Contrast Enhancement Method Using Region-Based Dynamic Clipping Technique for LWIR-Based Thermal Camera of Night Vision Systems.

In the autonomous driving industry, there is a growing trend to employ long-wave infrared (LWIR)-based uncooled thermal-imaging cameras, capable of robustly collecting data even in extreme environments. Consequently, both industry and academia are actively researching contrast-enhancement techniques to improve the quality of LWIR-based thermal-imaging cameras. However, most research results only showcase experimental outcomes using mass-produced products that already incorporate contrast-enhancement techniques. Put differently, there is a lack of experimental data on contrast enhancement post-non-uniformity (NUC) and temperature compensation (TC) processes, which generate the images seen in the final products. To bridge this gap, we propose a histogram equalization (HE)-based contrast enhancement method that incorporates a region-based clipping technique. Furthermore, we present experimental results on the images obtained after applying NUC and TC processes. We simultaneously conducted visual and qualitative performance evaluations on images acquired after NUC and TC processes. In the visual evaluation, it was confirmed that the proposed method improves image clarity and contrast ratio compared to conventional HE-based methods, even in challenging driving scenarios such as tunnels. In the qualitative evaluation, the proposed method demonstrated upper-middle-class rankings in both image quality and processing speed metrics. Therefore, our proposed method proves to be effective for the essential contrast enhancement process in LWIR-based uncooled thermal-imaging cameras intended for autonomous driving platforms.

Synergistic effect of hyperbaric oxygen therapy with PTH [1-34] on calvarial bone graft in irradiated rat.

OBJECTIVE: To determine the synergistic effect of parathyroid hormone (PTH) [1-34] in combination with hyperbaric oxygen (HBO) on bone graft in a rat calvarial bone defect model under impaired osteogenic conditions. MATERIALS AND METHODS: Twenty-four rats were divided into three groups. Localized radiation with a single 12 Gy dose was administered to the calvaria. Four weeks after radiation, calvarial circular defects were created in the parietal bones. All defects were filled with biphasic calcium phosphate. After the bone graft, PTH [1-34] was injected subcutaneously, and HBO was administered. At 6 weeks after the bone graft, the rats were sacrificed, and specimens were harvested. RESULTS: Histomorphometric evaluation showed that the percentage of new bone area was higher in the PTH and PTH/HBO groups than in the control group. The percent residual material area was decreased in the PTH/HBO group compared with the control group. The percentage blood vessel number was highest in the PTH group. Micro-CT evaluation showed that the new bone volume was highest in the PTH/HBO group. The residual material volume was lowest in the PTH/HBO group. CONCLUSION: Within the limitations of this study, our data indicate that PTH combined with HBO may reverse radiation-induced impairment of bone healing.

Control of dental-derived induced pluripotent stem cells through modified surfaces for dental application.

OBJECTIVE: The aim of this study is to investigate the behaviour of iPSc derived from dental stem cells in terms of initial adhesion, differentiation potential on differently surface-treated titanium disc. MATERIALS AND METHODS: iPSc derived from human gingival fibroblasts (hGFs) were established using 4-reprogramming factors transduction with Sendai virus. The hGF-iPSc established in this study exhibited the morphology and growth properties similar to human embryonic stem (ES) cells and expressed pluripotency makers. Alkaline Phosphatase (AP) staining, Embryoid Body (EB) formation and in vitro differentiation and karyotyping further confirmed pluripotency of hGF-iPSc. Then, hGF-iPSc were cultured on machined- and Sandblasted and acid etched (SLA)-treated titanium discs with osteogenic induction medium and their morphological as well as quantitative changes according to different surface types were investigated using Alizrin Red S staining, Scanning electron microscopy (SEM), Flow cytometry and RT-PCR. RESULTS: Time-dependent and surface-dependent morphological changes as well as quantitative change in osteogenic differentiation of hGF-iPSc were identified and osteogenic gene expression of hGF-iPSc cultured on SLA-treated titanium disc found to be greater than machined titanium disc, suggesting the fate of hGF-iPSc may be determined by the characteristics of surface to which hGF-iPSc first adhere. CONCLUSIONS: iPSc derived from dental stem cell can be one of the most promising and practical cell sources for personalized regenerative dentistry and their morphological change as well as quantitative change in osteogenic differentiation according to different surface types may be further utilized for future clinical application incorporated with dental implant.

Effect of Serial Use of Bone Morphogenetic Protein 2 and Fibroblast Growth Factor 2 on Periodontal Tissue Regeneration.

PURPOSE: This study evaluates the synergistic effect of serial application of bone morphogenetic protein 2 (BMP2) and fibroblast growth factor 2 (FGF2) on both new bone formation and periodontal tissue regeneration using 1-wall intrabony defect in mongrel dogs. MATERIALS AND METHODS: One-wall defects were created at the mesial aspect of the mandibular first molars of 6 male mongrel dogs. Each mandibular defect received 1 of the 2 experimental treatments randomly (BMP2 or BMP2 + FGF2), and it was allowed to heal for either 4 or 8 weeks postoperatively. Histologic and histomorphometric analyses were performed for the evaluation of the overall healing patterns of new bone formation and periodontal tissue regeneration. RESULTS: The results showed that after 8 weeks, serial application of BMP2 and FGF2 significantly improved the periodontal tissue regeneration, whereas application of BMP2 only showed greater new bone formation after 4 weeks. CONCLUSIONS: The serial application of BMP2 and FGF2 may have synergistic effects on periodontal tissue regeneration over time.

Effects of chronic dietary nitrate supplementation on the hemodynamic response to dynamic exercise.

While acute treatment with beetroot juice (BRJ) containing nitrate (NO3 (-)) can lower systolic blood pressure (SBP), afterload, and myocardial O2 demand during submaximal exercise, effects of chronic supplementation with BRJ (containing a relatively low dose of NO3 (-), 400 mg) on cardiac output (CO), SBP, total peripheral resistance (TPR), and the work of the heart in response to dynamic exercise are not known. Thus, in 14 healthy males (22 ± 1 yr), we compared effects of 15 days of both BRJ and nitrate-depleted beetroot juice (NDBRJ) supplementation on plasma concentrations of NOx (NO3 (-)/NO2 (-)), SBP, diastolic blood pressure (DBP), mean arterial pressure (MAP), CO, TPR, and rate pressure product (RPP) at rest and during progressive cycling exercise. Endothelial function was also assessed via flow-mediated dilation (FMD). BRJ supplementation increased plasma NOx from 83.8 ± 13.8 to 167.6 ± 13.2 µM. Compared with NDBRJ, BRJ reduced SBP, DBP, MAP, and TPR at rest and during exercise (P < 0.05). In addition, RPP was decreased during exercise, while CO was increased, but only at rest and the 30% workload (P < 0.05). BRJ enhanced FMD-induced increases in brachial artery diameter (pre: 12.3 ± 1.6%; post: 17.8 ± 1.9%). We conclude that 1) chronic supplementation with BRJ lowers blood pressure and vascular resistance at rest and during exercise and attenuates RPP during exercise and 2) these effects may be due, in part, to enhanced endothelium-induced vasodilation in contracting skeletal muscle. Findings suggest that BRJ can act as a dietary nutraceutical capable of enhancing O2 delivery and reducing work of the heart, such that exercise can be performed at a given workload for a longer period of time before the onset of fatigue.

Multicenter randomized trial of 3-month cilostazol use in addition to dual antiplatelet therapy after biolimus-eluting stent implantation for long or multivessel coronary artery disease.

BACKGROUND: There are conflicting data on the use of cilostazol as triple antiplatelet therapy (TAPT) for improving clinical outcomes after drug-eluting stent implantation. We aimed to evaluate whether 3-month use of cilostazol in addition to dual antiplatelet therapy (DAPT) improved clinical outcomes in patients with long or multivessel coronary artery disease (CAD) after biolimus-eluting stent (BES) implantation. METHODS: Patients (n = 630) who had been successfully treated with BES implantation for lesions with ≥28 mm in stent length or ≥2 stents for different coronary arteries were enrolled in this prospective randomized multicenter trial. All patients were randomly assigned to receive either DAPT (aspirin and clopidogrel for 12 months, n = 314) or TAPT (DAPT plus 3-month cilostazol use, n = 316). The primary end point was a device-oriented composite consisting of cardiac death, myocardial infarction (not clearly attributable to a nontarget vessel), and ischemia-driven target lesion revascularization at 1-year follow-up. RESULTS: A total of 314 patients in DAPT and 308 patients in TAPT were analyzed. Multivessel CAD was present in 65.7% of patients. Stents ≥28 mm in length were implanted in 58.1% of lesions. There were no significant differences in baseline and angiographic characteristics between the 2 groups. The primary end point was similar between the 2 groups (2.3% in DAPT vs 1.9% in TAPT, log-rank P = .799). CONCLUSIONS: In patients treated with BES implantation for long or multivessel CAD, 3 months of cilostazol use in addition to DAPT did not improve clinical outcome at 1-year follow-up.

Evaluating the marginal fit of zirconia copings with digital impressions with an intraoral digital scanner.

STATEMENT OF PROBLEM: Digital impression systems have been developed to overcome the disadvantages associated with conventional impression methods. PURPOSE: The purpose of this study was to compare the marginal fit of zirconia copings designed with the use of an iTero digital scanner with those designed by the conventional impression technique. MATERIAL AND METHODS: Thirty identical cast, base-metal dies from 1 maxillary central incisor prepared for a ceramic crown restoration were fabricated. For the conventional impression group (CI), base metal dies (n=10) were replicated as stone dies by means of a conventional impression technique with polyvinyl siloxane material. For the iTero with polyurethane group (iP), base metal dies (n=10) were replicated as polyurethane dies with the iTero digital impression system. For the iTero with no dies group (iNo), base metal dies (n=10) were scanned with the iTero digital impression system, but no dies were fabricated. For each group, 10 zirconia copings were fabricated based on the stone dies (CI group), polyurethane dies (iP group), or stereolithography files (iNo group). The marginal gap of each specimen was measured with a light microscope at ×50 magnification. One-way analysis of variance and the Tukey honestly significant difference test were used for statistical analysis (α=.05). RESULTS: Statistically significant differences were found between the CI group and iP group (P<.05) and between the CI group and iNo group (P<.05). CONCLUSIONS: The marginal gap between the restoration and definitive cast base metal die was greater in the groups that used the digital impression method than in the group that used the conventional impression method. However, the marginal discrepancies of all of the groups were clinically acceptable.

Study design and rationale of "a multicenter, open-labeled, randomized controlled trial comparing three 2nd-generation drug-eluting stents in real-world practice" (CHOICE trial).

BACKGROUND: The second-generation drug-eluting stents (DES) have shown superiority in many studies relating to safety and efficacy when compared with the first-generation DES. However, it is unclear whether there are differences in efficacy and safety among the second-generation DES after long-term follow-up. METHODS: This multicenter, prospective, randomized, open-labeled trial will directly compare the efficacy and safety among the patients treated with either everolimus-eluting stent (EES), zotarolimus-eluting stent with biolinx polymer (ZES-R), or biolimus-eluting stent (BES) with minimal exclusion criteria. The primary end point is a patient-oriented composite consisted of cardiac death, myocardial infarction not clearly attributable to a nontarget vessel and clinically indicated target lesion revascularization at 24-month clinical follow-up post-index procedure. With the hypothesis that "BES is non-inferior to EES" or "BES is non-inferior to ZES-R" in primary end point, approximately 2,600 patients will be assigned to one of the types of stents using a web-based randomization system. CONCLUSIONS: The CHOICE trial will directly compare the efficacy and safety of EES, ZES-R, and BES in everyday clinical practice for long-term follow-up.

Effects of Ovarian Cycle on Hemodynamic Responses during Dynamic Exercise in Sedentary Women.

This study tested the hypothesis that effects of the menstrual cycle on resting blood pressure carry over to dynamic exercise. Eleven healthy females were studied during the early (EP; low estrogen, low progesterone) and late follicular (LP; high estrogen, low progesterone) menstrual phases. Stroke volume (SV), heart rate (HR), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), and total vascular conductance (TVC) were assessed at rest and in response to mild and moderate cycling exercise during EP and LP. During EP, compared to LP, baseline SBP (111±1 vs. 103±2 mmHg), DBP (71±2 vs. 65±2 mmHg) and mean arterial pressure (MAP) (84±2 vs. 78±1 mmHg) were higher and TVC (47.0±1.5 vs. 54.9±4.2 ml/min/mmHg) was lower (p<0.05). During exercise, absolute values of SBP (Mild: 142±4 vs. 127±5 mmHg; Moderate: 157±4 vs. 144±5 mmHg) and MAP (Mild: 100±3 vs. 91±3 mmHg; Moderate: 110±3 vs. 101±3 mmHg) were also higher, while TVC was lower (Mild: 90.9±5.1 vs. 105.4±5.2 ml/min/mmHg; Moderate: 105.4±5.3 vs. 123.9±8.1 ml/min/mmHg) during EP (p<0.05). However, exercise-induced increases in SBP, MAP and TVC at both work intensities were similar between the two menstrual phases, even though norepinephrine concentrations were higher during LP. Results indicate that blood pressure during dynamic exercise fluctuates during the menstrual cycle. It is higher during EP than LP and appears to be due to additive effects of simultaneous increases in baseline blood pressure and reductions in baseline TVC.

Skeletal muscle metaboreflex is enhanced in postmenopausal women.

This study determined whether an elevated muscle metaboreflex contributes to the excessive blood pressure response to exercise in postmenopausal women. Thirty healthy female volunteers were studied (15 postmenopausal and 15 premenopausal). Stroke volume, heart rate, cardiac output (CO), systolic blood pressure, diastolic blood pressure, and total vascular conductance (TVC) were continuously assessed throughout the experiment. To activate the muscle metaboreflex, occlusion of the vasculature was induced via inflation of a blood pressure cuff (2 min) on the upper arm following static handgrip exercise. Muscle metaboreflex activation increased mean arterial pressure (MAP) in both groups. However, this pressor response was greater in the postmenopausal women (ΔMAP: 21.4 ± 3 vs. 14.5 ± 2 mmHg) (P < 0.05) even though the corresponding increase in CO was less (ΔCO: 0.0 ± 0.2 vs. 0.3 ± 0.2 l/min) (P < 0.05). TVC decreased in both the groups but was more pronounced in the postmenopausal group (ΔTVC: -10.7 ± 2.6 vs. -17.1 ± 3.6 ml/min/mmHg) (P < 0.05). In conclusion, the exaggerated blood pressure response to exercise in postmenopausal women is mediated, in part, by an overactive metaboreflex that is associated with enhanced peripheral vasoconstriction.

In Vivo Study for Clinical Application of Dental Stem Cell Therapy Incorporated with Dental Titanium Implants.

The aim of this study was to investigate the behavior of dental-derived human mesenchymal stem cells (d-hMSCs) in response to differently surface-treated implants and to evaluate the effect of d-hMSCs on local osteogenesis around an implant in vivo. d-hMSCs derived from alveolar bone were established and cultured on machined, sandblasted and acid-etched (SLA)-treated titanium discs with and without osteogenic induction medium. Their morphological and osteogenic potential was assessed by scanning electron microscopy (SEM) and real-time polymerase chain reaction (RT-PCR) via mixing of 5 × 106 of d-hMSCs with 1 mL of Metrigel and 20 µL of gel-cell mixture, which was dispensed into the defect followed by the placement of customized mini-implants (machined, SLA-treated implants) in New Zealand white rabbits. Following healing periods of 2 weeks and 12 weeks, the obtained samples in each group were analyzed radiographically, histomorphometrically and immunohistochemically. The quantitative change in osteogenic differentiation of d-hMSCs was identified according to the type of surface treatment. Radiographic analysis revealed that an increase in new bone formation was statistically significant in the d-hMSCs group. Histomorphometric analysis was in accordance with radiographic analysis, showing the significantly increased new bone formation in the d-hMSCs group regardless of time of sacrifice. Human nuclei A was identified near the area where d-hMSCs were implanted but the level of expression was found to be decreased as time passed. Within the limitations of the present study, in this animal model, the transplantation of d-hMSCs enhanced the new bone formation around an implant and the survival and function of the stem cells was experimentally proven up to 12 weeks post-sacrifice.

Effects of Elastic Band Exercise on Functional Fitness and Blood Pressure Response in the Healthy Elderly.

Purpose: This study investigated the effects of 12 weeks of moderate intensity elastic band exercise (EBE) on functional fitness and blood pressure parameters in the elderly. Methods: 27 healthy older adults were randomly assigned to an exercise group (n = 15, age: 75.1 ± 1.4 years) and a control group (n = 12, age: 72.3 ± 1.4 years). Participants performed EBE for 60 min, three times a week, over the course of three months. The EBE consisted of incremental resistance and aerobic exercises designed to improve whole body fitness. Functional fitness and resting cardiovascular parameters were assessed before and after the exercise training program. Results: Grip strength, sit and reach, and one-leg stance improved significantly in the exercise group, while no significant improvements were found in chair stand and timed up and go (p < 0.05). Cardiovascular parameters including systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure significantly decreased in the exercise group relative to the control group (p < 0.05). Conclusions: Findings of the present study suggest that safe, inexpensive, and easily accessible EBE program with circuit training components play a significant role in improving upper and lower body fitness, as well as cardiovascular fitness, in the elderly.

Clinical Anatomy of the Puboprostatic Ligament for the Safe Guidance for the Prostate Surgery.

OBJECTIVE: To provide the anatomy of the puboprostatic ligament and related structures to save urogenital competence after prostatectomy. MATERIALS AND METHODS: Pelvic areas of 31 adult cadavers were dissected to figure out the shape, number, and location of the puboprostatic ligaments. RESULTS: The puboprostatic ligament was the most important support structure between the pubic bone and prostate gland. Puboprostatic ligaments were bilaterally single (61.3%), bilaterally double (19.4%), or mixed (19.4%). Ligaments were mostly I-shaped (53.8%). If ligaments had extra attachment to or from the arcuate line, the ligaments were λ-shaped (36.3%), or Y-shaped (8.8%). In one case, the ligament had a central fusion with an irregular shape. I-shaped puboprostatic ligaments were observed more frequently in specimens with double ligaments, while λ-shaped puboprostatic ligaments were observed more frequently in the cases with single ligaments. The average distance between both puboprostatic ligaments was 8.1 mm at the pubic site and 14.2 mm at the prostate site. The distance was narrower when the specimen had double puboprostatic ligaments on both sides. The neurovascular bundle ran beneath the puboprostatic ligament. If the ligament was the λ-shaped type, the neurovascular bundle frequently pierced the lateral band of the ligament. CONCLUSION: Puboprostatic ligaments hold and stabilize the prostate against the pubic bone. It is believed that a pelvis with bilateral, double puboprostatic ligaments would have advantages in urogenital competence. The morphologic data of the shape, multiplicity, and location of the PPLs would help to make a plan to approach the prostate.

Toxicity evaluation of complex metal mixtures using reduced metal concentrations: application to iron oxidation by Acidithiobacillus ferrooxidans.

In this study, we investigated the inhibition effects of single and mixed heavy metal ions (Zn2+, Ni2+, Cu2+, and Cd2+) on iron oxidation by Acidithiobacillus ferrooxidans. Effects of metals on the iron oxidation activity of A. ferrooxidans are categorized into four types of patterns according to its oxidation behavior. The results indicated that the inhibition effects of the metals on the iron oxidation activity were noncompetitive inhibitions. We proposed a reduced inhibition model, along with the reduced inhibition constant (alpha i), which was derived from the inhibition constant (KI) of individual metals and represented the tolerance of a given inhibitor relative to that of a reference inhibitor. This model was used to evaluate the toxicity effect (inhibition effect) of metals on the iron oxidation activity of A. ferrooxidans. The model revealed that the iron oxidation behavior of the metals, regardless of metal systems (single, binary, ternary, or quaternary), is closely matched to that of any reference inhibitor at the same reduced inhibition concentration, [I]reduced, which defines the ratio of the inhibitor concentration to the reduced inhibition constant. The model demonstrated that single metal systems and mixed metal systems with the same reduced inhibitor concentrations have similar toxic effects on microbial activity.

The reproducibility and validity verification for body composition measuring devices using bioelectrical impedance analysis in Korean adults.

The purpose of this study is to examine the validity and reproducibility of impedance body fat measurement devices measuring the body composition of Korean male and female adults using three bioelectrical impedance analyzers. We compared two methods for evaluating body composition: dual energy X-ray absorptiometry (DEXA), and bioelectrical impedance analysis (BIA). Subjects were 200 healthy adult Korean males and females whose mean±standard deviation (range) age, standing height, body weight, and body mass index (BMI) were 44.1±14.5 years, 172.8±7.4 cm, 76.0±12.8 kg, and 25.4±3.3 kg/m2, and 44.5±14.7 years, 158.7±5.8 cm, 58.3±8.3 kg, and 23.2±3.0 kg/m2, respectively. As a result, first of all, the reproducibility of the bioelectrical impedance analyzer had very high coefficients at r=0.998, r=0.997 between men and women, respectively. The correlation coefficients among three comparisons for lean body mass (LBM) were provided the following coefficients: r=0.951 for DEXA vs. ACCUNIQ BC720, r=0.950 for DEXA vs. ACCUNIQ BC360, and r=0.946 for DEXA vs. ACCUNIQ BC380 in men. In the results for women, they also had the very high following coefficients: r=0.956 for DEXA vs. ACCUNIQ BC720, r=0.946 for DEXA vs. ACCUNIQ BC360, and r=0.957 for DEXA vs. ACCUNIQ BC380 in LBM. In conclusion, this research showed a higher correlation in terms of accuracy compared to existing BIA-based body composition measurement techniques, and the accuracy of LBM was improved with high correlation coefficients through the algorithm that was improved using the multifrequency BIA method in the ACCUNIQ BC products.

Multiscale Structures Aggregated by Imprinted Nanofibers for Functional Surfaces.

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing challenge in the field is the fabrication of hybrid micro-nano structures using a facile, cost-effective, and high-throughput method. To overcome these challenges, this paper proposes a protocol to fabricate multiscale structures using only an imprint process with an anodic aluminum oxide (AAO) filter and an evaporative self-aggregation process of nanofibers. Unlike previous attempts that have aimed to straighten nanofibers, we demonstrate a unique fabrication method for multiscale aggregated nanofibers with high aspect ratios. Furthermore, the surface morphology and wettability of these structures on various liquids were investigated to facilitate their use in multifunctional surfaces.

Grape Seed Extract Supplementation Attenuates the Blood Pressure Response to Exercise in Prehypertensive Men.

We tested the hypothesis that exaggerated pressor responses observed in prehypertensive males (N = 9) during dynamic exercise are attenuated following acute dietary supplementation with grape seed extract (GSE) (i.e., a single dose). Effects of placebo and GSE (300 mg) on systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), cardiac output (CO), stroke volume (SV), total vascular conductance (TVC), and rate × pressure product (RPP) in response to two submaximal cycling workloads (40% and 60% VO2peak) were compared 2 h after ingestion of GSE or placebo on different days, 1 week apart. Endothelial function was also evaluated using flow-mediated dilation (FMD). Placebo treatment had no effect on any of the variables. GSE supplementation attenuated MAP at both workloads (40% VO2peak: 115 ± 1 vs. 112 ± 2 mmHg; 60% VO2peak: 126 ± 2 vs. 123 ± 2 mmHg) and RPP at the lower workload. Conversely, SV, CO, and TVC were augmented during both workloads. FMD was augmented by GSE (18.9 ± 2.0 vs. 12.4% ± 2.0%). These findings indicate that in exercising prehypertensive males, a single dose of GSE reduces blood pressure, peripheral vasoconstriction, and work of the heart and enhances O2 delivery; effects that may be due, in part, to endothelium-dependent vasodilation. We propose that acute GSE treatment represents an intervention that may minimize potential increases in the risk of cardiovascular events during dynamic exercise in prehypertensives.

Evaluation of stability of interface between CCM (Co-Cr-Mo) UCLA abutment and external hex implant.

PURPOSE: The purpose of this study is to evaluate the stability of interface between Co-Cr-Mo (CCM) UCLA abutment and external hex implant. MATERIALS AND METHODS: Sixteen external hex implant fixtures were assigned to two groups (CCM and Gold group) and were embedded in molds using clear acrylic resin. Screw-retained prostheses were constructed using CCM UCLA abutment and Gold UCLA abutment. The external implant fixture and screw-retained prostheses were connected using abutment screws. After the abutments were tightened to 30 Ncm torque, 5 kg thermocyclic functional loading was applied by chewing simulator. A target of 1.0 × 106 cycles was applied. After cyclic loading, removal torque values were recorded using a driving torque tester, and the interface between implant fixture and abutment was evaluated by scanning electronic microscope (SEM). The means and standard deviations (SD) between the CCM and Gold groups were analyzed with independent t-test at the significance level of 0.05. RESULTS: Fractures of crowns, abutments, abutment screws, and fixtures and loosening of abutment screws were not observed after thermocyclic loading. There were no statistically significant differences at the recorded removal torque values between CCM and Gold groups (P>.05). SEM analysis revealed that remarkable wear patterns were observed at the abutment interface only for Gold UCLA abutments. Those patterns were not observed for other specimens. CONCLUSION: Within the limit of this study, CCM UCLA abutment has no statistically significant difference in the stability of interface with external hex implant, compared with Gold UCLA abutment.

Clinical Acceptability of the Internal Gap of CAD/CAM PD-AG Crowns Using Intraoral Digital Impressions.

The purpose of this study was to compare the internal gap between CAD/CAM palladium-silver crowns and cast gold crowns generated from intraoral digital versus conventional impressions and to determine the clinical acceptability. Nickel-chrome master dies were made from the prepared resin tooth with the conventional impression method (n = 40). For ICC (Intraoral, CAD/CAM) group, 10 intraoral digital impressions were made, and 10 CAD/CAM crowns of a PD-AG (palladium-silver) machinable alloy were generated. For IC (Intraoral, Cast) group, 10 gold crowns were cast from ten intraoral digital impressions. For CCC (Conventional, CAD/CAM) group, 10 CAD/CAM PD-AG crowns were made using the conventional impression method. For CC (Conventional, Cast) group, 10 gold crowns were fabricated from 10 conventional impressions. One hundred magnifications of the internal gaps of each crown were measured at 50 points with an optical microscope and these values were statistically analyzed using a two-way analysis of variance (α = 0.05). The internal gap of the intraoral digital impression group was significantly larger than in the conventional impression group (P < 0.05). No significant difference was observed between the CAD/CAM group and the cast group (P > 0.05). Within the limitations of this in vitro study, crowns from intraoral digital impressions showed larger internal gap values than crowns from conventional impressions.

Histamine H2 receptor blockade augments blood pressure responses to acute submaximal exercise in males.

Histamine is a potent vasodilator that has been found to increase during exercise. We tested the hypothesis that histamine would attenuate blood pressure (BP), cardiac output (CO), and vascular resistance responses to short-term, submaximal dynamic exercise during H2 receptor blockade. Fourteen healthy men (20-29 years of age) were studied. Systolic (SBP), diastolic (DBP), and mean arterial (MAP) BP and heart rate (HR) were assessed at rest and during the last minute of 10 min of submaximal cycling exercise (60% of peak oxygen consumption) in the absence and presence of histamine H2 receptor blockade (ranitidine, 300 mg). Stroke volume (SV) (impedance cardiography) and plasma norepinephrine (NE) were measured, and CO, rate × pressure product (RPP), and total peripheral resistance (TPR) were calculated. Plasma levels of histamine were also measured. H2 blockade had no effects on any variables at rest. During exercise, SBP (184 ± 3 mm Hg vs. 166 ± 2 mm Hg), MAP (121 ± 2 mm Hg vs. 112 ± 5 mm Hg), and RPP (25.9 ± 0.8 × 10(3) mm Hg·beats/min vs. 23.5 ± 0.8 × 10(3) mm Hg/beats·min) were greater during blocked conditions (P < 0.05), and an interaction was observed for TPR. SV, DBP, HR, and NE levels were unaffected by blockade. Plasma histamine increased from 1.83 ± 0.14 ng/mL at rest to 2.33 ± 0.23 ng/mL during exercise (P < 0.05) and was not affected by H2 blockade (1.56 ± 0.23 ng/mL vs. 1.70 ± 0.24 ng/mL). These findings suggest that, during submaximal exercise, histamine attenuates BP, vascular resistance, and the work of the heart via activation of H2 receptors and that these effects occurred primarily in the vasculature and not in the myocardium.