogroups in Cattle Feces.

Shiga toxin-producing Escherichia coli (STEC) serogroups O26, O45, O103, O111, O121, and O145, called non-O157 STEC, are important foodborne pathogens. Cattle, a major reservoir, harbor the organisms in the hindgut and shed them in the feces. Although limited data exist on fecal shedding, concentrations of non-O157 STEC in feces have not been reported. The objectives of our study were (i) to develop and validate two multiplex quantitative PCR (mqPCR) assays, targeting O-antigen genes of O26, O103, and O111 (mqPCR-1) and O45, O121, and O145 (mqPCR-2); (ii) to utilize the two assays, together with a previously developed four-plex qPCR assay (mqPCR-3) targeting the O157 antigen and three virulence genes (stx1, stx2, and eae), to quantify seven serogroups and three virulence genes in cattle feces; and (iii) to compare the three mqPCR assays to a 10-plex conventional PCR (cPCR) targeting seven serogroups and three virulence genes and culture methods to detect seven E. coli serogroups in cattle feces. The two mqPCR assays (1 and 2) were shown to be specific to the target genes, and the detection limits were 4 and 2 log CFU/g of pure culture-spiked fecal samples, before and after enrichment, respectively. A total of 576 fecal samples collected from a feedlot were enriched in E. coli broth and were subjected to quantification (before enrichment) and detection (after enrichment). Of the 576 fecal samples subjected, before enrichment, to three mqPCR assays for quantification, 175 (30.4%) were quantifiable (≥4 log CFU/g) for at least one of the seven serogroups, with O157 being the most common serogroup. The three mqPCR assays detected higher proportions of postenriched fecal samples (P > 0.01) as positive for one or more serogroups compared with cPCR and culture methods. This is the first study to assess the applicability of qPCR assays to detect and quantify six non-O157 serogroups in cattle feces and to generate data on fecal concentration of the six serogroups.