Expression and bioactivity of recombinant human lysozyme in the milk of transgenic mice

Human milk lysozyme is an important protein for innate immunity, but human breast milk is a fairly poor source for commercial production of this enzyme. Research on the expression of recombinant human lysozyme (rHlys) is therefore potentially valuable to the dairy industry. In this study, 2 different kinds of transgenic mice, PBC-hLY and PBC-sighLY, were generated and used as system models to express rHlys. Six lines of PBC-hLY transgenic mice with human lysozyme genomic DNA-based constructs were generated, and a maximum expression level of rHlys approaching 0.154 mg/mL was achieved. Antibacterial activity of the whey from PBC-hLY female transgenic mice was determined by a turbidimetric assay. Results showed that antibacterial activity of the whey was strongly enhanced, and confirmed that rHlys retained full activity. For rHlys to be secreted efficiently into the milk of transgenic mice, 5 lines of mice were also generated, in which the signal peptide DNA of bovine beta-casein was substituted for that of lysozyme in PBC-hLY transgenic mice. Compared with PBC-hLY transgenic mice, both the expression levels of rHlys and the antibacterial activity of the whey were much higher in the PBC-sighLY transgenic mice. The concentration of rHlys in one of these mice amounted to 1.405 mg/mL-3 times higher than the level in human whey. The antibacterial activity of the whey was also 3 times higher than that of human whey. The rHlys from both PBC-hLY and PBC-sighLY transgenic mice had the same antibacterial activity as human milk lysozyme. The effect of the signal peptide and copy numbers of the transgene on expression of rHlys was also evaluated. This work will certainly permit a better understanding of how mammary gland bioreactor systems can be applied to produce rHlys in other mammals, such as cattle.

Partial molecular characterization, polymorphism and chromosomal localization of the porcine PSMD4 gene

The complete coding sequence of porcine PSMD4 gene encoding proteasome 26S non-ATPase subunit 4 was obtained by the reverse transcriptase-polymerase chain reaction (RT-PCR) and deposited in GenBank nucleotide database (AY704418). The nucleotide sequence and the predicted protein sequence shared the high sequence identity with their mammalian counterparts. A G/A single nucleotide polymorphism in intron 9 detected as Hin6I PCR-restriction fragment length polymorphism (PCR-RFLP) shows allele frequency differences between Meishan, Erhualian, Tibetan, Large White and Duroc breeds. Analyses of somatic cell hybrid panel (SCHP) and radiation hybrid (IMpRH) panel revealed that PSMD4 gene maps to SSC 4q21-q23 and closely linked the SW512 (14 cR, LOD = 19.47).

Cooperative antitumor activity between the retinoid X receptor (RXR)-selective agonist bexarotene and EGFR-tyrosine kinase inhibitors in preclinical models of NSCLC

17073

Background: Gefitinib and erlotinib, small molecule inhibitors of the EGFR-tyrosine kinase (EGFR-TKI), can have antitumor activity in patients with advanced NSCLC. However, analysis of clinical samples and in vitro characterization of NSCLC cell lines has revealed EGFR mutations that correlate with the clinical responses. While EGFR-mutant cell lines are hypersensitive to EGFR-TKI-mediated growth inhibition and have a greater tendency to undergo apoptosis in response to EGFR inhibition, wild-type EGFR cell lines undergo growth inhibition only at high concentrations, and are resistant to apoptosis induction. Bexarotene (Targretin) is a RXR modulator with clinical activity enhancing survival in a subset of NSCLC patients. We have shown that bexarotene can suppress the growth of epithelial tumors by modulating the expression and function of the EGFR pathway. This study examined the effect of bexarotene/EGFR-TKI combinations in preclinical models of NSCLC, and evaluated the possible molecular mechanisms for cooperative antitumor activity between these agents. Results: Bexarotene enhanced the activity of gefitinib in most of the cell lines tested, and did so regardless of their EGFR mutation status or intrinsic sensitivity to gefitinib alone. Resistant lines were sensitized by the combination, which decreased gefitinib IC50s to clinically achievable concentrations. Bexarotene increased the pro-apoptotic activity of both gefitinib and erlotinib, an effect which was paralleled by enhanced repression of p-Akt and p-Her2 levels by the combinations. In ex vivo cultures of human NSCLC explant tissue, the addition of bexarotene enhanced the growth inhibitory activity of both gefitinib and erlotinib. Finally, combinations of bexarotene and EGFR-TKI produced growth inhibition of TKI-resistant A427 NSCLC xenograft tumors that was superior to either agent alone. Conclusions: These results indicate that bexarotene can sensitize NSCLC cells which are unresponsive to the effects of EGFR-TKIs, resulting in cooperative growth inhibition and apoptosis induction. Combination therapy using bexarotene in conjunction with EGFR-TKIs may provide a powerful new therapeutic strategy.

[Table: see text]

Efficacy of emergent transcatheter transplantation of stem cells for treatment of acute myocardial infarction (TCT-STAMI)

OBJECTIVE

To study whether emergent intracoronary autologous bone marrow cell transplantation (BMT) is applicable for the treatment of acute myocardial infarction (AMI).

METHODS

20 patients admitted within 24 h after the onset of a first AMI were randomly allocated to receive intracoronary autologous BMT (n = 10) or bone marrow supernatant (controls, n = 10) immediately after primary percutaneous coronary intervention. Left ventricular ejection fraction (LVEF), left ventricular end diastolic internal diameter (LVDd) and myocardial perfusion defect scores were examined respectively by echocardiography and single-photon emission computed tomography at one week and six months after AMI.

RESULTS

From one week to six months after AMI, LVEF was enhanced from mean 53.8 (SD 9.2)% to 58.6 (9.9)% (p < 0.05) in the BMT group but was unchanged in the control group (58.2 (7.5)% v 56.3 (3.5)%, p > 0.05); LVDd remained unchanged (52.5 (2.8) v 52.1 (3.2) mm, p > 0.05) in the BMT group but was significantly enlarged in the control group (50.4 (6.0) v 55.2 (7.1) mm, p < 0.05). Additionally, myocardial perfusion defect scores decreased from 21 (11) to 13 (10) (p < 0.01) in the BMT group but were unchanged in the control group (20 (14) v 17 (15), p > 0.05).

CONCLUSION

Emergent intracoronary transplantation of bone marrow mononuclear cells after AMI is practicable, and it improved cardiac function, prevented myocardial remodelling and increased myocardial perfusion at six months' follow up.

Sequence identification, tissue distribution, mapping and polymorphism of the porcine sar1b gene

The predicted full-length cDNA sequence of the porcine Sar1b gene was characterized by assembling pig ESTs from GenBank. The coding sequence (CDS) shares high sequence identity with the corresponding sequences of human (93%) and mouse (91%). The reverse transcription-polymerase chain reaction (RT-PCR) displayed that porcine Sar1b gene is expressed in all eight tissues (liver, small intestine, stomach, heart, lung, spleen, muscle and fat). Analysis of the somatic cell hybrid panel (SCHP) and the INRA-University of Minnesota porcine radiation hybrid (IMpRH) panel indicated the gene maps to SSC2 (1/2 q24)-q29 and most closely links to the interleukin-4 (IL4) gene. One base-pair deletion polymorphism in the 3' untranslated region (UTR) detected by PCR-single strand conformational polymorphism (PCR-SSCP) analysis shows allele frequency differences between Meishan, Yushan Black, Dahuabai, Qingping, Tibetan, Landrace, Large White and Duroc. The association analysis using pigs of Tongcheng, Landrace x (Large White x Tongcheng) and Large White x (Landrace x Tongcheng) suggested that the deletion polymorphism was associated with the porcine muscle pH value.

Evaluation of the accuracy of three electronic apex locators using glass tubules

AIM

To evaluate the accuracy of three different electronic apex locators (EALs) using glass tubules.

METHODOLOGY

Forty-eight glass tubules with different diameters and an agar model were used to mimic root canals. A size 15 stainless steel K-file was used as the measuring electrode. The Root ZX, Propex and Neosono Ultima EZ were used to measure the tubule length with tubules dry, or filled with 0.9% NaCl, 3% H(2)O(2), 2.5% NaOCl or 17% EDTA. The distance between the real length (RL) and measured length (ML) of the tubules was recorded. The range of RL +/- 0.5 mm and RL +/- 1 mm was used to evaluate the accuracy of the EALs. Results were subject to correlation analysis and Friedman's test.

RESULTS

In dry tubules, the accuracy of Root ZX was 75-91.7% for RL +/- 0.5 mm and 100% for RL +/- 1 mm, whilst the measurements of the other two EALs were all within the RL +/- 0.5 mm. No influence from the increase in tubule diameter on the accuracy of all three EALs was observed in dry tubules. In tubules filled with electrolyte, the accuracy of the Root ZX decreased as tubule diameter increased (R(d) > 0, P < 0.05). The RL-ML distance recorded by Propex was inversely related to the tubule diameter (R(d) < 0, P < 0.05). The accuracy of Propex was 75-100% for RL +/- 0.5 mm and 100% for RL +/- 0.5 mm when the tubule diameter was not more than 0.80 mm, but decreased in tubules with diameter over 0.80 mm and filled with 2.5% NaOCl or 17% EDTA. Nearly, all the measurements (except for six tubules) using Neosono Ultima EZ were within 1 mm shorter than RL despite the contents in tubules and the increase of tubule diameter.

CONCLUSIONS

The accuracy of the Root ZX decreased as the tubule diameter increased when tubules were filled with electrolytes. The electrolytes in the tubules decreased the accuracy of Propex when the tubule diameter was large. The electrolytes in tubules and tubule diameter had no influence on the accuracy of Neosono Ultima EZ. The Propex and Neosono Ultima EZ were more accurate than the Root ZX under various conditions in this laboratory study.

Comparison of BMD precision for Prodigy and Delphi spine and femur scans

INTRODUCTION

Precision error in bone mineral density (BMD) measurement can be affected by patient positioning, variations in scan analysis, automation of software, and both short- and long-term fluctuations of the densitometry equipment. Minimization and characterization of these errors is essential for reliable assessment of BMD change over time.

METHODS

We compared the short-term precision error of two dual-energy X-ray absorptiometry (DXA) devices: the Lunar Prodigy (GE Healthcare) and the Delphi (Hologic). Both are fan-beam DXA devices predominantly used to measure BMD of the spine and proximal femur. In this study, 87 women (mean age 61.6+/-8.9 years) were measured in duplicate, with repositioning, on both systems, at one of three clinical centers. The technologists were International Society for Clinical Densitometry (ISCD) certified and followed manufacturer-recommended procedures. All scans were acquired using 30-s scan modes. Precision error was calculated as the root-mean-square standard deviation (RMS-SD) and coefficient of variation (RMS-%CV) for the repeated measurements. Right and left femora were evaluated individually and as a combined dual femur precision. Precision error of Prodigy and Delphi measurements at each measurement region was compared using an F test to determine significance of any observed differences.

RESULTS

While precision errors for both systems were low, Prodigy precision errors were significantly lower than Delphi at L1-L4 spine (1.0% vs 1.2%), total femur (0.9% vs 1.3%), femoral neck (1.5% vs 1.9%), and dual total femur (0.6% vs 0.9%). Dual femur modes decreased precision errors by approximately 25% compared with single femur results.

CONCLUSIONS

This study suggests that short-term BMD precision errors are skeletal-site and manufacturer specific. In clinical practice, precision should be considered when determining: (a) the minimum time interval between baseline and follow-up scans and (b) whether a statistically significant change in the patient's BMD has occurred.

Polymorphism detection of porcine PSMC3, PSMC6 and PSMD3 genes and their association with partial growth, carcass traits, meat quality and immune traits

PSMC3, PSMC6 and PSMD3 genes encode the proteasome 26S ATPase subunit 3, subunit 6 and the non-ATPase subunit 3, respectively, and exert the function in antigen processing and presentation. So these three genes were considered as the candidate genes that have the effect on porcine production and immune traits in this study. Genetic variations of these three genes were investigated and the single nucleotide polymorphism-based (SNPs-based) association analyses were studied initially. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) revealed that there is a MvaI polymorphic site in intron3 of PSMC3 gene and a MboI polymorphic site within intron 5 of PSMC6 gene, as well as a RsaI polymorphic site within exon 10 of the PSMD3 gene. χ2 analysis presented that allele frequencies differed among four breeds (Meishan, Erhualian, Qingping pig and Duroc) at PSMC3 and PSMD3 loci (P < 0.01). Association analysis showed that the PSMC3 gene has an effect on average backfat thickness (P < 0.01), total erythrocytes (P < 0.01) and hematocrit (P < 0.01), and there is a significant association between the PSMD3 genotypes and the mean corpuscular volume. PSMC6 has no effect on the production and immune traits we studied. Key words: Porcine, PSMC3, PSMC6, PSMD3, polymorphism, association analysis

PRNP polymorphisms in Chinese ovine, caprine and bovine breeds

Transmissible spongiform encephalopathy (TSE) is a neurodegenerative disorder in humans and animals. Polymorphisms and mutations in the prion protein (PRNP) gene have been associated with the incidence of natural and experimental TSE and the incubation period length. In this study, we determined PRNP polymorphisms in Chinese ovine, caprine and bovine breeds using 400 samples from 13 ovine and caprine breeds and 250 samples from nine bovine breeds. In the ovine and caprine PRNP gene, we found five previously unreported amino acid polymorphisms and two silent nucleotide alterations. In bovine PRNP, we found eight previously unreported amino acid polymorphisms and six silent nucleotide alterations.

Sequence characterization, polymorphism and chromosomal localizations of the porcine PSME1 and PSME2 genes

The full-length cDNA of porcine genes (PSME1 and PSME2) encoding proteasome activators PA28alpha- and beta-subunits were obtained by the rapid amplification of cDNA ends (RACE). The nucleotide sequences and the predicted protein sequences share high sequence identity with their mammalian counterparts. The reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that porcine PSME1 and PSME2 genes are expressed in all eight tissues studied (liver, spleen, bladder, small intestine, kidney, heart, skeletal muscle and lung). The full-length genomic DNA of the porcine PSME1 and PSME2 genes were amplified by PCR. These two genes shared the same structure and were similar in size. A C/T single nucleotide polymorphism in PSME1 intron 8 detected as an SphI PCR-restriction fragment length polymorphism (PCR-RFLP) shows allele frequency differences between Meishan, Tibetan, Large White, Qingping, and Duroc pigs. The association analysis using two experimental GY selection lines selected for growth rate or leanness suggested that the PSME1 genotype was associated with weaning weight. Analyses of somatic cell hybrid (SCHP) and radiation hybrid (IMpRH) panels revealed that both genes map to SSC7q15.3-q21 and closely linked to the T-cell receptor alpha (TCRA) gene.

Genetic diversity analyses of 10 indigenous Chinese pig populations based on 20 microsatellites

To study the genetic diversity of Chinese indigenous pig breeds, a total of 403 pigs from 10 local populations and 1 exotic Duroc breed were genotyped for 20 microsatellite markers. Heterozygosity and Wright's F-statistics (F(IS), F(ST), and F(IT)) were calculated to determine the genetic variation in those populations. The observed heterozygosities were in the range of 0.31 (Duroc) to 0.66 (Shengxian). The F(IS) value was in a range of -0.07 to 0.48. The mean F(ST) showed that approximately 78% of the genetic variation was within-population and 22% was across the populations. The 10 Chinese local breeds were classified into two major groups according to the phylogenetic tree, which was based on standard genetic distance. Four pig populations, Jianli, Ganxi Two Ends Black, Shaziling, and Dongshan were grouped into one branch. Before the study, these four populations were all classified as Central China Two Ends Black according to coat color, shape of the head, and shape of the ear. The Jinhua pig, which also has the two-ends-black coat color, was also grouped to the same branch but was not traditionally classified into this type. The five populations were located in various provinces in central China. The other five populations, Nanyang Black, Hainan Spotted, Huainan Black, Jiaxing Black, and Shengxian Spotted (black body, white feet), were grouped into another branch. The two groups of pig breeds had the same F(ST) value (0.14) when calculated separately. This value was similar to that of Iberian pigs (0.13) but smaller than that of the European pigs (0.27) as reported by other researchers. Our study showed that large genetic differentiation exists in Chinese pig breeds. The grouping of the five two-ends-black populations into one branch of the phylogenetic tree may indicate that the number of conservation farms can be decreased for this type of pig.

Distinct patterns of genetic alterations in adenocarcinoma and squamous cell carcinoma of the lung

Squamous cell carcinoma (SqC) and adenocarcinoma (AdC) are the two most common subtypes of non-small cell lung cancer (NSCLC). Cumulative information suggests that the SqC and AdC subtypes progress through different carcinogenic pathways, but the genetic aberrations promoting such differences remain unclear. Here we have assessed the overall genomic imbalances and structural abnormalities in SqC and AdC. By parallel analyses with comparative genomic hybridisation (CGH) on tumorous lung tissues and spectral karyotyping (SKY) on short-term cultured primary tumours, genome-wide characterisation was carried out on 69 NSCLC (35 SqC, 34 AdC). Molecular cytogenetic characterisation indicated common and distinct genetic changes in SqC and AdC. Common events of +1q21-q24, +5p15-p14, and +8q22-q24.1, and -17p13-p12 were found in both groups, although hierarchical clustering simulation on CGH findings depicted +2p13-p11.2, +3q25-q29, +9q13-q34, +12p, +12q12-q15 and +17q21, and -8p in preferential association with SqC pathogenesis (P<0.05). Corresponding SKY analysis suggested that these changes occur in simple and complex rearrangements, and further indicated the clonal presence of translocation partners leading to chromosomal over-representations. These recurring rearrangements involved chromosome pairs of t(1;13), t(1;15), t(7;8), t(8;15), t(8;9), t(2;17) and t(15;20). Of particular interest was the finding that the t(8;12) translocation partner was exclusive to AdC. The combined application of SKY and CGH has thus uncovered the genome-wide chromosomal aberrations in NSCLC. Specific chromosomal imbalances and translocation partners found in SqC and AdC have highlighted regions for further molecular investigation into gene(s) that may hold importance in the carcinogenesis of NSCLC.

A comparison of instrument-centering ability within the root canal for three contemporary instrumentation techniques

AIM

To study and compare Great Taper (GT) hand files using a reversed balanced force technique, nickel-titanium (NiTi)flex files with a balanced force technique and stainless steel (SS) K-type files using a step-back technique.

METHODOLOGY

Forty-eight extracted mandibular premolar teeth with single root canals having curvatures between 15 and 45 degrees were prepared using a modified Bramante model and randomly divided into three groups. The teeth were cross-sectioned at 2, 6 and 10 mm from the working length. Preoperative images of canals at three levels were captured at 20x magnification using a stereomicroscope. Canals in each group were, respectively, prepared to an apical size.10 GT file with 0.2 mm tip diameter, size 30 NiTiflex file and size 30 SS K-file. The GT file was used in a reversed balanced force technique, the NiTiflex file was used in a balanced force technique, and the SS K-file was used in a step-back technique. Postoperative canals were imaged under the conditions same as those for the preoperative canals. The postoperative images were superimposed over the preoperative images using software photoshop 6.0. The ability to maintain the instrument in the central axis of the canal and the deviation from the central canal axis were determined and compared by statistical analysis, along with the assessment of the amount of dentine removed.

RESULTS

At apical level, the centering ratio, the distance of transportation and the dentine removed in GT and NiTiflex groups were significantly less than those in SS group (P < 0.01), but no statistical differences were found between the two NiTi groups. At other levels, there were no substantial differences amongst the groups.

CONCLUSIONS

Compared with SS K-files, GT hand files and NiTiflex files remain better centered and produce significantly less transportation in curved canals.

Improving low-temperature performance of infrared thin-film interference filters utilizing the intrinsic properties of IV-VI narrow-gap semiconductors

Pb(1) (-x)Ge(x)Te is a pseudobinary alloy of IV-VI narrow-gap semiconductor, of which maximum refractive index corresponds to the ferroelectric phase transition. Since the temperature coefficient of refractive index can be tunable from negative to positive by changing the Ge composition, it is possible to utilize the intrinsic property in the fabrication of infrared thin-film interference filters. In this letter, we report a narrow-bandpass filter, in which Pb(0.94)Ge(0.06)Te was substituted for PbTe. It found that the low-temperature stability of the filter is obviously improved: in the temperature range of 80-300K, the shift of center wavelength with temperature is reduced from 0.48nm.K(-1) to 0.23nm K(-1); furthermore, the peak transmittance of filter fabricated with Pb(0.94)Ge(0.06)Te is ~3% over that fabricated with PbTe.

Palangeal quantitative ultrasound, phalangeal morphometric variables, and vertebral fracture discrimination

The aim of this study was to evaluate the association among phalangeal morphometric parameters, amplitude-dependent speed of sound (AD-SOS), ultrasound bone profile index (UBPI), and spinal bone mineral density (BMD) and fracture status. One hundred women (controls, mean age 53 +/- 12 years) and 40 osteoporotic women (mean age 59 +/- 7 years) with atraumatic fractures, diagnosed by spinal radiographs, were investigated. Quantitative ultrasound (QUS) assessment was performed using the DBM Sonic 1200. Morphological properties of the phalanges were measured from a digitized X-ray image of the hand acquired using industrial film. Spinal BMD was assessed by dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). An increase in medullary canal width and a decrease in cortical thickness with aging were observed from the morphometric analysis of the hand radiographs. This phenomenon can be attributed mainly to endosteal resorption. QUS measurements at the phalanges were not significantly related to finger thickness (r <0.20, n.s.). They were significantly correlated to medullary canal ratio (r = -0.57, P <0.0001, for AD-SOS and r = -0.64, P <0.0001, for UBPI) and to cortical thickness (r = +0.52, P <0.0001 for AD-SOS and r = +0.59, P <0.0001 for UBPI). In the discrimination analysis between nonfractured and atraumatic vertebral fracture subjects we found that cortical thickness at the level of the phalanges were similar to lumbar spine BMD. The age and BMI-adjusted odds ratio ranged from 2.0 to 3.1 for QUS, 4.28 for BMD by QCT, 4.1 for BMD by DXA, and 4.1 for cortical thickness. We conclude from these data that phalangeal QUS is related to cortical thickness, which in turn is influenced by endosteal bone resorption occurring in association with spinal osteoporosis.

Genetic variation analysis within and among Chinese indigenous swine populations using microsatellite markers

The genetic structure of five types of Taihu pig (Erhualian, Middle Meishan, Small Meishan, Mizhu and Shawutou), Jiangquhai and Dongchuan pigs in China were investigated, by means of 27 microsatellite markers proposed by the Food and Agriculture Organisation, International Society for Animal Genetics (FAO-ISAG). The Hardy-Weinberg equilibrium test indicated that genetic drift had occurred in these populations, which may be caused by founder effects, intensive selection and close breeding. Genetic heterozygosity and the effective number of alleles per population were calculated, and showed that the genetic variability of the Jiangquhai pig was the largest, while the Small Meishan had the lowest. Genetic differentiation was within each population as shown by the fixation index (F(ST)=0.18). Both a neighbour-joining (NJ) tree constructed from Nei's standard genetic distance and principal component analysis based on allele frequencies can distinguish types of Taihu pig from the other two breeds. Among Taihu pig populations, Erhualian and Mizhu grouped into one branch, while Middle Meishan, Small Meishan and Shawutou clustered as another branch. By including previously published data on European pigs reported, we confirmed that Chinese indigenous pigs and European pigs have diverged into two distinct groups.

[In vitro sensitivity of Plasmodium falciparum to chloroquine, piperaquine, pyronaridine and artesunate in Yuxi prefecture of Yunnan province]

AIM

To assess the sensitivity of Plasmodium falciparum to four antimalarials.

METHODS

WHO standard in vitro microtest was used.

RESULTS

The resistance rates of the malaria parasite to chloroquine, piperaquine pyronaridine and artesunate were 85.7%, 66.7%, 38.1% and 5.0%, respectively.

CONCLUSION

Among the antimalarials tested in Yuxi Prefecture, Yunnan Province, high resistance of P. falciparum to chloroquine and piperaquine was found. The sensitivity of P. falciparum in part of the cases to pyronaridine decreased. However, most of the cases were relatively sensitive to artesunate.

Influence of region of interest and bone size on calcaneal BMD: implications for the accuracy of quantitative ultrasound assessments at the calcaneus

There is considerable technological diversity among quantitative ultrasound (QUS) devices used to assess osteoporosis. Because the distance between the transducer and the footplate remains constant, the location of the calcaneus measured will vary with foot size. This study was designed to quantify the variation in bone mineral density (BMD) between a manufacturer's region of interest (ROI_M), which is fixed relative to the footplate, and an anatomical region of interest (ROI_A), which is defined as 20% of calcaneal length. The effect of foot length and width on QUS variables measured using two Food and Drug Administration cleared QUS devices, the Sahara (Hologic) and the Achilles+ (Lunar) was assessed. 26 healthy subjects (12 male and 14 female), aged 22-54 years (35.6+/-10 years) and with foot lengths of 21.5 cm to 29.7 cm (25.1+/-2.3 cm) were recruited. QUS assessments were performed at the right calcaneus. In addition, a Hologic 4500 densitometer was used to measure the BMD of the calcaneus in the ROI_M and ROI_A. The sizes of the ROIs were approximated to the sizes of the transducers of the Sahara and Achilles+ devices. The results showed a significant difference in BMD between the two ROI locations for the Sahara device (BMD 0.642+/-0.135 g cm(-2) vs 0.616+/-0.114 g cm(-2), p=0.014), but no significant difference was found in BMD between the two locations for the Achilles device (BMD 0.661+/-0.120 g cm(-2) vs 0.662+/-0.123 g cm(-2), p=0.818). At the ROI_A, there was a significant difference in BMD between the two QUS devices (p<0.001). The correlation between QUS variables and BMD was slightly higher for the ROI_M (r=0.68-0.79, since this is site-matched) than the ROI_A (r=0.59-0.70) for the Achilles device, while for the Sahara device the correlations were r=0.35-0.40 and r=0.51-0.54, respectively. The smaller ROI of the Sahara device resulted in more than 50% of the subjects having BMD differences of greater than 5% between the ROI_A and the ROI_M, compared with only 20% of the subjects on the Achilles device. ROIs containing cortical bone edge and other soft tissues were found in 58% of cases for the Achilles device and 46% of cases for the Sahara device. The greatest differences occurred in very small and very large feet. Calcaneal length correlated significantly with Sahara speed of sound (SOS), and heel width correlated significantly with Achilles SOS. Heel width also correlated significantly with Sahara broadband ultrasound attenuation (BUA) but not Achilles+ BUA. These results suggest that variation in ROI and bone size might affect the accuracy of QUS measurements, since the calcaneus is heterogeneous both in terms of its external geometry and its internal structure and density.

[Autotrophic denitrification of groundwater by electrochemical process]

An autotrophic denitrification process and its reactor for removing nitrate from groundwater was investigated in this paper. Using activated carbon fiber(ACF) as electrodes, the electrochemical reactions could produce hydrogen as the donor for autotrophic denitrification. In the process, nitrate was removed effectively and no accumulation of nitrite in the effluent. The results in this study proved that some key factors, such as the applied current density, flow rate of water, oxidation-reduction potential and the nitrate concentration in raw water, influenced the electrochemically denitrifying effect. When the concentration of NO3(-)-N was 28.8 mg/L in inlet water, the optimum applied density was 9 mA, the highest hydraulic load of the reactor was 35 ml/h, and the reactor performed a practical buffering capacity to pH. After applying electricity to the reactor for 1 h, the oxidation-reduction potential decreased to below--200 mA, so an adaptable reductive environment could be provided in the reactor for denitrification.