Toxicity assessment of combined fluoroquinolone and tetracycline exposure in zebrafish (Danio rerio)

Fluoroquinolones (FQs) and tetracyclines (TCs), the two β-diketone antibiotics (DKAs), are two frequently detected pollutants in the environment; however, little data are available on their combined toxicity to zebrafish (Danio rerio). This study reports that toxicologic effects of combined DKA (FQs-TCs) exposure on zebrafish were comparable with or slightly less than those of TCs alone, showing that TCs played a major toxicologic role in the mixtures. The effects of FQs, TCs, and DKAs on malformation rates of zebrafish were dose dependent, with EC50 values of 481.3, 16.4, and 135.1 mg/L, respectively. According to the combined effects of DKAs on zebrafish hatching, mortality, and malformation rates, the interaction between FQs and TCs was shown to be antagonistic based on three assessment methods: Toxic Unit, Additional Index, and Mixture Toxic Index. The 1.56 mg/L TC and 9.38 mg/L DKA treatments resulted in higher zebrafish basal swimming rate compared with the control group at 120 hours postfertilization (hpf). in both light and light-to-dark photoperiod experiments. Under conditions of no obvious abnormality in cardiac development, the heart beats were decreased significantly because of DKA exposure, such as decreasing by ∼20% at 150 mg/L DKAs. Transmission electron microscopy observation of myocytes from DKA-exposed hearts displayed prominent interruptions and myofibrillar disorganization of the normal parallel alignment of thick and thin filaments, and partial edematous and dissolved membranes of cell nuclear tissues. At 90 mg/L DKAs, the transcriptional levels of the acta1a, myl7, and gle1b genes, related to heart development and skeletal muscle formation, were significantly changed. This is consistent with the swimming behavior and histopathologic results obtained by transmission electron microscopy. In summary, the toxicity of the combined DKAs to zebrafish was comparable with or less than that of TCs alone and had the ability to impair individual behaviors that are of great importance in the assessment of their ecologic fitness. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 736-750, 2016.

[Effect of unfractionated heparin on the expression of heme oxygenase-1 in intestinal mucosa of mice with sepsis]

OBJECTIVE

To investigate the effect of unfractionated heparin (UFH) on the expression of heme oxygenase-1 (HO-1) in intestinal mucosa of mice with sepsis.

METHODS

Thirty-six male C57BL/6J mice were randomly divided into sham group, cecal ligation and puncture (CLP) group and UHF group, n =12 in each group. Model of intestinal injury in sepsis was induced by CLP. In sham group, the mice were exposed without ligation of cecum. In UFH group, the mice were treated intravenously with 8 U of UFH via the tail vein half an hour before the operation and 12 hours after the surgery respectively. Six mice in each group were randomly chosen at 4 hours and 24 hours after operation to collect inferior vena venous blood samples and terminalileum tissues. The serum levels of interleukins (IL-1 β,IL-6),and tumor necrosis factor-α (TNF-α) were determined by enzyme linked immunosorbent assay (ELISA).The serum level of D-lactate was determined by colorimetry.Pathological changes of ileum tissue and Chiu score were observed after hematoxylin eosin (HE) staining. The HO-1 expression was detected immunohistochemically.

RESULTS

In sham group, no significant changes in the serum levels of IL-1 β,IL-6,TNF-α and D-lactate were observed. Twenty-four hours after the operation, the structure of intestinal mucosa was basically normal without obvious pathology change and no HO-1 positive cells were found. The serum levels of IL-1 β,IL-6,TNF-α,and D-lactate in CLP group were gradually increased, and they were significantly increased as compared with sham group [IL-1 β (ng/L):40.87±2.88 vs.22.60±2.05 at 4 hours,113.73±3.96 vs.22.07±2.74 at 24 hours;IL-6 (ng/L):63.89±3.26 vs.44.89±3.38 at 4 hours,176.56±5.45 vs.45.76±4.02 at 24 hours; TNF-α (ng/L):194.62± 14.13 vs.152.05±6.22 at 4 hours,599.62± 10.20 vs.155.90± 14.18 at 24 hours; D-lactate (mmol/L):0.24± 0.02 vs.0.19 ± 0.01 at 4 hours,0.33 ± 0.04 vs.0.20 ± 0.02 at 24 hours, all P ＜ 0.05].Twenty-four hours after the operation, edema and inflammation in ileal mucosa, intestinal villi structural damage were observed, the Chiu score was significantly higher than those in the sham group [4.5 (3.0-5.0) vs.0 (0-1.0),P ＜ 0.05],and a small amount of HO-1 positive cells were localized in the intestinal mucosa. Compared with CLP group, the serum levels of IL-1 β,IL-6,TNF-α,and D-lactate of UFH group were significantly decreased [IL-1 β (ng/L):31.53 ± 2.90 vs.40.87 ± 2.88 at 4 hours,61.13 ± 2.80 vs.113.73 ± 3.96 at 24 hours;IL-6 (ng/L):51.16 ± 5.68 vs.63.89 ± 3.26 at 4 hours,81.16 ± 4.54 vs.176.56 ± 5.45 at 24 hours; TNF-α (ng/L):171.76± 5.60 vs.194.62± 14.13 at 4 hours,328.48 ± 10.79 vs.599.62± 10.20 at 24 hours; D-lactate (mmol/L):0.21 ±0.01 vs.0.24±0.02 at 4 hours,0.24±0.02 vs.0.33±0.04 at 24 hours, all P ＜ 0.05]. Twenty-four hours after the operation, intestinal injury was ameliorated, the Chiu score was significantly lower [1.5 (1.0-5.0) vs.4.5 (3.0-5.0),P ＜ 0.05],and HO-1 positive cells in the intestinal mucosa was remarkably increased.

CONCLUSION

UFH can enhance the expression of HO-1 in intestinal mucosa, reduce the release of inflammatory factors, ameliorate the intestinal inflammatory response, and thus play a protective role in intestinal tissue in mice with sepsis.

Performance of blood pressure-to-height ratio as a screening tool for elevated blood pressure in pediatric population: a systematic meta-analysis

The aim of this study was to assess the performance of the blood pressure-to-height ratio (BPHR) for screening elevated blood pressure (BP) in children and adolescents using a meta-analysis of eligible published studies. We retrieved studies that investigated the performance of the BPHR for identifying elevated BP from Pubmed and other databases. We performed meta-analyses by subgroups of sex, age and ethnicity using a fixed or random effect model based on whether there was between-study heterogeneity. A total of 13 publications including 262 830 children and adolescents aged 6-18 years on BPHR and a total of three publications including 95 343 children on the modified BPHR were included in this meta-analysis. The summary results suggested that BPHR performed well to identify pre-high BP and high BP for children aged 6-11 years and adolescents aged 12-18 years. The performance of BPHR was perfect for identifying severe high BP in adolescents aged 12-18 years. However, the modified BPHR did not improve accuracy for screening high BP in children aged 6-12 years. In summary, BPHR performed well for identifying elevated BP in children and adolescents, independently of sex, age and ethnicity group. In addition, the modified BPHR performed similarly with BPHR for screening high BP in childhood.

A single CT-guided percutaneous intraosseous injection of thermosensitive simvastatin/poloxamer 407 hydrogel enhances vertebral bone formation in ovariectomized minipigs

The ultimate goal of osteoporosis treatment is prevention of fragile fracture. Local treatment targeting specific bone may decrease the incidence of osteoporotic fractures. We developed an injectable, thermosensitive simvastatin/poloxamer 407 hydrogel; a single CT-guided percutaneous intraosseous injection augmented vertebrae in ovariectomized minipigs.

INTRODUCTION

The greatest hazard associated with osteoporosis is local fragility fractures. An adjunct, local treatment might be helpful to decrease the incidence of osteoporotic fracture. Studies have found that simvastatin stimulates bone formation, but the skeletal bioavailability of orally administered is low. Directly delivering simvastatin to the specific bone that is prone to fractures may reinforce the target bone and reduce the incidence of fragility fractures.

METHODS

We developed an injectable, thermosensitive simvastatin/poloxamer 407 hydrogel, conducted scanning electron microscopy, rheological, and drug release analyses to evaluate the delivery system; injected it into the lumbar vertebrae of ovariectomized minipigs via minimally invasive CT-guided percutaneous vertebral injection. Three months later, BMD, microstructures, mineral apposition rates, and strength were determined by DXA, micro-CT, histology, and biomechanical test; expression of VEGF, BMP2, and osteocalcin were analyzed by immunohistochemistry and Western blots.

RESULTS

Poloxamer 407 is an effective controlled delivery system for intraosseous-injected simvastatin. A single injection of the simvastatin/poloxamer 407 hydrogel significantly increased BMD, bone microstructure, and strength; the bone volume fraction and trabecular thickness increased nearly 150 %, bone strength almost doubled compared with controls (all P < 0.01); and induced higher expression of VEGF, BMP2, and osteocalcin.

CONCLUSIONS

CT-guided percutaneous vertebral injection of a single simvastatin/poloxamer 407 thermosensitive hydrogel promotes bone formation in ovariectomized minipigs. The underlying mechanism appears to involve the higher expression of VEGF and BMP-2.

Vitamin D prevents articular cartilage erosion by regulating collagen II turnover through TGF-β1 in ovariectomized rats

OBJECTIVE

To explore the effect of vitamin D on turnover of articular cartilage with ovariectomy (OVX) induced OA, and to investigate transforming growth factor-β1 (TGF-β1) as a possible underlying mechanism mediated by 1α,25(OH)2D3.

DESIGN

Sixty-six rats were randomly allocated into seven groups: sham plus control diet (SHAM+CTL), OVX+CTL diet, sham plus vitamin D-deficient (VDD) diet, OVX+VDD diet, and three groups of ovariectomized rats treated with different doses of 1α,25(OH)2D3. The cartilage erosion and the levels of serum 17β-estradiol, 1α,25(OH)2D3 and C-telopeptide of type II collagen (CTX-II) were measured. TGF-β1, type II Collagen (CII), matrix metalloproteinases (MMP)-9,-13 in articular cartilage were assessed by immunohistochemistry. TGF-β1 and CTX-II expression were measured in articular cartilage chondrocytes treated with/without tumor necrosis factor (TNF-α), 1α,25(OH)2D3, and TGF-β receptor inhibitor (SB505124) in vitro.

RESULTS

Cartilage erosion due to OVX was significantly reduced in a dose-dependent manner by 1α,25(OH)2D3 supplementation, and exacerbated by VDD. The expressions of TGF-β1 and CII in articular cartilage were suppressed by OVX and VDD, and rescued by 1α,25(OH)2D3 supplementation. The expression of MMP-9,-13 in articular cartilage increased with OVX and VDD, and decreased with 1α,25(OH)2D3 supplementation. In vitro experiments showed that 1α,25(OH)2D3 increased the TGF-β1 expression of TNF-α stimulated chondrocytes in a dose-dependent manner. 1α,25(OH)2D3 significantly counteracted the increased CTX-II release due to TNF-α stimulation, and this effect was significantly suppressed by SB505124.

CONCLUSION

VDD aggravated cartilage erosion, and 1α,25(OH)2D3 supplementation showed protective effects in OVX-induced OA partly through the TGF-β1 pathway.

FOXE1 polymorphisms and non-syndromic orofacial cleft susceptibility in a Chinese Han population

OBJECTIVE

FOXE1 plays an important role in craniofacial development. The aim of this study was to investigate associations between genetic variants of FOXE1 and risk of non-syndromic orofacial clefts in a Chinese population.

MATERIALS AND METHODS

Three potentially functional SNPs of FOXE1 (rs3758250 and rs907577 in the 5' upstream and rs7043516 in the 3'-UTR) were selected and their associations with non-syndromic orofacial cleft susceptibility were investigated in a case-control study from a Chinese population (602 cases and 605 controls). Genotyping was performed with double ligation and multiplex fluorescence PCR. Associations between the SNPs and risk of non-syndromic orofacial clefts and its subgroups were estimated from unconditional logistic regression analysis. Luciferase reporter assay was conducted to assess SNP function.

RESULTS

Overall, we did not find any of the individual SNP or haplotype was associated with NSOC susceptibility. Nevertheless, in stratified analysis, we found rs7043516, locating in the 3'-UTR of FOXE1, was associated with risk of cleft lip only. Further in vitro luciferase assay indicated that this SNP could contribute to differential binding ability with miRNA.

CONCLUSIONS

Taken together, this study showed that rs7043516 may be considered as a potentially susceptible marker of cleft lip only among Chinese Han populations.

Nickel-responsive regulation of two novel Helicobacter pylori NikR-targeted genes

Nickel is an essential transition metal for the survival of Helicobacter pylori in the acidic human stomach. The nickel-responsive transcriptional regulator HpNikR is important for maintaining healthy cytosolic nickel concentrations through the regulation of multiple genes, but its complete regulon and role in nickel homeostasis are not well understood. To investigate potential gene targets of HpNikR, ChIP sequencing was performed using H. pylori grown at neutral pH in nickel-supplemented media and this experiment identified HPG27_866 (frpB2) and HPG27_1499 (ceuE). These two genes are annotated to encode a putative iron transporter and a nickel-binding, periplasmic component of an ABC transporter, respectively. In vitro DNA-binding assays revealed that HpNikR binds both gene promoter sequences in a nickel-responsive manner with affinities on the order of ∼10(-7) M. The recognition sites of HpNikR were identified and loosely correlate with the HpNikR pseudo-consensus sequence (TATTATT-N11-AATAATA). Quantitative PCR experiments revealed that HPG27_866 and HPG27_1499 are transcriptionally repressed following growth of H. pylori G27 in nickel-supplemented media, and that this response is dependent on HpNikR. In contrast, iron supplementation results in activation of HPG27_1499, but no impact on the expression of HPG27_866 was observed. Metal analysis of the Δ866 strain revealed that HPG27_866 has an impact on nickel accumulation. These studies demonstrate that HPG27_866 and HPG27_1499 are both direct targets of HpNikR and that HPG27_866 influences nickel uptake in H. pylori.

c-MYC responds to glucose deprivation in a cell-type-dependent manner

Metabolic reprogramming supports cancer cells’ demands for rapid proliferation and growth. Previous work shows that oncogenes, such as MYC, hypoxia-inducible factor 1 (HIF1), have a central role in driving metabolic reprogramming. A lot of metabolic enzymes, which are deregulated in most cancer cells, are the targets of these oncogenes. However, whether metabolic change affects these oncogenes is still unclear. Here we show that glucose deprivation (GD) affects c-MYC protein levels in a cell-type-dependent manner regardless of P53 mutation status. GD dephosphorylates and then decreases c-MYC protein stability through PI3K signaling pathway in HeLa cells, but not in MDA-MB-231 cells. Role of c-MYC in sensitivity of GD also varies with cell types. c-MYC-mediated glutamine metabolism partially improves the sensitivity of GD in MDA-MB-231 cells. Our results reveal that the heterogeneity of cancer cells in response to metabolic stress should be considered in metabolic therapy for cancer.

HOI-02 induces apoptosis and G2-M arrest in esophageal cancer mediated by ROS

Reactive oxygen species (ROS) are chemically reactive molecules that perform essential functions in living organisms. Accumulating evidence suggests that many types of cancer cells exhibit elevated levels of ROS. Conversely, generation of ROS has become an effective method to kill cancer cells. (E)-3-hydroxy-3-(4-(4-nitrophenyl)-2-oxobut-3-en-1-yl) indolin-2-one, which is an NO2 group-containing compound designated herein as HOI-02, generated ROS and, in a dose-dependent manner, decreased esophageal cancer cell viability and inhibited anchorage-independent growth, followed by apoptosis and G2-M arrest. Moreover, results of an in vivo study using a patient-derived xenograft mouse model showed that HOI-02 treatment suppressed the growth of esophageal tumors, without affecting the body weight of mice. The expression of Ki-67 was significantly decreased with HOI-02 treatment. In addition, the phosphorylation of c-Jun, and expression of p21, cleaved caspase 3, and DCFH-DA were increased in the HOI-02-treated group compared with the untreated control group. In contrast, treatment of cells with (E)-3-(4-(4-aminophenyl)-2-oxobut-3-en-1-yl)-3-hydroxyindolin-2-one, which is an NH2 group-containing compound designated herein as HOI-11, had no effect. Overall, we identified HOI-02 as an effective NO2 group-containing compound that was an effective therapeutic or preventive agent against esophageal cancer cell growth.

Efficacy of adjunctive laser in non-surgical periodontal treatment: a systematic review and meta-analysis

To evaluate the efficacy of the adjunctive laser therapy in conventional non-surgical treatment of chronic periodontitis, an electronic search was performed through the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, MEDLINE, EMBASE, Scopus, Web of Science, China National Knowledge Infrastructure (CNKI), and China Biology Medicine (CBM) Disc, for relevant randomized controlled trials (RCTs) or quasi-RCTs. All the 12 included studies (11 RCTs and 1 quasi-RCT) were qualified for descriptive and quantitative analysis. Outcomes were divided into two groups according to the length of follow-ups (long term and short term). Subgroup analyses were performed based on the mode of laser (inside and outside mode). Among all included researches, reduction in probing depth (PD) and gain in clinical attachment level (CAL) were presented with the mean value and 95 % confidence interval, while bleeding on probing (BOP) was assessed descriptively. Meta-analysis suggested that adjunctive laser therapy reduced PD at 3 months [mean difference (MD) = -0.26, 95 % confidence interval (CI) range = -0.43 to -0.09, p = 0.003] but did not demonstrate significant effect on the CAL at either 3 months (MD = -0.03, 95 % CI range = -0.25 to 0.19, p = 0.79) or 6 months (MD = -0.11, 95 % CI range = -0.38 to 0.16, p = 0.43). Subgroup analyses indicated that laser therapy would be more effective when the probes were set up outside the periodontal pockets.

Wnt Signaling and Its Contribution to Craniofacial Tissue Homeostasis

A new field of dental medicine seeks to exploit nature's solution for repairing damaged tissues, through the process of regeneration. Most adult mammalian tissues have limited regenerative capacities, but in lower vertebrates, the molecular machinery for regeneration is an elemental part of their genetic makeup. Accumulating data suggest that the molecular pathways responsible for the regenerative capacity of teleosts, amphibians, and reptiles have fallen into disuse in mammals but that they can be "jumpstarted" by the selective activation of key molecules. The Wnt family of secreted proteins constitutes one such critical pathway: Wnt proteins rank among the most potent and ubiquitous stem cell self-renewing factors, with tremendous potential for promoting human tissue regeneration. Wnt reporter and lineage-tracing strains of mice have been employed to create molecular maps of Wnt responsiveness in the craniofacial tissues, and these patterns of Wnt signaling colocalize with stem/progenitor populations in the rodent incisor apex, the dental pulp, the alveolar bone, the periodontal ligament, the cementum, and oral mucosa. The importance of Wnt signaling in both the maintenance and healing of these craniofacial tissues is summarized, and the therapeutic potential of Wnt-based strategies to accelerate healing through activation of endogenous stem cells is highlighted.

Rapid differentiation of mycobacteria by simplex real-time PCR with melting temperature calling analysis

AIMS

This study aimed to develop a rapid, simple and cost-effective method for the differentiation of Mycobacterium species.

METHODS AND RESULTS

A total of 80 clinical mycobacterial isolates belonging to 12 different species and 16 reference strains of 16 different species were differentiated by the simplex real-time PCR coupled with melting temperature calling analysis. By comparing their melting profiles with those of the reference strains, all clinical mycobacterial isolates were differentiated as Mycobacterium tuberculosis complex or nontuberculous mycobacteria, and the latter were further divided into five groups. In comparison with 16S-23S internal transcribed spacer sequencing method as the gold standard method, both sensitivity and specificity of the assay were 100% when it was used for the differentiation between Myco. tuberculosis complex and nontuberculous mycobacteria.

CONCLUSIONS

The simplex real-time PCR coupled with melting temperature calling analysis could be an alternative method for the differentiation between Myco. tuberculosis complex and nontuberculous mycobacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

Rapid differentiation of mycobacteria could shorten the diagnostic time of mycobacterial diseases. It is also helpful for achieving optimal therapy and appropriate patient management.

A novel highly differentially expressed gene in wheat endosperm associated with bread quality

Analysis of gene expression in developing wheat seeds was used to identify a gene, wheat bread making (wbm), with highly differential expression (~1000 fold) in the starchy endosperm of genotypes varying in bread making quality. Several alleles differing in the 5’-upstream region (promoter) of this gene were identified, with one present only in genotypes with high levels of wbm expression. RNA-Seq analysis revealed low or no wbm expression in most genotypes but high expression (0.2-0.4% of total gene expression) in genotypes that had good bread loaf volume. The wbm gene is predicted to encode a mature protein of 48 amino acids (including four cysteine residues) not previously identified in association with wheat quality, possibly because of its small size and low frequency in the wheat gene pool. Genotypes with high wbm expression all had good bread making quality but not always good physical dough qualities. The predicted protein was sulphur rich suggesting the possibility of a contribution to bread loaf volume by supporting the crossing linking of proteins in gluten. Improved understanding of the molecular basis of differences in bread making quality may allow more rapid development of high performing genotypes with acceptable end-use properties and facilitate increased wheat production.

Mid-infrared Fourier-transform spectroscopy with a high-brilliance tunable laser source: investigating sample areas down to 5 μm diameter

We demonstrate highly sensitive infrared spectroscopy of sample volumes close to the diffraction limit by coupling a femtosecond fiber-feedback optical parametric oscillator (OPO) to a conventional Fourier-transform infrared (FTIR) spectrometer. The high brilliance and long-term stable infrared radiation with 1e(2)-bandwidths up to 125 nm is easily tunable between 1.4 μm and 4.2 μm at 43 MHz repetition rate and thus enables rapid and low-noise infrared spectroscopy. We demonstrate this by measuring typical molecular vibrations in the range of 3 μm. Combined with surface-enhanced infrared spectroscopy, where the confined electromagnetic near-fields of resonantly excited metal nanoparticles are employed to enhance molecular vibrations, we realize the spectroscopic detection of a molecular monolayer of octadecanethiol. In comparison to conventional light sources and synchrotron radiation, our compact table-top OPO system features a significantly improved performance making it highly suitable for rapid analysis of minute amounts of molecular species in life science and medicine laboratories.

Expression and significance of SATB1 in the development of breast cancer

Special AT-rich sequence binding protein 1 (SATB1) is a recently discovered gene regulator that can promote the growth and metastasis of breast cancer. However, its expression in different stages of breast cancer development have not been examined. We explored the role of SATB1 in the development of breast cancer by detecting SATB1 expression levels in different stages of breast cancer. SATB1 expression was determined using an immunohistochemical streptavidin peroxidase method; the relationship between clinicopathological features of breast cancer and SATB1 expression was analyzed using the X(2) test. Positive rates of SATB1 protein in normal breast tissue, normal breast ductal hyperplasia tissue, precancerous lesions of breast cancer, non-invasive cancer, early invasive carcinoma, and invasive breast cancer tissue were, respectively, 6.25 (2/32), 6.4 (3/47), 20.4 (10/49), 45.0 (9/20), 52.9 (9/17), and 76.6% (72/94). SATB1 in the latter 3 groups was significantly higher than in the first 3 groups (P < 0.05). The positive rate of SATB1 protein in invasive non-special types of breast cancer (88.5%, 54/61) was significantly higher than in the special type of invasive breast cancer (54.5%, 18/33) and early invasive breast cancer (52.9%, 9/17) (P < 0.05). SATB1 protein expression in breast cancer with lymph node metastasis was generally increased, and the difference was statistically significant (P < 0.05). SATB1 protein expression showed an increasing trend in different stages of breast cancer development. Overexpression indicated poor prognosis.

A unique disulfide bridge of the thermophilic xylanase SyXyn11 plays a key role in its thermostability

Based on the hyperthermostable family 11 xylanase (EvXyn11(TS)) gene sequence (EU591743), the gene Syxyn11 encoding a thermophilic xylanase SyXyn11 was synthesized with synonymous codons biasing towards Pichia pastoris. The homology alignment of primary structures among family 11 xylanases revealed that, at their N-termini, only SyXyn11 contains a disulfide bridge (Cys5-Cys32). This to some extent implied the significance of the disulfide bridge of SyXyn11 to its thermostability. To confirm the correlation between the N-terminal disulfide bridge and thermostability, a SyXyn11(C5T)-encoding gene, Syxyn11(C5T), was constructed by mutating the Cys5 codon of Syxyn11 to Thr5. Then, the genes for the recombinant xylanases, reSyXyn11 and reSyXyn11(C5T), were expressed in P. pastoris GS115, yielding xylanase activity of about 35 U per ml cell culture. Both xylanases were purified to homogeneity with specific activities of 363 and 344 U/mg, respectively. The temperature optimum and stability of reSyXyn11(C5T) decreased to 70 and 50°C from 85 and 80°C of reSyXyn11, respectively. There was no obvious change in pH characteristics.

Multiscale analyses of the bone-implant interface

Implants placed with high insertion torque (IT) typically exhibit primary stability, which enables early loading. Whether high IT has a negative impact on peri-implant bone health, however, remains to be determined. The purpose of this study was to ascertain how peri-implant bone responds to strains and stresses created when implants are placed with low and high IT. Titanium micro-implants were inserted into murine femurs with low and high IT using torque values that were scaled to approximate those used to place clinically sized implants. Torque created in peri-implant tissues a distribution and magnitude of strains, which were calculated through finite element modeling. Stiffness tests quantified primary and secondary implant stability. At multiple time points, molecular, cellular, and histomorphometric analyses were performed to quantitatively determine the effect of high and low strains on apoptosis, mineralization, resorption, and collagen matrix deposition in peri-implant bone. Preparation of an osteotomy results in a narrow zone of dead and dying osteocytes in peri-implant bone that is not significantly enlarged in response to implants placed with low IT. Placing implants with high IT more than doubles this zone of dead and dying osteocytes. As a result, peri-implant bone develops micro-fractures, bone resorption is increased, and bone formation is decreased. Using high IT to place an implant creates high interfacial stress and strain that are associated with damage to peri-implant bone and therefore should be avoided to best preserve the viability of this tissue.

High sensitivity 10Gb/s Si photonic receiver based on a low-voltage waveguide-coupled Ge avalanche photodetector

We demonstrate low-voltage germanium waveguide avalanche photodetectors (APDs) with a gain × bandwidth product above 100GHz. A photonic receiver based on such a Ge APD, including a 0.13μm SiGe BiCMOS low-noise trans-impedance amplifier and a limiting amplifier, is realized. A 5.8dB sensitivity improvement is demonstrated at -5.9V bias at an avalanche gain of 6 through bit error ratio measurements. The absolute sensitivity in avalanche mode is -23.4dBm and -24.4dBm at a bit error ratio of 1 × 10(-12) and 1 × 10(-9) respectively.