Atomic Layer Deposition of Zirconia on Titanium Implants Improves Osseointegration in Rabbit Bones.

Purpose: Atomic layer deposition (ALD) is a method that can deposit zirconia uniformly on an atomic basis. The effect of deposited zirconia on titanium implants using ALD was evaluated in vivo. Methods: Machined titanium implants (MTIs) were used as the Control. MTIs treated by sandblasting with large grit and acid etching (SA) and MTIs deposited with zirconia using ALD are referred to as Groups S and Z, respectively. Twelve implants were prepared for each group. Six rabbits were used as experimental animals. To evaluate the osteogenesis and osteocyte aspects around the implants, radiological and histological analyses were performed. The bone-to-implant contact (BIC) ratio was measured and statistically analyzed to evaluate the osseointegration capabilities. Results: In the micro-CT analysis, more radiopaque bone tissues were observed around the implants in Groups S and Z. Histological observation found that Groups S and Z had more and denser mature bone tissues around the implants in the cortical bone area. Many new and mature bone tissues were also observed in the medullary cavity area. For the BIC ratio, Groups S and Z were significantly higher than the Control in the cortical bone area (P < 0.017), but there was no significant difference between Groups S and Z. Conclusion: MTIs deposited with zirconia using ALD (Group Z) radiologically and histologically showed more mature bone formation and activated osteocytes compared with MTIs (Control). Group Z also had a significantly higher BIC ratio than the Control. Within the limitations of this study, depositing zirconia on the surface of MTIs using ALD can improve osseointegration in vivo.

Calibration and simulation of a silicon dosemeter for ambient dose equivalent in low-earth orbit space.

A particle dosemeter (PD) is a payload of NEXTSat-2 in the low-earth orbit (LEO). The absorbed dose in LEO needs to be converted into the ambient dose equivalent (H*(10)). Due to a mixed field in LEO, the calibration factors (klow and khigh) should be determined for the low-and high-linear energy transfers (LET) (below and above 1.5 keV/µm), respectively. The PD was irradiated with a 137Cs source at the Korea Radiation Solution facility to obtain H*(10) and absorbed doses. However due to the lack of sources for the high-LET calibration, H*(10) and an absorbed dose were calculated by simulating PD for the high-energy neutron field at CERN-EU high-energy Reference Field. The measured klow of PD had a difference of 5.1% and 9.5% from the calculated value of PD and the measured value of Liulin detectors, respectively. However, a difference in khigh between PD and Liulin was explained by the contribution of non-neutron components to Liulin in the measurements.

An induced annual modulation signature in COSINE-100 data by DAMA/LIBRA's analysis method.

The DAMA/LIBRA collaboration has reported the observation of an annual modulation in the event rate that has been attributed to dark matter interactions over the last two decades. However, even though tremendous efforts to detect similar dark matter interactions were pursued, no definitive evidence has been observed to corroborate the DAMA/LIBRA signal. Many studies assuming various dark matter models have attempted to reconcile DAMA/LIBRA's modulation signals and null results from other experiments, however no clear conclusion can be drawn. Apart from the dark matter hypothesis, several studies have examined the possibility that the modulation is induced by variations in detector's environment or their specific analysis methods. In particular, a recent study presents a possible cause of the annual modulation from an analysis method adopted by the DAMA/LIBRA experiment in which the observed annual modulation could be reproduced by a slowly varying time-dependent background. Here, we study the COSINE-100 data using an analysis method similar to the one adopted by the DAMA/LIBRA experiment and observe a significant annual modulation, however the modulation phase is almost opposite to that of the DAMA/LIBRA data. Assuming the same background composition for COSINE-100 and DAMA/LIBRA, simulated experiments for the DAMA/LIBRA without dark matter signals also provide significant annual modulation with an amplitude similar to DAMA/LIBRA with opposite phase. Even though this observation does not directly explain the DAMA/LIBRA results directly, this interesting phenomenon motivates more profound studies of the time-dependent DAMA/LIBRA background data.

Convolutional neural network-based reconstruction for positronium annihilation localization.

A novel hermetic detector composed of 200 bismuth germanium oxide crystal scintillators and 393 channel silicon photomultipliers has been developed for positronium (Ps) annihilation studies. This compact 4π detector is capable of simultaneously detecting γ-ray decay in all directions, enabling not only the study of visible and invisible exotic decay processes but also tumor localization in positron emission tomography for small animals. In this study, we investigate the use of a convolutional neural network (CNN) for the localization of Ps annihilation synonymous with tumor localization. Two-γ decay systems of the Ps annihilation from 22Na and 18F radioactive sources are simulated using a GEANT4 simulation. The simulated datasets are preprocessed by applying energy cutoffs. The spatial error in the XY plane from the CNN is compared to that from the classical weighted k-means algorithm centroiding, and the feasibility of CNN-based Ps annihilation reconstruction with tumor localization is discussed.

Strong constraints from COSINE-100 on the DAMA dark matter results using the same sodium iodide target.

We present new constraints on dark matter interactions using 1.7 years of COSINE-100 data. The COSINE-100 experiment, consisting of 106 kg of tallium-doped sodium iodide [NaI(Tl)] target material, is aimed to test DAMA's claim of dark matter observation using the same NaI(Tl) detectors. Improved event selection requirements, a more precise understanding of the detector background, and the use of a larger dataset considerably enhance the COSINE-100 sensitivity for dark matter detection. No signal consistent with the dark matter interaction is identified and rules out model-dependent dark matter interpretations of the DAMA signals in the specific context of standard halo model with the same NaI(Tl) target for various interaction hypotheses.

Magnetic Resonance Spectroscopy of Hepatic Fat from Fundamental to Clinical Applications.

The number of individuals suffering from fatty liver is increasing worldwide, leading to interest in the noninvasive study of liver fat. Magnetic resonance spectroscopy (MRS) is a powerful tool that allows direct quantification of metabolites in tissue or areas of interest. MRS has been applied in both research and clinical studies to assess liver fat noninvasively in vivo. MRS has also demonstrated excellent performance in liver fat assessment with high sensitivity and specificity compared to biopsy and other imaging modalities. Because of these qualities, MRS has been generally accepted as the reference standard for the noninvasive measurement of liver steatosis. MRS is an evolving technique with high potential as a diagnostic tool in the clinical setting. This review aims to provide a brief overview of the MRS principle for liver fat assessment and its application, and to summarize the current state of MRS study in comparison to other techniques.

A cryogenic setup for multifunctional characterization of luminescence and scintillation properties of single crystals.

This article reports on a cryogenic setup that can be used for multifunctional experimental purposes. The temperature of the setup can be set from 10 K to 300 K. Different kinds of experiments were carried out in this experimental setup such as (1) luminescence emission, light yield, and decay time measurement under excitation of 266 nm laser and 280 nm LED sources, (2) thermoluminescence (TL) measurement under an x-ray excitation source, (3) scintillation property measurements such as light output, energy resolution, and decay time under 137Cs (662 keV γ-rays) and 241Am (5.4 MeV α) isotope sources, and (4) scintillation measurement under a 90Sr beta source through the continuous single-photon counting technique. The luminescence and scintillation properties of various molybdate and tungstate crystals such as CaMoO4, Na2Mo2O7, Pb2MoO5, CdWO4, and ZnWO4 are characterized and reported in the present work. The TL measurement of a CaMoO4 crystal is carried out from 10 K to 300 K, and various kinetic parameters such as order of kinetics, frequency factor, activation energy, and figure of merit are calculated for different TL peaks. As the temperature goes down from room to 10 K, the light yield of all studied crystals increases. Since the light yield of the crystal increases as temperature decreases toward 10 K, this experimental setup can be used for the characterization of luminescence and scintillation properties of a single crystal for rare event searches such as neutrinoless double-beta decay and dark matter.

Risk Factors of a Pulmonary Thromboembolism After Colorectal Surgery.

PURPOSE: Previous studies have revealed that predictors and risk factors of pulmonary thromboembolism (PTE) are malignancy, immobilization, diabetes, and obesity in the postoperative patients. However, in patients undergoing colorectal cancer, studies of PTE have not been enough. Thus, we investigated the risk factors of PTE related to colorectal surgery. METHODS: From January 2009 to October 2014, 312 patients received colorectal surgery without other organ resection. The postoperative patients with PTE were 14 (4.5%), and they were classified by sex, age, and stage as a 1:3 paired match to the control group. A multiple logistic regression was performed to identify which factors were associated with PTE. RESULTS: One patient was in stage I, 3 in stage II, 9 in stage III, and 1 in stage IV. In the binary logistic regression analysis, history of diabetes mellitus (odds ratio, 6.498; P = 0.031) and being overweight (odds ratio, 10.018; P = 0.014) were independent risk factors for PTE in patients undergoing colorectal cancer. CONCLUSION: A history of diabetes mellitus and being overweight were independent risk factors of PTE after colorectal cancer.

Analysis of the potent prognostic factors in luminal-type breast cancer.

PURPOSE: Luminal-type breast cancer has a good prognosis compared to other types, such as human epidermal growth factor receptor 2 and triple negative types. Luminal-type breast cancer is classified into luminal A and B, according to the proliferation index. We investigated the clinicopathological factors that affect the prognosis of the luminal-type subgroups. METHODS: We reviewed the medical records and the pathologic reports of 159 luminal-type breast cancer patients who were treated between February 2005 and November 2007. We divided luminal-type breast cancer into luminal A and B, according to Ki-67 (cutoff value, 14%) and analyzed the clinicopathologic factors, such as age at diagnosis, intensity score of estrogen receptor and progesterone receptor, histologic grade, and Bcl-2. Moreover, we compared the disease-free survival (DFS) of each group. RESULTS: In the univariate analysis, age (p=0.004), tumor size (p=0.010), lymph node metastasis (p=0.001), and Bcl-2 (p=0.002) were statistically significant factors in luminal-type breast cancer. In the multivariate analysis, lymph node (p=0.049) and Bcl-2 (p=0.034) were significant relevant factors in luminal-type breast cancer. In the subgroup analysis, the increased Bcl-2 (cutoff value, 33%) was related with a longer DFS in the luminal B group (p=0.004). CONCLUSION: In our study, luminal A breast cancer showed a longer DFS than luminal B breast cancer, further, Bcl-2 may be a potent prognostic factor in luminal-type breast cancer.

Comparative study of a single-incision laparoscopic and a conventional laparoscopic appendectomy for the treatment of acute appendicitis.

PURPOSE: For the treatment of acute appendicitis, a conventional laparoscopic appendectomy (LA) has been widely performed. Recently, the use of single incision laparoscopic surgery (SILS) is increasing because it is believed to have advantages over conventional laparoscopic surgery. In this study, we compared SILS and a conventional LA. METHODS: We analyzed the 217 patients who received laparoscopy-assisted appendectomies between August 2010 and April 2012 at Inje University Sanggye Paik Hospital. One hundred-twelve patients underwent SILS, and 105 patients underwent LA. For the two groups, we compared the operation times, postoperative laboratory results, postoperative pain, hospital stay, and postoperative complications. RESULTS: The patients' demographics, including body mass index, were not significantly different between the two groups. There were 6 perforated appendicitis cases in the SILS group and 5 cases in the LA group. The mean operative time in the SILS group was 65.88 ± 22.74 minutes whereas that in the LA group was 61.70 ± 22.27 minutes (P = 0.276). There were no significant differences in the mean hospital stays, use of nonsteroidal antiinflammatory drugs, and wound infections between the two groups. CONCLUSION: Postoperative pain, complications and hospital stay showed no statistically significant differences between the SILS and the LA groups. However, our SILS method uses a single trocar and two latex tubes, so cost savings and reduced interference during surgery are expected.

Effect of zirconia surface treatments on the shear bond strength of veneering ceramic.

STATEMENT OF PROBLEM: Various surface treatments of zirconia have been recommended for veneering ceramics. However, it has not been determined which of these treatments produces the highest bond strength. PURPOSE: This study examined the effects of various surface treatments on the shear bond strength of zirconia and veneering ceramic. MATERIAL AND METHODS: Square-shaped (5 × 10 × 10 mm) zirconia (Everest) specimens were divided into 4 groups (n=8) according to surface treatment as follows: group C, grinding with #320 diamond disc (control); group A, airborne-particle abrasion with 110 µm Al(2)O(3); group L, application of liner (Cerabien); and group AL, airborne-particle abrasion with 110 µm Al(2)O(3) and application of liner. A cylinder of veneering ceramic (2.4 mm in diameter and 3 mm in height) (Cerabien) was fabricated and fired on the zirconia specimens. The shear bond strength was tested using a universal testing machine. The data were analyzed statistically using a 1-way ANOVA and Tukey's multiple comparisons test (α=.05). The interface and fractured surfaces of the specimens were also evaluated by field emission scanning electron microscopy (FE-SEM). RESULTS: The mean and SD values for the shear bond strength of the groups ranged from 27.87 ± 3.59 MPa (for group L) to 36.63 ± 2.96 MPa (for group A). The 1-way ANOVA revealed a significant difference between groups (P=.001). The airborne-particle abrasion group showed significantly higher bond strength than liner applied groups (L, AL) (P<.05). The SEM revealed that liner-applied groups (L, AL) showed primarily adhesive failure. Complete delamination and microspaces were also observed in the liner-applied groups. CONCLUSIONS: The mean in vitro shear bond strength of veneering ceramic on zirconia treated with airborne-particle abrasion was significantly higher than that subjected to liner-applied treatments.

Serum adipocyte-specific fatty acid-binding protein is associated with nonalcoholic fatty liver disease in apparently healthy subjects.

Adipocyte-specific fatty acid-binding protein (A-FABP) is a cytoplasmic protein that is expressed in adipocytes and is closely associated with insulin resistance, metabolic syndrome, and Type 2 diabetes. We investigated the relationship between A-FABP as a surrogate marker of metabolic syndrome and non-alcoholic fatty liver disease (NAFLD) in apparently healthy subjects. We assessed clinical and biochemical metabolic parameters and measured serum levels of A-FABP, high-sensitivity C-reactive protein and tumor necrosis factor-α (TNF-α) in 494 subjects who were divided into two groups according to the presence of NAFLD by abdominal ultrasonography. All parameters associated with metabolic syndrome were significantly higher in patients with NAFLD (P<.001). A-FABP showed positive correlation with TNF-α, homeostasis model assessment index of insulin resistance (HOMA-IR), and metabolic syndrome (P<.001) when adjusted for age and sex. The odds ratio for the risk of NAFLD in the highest tertile of A-FABP compared with the lowest tertile was 7.36 (CI 3.80-14.27, P<.001) after adjustment for age and sex; 4.52 (CI 2.22-9.20, P<.001) after adjustment for age, sex, HOMA-IR and metabolic syndrome and 2.86 (CI 1.11-7.35, P<.05) after further adjustment for all metabolic parameters including TNF-α. The serum level of A-FABP was independently associated with NAFLD and showed significant correlation with TNF-α, HOMA-IR, and metabolic syndrome.

Pre-operative predictive factors for gallbladder cholesterol polyps using conventional diagnostic imaging.

AIM: To determine the clinical data that might be useful for differentiating benign from malignant gallbladder (GB) polyps by comparing radiological methods, including abdominal ultrasonography (US) and computed tomography (CT) scanning, with postoperative pathology findings. METHODS: Fifty-nine patients underwent laparoscopic cholecystectomy for a GB polyp of around 10 mm. They were divided into two groups, one with cholesterol polyps and the other with non-cholesterol polyps. Clinical features such as gender, age, symptoms, size and number of polyps, the presence of a GB stone, the radiologically measured maximum diameter of the polyp by US and CT scanning, and the measurements of diameter from postoperative pathology were recorded for comparative analysis. RESULTS: Fifteen of the 41 cases with cholesterol polyps (36.6%) were detected with US but not CT scanning, whereas all 18 non-cholesterol polyps were observed using both methods. In the cholesterol polyp group, the maximum measured diameter of the polyp was smaller by CT scan than by US. Consequently, the discrepancy between those two scanning measurements was greater than for the non-cholesterol polyp group. CONCLUSION: The clinical signs indicative of a cholesterol polyp include: (1) a polyp observed by US but not observable by CT scanning, (2) a smaller diameter on the CT scan compared to US, and (3) a discrepancy in its maximum diameter between US and CT measurements. In addition, US and the CT scan had low accuracy in predicting the polyp diameter compared to that determined by postoperative pathology.

Agent-based spin model for financial markets on complex networks: emergence of two-phase phenomena.

We study a microscopic model for financial markets on complex networks, motivated by the dynamics of agents and their structure of interaction. The model consists of interacting agents (spins) with local ferromagnetic coupling and global antiferromagnetic coupling. In order to incorporate more realistic situations, we also introduce an external field which changes in time. From numerical simulations, we find that the model shows two-phase phenomena. When the local ferromagnetic interaction is balanced with the global antiferromagnetic interaction, the resulting return distribution satisfies a power law having a single peak at zero values of return, which corresponds to the market equilibrium phase. On the other hand, if local ferromagnetic interaction is dominant, then the return distribution becomes double peaked at nonzero values of return, which characterizes the out-of-equilibrium phase. On random networks, the crossover between two phases comes from the competition between two different interactions. However, on scale-free networks, not only the competition between the different interactions but also the heterogeneity of underlying topology causes the two-phase phenomena. Possible relationships between the critical phenomena of spin system and the two-phase phenomena are discussed.

Metabolic syndrome is associated with erosive esophagitis.

AIM: To clarify whether insulin resistance and metabolic syndrome are risk factors for erosive esophagitis. METHODS: A case-control study was performed using the database of the Kangbuk Samsung Hospital Medical Screening Center. RESULTS: A total of 1679 cases of erosive esophagitis and 3358 randomly selected controls were included. Metabolic syndrome was diagnosed in 21% of the cases and 12% of the controls (P < 0.001). Multiple logistic regressions confirmed the association between erosive esophagitis and metabolic syndrome (Odds ratio, 1.25; 95% CI, 1.04-1.49). Among the components of metabolic syndrome, increased waist circumference, elevated serum triglyceride levels and hypertension were significant risk factors for erosive esophagitis (all P < 0.01). Furthermore, increased insulin resistance (Odds ratio, 0.91; 95% CI, 0.85-0.98) and fatty liver, as diagnosed by ultrasonography (Odds ratio, 1.39; 95% CI, 1.20-1.60), were also related to erosive esophagitis even after adjustment for a series of confounding factors. CONCLUSION: Metabolic syndrome and increased insulin resistance are associated with an increased risk of developing erosive esophagitis.

The association between increased alanine aminotransferase activity and metabolic factors in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) has been associated with metabolic disorders, including central obesity, dyslipidema, hypertension, and hyperglycemia. Metabolic syndrome, obesity, and insulin resistance are major risk factors in the pathogenesis of NAFLD. The aim of this study was to identify the relative contribution of the metabolic syndrome, obesity, and insulin resistance to alanine aminotransferase (ALT) activity in NAFLD. A total of 3091 subjects diagnosed with fatty liver by ultrasonography were enrolled. All components of metabolic syndrome criteria, anthropometric parameters, fasting insulin levels, high-sensitivity C-reactive protein (hs-CRP) as an inflammation marker, and ALT were measured in each subject. Homeostasis model assessment--insulin resistance (HOMA-IR) as a measure of insulin resistance and body mass index (BMI) as a measure of obesity were calculated. The prevalence of increased ALT levels (>40 IU/L) was 26.7%. Increased ALT activity was significantly associated with the following characteristics: male sex, young age, increased triglycerides, fasting glucose, fasting insulin, HOMA-IR, hs-CRP, waist circumference, BMI and diastolic blood pressure, and decreased high-density lipoprotein cholesterol (HDL-C). According to the increase in the number of metabolic syndrome components, BMI, HOMA-IR, and hs-CRP, the prevalence and odds ratio for having increased ALT activity were significantly increased. Central obesity, raised triglycerides, reduced HDL-C, and raised fasting glucose were strongly associated with increased ALT activity. In conclusion, a number of metabolic syndrome components, obesity, insulin resistance, and hs-CRP, are strong predictors of increased ALT activity in NAFLD. Central obesity, raised triglycerides, reduced HDL-C, and raised fasting glucose are metabolic syndrome components that contributed to increased ALT activity.

Modification of surface crystal formation on mother crystal by additive molecules.

Additive molecules and excess reactant species (NaOH and NH4F) in NaF crystallization were used to control surface crystal formation on a mother crystal. When the surface integration was inhibited or bulk diffusion facilitated, more surface crystals were found on the mother crystal due to an increase in the interfacial supersaturation on the crystal. The inclusion of KCl as an additive and increases in the reactant concentration and agitation speed resulted in a higher population of surface crystals on the mother crystal, because surface integration was inhibited. However, surface crystal formation was suppressed by the polymer gelatin due to retardation of the bulk diffusion by the gelatin layer formed around the crystal. In addition, surface crystal formation significantly changed according to the feeding mode, and the excess species of NaOH originating from the NH4F feeding mode were more effective in facilitating surface crystal formation than the excess species of NH4F coming from the NaOH feeding mode due to the smaller ionic radii of NaOH than of NH4F.

A new method of EMR: submucosal injection of a fibrinogen mixture.

BACKGROUND: The technical limitation associated with submucosal injection of normal saline solution during EMR is the relatively short duration of mucosal elevation. The clinical application of a new method of EMR with submucosal injection of a fibrinogen mixture was evaluated. METHODS: Thirty-five early stage neoplastic gastric lesions were resected by EMR with submucosal injection of a fibrinogen mixture. The efficacy and clinical outcomes were analyzed. RESULTS: Additional submucosal injection was not required for any of the 35 lesions to complete the EMR with submucosal injection of a fibrinogen mixture procedure. The rates of en bloc resection and complete resection were, respectively, 82.9% and 88.6%. The en bloc resection rate was significantly lower for lesions over 20 mm in diameter (60% vs. 92%; p<0.05) and for lesions on the lesser curvature or posterior wall of the stomach compared with those on the greater curvature or anterior wall (55.6% vs. 92.3%; p<0.05). The rate of complete resection also was dependent on the size and location of the lesions. There was no major EMR with submucosal injection of a fibrinogen mixture related complication including bleeding or perforation. CONCLUSIONS: EMR with submucosal injection of a fibrinogen mixture is an easy, safe, and technically efficient method for complete EMR.

E2F1 expression is related with the poor survival of lymph node-positive breast cancer patients treated with fluorouracil, doxorubicin and cyclophosphamide.

The expressions of E2F1 and retinoblastoma protein (pRB) were analyzed in 165 lymph node-positive breast cancers. All patients underwent adjuvant chemotherapy with fluorouracil, doxorubicin and cyclophosphamide (FAC). E2F1 was expressed in 43.6% and pRB was expressed in 46.1%. E2F1 expression was significantly increased in pRB-expressing tumors and was associated with an S-phase fraction. By univariate survival analyses, E2F1 expression and ER were identified as significant prognostic factors for disease recurrence and patient survival. E2F1 was the only significant prognostic factor of patient outcome after FAC chemotherapy by multivariate analysis.