bluuebunny/crossref_metadata_2025 huggingface dataset:
Metronidazole concentrations in plasma, saliva and periodontal pockets in patients with periodontitis
Authors: Pähkla Ene‐Renate , Koppel Taive , Saag Mare , Pähkla Rein
Published: February 2005

Objectives: Metronidazole is widely used antibacterial compound in the treatment of some types of periodontal disease. Pharmacokinetics of metronidazole in plasma has been well‐described but few data exist about penetration f the drug to the gingival crevice fluid. The aim of the present study was to compare the concentrations of metronidazole in plasma, saliva and gingival crevice fluid in patients with periodontitis after multiple administration.

Materials and methods: Eleven patients with severe generalised adult periodontitis participated in the study. Metronidazole, 500 mg, was administered orally two or three times per day for at least 2 days before sample collection. Samples were collected 2 h after last dose. Metronidazole concentrations in all fluids were measured with high‐performance liquid chromatography.

Results: Mean drug concentrations in palsma, saliva and crevice fluid were 14.33, 15.15 and 12.86 μg/ml, respectively. Difference between plasma and crevice fluid or between plasma and saliva did not reach statistical significance.

Conclusion: Present study revealed that metronidazole penetrates well into gingival crevice fluid and saliva. Metronidazole concentrations in crevice fluid are about equal to the protein unbound drug concentrations in plasma. Therefore, general pharmacokinetic data of metronidazole can be also applied in the treatment of periodontal disease and in the design of respective treatment regimens.
The amount of newly formed bone in sinus grafting procedures depends on tissue depth as well as the type and residual amount of the grafted material
Authors: Artzi Zvi , Kozlovsky Avital , Nemcovsky Carlos E. , Weinreb Miron
Published: February 2005

Objectives: Bone replacement substitutes are almost unavoidable in augmentation procedures such as sinus grafting. The objective of the present study was to evaluate the osteoconductive capability of two different scaffold fillers in inducing newly formed bone in this procedure.

Material and Methods: Sinus floor augmentation and implant placement were carried out bilaterally in 12 patients. Bovine bone mineral (BBM) was grafted on one side and β‐tricalcium phosphate (β‐TCP) on the contralateral side. Both were mixed (1:1 ratio) with autogenous cortical bone chips harvested from the mandible by a scraper. Hard tissue specimen cores were retrieved from the augmented sites (at the previous window area) at 12 months. Decalcified sections were stained with haematoxylin–eosin and the fraction area of new bone and filler particles was measured. In addition to the effect of the filler on new bone formation, the latter was tested to determine whether it correlated with the tissue depth and residual amount of the grafted material.

Results: Bone area fraction increased significantly from peripheral to deeper areas at both grafted sites in all cores: from 26.0% to 37.7% at the β‐TCP sites and from 33.5% to 53.7% at the BBM‐grafted sites. At each depth the amount of new bone in BBM sites was significantly greater than that in TCP sites. However, the average area fraction of grafted material particles was similar in both fillers and all depth levels (β‐TCP=27.9–23.2% and BBM=29.2–22.6%, NS). A significant negative correlation was found between bone area fraction and particle area fraction at the middle (p=0.009) and deep (p=0.014) depths in the β‐TCP sites, but not at the BBM sites.

Conclusion: At 12 months post‐augmentation, the two examined bone fillers, β‐TCP and BBM, promoted new bone formation in sinus grafting but the amount of newly formed bone was significantly greater in BBM‐grafted sites. However, both exhibited similar residual grafted material area fraction at this healing period. This could imply that BBM possesses better osteoconductive properties.
Periodontal infections and pre‐term low birth weight: a case‐control study
Authors: Buduneli Nurcan , Baylas Haluk , Buduneli Eralp , Türkoğlu Oya , Köse Timur , Dahlen Gunnar
Published: February 2005

Objective: Pre‐term delivery of low‐birth‐weight infants [pre‐term low birth weight (PLBW)] remains a significant public health issue and a major cause of neonatal death and long‐term health problems. There is a growing consensus that infections remote from fetal–placental unit may influence PLBW infants. Recent studies have suggested that maternal periodontal disease may be an independent risk factor for PLBW. The purpose of the present study was to evaluate the possible link between periodontal infections and PLBW by means of clinical and microbiological data in post‐partum women with low socioeconomic level.

Methods: Clinical periodontal recordings comprising dental plaque, bleeding on probing, probing pocket depth and gingival recession were performed (six sites/tooth) in a total number of 181 women (53 cases and 128 controls) within 3 days post‐partum. Subgingival plaque samples from mesio–or disto–buccal aspect of randomly selected one first molar and one incisor tooth have been obtained by paperpoints and were analysed by checkerboard DNA–DNA hybridization with respect to 12 bacterial species. In all analyses, the individual subject was the computational unit. Thus, mean values for all clinical parameters were calculated and bacterial scores from each individual sample were averaged. Statistical methods included Student's t‐test, Fisher's exact test/χ2 test, and multiple logistic regression analysis.

Results: The cases have gained significantly less weight during the pregnancy than did the controls (p<0.05). There were no statistically significant differences between the cases and controls with regard to the dental and periodontal parameters and the values of clinical periodontal recordings were found to be very similar (p>0.05). Mean and median scores (bacterial loads) of Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Actinobacillus actinomycetemcomitans, and Streptococcus intermedius in the subgingival plaque sampling sites were significantly higher in the controls than in the cases (p<0.05). The occurrence rates of P. intermedia, Fusobacterium nucleatum, Peptostreptococcus micros, Campylobacter rectus, Eikenella corrodens, Selenomonas noxia and S. intermedius were higher in the cases compared with the controls, but the differences were not statistically significant (p>0.05). According to the model created by the multiple logistic regression analysis, P. micros and C. rectus were found to significantly increase the risk of PLBW (p<0.01 and p<0.05 respectively), while P. nigrescens and A. actinomycetemcomitans decreased this risk (p<0.01).

Conclusion: The present findings indicated that when subgingival bacteria were evaluated together, P. micros and C. rectus may have a role in increasing the risk for PLBW, although no single bacteria exhibited any relation with the risk of PLBW. Further studies are required to better clarify the possible relationship between periodontal diseases and PLBW.
The effect of systemic administration of ibuprofen in the experimental gingivitis model
Authors: Sekino Satoshi , Ramberg Per , Lindhe Jan
Published: February 2005

Background: Studies in humans have indicated that systemically administered flurbiprofen and ibuprofen may reduce gingivitis. De novo plaque formation is enhanced at tooth surfaces adjacent to inflamed gingivae.

Objective: The aim of the present clinical trial was to evaluate the effect of systemic administration of ibuprofen on gingivitis and plaque build‐up.

Material and Methods: Eleven subjects were recruited for the study and were given oral hygiene instruction, scaling and professional mechanical tooth cleaning (PTC). At the end of a preparatory period (Day 0), the participants were told to abstain from all mechanical plaque control measures during a 2‐week experimental period but to rinse with an assigned mouth rinse (positive control: 0.1% chlorhexidine digluconate; negative control: saline) or administer ibuprofen (tablets of 200 mg twice daily). Mouth rinsing was performed twice a day (after breakfast and in the evening), for 60 s with 10 ml. Re‐examination was performed after 14 days of experiment. After a 2‐week “wash‐out” period, the participants received a new PTC and a second 14‐day experimental period was initiated. The experimental and “wash‐out” periods were repeated until all volunteers had been involved in all three regimens. Dental plaque was scored using the Quigley & Hein Plaque Index system and gingivitis according to the Gingival Index (GI) system. Supragingival plaque was collected and prepared for dark‐field microscopy. One hundred bacterial cells were counted and classified into six different groups: coccoid cells, straight rods, filaments, fusiforms, spirochetes and motile rods. Gingival crevicular fluid (GCF) was collected from the same sites that were sampled for plaque. The volume of GCF collected in each strip was measured and analysed regarding content of lactoferrin and albumin.

Results: During the period when the panelists rinsed with saline they accumulated large amounts of plaque and developed marked signs of gingivitis. When they rinsed with chlorhexidine digluconate, small amounts of plaque formed and few sites received GI score2. After the 2 weeks of ibuprofen administration, the panelists presented with significantly fewer sites that scored GI2 but had formed similar amounts of plaque as during the negative control period.

Conclusion: It is suggested that ibuprofen administered via the systemic route has an effect on gingivitis but not on de novo plaque formation.
Maxillary incisor root resorption after rapid palatal expansion in Felis catus
Authors: Vardimon Alexander D. , Levy Thierry , Weinreb Miron
Published: February 2005

Root resorption after rapid palatal expansion (RPE) treatment was found in anchored teeth but has not been studied on non‐anchored incisors. This study evaluated root resorption, root tipping, and root proximity of maxillary incisors after RPE treatment. Fourteen cats were divided into treated (n = 10) and untreated (n = 4) groups. The RPE treatment consisted of active, retention, and relapse phases, lasting 25, 60 and 60 d, respectively. Standardized occlusal radiographs were taken to measure tipping and root proximity before and after each treatment phase. Maxillary incisors were analysed histologically by fluorescent microscopy for root resorption. Data was analysed statistically with anova with repeated measures, t‐test and Pearson's coefficient of correlation. Root resorption was confined to the first incisors and was 750‐fold greater in the treated vs. the control group. Root tipping and root proximity were significantly greater (2.5‐ and 17‐fold, respectively) in the first than in the second maxillary incisor and highly correlated with root resorption (r = −0.927 and 0.723, respectively). This suggests a cause (tipping and root proximity) and effect (root resorption) relationship. Data suggest that first maxillary incisor susceptibility to root resorption during RPE is associated with severe tipping and root proximity.
Grape seed proanthocyanidins extract promotes bone formation in rat's mandibular condyle
Authors: Ishikawa Makoto , Maki Kenshi , Tofani Iwan , Kimura Kyoko , Kimura Mitsutaka
Published: February 2005

We studied the effect of dietary supplementation with grape seed proanthocyanidins extract (GSPE) 3 mg added in 100 g high‐calcium diet with a calcium content of 1697 mg 100 g−1 on mandibular condyle bone debility, which was induced by a low‐calcium diet. Forty Wistar male rats, 5 week old, were randomly divided into control (Co), low‐calcium diet (LC), low‐calcium/high‐calcium diet (LCH), and low‐calcium/high‐calcium with supplementary GSPE diet (LCHG) groups for 6 wk. Bone formation of the mandibular condyle was measured using peripheral quantitative computed tomography (pQCT). Significant differences were not seen among the four groups for body weight, measured weekly. The LCHG group scored significantly higher in cortical bone density, total bone cross‐sectional area, cortical bone cross‐sectional area, cortical bone mineral content, total bone density, total bone mineral content, and in the stress‐strain index to the reference axis x when compared with the LCH group. We concluded that a high‐calcium diet combined with GSPE supplementation is more effective in reversing mandibular condyle bone debility in rats than is a low‐calcium diet, standard diet, or high‐calcium diet alone.
The release of vitamin C from chewing gum and its effects on supragingival calculus formation
Authors: Lingström Peter , Fure Solveig , Dinitzen Bettina , Fritzne Christina , Klefbom Carin , Birkhed Dowen
Published: February 2005

The aims of this study were to evaluate (i): whether vitamin C in chewing gum, alone or in combination with carbamide, influences calculus formation, and (ii) whether carbamide affects the release, stability and uptake of vitamin C in a chewing gum. In two test series (Series I and II), 30 subjects, all calculus formers, participated. They were instructed to chew on five (Series I) or 10 (Series II) pieces of gum per day for a period of 3 months. The chewing gums were: vitamin C (60 mg, Series I), non‐vitamin C (Series I) and vitamin C + carbamide (30 mg + 30 mg, Series II). In both series, no gum was used as a negative control. Calculus formation was scored on three lingual sites on the six anterior mandibular teeth according to the Volpe–Manhold index. The effect on plaque and gingivitis was also determined. A significant reduction in the total calculus score was observed after the use of vitamin C (33%) and vitamin C + carbamide (12%) gums compared with no gum use; this reduction was most pronounced in the heavy calculus formers. A reduced amount of visible plaque was also observed after use of vitamin C and non‐vitamin C gum, but only the vitamin C gum reduced the number of bleeding sites (37%). In a separate study, the release, stability and uptake of vitamin C were evaluated using the iodine titration method in both saliva and urine after exposure to the following gums: vitamin C + carbamide (30 mg + 30 mg) and vitamin C (30 mg). There was no indication that carbamide affected the release, stability or uptake of vitamin C when used in a chewing gum.
Expression of type IV collagen and laminin at the interface between epithelial cells and fibroblasts from human periodontal ligament
Authors: Shimonishi Mitsuru , Sato Juta , Takahashi Nobuhiro , Komatsu Masashi
Published: February 2005

The present study was undertaken to examine whether synthesis of type IV collagen and laminin around the epithelial rests of Malassez (ERM) requires direct contact between cells from ERM and periodontal ligament fibroblasts. Human periodontal ligament (HPDL) explants produced outgrowths containing both ERM cells and fibroblasts when cultured in a modified serum‐free medium. The interface between ERM cells and fibroblasts was examined using phase‐contrast microscopy (PCM) and scanning electron microscopy (SEM). Expression of type IV collagen and laminin was studied by immunohistochemistry and in situ hybridization. It was observed that ERM cells grew underneath fibroblasts or attached to them. At the interface, type IV collagen and laminin and their respective mRNAs were abundant in both ERM cells and fibroblasts, while these proteins and mRNAs showed little if any staining in cells further away from the interface. Hence, these findings indicate that synthesis of type IV collagen and laminin is induced by direct interaction between ERM cells and periodontal ligament fibroblasts.
Evaluation of bacterial nitrate reduction in the human oral cavity
Authors: Doel Justin Johnston , Benjamin Nigel , Hector Mark Pritchard , Rogers Michael , Allaker Robert Patrick
Published: February 2005

It is hypothesized that the enterosalivary nitrate circulation encourages nitrate reducing bacteria to reside within the oral cavity. Nitrite production may then limit the growth of acidogenic bacteria as a result of the production of antimicrobial oxides of nitrogen, including nitric oxide. This study was carried out with 10 subjects to characterize oral nitrate reduction and identify the bacteria responsible. Nitrate reduction varied between individuals (mean 85.4 ± 15.9 nmol nitrite min−1 with 10 ml 1 mm KNO3 mouth wash) and was found to be concentrated at the rear of the tongue dorsal surface. Nitrate reductase positive isolates identified, using 16S rDNA sequencing, from the tongue comprised Veillonella atypica (34%), Veillonella dispar (24%), Actinomyces odontolyticus (21%), Actinomyces naeslundii (2%), Rothia mucilaginosa (10%), Rothia dentocariosa (3%) and Staphylococcus epidermidis (5%). Nitrite production rates, using intact and permeabilized cells, of the major tongue nitrate reducers were determined in the presence of methyl and benzyl viologen. Under anaerobic conditions in the presence of nitrate, rates in decreasing order were: A. odontolyticus > R. mucilaginosa > R. dentocariosa > V. dispar > V. atypica. In conclusion, Veillonella spp. were found to be the most prevalent taxa isolated and thus may make a major contribution to nitrate reduction in the oral cavity.
Effect of endodontic irrigation on bonding of resin cement to radicular dentin
Authors: Hayashi Mikako , Takahashi Yutaka , Hirai Maki , Iwami Yukiteru , Imazato Satoshi , Ebisu Shigeyuki
Published: February 2005

The influence of endodontic irrigation on shear bond strengths of resin cement to radicular dentin was investigated. Human radicular dentin blocks were divided into four groups and subjected to one of four endodontic irrigations: ethylenediaminetetraacetic acid (EDTA) group, 17% EDTA for 60 s; EDTA/sodium hypochlorite (NaOCl) group, 17% EDTA for 60 s followed by 10 ml of 5% NaOCl for 15 s; NaOCl group, 10 ml of 5% NaOCl for 15 s; and control group, no treatment. Morphological changes of dentin surface after endodontic irrigation were observed by scanning electron microscopy (SEM). A resin block was bonded to the radicular dentin after irrigation using resin cement with either wet‐bonding (Uni‐Etch/One‐Step; Bisco) or self‐etching (Tyrian SPE/One‐Step Plus; Bisco) adhesives. Shear bond strengths were measured and the penetration of resin tags into dentinal tubules at resin–dentin interface was observed by SEM. With the wet‐bonding system, the shear bond strengths for the EDTA/NaOCl group, in which dentinal tubules openings and uniform resin tag penetration into dentinal tubules were observed, were significantly higher than the EDTA and control groups. With the self‐etching system, the shear bond strengths were significantly lower in the EDTA group compared with the NaOCl and control groups. The effects of endodontic irrigation on the bonding of resin cement to radicular dentin depended on the dentin bonding system used.
Corrosion resistance of cobalt‐chromium and palladium‐silver alloys used in fixed prosthetic restorations
Authors: Viennot Stéphane , Dalard Francis , Lissac Michèle , Grosgogeat Brigitte
Published: February 2005

The corrosion resistance of a cobalt‐chromium (Co‐Cr) alloy was assessed with a view to determining its potential use in the manufacture of fixed dental prostheses. The electrochemical behaviour of the alloy was compared with that of two palladium (Pd)‐based alloys. Measurements of corrosion potential and anodic polarization were performed on the alloys, and the specimen surfaces were examined by using scanning electron microscopy. Although the corrosion potential of the Co‐Cr alloy was lower than that of the Pd‐based alloys, the corrosion currents and polarization resistance values were similar for all three alloys. All materials showed a very high resistance to corrosion. Given that the beneficial mechanical properties of Co‐Cr alloys have already been established, this type of alloy may be a suitable alternative for use in the manufacture of fixed dental prostheses.
The value of full‐thickness bowel biopsy in the management of acute intestinal pseudo‐obstruction
Authors: Gokul Krishnan , Iddon Julie , Brown M. Anita , Campbell Fiona , Artioukh Dmitri Y.
Published: February 2005

A case of paraneoplastic syndrome leading to inflammatory neuropathy of the intestinal myenteric (Auerbach’s) plexus and manifesting as an acute pseudo‐obstruction is reported. Surgical intervention and full‐thickness small bowel biopsy proved to be the only way to establish the reason for impaired intestinal motility and lead to the diagnosis of otherwise occult bronchial neoplasia. The value of full‐thickness intestinal biopsy during negative laparotomy for suspected mechanical bowel obstruction is discussed.
Inguinal hernia repair in Hospital Authority hospitals: The role of laparoscopic hernioplasty
Authors: Lam Chi‐Ming , Wai Andy Chun‐Kit , Yuen Albert Wai‐Cheung
Published: February 2005

Objective:  Two major changes have occurred in inguinal hernia repair during the last two decades: (i) the use of tension‐free mesh repair; and (ii) the application of laparoscopic technique for repair. The aims of the present study were to study: (i) how inguinal hernia repair was carried out; and (ii) the outcome of inguinal hernia repair in Hospital Authority (HA) hospitals.

Methodology:  This was a retrospective analysis on 8311 elective inguinal hernia repairs performed in 16 HA hospitals from January 2001 to December 2003. The mean age was 63.9 ± 14.2 years, and the male to female ratio was 22.0 : 1.0. Among these, 869 (10.5%) repairs were performed with the laparoscopic approach and 7442 (89.5%) repairs with the open approach. The proportion of laparoscopic hernia repair increased from 8.7% to 12.6%.

Results:  For open repair, 39% of cases were carried out with regional anaesthesia, 32% with general anaesthesia and 29% with local anaesthesia (LA). Furthermore, mesh repair was used in 88% of the patients. For laparosocpic repair, 98.4% of cases were carried out under general anaesthesia, and all patients had mesh repair using the totally extraperitoneal approach. A significantly higher proportion of bilateral repair and recurrent hernia repair was performed with the laparoscopic approach (P = 0.000). For primary unilateral repair, there was no significant difference in the postoperative length of stay (LOS) and the total LOS between the laparoscopic and the open surgery groups. No difference in LOS was found in recurrent hernia repair between the two groups. With respect to bilateral repair, both the preoperative LOS (P = 0.036) and total LOS (P = 0.039) were shorter in the laparoscopic group. Furthermore, a significantly higher proportion of day‐surgery patients was observed in the laparoscopic group than the open surgery group (21.3%vs 16.9%, P = 0.001). Nevertheless, when only the results of 2003 were analyzed, the postoperative LOS (P = 0.000) and total LOS (P = 0.000) were significantly shorter in the laparoscopic group than the open surgery group. The LOS parameters were significantly shorter in the open surgery LA subgroup compared with the non‐LA subgroup (P = 0.000), and they were not different from those in the laparoscopic group.

Conclusions:  The open mesh repair is the predominant approach for inguinal hernia repair in HA hospitals. The originally described local anaesthetic approach was under utilized, although it resulted in good outcome. The use of laparoscopic hernia repair is increasing and a learning curve was recently observed with improved outcome.
The abundance of Lyα emitters in hierarchical models
Authors: Le Delliou M. , Lacey C. , Baugh C. M. , Guiderdoni B. , Bacon R. , Courtois H. , Sousbie T. , Morris S. L.
Published: February 2005

We present predictions for the abundance of Lyα emitters in hierarchical structure formation models. We use the GALFORM semi-analytical model of galaxy formation to explore the impact on the predicted counts of varying assumptions about the escape fraction of Lyα photons, the redshift at which the Universe reionized and the cosmological density parameter. A model with a fixed escape fraction gives a remarkably good match to the observed counts over a wide redshift interval. The counts at bright fluxes are dominated by ongoing starbursts. We present predictions for the expected counts in a typical observation with the Multi-Unit Spectroscopic Explorer (MUSE) instrument proposed for the Very Large Telescope.
Oscillations of thick accretion discs around black holes
Authors: Rubio-Herrera Eduardo , Lee William H.
Published: February 2005

We present a numerical study of the response of a thick accretion disc to a localized, external perturbation with the aim of exciting internal modes of oscillation. We find that the perturbations efficiently excite global modes recently identified as acoustic p-modes, and closely related to the epicyclic oscillations of test particles. The two strongest modes occur at eigenfrequencies which are in a 3:2 ratio. We have assumed a constant specific angular momentum distribution within the disc. Our models are in principle scale-free and can be used to simulate accretion tori around stellar or super-massive black holes.
A Chandra observation of the z= 2.285 galaxy FSC 10214+4724: evidence for a Compton-thick quasar?
Authors: Alexander D. M. , Chartas G. , Bauer F. E. , Brandt W. N. , Simpson C. , Vignali C.
Published: February 2005

We present a ≈20 ks Chandra ACIS-S observation of the strongly lensed z= 2.285 ultraluminous infrared galaxy FSC 10214 + 4724. Although this observation achieves the equivalent sensitivity of an up to ≈4 Ms Chandra exposure (when corrected for gravitational lensing), the rest-frame 1.6–26.3 keV emission from FSC 10214 + 4724 is weak (LX≈ 2 × 1042 erg s−1 for a lensing boost of ≈100); a significant fraction of this X-ray emission appears to be due to vigorous star formation activity. If FSC 10214 + 4724 hosts a quasar, as previously suggested, then it must be obscured by Compton-thick material. We compare FSC 10214 + 4724 to high-redshift SCUBA galaxies and discuss the X-ray identification of Compton-thick AGNs at high redshift.
Mapping substructures in dark matter haloes
Authors: Knebe Alexander , Gill Stuart P. D. , Kawata Daisuke , Gibson Brad K.
Published: February 2005

We present a detailed study of the real and integrals-of-motion space distributions of a disrupting satellite obtained from a fully self-consistent high-resolution cosmological simulation of a galaxy cluster. The satellite has been re-simulated using various analytical halo potentials, and we find that its debris appears as a coherent structure in integrals-of-motion space in all models (‘live’ and analytical potential), although the distribution is significantly smeared for the live host halo. The primary mechanism for the dispersion is the mass growth of the host. However, when quantitatively comparing the effects of ‘live’ and time-varying host potentials, we conclude that not all of the dispersion can be accounted for by the steady growth of the mass of the host. We ascribe the remaining discrepancies to additional effects in the ‘live’ halo such as non-sphericity of the host and interactions with other satellites which have not been modelled analytically.
FEEDING LOW CALCIUM AND ZINC MOLT DIETS SUSTAINS GASTROINTESTINAL FERMENTATION AND LIMITS SALMONELLA ENTERICA SEROVAR ENTERITIDIS COLONIZATION IN LAYING HENS
Authors: RICKE S.C. , PARK S.Y. , MOORE R.W. , KWON Y.M. , WOODWARD C.L. , BYRD J.A. , NISBET D.J. , KUBENA L.F.
Published: February 2005

The objective of these experiments was to determine whether alternative molting diets would minimize Salmonella enterica serovar Entertitidis (S. Enteritidis) colonization in molting hens. Hens were randomly assigned to four treatment groups of 12 hens either full‐fed (nonmolt, NM), molted by feed withdrawal (molt, M), a low calcium (LC containing 800 mg calcium), or LC diet supplemented with 110 mg zinc/ kg of diet (LC‐ZN) in two trials. All hens were challenged orally with 10 5SE on day 4 of experiment. Hen body weight loss was significantly (P < 0.05) increased and ovarian weight was significantly (P < 0.05) decreased in hens fed the LC or LC‐ZN diets compared to NM. Cecal lactic acid concentrations were significantly (P < 0.05) increased in hens fed alternative molting diets. Feed withdrawal molted hens exhibited significantly (P < 0.05) more S. Enteritidis positive and S. Enteritidis crop, cecal, and organ colonization than NM, LC and LC‐ZN hens. Alternative molt diets retain sufficient fermentative activity to limit S. Enteritidis colonization and therefore may have potential to avoid the risk of increasing S. Enteritidis colonization associated with feed withdrawal.
COMPARISON OF REVERSE PASSIVE LATEX AGGLUTINATION TEST AND IMMUNOBLOTTING FOR DETECTION OF STAPHYLOCOCCAL ENTEROTOXIN A AND B
Authors: DI PINTO A. , FORTE V.T. , CICCARESE G. , CONVERSANO M.C. , TANTILLO G.M.
Published: February 2005

Staphylococcal foodborne diseases resulting from consumption of food contaminated with staphylococcal enterotoxins (SEs) produced by certain strains of Staphylococcus aureus are the second most common foodborne illnesses in the world. Analytical methods are essential for routine monitoring purposes and safeguard public health. Different methods for SE detection have been proposed although their use in a complex matrix is often limited by the presence of substances that interfere with tests. In this article reverse passive latex agglutination (RPLA) and immunoblotting methods based on specific antibodies and currently available for SE detection have been compared. Culture filtrates from enterotoxin S. aureus strains isolated from cheese samples were identified by SET‐RPLA. Then the culture filtrates identified as staphylococcal enterotoxin A and staphylococcal enterotoxin B by RPLA test were analyzed with immunoblotting. The results obtained suggest that either SET‐RPLA or immunoblotting may be applied to culture filtrates for the detection of SEs with good correspondence of results. Although SET‐RPLA represents a simple method for routine monitoring purposes, a positive result by a rapid method (RPLA) is only regarded as presumptive and must be confirmed by standard methods (Feng 1996), such as immunoblotting method.
DETECTION AND CHARACTERIZATION OF VEROTOXIN‐PRODUCINGESCHERICHIA COLI(VTEC) ISOLATED FROM BUFFALO MEAT
Authors: HAZARIKA R.A. , SINGH D.K. , KAPOOR K.N. , AGARWAL R.K. , PANDEY A.B. , RAJKUMAR D.N.
Published: February 2005

The emergence of Verotoxin‐producingEscherichia coli(VTEC) as zoonotic foodborne pathogens in recent years has become a public health concern because of its life threatening human diseases. In the present investigation, out of 87 strains ofE. coli, 22 (25%) belonging to 13 different serotypes isolated from raw buffalo meat and its products were found to be verotoxic as tested by Vero cell cytotoxic assay. Serotype O26 followed by O153 and O157 were the predominant VTEC. All the VTEC strains were found positive forvtgenes by polymerase chain reaction (PCR). Among thevtgenotypes,vt2(77%) was most predominant followed byvt1(14%) and bothvt1andvt2(9%). Production of enterohaemolysin on washed sheep blood agar supplemented with CaCl2showed 19 (86%) VTEC strains to be positive. Presence of VTEC in cooked buffalo meat products, namely shami kabab and kabab, appears to be a matter of concern and a potential threat to public health. VTEC detection by different methods suggests that PCR can be useful to evaluate the distribution of virulence genes (vt1orvt2or both) inE. coliisolates from buffalo meat and its products.
EVALUATION OF THE TOXICITY OF LACTOBACILLUS ACIDOPHILUS LAP5 IN A 28‐DAY FEEDING STUDY IN WISTAR RATS
Authors: TSAI CHENG‐CHIH , CHEN MING‐HUI , LIU TSENG‐HUANG , CHAU CHIN‐GIN , CHANG LI‐TUNG , TSAI CHIN‐CHUAN , TSEN HAU‐YANG
Published: February 2005

We have previously screened lactic acid bacteria strains from porcine intestine and evaluated their functional properties. We found a strain of Lactobacillus acidophilus LAP5 is with potential for use as human and animal probiotics. However, the safety of the strain in consideration must be evaluated. The present study was conducted to evaluate the toxicity of strain L. acidophilus LAP5 in Wistar rats by dietary administration at concentrations of 2.1 × 1011, 1.05 × 1011 and 4.2 × 109 CFU per kg body weight of rat per day for 28 days. There were no adverse effects on the general condition and behavior, growth, feed and water consumption, hematology, clinical chemistry indexes, organ weights and histopathologic analysis. Results of this study demonstrated that consumption of strain L. acidophilus LAP5 was not associated with any signs of toxicity in Wistar rats even following consumption of large quantities.
CONTROL OF BACILLUS CEREUS IN HIGH‐pH CRUMPETS
Authors: KOUKOUTSIS JOHN , SMITH JAMES P. , DAIFAS DAPHNE PHILLIPS , YAYALAN VAROUJAN , CAYOUETTE BERNARD , NGADI MICHAEL , EL‐KHOURY WASSIM
Published: February 2005

Studies were performed to determine the effects of sorbic hydroxamic acid (SHA) and mastic oil–ethanol (ME) or water‐ethanol (WE) emitters on the growth of Bacillus cereus in high‐moisture, high‐pH (∼8.9) English‐style crumpets stored at ambient temperature (25C). While SHA (3000 p.p.m.), alone or in combination with ME emitters, was effective in inhibiting the growth of B. cereus for 14 days in high‐pH crumpets, only SHA formulated crumpets packaged in air had acceptable sensory scores at the end of storage. However, ME emitters alone were ineffective in controlling the growth of this pathogen. This lack of inhibition in crumpets was attributed to the poor absorption of mastic volatiles from the package headspace into the food matrix. Whatever the reason, these preliminary studies showed that SHA has the potential to control the growth of B. cereus in high‐moisture, high‐pH crumpets without compromising product quality.
Temperature effects on neuronal membrane potentials and inward currents in rat hypothalamic tissue slices
Authors: Zhao Yanmei , Boulant Jack A.
Published: February 2005

Preoptic–anterior hypothalamic (PO/AH) neurones sense and regulate body temperature. Although controversial, it has been postulated that warm‐induced depolarization determines neuronal thermosensitivity. Supporting this hypothesis, recent studies suggest that temperature‐sensitive cationic channels (e.g. vanilloid receptor TRP channels) constitute the underlying mechanism of neuronal thermosensitivity. Moreover, earlier studies indicated that PO/AH neuronal warm sensitivity is due to depolarizing sodium currents that are sensitive to tetrodotoxin (TTX). To test these possibilities, intracellular recordings were made in rat hypothalamic tissue slices. Thermal effects on membrane potentials and currents were compared in PO/AH warm‐sensitive, temperature‐insensitive and silent neurones. All three types of neurones displayed slight depolarization during warming and hyperpolarization during cooling. There were no significant differences in membrane potential thermosensitivity for the different neuronal types. Voltage clamp recordings (at −92 mV) measured the thermal effects on persistent inward cationic currents. In all neurones, resting holding currents decreased during cooling and increased during warming, and there was no correlation between firing rate thermosensitivity and current thermosensitivity. To determine the thermosensitive contribution of persistent, TTX‐sensitive currents, voltage clamp recordings were conducted in the presence of 0.5 μm TTX. TTX decreased the current thermosensitivity in most neurones, but there were no resulting differences between the different neuronal types. The present study found no evidence of a resting ionic current that is unique to warm‐sensitive neurones. This supports studies suggesting that neuronal thermosensitivity is controlled, not by resting currents, but rather by currents that determine rapid changes in membrane potential between successive action potentials.
Subthreshold voltage noise of rat neocortical pyramidal neurones
Authors: Jacobson Gilad A. , Diba Kamran , Yaron‐Jakoubovitch Anat , Oz Yasmin , Koch Christof , Segev Idan , Yarom Yosef
Published: February 2005

Neurones are noisy elements. Noise arises from both intrinsic and extrinsic sources, and manifests itself as fluctuations in the membrane potential. These fluctuations limit the accuracy of a neurone's output but have also been suggested to play a computational role. We present a detailed study of the amplitude and spectrum of voltage noise recorded at the soma of layer IV–V pyramidal neurones in slices taken from rat neocortex. The dependence of the noise on holding potential, synaptic activity and Na+ conductance is systematically analysed. We demonstrate that voltage noise increases non‐linearly as the cell depolarizes (from a standard deviation (s.d.) of 0.19 mV at −75 mV to an s.d. of 0.54 mV at −55 mV). The increase in voltage noise is accompanied by an increase in the cell impedance, due to voltage dependence of Na+ conductance. The impedance increase accounts for the majority (70%) of the voltage noise increase. The increase in voltage noise and impedance is restricted to the low‐frequency range (0.2–2 Hz). At the high frequency range (5–100 Hz) the voltage noise is dominated by synaptic activity. In our slice preparation, synaptic noise has little effect on the cell impedance. A minimal model reproduces qualitatively these data. Our results imply that ion channel noise contributes significantly to membrane voltage fluctuations at the subthreshold voltage range, and that Na+ conductance plays a key role in determining the amplitude of this noise by acting as a voltage‐dependent amplifier of low‐frequency transients.
Subunit composition and role of Na+,K+‐ATPases in adrenal chromaffin cells
Authors: Lin Hai , Ozaki Shoichiro , Fujishiro Naoji , Takeda Kazuo , Imanaga Issei , Prestwich Glenn D. , Inoue Masumi
Published: February 2005

Adrenal medullary (AM) cells are exposed to high concentrations of cortical hormones, one of which is a ouabain‐like substance. Thus, the effects of ouabain on catecholamine secretion and distribution of Na+,K+‐ATPase α and β subunits in rat and guinea‐pig AM cells were examined using amperometry and immunological techniques. While exposure to 1 μm ouabain did not have a marked effect on resting secretion, it induced an increase in secretion due to mobilization of Ca2+ ions that were stored during a 4 min interval between muscarine applications. Immunocytochemistry revealed that Na+,K+‐ATPase α1 subunit‐like and β3 subunit‐like immunoreactive (IR) materials were distributed ubiquitously at the cell periphery, whereas α2‐ and β2‐like IR materials were present in restricted parts of the cell periphery. The α1 and α2 subunits were mainly immunoprecipitated from AM preparations by anti‐β3 and anti‐β2 antisera, respectively. Peripheral BODIPY‐FL‐InsP3 binding sites were localized below membrane domains with α2‐ and β2‐like IR materials. The results indicate that in AM cells, α1β3 isozymes of Na+,K+‐ATPase were present ubiquitously in the plasma membrane, while α2β2 isozymes were in the membrane domain closely associated with peripheral Ca2+ store sites. This close association of the α2β2 isozyme with peripheral Ca2+ store sites may account for the facilitation of mobilization‐dependent secretion in the presence of 1 μm ouabain.
Tonic release of glutamate by a DIDS‐sensitive mechanism in rat hippocampal slices
Authors: Cavelier Pauline , Attwell David
Published: February 2005

Tonic release of glutamate into the extracellular space of the hippocampus and striatum is non‐vesicular, and has been attributed largely to a cystine–glutamate exchanger which is blockable by the glutamate analogue (S)‐4‐carboxyphenylglycine (CPG). Tonic glutamate release may be functionally important: modulation of this release in the striatum has been suggested to underlie relapse in the use of cocaine. We monitored tonic glutamate release in area CA1 of hippocampal slices by measuring the glutamate receptor‐mediated current evoked in pyramidal cells on block of Na+‐dependent glutamate uptake with dl‐threo‐β‐benzyloxyaspartate (TBOA). Superfused cystine increased tonic glutamate release, and this increase was blocked by CPG, but CPG did not affect tonic glutamate release in the absence of superfused cystine. Tonic glutamate release was not affected by blocking gap junctional hemichannels with 18α‐glycyrrhetinic acid, blocking ATP receptors with pyridoxal‐phosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (PPADS), blocking Ca2+‐dependent exocytosis from neurones with Cd2+ or bafilomycin, blocking Ca2+‐dependent release from glia with indomethacin, or blocking anion channels with 5‐nitro‐2‐(3‐phenylpropyl amino) benzoic acid (NPPB) or tamoxifen. However tonic glutamate release was reduced by 4,4′‐diisothiocyanostilbene‐2,2′‐disulphonic acid (DIDS), and was potentiated by inhibiting astrocytic conversion of glutamate to glutamine with methionine sulfoximine. These data suggest that although cystine–glutamate exchange is present in the hippocampus it does not generate significant tonic release of glutamate when the extracellular [cystine] is at a physiological level, and that tonic glutamate release is at least partly from astrocytes and is mediated by a DIDS‐sensitive mechanism. Theoretical calculations suggest that a significant fraction of tonic glutamate release in hippocampal slices could occur via diffusion of glutamate across lipid membranes.
An Explanation for the Size-Effect in Machining Using Strain Gradient Plasticity
Authors: Joshi Suhas S. , Melkote Shreyes N.
Published: February 2005

This paper aims to explain the size-effect in the Primary Deformation Zone (PDZ) in machining using strain gradient plasticity theory. Considering a parallel-sided shear zone configuration, models are formulated for the evaluation of strain gradient, density of geometrically necessary dislocations, shear strength and the specific shear energy. The analysis of deformation in the PDZ shows that the length of the shear plane represents the fundamental material length scale governing the size-effect. It also provides an estimate of the lower bound on the size-effect observed in the specific shear energy. The general trends predicted by the model are shown to agree well with the experimental values obtained from the literature.
Effect of Fixture Compliance on Thermally Enhanced Edge Registration in Microlamination
Authors: Wattanutchariya Wassanai , Paul Brian K.
Published: February 2005

Microlamination involves the patterning, registration, and bonding of thin layers of material, called laminae, to produce highly paralleled, spatially intensified microchannel systems for the bulk processing of mass and energy. A Thermally Enhanced Edge Registration (TEER) technique has been developed for precision aligning large numbers of laminae in diffusion-bonding processes based on the differential thermal expansion between the laminae and bonding fixture. However, fixture tolerances necessary to promote buckle-free TEER bonding have been found to be very small (below 10 μm). This research focuses on the development of a new approach to thermal registration based on fixture compliance to permit looser fixture tolerances. An analysis based on both fin-buckling behavior and the compliance of the fixture is implemented to investigate the tolerance limit of a compliant TEER fixture. Experiments are conducted to verify the theoretical model. Results show that a compliant fixture can permit an acceptable tolerance limit in TEER.
Surface Finishing and Evaluation of Three-Dimensional Silicon Microchannel Using Magnetorheological Fluid
Authors: Kim Wook-Bae , Lee Seung-Hwan , Min Byung-Kwon
Published: February 2005

A surface-finishing method for three-dimensional microchannel structures is proposed. The method utilizes magnetorheological fluid mixed with abrasives as a polishing tool. The influences of the process parameters on the material removal were investigated, and the surface topographies before and after finishing were compared. When a microchannel was finished by proposed method, the roughness of bottom and side surfaces of the silicon channel was reduced by a factor of 5–10, and the pressure drop of a gas flow through the single microchannel was lowered to 26.7% of the pressure drop in an unfinished microchannel. The experimental results demonstrated that the proposed method was effective in finishing of microstructures.
Ceramic Micro/Nanoparticle Size Evolution in Wet Grinding in Stirred Ball Mill
Authors: Su Jiann-Cherng , Liang Steven Y. , Liu Wang Lin , Jan Tzu Chi
Published: February 2005

Micro- and nanostructured ceramic materials have received increasing attention in light of the attainable mechanical properties of the resulting components, parts, and products. Stirred ball mill grinding is an important process in reducing the size of ceramic micro- and/or nanoparticles to a desirable range to be used as a constituent for micro- and nanostructured materials. In this study, the time change of particle size of titanium dioxide TiO2 micro- and nanoparticles in the stirred ball mill grinding process is characterized with a fracture mechanics analysis combined with a population balance model. The approach provides both the mean and the statistical distribution of particle sizes produced by ball grinding. It also yields an estimate for the amount of time necessary to achieve a desired particle size. The model examines the effects of process parameters, including the grinding speed, the viscosity of the suspending fluid, and the concentration of the feed as input variables. Experiments performed with TiO2 suspended in ethylene glycol are used for comparison to model predictions for validation. The results show that the initial particle-size reduction rate is relatively high, however, as the particle size decreases, the time required for further reduction increases significantly. Good agreement exists between the model predictions and the experimental results in the context of micro- and nanoparticle-size reduction trends.
Deposition Technologies For Micromanufacturing: A Review
Authors: Kadekar Vinay , Fang Weiya , Liou Frank
Published: February 2005

This paper discusses the microdeposition technologies used in the fabrication of meso- and microscale structures. The ability to process a wide range of materials and the flexibility to build functional and geometrically complex structures in meso- and microscale gives the microdeposition method some advantages over micromachining or lithography methods investigated extensively in the past. In this paper, work on deposition technology is reviewed, including material, supply of material, powder flow rate, and manipulation of particles and microdeposition technologies. The advantages and disadvantages of each technology are summarized at the end of the paper.
Three Dimensional Imaging of LIGA-Made Microcomponents
Authors: Chinn Douglas , Ostendorp Peter , Haugh Mike , Kershmann Russell , Kurfess Thomas , Claudet Andre , Tucker Thomas
Published: February 2005

Nickel and nickel-alloy microparts sized on the order of 5–1000 microns have been imaged in three dimensions using a new microscopic technique, Digital Volumetric Imaging (DVI). The gears were fabricated using Sandia National Laboratories’ LIGA technology (lithography, molding, and electroplating). The images were taken on a microscope built by Resolution Sciences Corporation by slicing the gear into one-micron thin slices, photographing each slice, and then reconstructing the image with software. The images were matched to the original CAD (computer aided design) model, allowing LIGA designers, for the first time, to see visually how much deviation from the design is induced by the manufacturing process. Calibration was done by imaging brass ball bearings and matching them to the CAD model of a sphere. A major advantage of DVI over scanning techniques is that internal defects can be imaged to very high resolution. In order to perform the metrology operations on the microcomponents, high-speed and high-precision algorithms are developed for coordinate metrology. The algorithms are based on a least-squares approach to data registration the {X,Y,Z} point clouds generated from the component surface onto a target geometry defined in a CAD model. Both primitive geometric element analyses as well as an overall comparison of the part geometry are discussed. Initial results of the micromeasurements are presented in the paper.