Optimal Positioning of Inertial Measurement Units in a Smart Shirt for Determining Respiratory Volume.

Tidal volume can be estimated using the surface motions of the upper body induced by respiration. However, the precision and instrumentation of such estimation must be improved to allow widespread application. In this study, respiration induced changes in parameters that can be recorded with inertial measurement units are examined to determine tidal volumes. Based on the data of an optical motion capture system, the optimal positions of inertial measurement units (IMU) in a smart shirt for sets of 4, 5 or 6 sensors were determined. The errors observed indicate the potential to determine tidal volumes using IMUs in a smart shirt.Clinical Relevance- The measurement of respiratory volumes via a low-cost and unobtrusive smart shirt would be a major advance in clinical diagnostics. In particular, conventional methods are expensive, and uncomfortable for conscious patients if measurement is desired over an extended period. A smart-shirt based on inertial sensors would allow a comfortable measurement and could be used in many clinical scenarios - from sleep apnoea monitoring to homecare and respiratory monitoring of comatose patients.

Effects of Intra-Abdominal Pressure on Lung Mechanics during Laparoscopic Gynaecology.

Investigating the relations between surgical actions and physiological reactions of the patient is essential for developing pre-emptive model-based systems. In this study, the effects of insufflating abdominal cavity with CO2 in laparoscopic gynaecology on the respiration system were analysed. Real-time recordings of anaesthesiology and surgical data of five subjects were acquired and processed, and the correlation between lung mechanics and the intra-abdominal pressure was evaluated. Alterations of ventilation settings undertaken by the anaesthesiologist were also considered. Experimental results demonstrated the high correlation with a mean Pearson coefficient of 0.931.Clinical Relevance- This study demonstrates the effects of intra-abdominal pressure during laparoscopy on lung mechanics and enables developing predictive models to promote a greater awareness in operating rooms.

An alternative way to measure respiration induced changes of circumferences: a pilot study.

Various measurement systems can be used to obtain dynamic circumferences of the human upper body, but each of these systems has disadvantages. In this feasibility study we introduce a non-invasive and wearable thoracic belt to measure dynamic changes of circumferences of thorax or abdomen. To evaluate this approach, five subjects undertook various breaths of disparate tidal volumes, which were measured by the belt and simultaneously by a motion capture system which provided a reference metric.The results of the belt concurred with the reference system. A coefficient of determination (adjusted R2) of 0.99 and a mean squared error of less than 0.87 mm2 showed that the belt is capable of measuring changes accurately and a couple of respiratory parameters, such as the respiratory rate, can be obtained.Clinical Relevance-The introduced system links surface motions of the upper body with the underlying respiratory mechanics. Thus it provides some respiratory parameters without the disadvantages of a facemask or a mouthpiece. The system could allow the analysis of breathing status in some clinical applications and could be used for low-cost monitoring in homecare or to analyse respiratory parameters during sports.

Epigenomic Convergence of Neural-Immune Risk Factors in Neurodevelopmental Disorder Cortex.

Neurodevelopmental disorders (NDDs) affect 7-14% of all children in developed countries and are one of the leading causes of lifelong disability. Epigenetic modifications are poised at the interface between genes and environment and are predicted to reveal insight into NDD etiology. Whole-genome bisulfite sequencing was used to examine DNA cytosine methylation in 49 human cortex samples from 3 different NDDs (autism spectrum disorder, Rett syndrome, and Dup15q syndrome) and matched controls. Integration of methylation changes across NDDs with relevant genomic and genetic datasets revealed differentially methylated regions (DMRs) unique to each type of NDD but with shared regulatory functions in neurons and microglia. NDD DMRs were enriched within promoter regions and for transcription factor binding sites with identified methylation sensitivity. DMRs from all 3 disorders were enriched for ontologies related to nervous system development and genes with disrupted expression in brain from neurodevelopmental or neuropsychiatric disorders. Genes associated with NDD DMRs showed expression patterns indicating an important role for altered microglial function during brain development. These findings demonstrate an NDD epigenomic signature in human cortex that will aid in defining therapeutic targets and early biomarkers at the interface of genetic and environmental NDD risk factors.

Tidal volume via circumferences of the upper body: a pilot study.

The gold standard for tidal volume measurement is spirometry. Based on retrospective data, this study evaluates different geometric lung models in their ability to deliver accurate tidal volumes from changes in thoracic and abdominal circumference. The geometric lung models showed good coefficients of determination (adjusted R2 >0.97) compared to the tidal volumes measured by a body plethysmograph. Tidal volumes obtained by circumference changes might be used in surveillance systems to analyze respiration without a face mask.

Fatal Clostridium difficile enteritis caused by the BI/NAP1/027 strain: a case series of ileal C. difficile infections.

Clostridium difficile generally causes diarrhoea and colitis. Small-bowel infections are considered to be rare. Twelve cases of ileal C. difficile infections are presented, including the first reported case proven to be caused by the hypervirulent BI/NAP1/027 strain. This case series suggests that small bowel involvement in C. difficile infections may be more frequent than previously thought.

Efficient factor VIII affinity purification using a small synthetic ligand.

BACKGROUND: Hemophilia A is currently treated by infusions of the coagulation factor (F) VIII, of which production and purification remain a challenging task. Current purification procedures using immunoaffinity chromatography are cumbersome, expensive, and suffer from the instability of the applied antibody ligands, which elute along with the product and contaminate it. Recently, FVIII was purified using octapeptide ligands, but their use is limited due to the low resistance to proteases. OBJECTIVE: Our goal was to develop and evaluate a novel ligand for FVIII purification, overcoming the drawbacks of current procedures. METHODS: Peptide ligands were screened for binding of (125)I-plasma-derived-FVIII (pdFVIII) in a microbead assay. A selected ligand-coated Toyopearl resin was then used for pdFVIII purification from cell-conditioned Delbucco's modified Eagle's medium (DMEM) containing fetal bovine serum. The proteolytic stability of ligand was measured by incubating with human serum and proteinase K, and its cytotoxicity towards human OV-MZ-6 cells was assayed. RESULTS: A high-affinity octapeptidic FVIII ligand was modified into the small, highly stable and non-toxic peptidomimetic ligand L4 by rational and combinatorial design without affecting its affinity for FVIII. Using ligand L4-coated Toyopearl resin, pdFVIII was isolated from cell-conditioned medium with high purity and 89% column retention after elution with a mild buffer containing 0.6 m NaCl at pH 6.8. CONCLUSIONS: Ligand L4 offers a valuable alternative to antibody-based procedures for laboratory and industrial production. Its synthesis by established solid-phase procedures is straightforward and considerably cheaper than the biotechnological production of antibodies, and safety concerns associated with the use of biological material are overcome.

Accuracy of three polyvinyl siloxane putty-wash impression techniques.

STATEMENT OF PROBLEM: There is much discussion in the dental literature concerning the effect of the impression technique on the accuracy of cast restorations. PURPOSE: This study assessed the accuracy of 3 putty-wash impression techniques using the same impression material (polyvinyl siloxane) in a laboratory model. MATERIAL AND METHODS: The 3 putty-wash impression techniques used were (1) 1-step (putty and wash impression materials used simultaneously); (2) 2-step with 2-mm relief (putty first as a preliminary impression to create 2-mm wash space with prefabricated copings. In the second step, the wash stage was carried out); and (3) 2-step technique with a polyethylene spacer (plastic spacer used with the putty impression first and then the wash stage). For each technique, 15 impressions were made of a stainless steel master model that contained 3 complete crown abutment preparations, which were used as the positive control. Accuracy was assessed by measuring 6 dimensions (intraabutment and interabutment) on stone dies poured from impressions of the master model. RESULTS: One-way analysis of variance showed statistically significant differences among the 3 putty-wash impression techniques, for all intraabutment and interabutment measurements (P <.001). Overall discrepancies of the 2-step technique with 2-mm relief putty-wash impression technique were significantly smaller than that in the 1-step and polyethylene putty-wash impression techniques. CONCLUSION: The polyvinyl siloxane 2-step, 2-mm, relief putty-wash impression technique was the most accurate for fabricating stone dies.

An investigation of heat transfer to the implant-bone interface related to exothermic heat generation during setting of autopolymerizing acrylic resins applied directly to an implant abutment.

Excessive heat generation at the implant-bone interface may cause bone damage and compromise osseointegration. Autopolymerizing acrylic resins are commonly used intraorally to join impression copings and suprastructure components for soldering. The effect of heat generation at the implant surface related to the exothermic setting reaction of autopolymerizing acrylic resins applied to an attached abutment was examined in vitro. Two brands of autopolymerizing acrylic resin, Duralay and GC Pattern Resin, were compared. Acrylic resin was applied to a titanium alloy abutment connected to a titanium alloy cylindric implant in varying controlled volumes, with both bulk application and brush paint-on techniques. The implant was embedded in an acrylic resin mandible in a 37 degrees C water bath. Temperature changes were recorded via embedded thermocouples at the cervical and apical of the implant surface. Analysis of variance for repeated measures was used to compare treatment groups. A mean maximum increase in temperature of 4 to 5 degrees C was seen at the implant cervical for both materials, with a maximum temperature increase of 6 degrees C. No difference between Duralay and GC Pattern Resin was seen, except for bulk application to medium-sized copper bands at the implant cervical (P < .05). No difference between the bulk and brush techniques was seen for all options, except for GC, where bulk application to medium-sized copper bands produced higher temperatures than the brush technique (P < .05). Spray coolant reduced temperatures for bulk application of both Duralay and GC (P < .05).

Metabolic state of Zymomonas mobilis in glucose-, fructose-, and xylose-fed continuous cultures as analysed by 13C- and 31P-NMR spectroscopy.

The reasons for the well-known significantly different behaviour of the anaerobic, gram-negative, ethanologenic bacterium Zymomonas mobilis during growth on fructose (i.e. decreased growth and ethanol yields, increased by-product formation) as compared to that on its second natural substrate, glucose, have remained unexplained. A xylose-fermenting recombinant strain of Z. mobilis that was recently constructed in our laboratory also unexpectedly displayed an increased formation of by-products and a strongly reduced growth rate as compared to the parent strain. Therefore, a comprehensive study employing recently developed NMR-based methods for the in vivo analysis of intracellular phosphorylated pool sizes and metabolic fluxes was undertaken to enable a global characterization of the intracellular metabolic state of Z. mobilis during growth on 13C-labelled glucose, fructose and xylose in defined continuous cultures. The 13C-NMR flux analysis indicated that ribose 5-phosphate is synthesized via the nonoxidative pentose phosphate pathway in Z. mobilis, and it identified a metabolic bottleneck in the recombinant xylose-fermenting Z. mobilis strain at the level of heterologous xylulokinase. The 31P-NMR analyses revealed a global alteration of the levels of intracellular phosphorylated metabolites during growth on fructose as compared to that on glucose. The results suggest that this is primarily caused by an elevated concentration of intracellular fructose 6-phosphate.

Effect of glaze thickness on the fracture toughness and hardness of alumina-reinforced porcelain.

STATEMENT OF PROBLEM: Although porcelain is the most esthetic restorative material available, it is subject to fracture during function. Glazing reduces the size of flaws in the surface of the porcelain and increases its resistance to crack propagation, but the optimum thickness of this glazed layer has not been determined. PURPOSE: This study compared the fracture toughness (Kc ) and Vickers hardness number (VHN) of an alumina-reinforced porcelain at different thicknesses of glaze. MATERIAL AND METHODS: Disks of feldspathic porcelain reinforced with 2% aluminum oxide were prepared and glazed for 0, 30, 60, 90, and 120 seconds. Fracture toughness and Vickers microhardness were determined with a microindentation technique. Thickness of the glazed layers was measured with a SEM. RESULTS: Mean Vickers hardness number and fracture toughness values both decreased significantly with glazing times from 0 to 60 seconds, and increased significantly with glazing times from 60 to 120 seconds (P <.001, ANOVA). SEM examination revealed an increase in glazed layer thickness with increased glazing time. CONCLUSIONS: Minimal and maximum thicknesses of glaze layers on alumina-reinforced porcelain resulted in a surface that was harder and more resistant to fracture than moderate glaze thicknesses.

Manual closing torque in five implant abutment systems: an in vitro comparative study.

STATEMENT OF PURPOSE: A significant percentage of abutment/implant (A/I) assemblies tend to unscrew on functional loading. PURPOSE: This in vitro study evaluated the maximum closing torque generated manually for comparison with recommended closing torque values in 5 implant systems. METHODS: Closing torque generated by 9 operators with 5 manual torque drivers was measured and compared by using a mannequin and torque gauge assembly. RESULTS: Closing torque values were found to be significantly different between operators and between implant systems (P <.0001). Mean closing torque values of 9 operators performing 5 closures for 5 systems ranged from 7 to 14.6 N/cm for habitual closures and from 9.4 to 19.9 N/cm for maximum closures. CONCLUSIONS: The results demonstrated that maximum manual closure did not approach recommended closing torque in any of the system measured. Significant interoperator and intraoperator variability was found in the closing torque with manual drivers, and the driver diameter and grip were probably an important feature in the generation of high closing torque.

Posterior bite collapse--revisited.

Although there are different definitions of posterior bite collapse, only the classical definition of Amsterdam provides a definite diagnosis and treatment plan. This situation entails a subtle loss of the occlusal vertical dimension with resultant flaring of the maxillary incisors. Other causes for flaring, such as derangements of form and functions of lips and tongue, bruxism, habits, as well as the presence of advanced periodontal disease or malocclusions, should be ruled out before the diagnosis of posterior bite collapse can be made. The complexity of differential diagnosis is illustrated with three case reports.

Splinting osseointegrated implants and natural teeth in rehabilitation of partially edentulous patients. Part II: principles and applications.

Lone standing splinted implant segments are accepted as optimal. However, in the treatment of partial edentulism, clinical reality often predicates the consideration of splinting teeth and implants due to variables of tooth/implant location and available bone support. This article presents a review on biomechanical aspects of splinting teeth and some considerations of splinting teeth and implants. A proposed classification of splinting applicable to both teeth and implants is presented as well as a discussion of the clinical aspects of splinting illustrated with clinical cases.

The closure of the gingival crevice following gingival retraction for impression making.

Scant attention has been paid to the effectiveness of chemomechanical displacement of the gingiva prior to impression making for fixed partial dentures. The closure of the gingival crevice following removal of medicated retraction cord was observed using a miniature video camera. Sulcular widths were measured at time intervals at the midbuccal and transitional line angle areas. The closure rate of the transitional line angle area was significantly faster than that of the mid-buccal area during the first 90 s. An average sulcular width of 0.2 mm was reached at the transitional line angle after less than 30 s.

The influence of surface loading and irradiation time during curing on mechanical properties of a composite.

PURPOSE: The aim of this study was to determine the influence of different surface loadings during curing with various irradiation times on hardness and diametral tensile strength of a light-cured composite. MATERIAL AND METHODS: A mold was fabricated to allow loading during curing of cylindrical specimens of a composite. Four surface loadings of 0, 0.35, 0.87, and 1.73 MPa and four irradiation times of 20, 40, 60, and 180 seconds were used (n = 15). Each specimen was subjected to a microhardness test and to a diametral tensile strength test. RESULTS: Surface loading during curing affected both hardness and strength properties, whereas irradiation time influenced only the hardness of the material. Both parameters gained between 15% and 20% improvement when the material was loaded with 0.87 MPa surface pressure and cured by 60-second irradiation time. Higher loading or longer irradiation times did not improve these properties. CONCLUSION: Loading composite during curing improves its mechanical properties, probably through decreasing flaws and air voids of the material.

The effect of displacement time on gingival crevice width.

The authors investigated the length of time medicated displacement cord should remain in the gingival crevice prior to impression making. A silk cord (Deknatel) was placed into the sulcus and was not removed during the study. Medicated cords (Hemodent on Ultrapak #1) were placed into the gingival sulcus for 2, 4, 6, and 8 minutes. Following cord removal, closure of the sulcus was recorded at intervals using a miniature video camera. Crevicular widths were measured at the midbuccal and transitional line angle areas. At both the midbuccal and transitional line angle areas, gingival crevices displaced for 2 minutes were significantly smaller at 20 seconds (P < .05) than crevices following displacement for 4, 6, and 8 minutes. No significant difference in crevicular width was found at any time period after cord removal for crevices displaced for 4, 6, and 8 minutes. At the transitional line angle, crevicular widths were significantly smaller than at the midbuccal at 20 seconds for all times and remained so up to 180 seconds. To achieve a crevicular width of 0.2 mm, cord should remain in the gingival crevice for an optimum time of 4 minutes prior to impression making when using the materials evaluated in this study.

Splinting osseointegrated implants and natural teeth in rehabilitation of partially edentulous patients. Part I: laboratory and clinical studies.

A significant clinical consideration in the restoration of partial edentulism with implant and tooth-supported prostheses is whether implants and natural teeth abutments should be splinted, and if so, in what manner. This article presents a review of laboratory and clinical studies related to splinting. Stress analysis studies reveal high stress concentration around the implant neck when rigidly connected to teeth. This was not borne out in in vivo studies in short-span bridges. While stress absorbing elements have been advocated to redistribute and reduce stress concentration away from the implant neck where bone resorption is often seen, finite element analysis and photo-elastic studies demonstrate that such stress absorbing elements may be effective only when their resiliency is in the same order of magnitude as the periodontal ligament. Clinical studies reporting life table statistics in combined implant and tooth restorations do not show adverse effects of splinting teeth to implants. These studies, however, are mostly short-term reports on survival with results that are as yet inconclusive. The issue of connecting with rigid or non-rigid connectors remains unresolved with a growing body of information favouring retrievable short-span rigid connection to non-mobile teeth. Root intrusion is a potential clinical hazard of non-rigid connection.

The effect of marginal thickness on the distortion of different impression materials.

An impression of the margins of a prepared tooth and adjacent gingival sulcus must be of sufficient thickness to withstand distortion and tearing when the impression is removed from the mouth. The purpose of this study was to compare the dimensional accuracy of Elite, Examix, and Express polyvinyl siloxanes; Permadyne polyether; and Permlastic polysulfide elastomeric impression materials. These materials were used to make impressions of a metal model that simulated prepared abutments with gingival sulci of various widths. A traveling microscope was used to measure the abutments and impression widths, and the number of defects in each impression was recorded. Between 70% and 100% of the abutment impressions with sulcular widths of 0.05 mm exhibited defects, which prevented accurate measurements in this group. Express material demonstrated a high number of defects in the 0.10 and 0.16 mm sulcular width groups. No great difference in average maximum distortion values or coefficients of variation (CV) were detected among the materials used to make impressions of abutments with sulcular width groups of 0.2 to 0.4 mm. For the sulci of 0.16 mm and less, Examix and Permiastic materials exhibited distortion and a CV comparable to the impressions of the wider sulcular groups, whereas Elite and Permadyne showed greater distortions and CVs. The differences were not statistically significant (analysis of variance) because of the larger CV among the groups. The larger coefficient of variation in the 0.1 and 0.16 mm sulcular width groups demonstrated inconsistencies in obtaining good impressions of abutments with such narrow sulcular widths.

Effect of different cooling rates on fracture toughness and microhardness of a glazed alumina reinforced porcelain.

Dental porcelain has superior esthetics but may be subject to fracture during mastication. Residual compressive stresses on the porcelain surface after cooling enhance resistance of porcelain to crack initiation, as quantified by its fracture toughness (Kc). The effect of different cooling rates on Kc and hardness of a glazed porcelain reinforced with approximately 2% aluminum oxide was examined in 45 porcelain disks that were divided into three groups. After final glaze firing, one group was cooled rapidly, the second was cooled at a medium rate, and the third was cooled slowly. Fracture toughness was determined with a microindentation procedure. The mean Kc recorded for rapidly cooled porcelain (1.74 +/- 0.09 MN/m3/2), for medium-cooled porcelain (1.41 +/- 0.07 MN/m3/2), and for slow-cooled porcelain (1.29 +/- 0.07 MN/m3/2) was statistically different (p < 0.001, analysis of variance and Bonferroni post hoc test). No statistically significant differences in Vickers hardness values were recorded when porcelain was cooled at different rates (530 to 540) (analysis of variance). The faster cooling rate of a glazed alumina reinforced porcelain resulted in greater fracture toughness but had no effect on hardness.