Correlation between occlusal contact area at various levels of interocclusal thicknesses and masticatory performance.

BACKGROUND: This study aimed to determine the correlation between occlusal contact area and masticatory performance using BiteEye® , a photo occlusal analysis device and the multiple sieve method. OBJECTIVES: To calculate the occlusal contact area at various levels of interocclusal thicknesses and to measure masticatory performance with peanuts as the test material. METHODS: Fifty-two adults (30 men and 22 women) were enrolled according to specific exclusion/inclusion criteria. The occlusal contact area was measured by obtaining the interocclusal record of the maximum intercuspal position (MIP) using silicone impression material. Occlusal contact area measurements were performed in the ranges of 0-149, 0-89, 0-59, 0-29 and 0-9 µm. Masticatory performance was measured by obtaining the median particle size (X 50 ) after converting the weight of comminuted peanuts into size using the multiple sieve method. Statistical analysis was performed at 95% significance level. RESULTS: Interocclusal thickness comparison revealed the highest correlation with X 50 in the 0-149 µm range. Stronger correlations between the occlusal contact area and X 50 were observed in cases of 20 strokes of mastication (r = -.451) than in cases of 10 strokes (r = -.383), in the posterior occlusal contact area (r = -.456) than in the full arch occlusal contact area (r = -.451) and the molar area (r = -.478) than in the premolar area (r = -.296). CONCLUSIONS: The larger the occlusal contact area, the higher the masticatory performance; this correlation was statistically significant. Regarding interocclusal thickness, the highest correlation between the occlusal contact area and masticatory performance was observed in the 0-149 µm range. CLINICAL TRIAL REGISTRATION NUMBER: GWNUDH IRB 2020-A001.

Comorbidity of Internet gaming disorder and alcohol use disorder: A focus on clinical characteristics and gaming patterns.

BACKGROUND AND OBJECTIVES: Although Internet gaming disorder (IGD), which has been considered as a behavioral addiction in DSM-5, shares core features with alcohol use disorder (AUD), there has been minimal research on the clinical implications of the comorbidity between IGD and AUD. The purpose of this study is to investigate clinical psychopathologies and Internet game usage patterns of IGD, AUD, and their comorbid status. METHODS: Participants (n = 1819) completed a cross-sectional web-based survey. The survey questionnaire included socio-demographic data, the IGD scale according to DSM-5 criteria, the Korean version of Alcohol Use Disorders Identification Test for AUD, the Dickman Impulsivity Inventory (DII)-short version for impulsivity, the Brief Self-Control Scale (BSCS) for self-control, the subscales of the Symptom Check-List 90 Items-Revised (SCL-90-R) for depression and anxiety, and the Behavioral Inhibition System/Behavioral Approach System Scale, and the Internet game usage patterns. RESULTS: The comorbidity group had substantially more severe clinical features such as impulsivity, impaired self-control, and mood symptoms than either IGD or AUD only. Especially the depression scale for the comorbidity group (26.0) is considerably higher than 13.0 for IGD and 16.0 for AUD alone. Furthermore, the comorbidity group spent twice as much money on Internet gaming as IGD alone (all p < .05). CONCLUSIONS AND SIGNIFICANCE: The findings of this study indicate that the comorbidity between IGD with AUD showed more severe psychopathological impairments, and the respective persons spent more money on gaming than either IGD or AUD alone. These particular characteristics may serve as feasible therapeutic targets in clinical settings. (Am J Addict 2017;26:326-334).

Comparative analysis of the efficacy of low- and moderate-intensity statins in Korea.

PURPOSE: The American College of Cardiology/American Heart Association (ACC/AHA) guidelines are based on studies with a limited number of Asian subjects; therefore, they are difficult to apply to Asian patients, including Korean patients. MATERIALS AND METHODS: Data were extracted from the clinical data warehouse system of Seoul St. Mary's hospital (January 2010 - December 2012) to determine the percent change in low-density lipoprotein cholesterol (LDL-C) levels at an average 3 and 6 months from baseline. Statins with statistically similar lowering effects were placed in one group (group A, B, or C). The proportions of patients who achieved LDL-C < 100 mg/dL were compared between baseline LDL-C levels: low (< 130 mg/dL), medium (130 - 160 mg/dL), and high (> 160 mg/dL). RESULTS: The majority of the 9 statins of various doses (2,349 patients) were effective at 3 months, with additional, smaller decreases at 6 months. The LDL-C lowering effect of group A (atorvastatin (20 mg), rosuvastatin (10 mg)) was ~ 45%; that of group B (atorvastatin (10 mg), pitavastatin (2 mg), pravastatin (40 mg), simvastatin (20 mg)) was 35 - 37%. groups A and B contained only moderate-intensity statins (ACC/AHA guidelines). With baseline LDL-C ≥ 130 mg/dL, greater proportions of patients achieved LDL-C < 100 mg with atorvastatin (20 mg) and rosuvastatin (10 mg). CONCLUSION: Because of the demonstrated LDL-C lowering effects and target achievement rates, the ACC/AHA guidelines might not apply to Korean patients. Korean treatment guidelines should consider statins with relatively low potency. Additional studies regarding appropriate statin doses should be conducted with Asian populations.

Gamma knife radiosurgery for elderly patients with brain metastases: evaluation of scoring systems that predict survival.

BACKGROUND: Gamma knife radiosurgery (GKRS) has been increasingly employed for the treatment of elderly patients with brain metastases, mainly due to its demonstrated effectiveness and low complication rate. However, only a few studies have investigated the prognostic factors that influence the survival of elderly patients after GKRS. The purpose of this study was to identify a scoring system that is able to predict the survival of elderly patients undergoing GKRS using data obtained at the time of diagnosis for brain metastases. METHODS: Between 2004 and 2011, death was confirmed in 147 patients aged 70 years and older who had been treated with GKRS for brain metastases. Median age at the time of GKRS was 75.7 years (range, 70-86 years). The median tumor volume was 5.1 cm(3) (range, 0.05-59.9 cm(3)). The median marginal prescription dose was 21.4 Gy (range, 14-25 Gy). RESULTS: The median survival was 167 days. Overall survival rates at 6 months and 1 year were 60.4% and 29.4%, respectively. Among the patient characteristics pertaining to systemic cancer and brain metastasis for which data were obtained preoperatively, a multivariate analysis showed that low Karnofsky performance status (KPS ≤ 80, P = 0.047) and the presence of extracranial metastases (P = 0.014) detected at the time of brain metastasis diagnosis were independent prognostic factors for short survival. A high score index for radiosurgery (SIR score ≥ 4, P = 0.024) and a high graded prognostic assessment (GPA score ≥ 2, P = 0.004) were associated with longer survival. A multivariate analysis of the important characteristics of systemic cancer, and the scoring system evaluating survival duration showed that a low GPA score was the most powerful independent factor for predicting short survival (hazard ratio 1.756, 95% confidence interval 1.252-2.456, P = 0.001). CONCLUSIONS: GKRS is a safe approach to treat brain metastases in patients age 70 years and older. In this group, our study identified GPA score at the time of GKRS as a powerful prognostic factor for survival.

Enhanced Dural Repair Using Biodegradable Sealants Based on Photocurable Hyaluronic Acid.

Cerebrospinal fluid (CSF) leakage is a common complication of intradural surgery or incidental durotomy in neurosurgery. Dural suturing is a common method for durotomy repair, but this technique requires a long operation time and includes the risk of CSF leakage by incomplete sealing. Glue-type sealants are effective for watertight dural closure. However, unresolved shortcomings include insufficient sealing performance, poor biocompatibility, and excessive swelling. Here, a dural sealant using light-activated hyaluronic acid (HA) with multi-networks (HA photosealant) that provides fast sealing performance and high biocompatibility is reported. The HA photosealants form a watertight hydrogel barrier with multilength networks under low-energy visible light exposure (405 nm, <1 J cm-2) for 5 s and allow firm tissue adhesion on the wet dural surface. In a rabbit model of craniectomy and durotomy, HA photosealants exhibit the faster sealing performance of dural tears and enhance dural repair with accelerated bone formation compared to commercial surgical glues, with no degenerative changes, such as inflammation or necrosis, in histopathological evaluation. This biocompatible HA photosealant can be applied in a variety of clinical settings that require fast wound closure as a promising potential.

3D bioprinting of stromal cells-laden artificial cornea based on visible light-crosslinkable bioinks forming multilength networks.

3D bioprinting has the potential for the rapid and precise engineering of hydrogel constructs that can mimic the structural and optical complexity of a healthy cornea. However, the use of existing light-activated bioinks for corneal printing is limited by their poor cytocompatibility, use of cytotoxic photoinitiators (PIs), low photo-crosslinking efficiency, and opaque/colored surface of the printed material. Herein, we report a fast-curable, non-cytotoxic, optically transparent bioprinting system using a new water-soluble benzoyl phosphinate-based PI and photocrosslinkable methacrylated hyaluronic acid (HAMA). Compared with commercially available PIs, the newly developed PI, lithium benzoyl (phenyl) phosphinate (BP), demonstrated increased photoinitiation efficiency under visible light and low cytotoxicity. Using a catalytic amount of BP, the HA-based bioinks quickly formed 3D hydrogel constructs under low-energy visible-light irradiation (405 nm, <1 J cm-2). The mechanical properties and printability of photocurable bioinks were further improved by blending low (10 kDa) and high (100 kDa) molecular weight (MW) HAMA by forming multilength networks. For potential applications as corneal scaffolds, stromal cell-laden dome-shaped constructs were fabricated using MW-blended HAMA/BP bioink and a digital light processing printer. The HA-based photocurable bioinks exhibited good cytocompatibility (80%-95%), fast curing kinetics (<5 s), and excellent optical transparency (>90% in the visible range), potentially making them suitable for corneal tissue engineering.

Antiadhesive Hyaluronic Acid-Based Wound Dressings Promote Wound Healing by Preventing Re-Injury: An In Vivo Investigation.

Wound dressings are widely used to protect wounds and promote healing. The water absorption and antifriction properties of dressings are important for regulating the moisture balance and reducing secondary damages during dressing changes. Herein, we developed a hyaluronic acid (HA)-based foam dressing prepared via the lyophilization of photocrosslinked HA hydrogels with high water absorption and antiadhesion properties. To fabricate the HA-based foam dressing (HA foam), the hydroxyl groups of the HA were modified with methacrylate groups, enabling rapid photocuring. The resulting photocured HA solution was freeze-dried to form a porous structure, enhancing its exudate absorption capacity. Compared with conventional biopolymer-based foam dressings, this HA foam exhibited superior water absorption and antifriction properties. To assess the wound-healing potential of HA foam, animal experiments involving SD rats were conducted. Full-thickness defects measuring 2 × 2 cm2 were created on the skin of 36 rats, divided into four groups with 9 individuals each. The groups were treated with gauze, HA foam, CollaDerm®, and CollaHeal® Plus, respectively. The rats were closely monitored for a period of 24 days. In vivo testing demonstrated that the HA foam facilitated wound healing without causing inflammatory reactions and minimized secondary damages during dressing changes. This research presents a promising biocompatible foam wound dressing based on modified HA, which offers enhanced wound-healing capabilities and improved patient comfort and addresses the challenges associated with conventional dressings.

Improving the classification accuracy for IR spectroscopic diagnosis of stomach and colon malignancy using non-linear spectral feature extraction methods.

Non-linear feature extraction methods, neighborhood preserving embedding (NPE) and supervised NPE (SNPE), were employed to effectively represent the IR spectral features of stomach and colon biopsy tissues for classification, and improve the classification accuracy for diagnosis of malignancy. The motivation was to utilize the NPE and SNPE's capability of capturing non-linear spectral behaviors by simultaneously preserving local relationships in order that minute spectral differences among classes would be effectively recognized. NPE and SNPE derive an optimal embedding feature such that the local neighborhood structure can be preserved in reduced spaces (variables). The IR spectra collected from stomach and colon tissues were represented by several new variables through NPE and SNPE, and also by using the principal component analysis (PCA). Then, the feature-extracted variables were subsequently classified into normal, adenoma and cancer tissues by using both k-nearest neighbor (k-NN) and support vector machine (SVM), and the resulting accuracies were compared with each other. In both cases, the combination of SNPE-SVM provided the best classification performance, and the accuracy was substantially improved compared to when PCA-SVM was used. Overall results demonstrate that NPE and SNPE could be potential feature-representation strategies useful in biomedical diagnosis based on vibrational spectroscopy where effective recognition of minute spectral differences is critical.

Fast-Embeddable Grooved Microneedles by Shear Actuation for Accurate Transdermal Drug Delivery.

Percutaneous drug delivery using microneedles (MNs) has been extensively exploited to increase the transdermal permeability of therapeutic drugs. However, it is difficult to control the precise dosage with existing MNs and they need to be attached for a long time, so a more simple and scalable method is required for accurate transdermal drug delivery. In this study, we developed grooved MNs that can be embedded into the skin by mechanical fracture following simple shear actuation. Grooved MNs are prepared from hyaluronic acid (HA), which is a highly biocompatible and biodegradable biopolymer. By adjusting the aspect ratio (length:diameter) of the MN and the position of the groove, the MN tip inserted into the skin can be easily broken by shear force. In addition, it was demonstrated that it is possible to deliver the desired amount of triamcinolone acetonide (TCA) for alopecia areata by controlling the position of the groove structure and the concentration of TCA loaded in the MN. It was also confirmed that the tip of the TCA MN can be accurately delivered into the skin with a high probability (98% or more) by fabricating an easy-to-operate applicator to provide adequate shear force. The grooved MN platform has proven to be able to load the desired amount of a drug and deliver it at the correct dose.

Evaluation of disease activity indices in Korean patients with rheumatoid arthritis.

The aim of this study is to examine the validity of the rheumatoid arthritis (RA), disease activity score (DAS), 28-C-reactive protein (CRP), the simplified disease activity index (SDAI), and the clinical disease activity index (CDAI) against the DAS28-erythrocyte sedimentation rate (ESR) and determine cut-off values for each tool in Korean patients with RA. A total of 223 RA patients were consecutively recruited from the Hanyang University Hospital for Rheumatic Diseases in Seoul, Korea. DAS28-CRP, SDAI, and CDAI were measured and compared with DAS28-ESR. The correlation coefficients of DAS28-ESR with DAS28-CRP, SDAI, and CDAI were 0.93, 0.85, and 0.84, demonstrating strong linear relationships. The cut-off values of DAS28-CRP classifying RA patients into four categories of disease activity were defined as 2.19, 2.60, and 4.07. SDAI cut-off values were defined as 3.75, 7.50, and 16.88. CDAI cut-off values were defined as 3.62, 7.38, and 16.50. DAS28-CRP, SDAI, and CDAI are valid and sensitive assessment indices of disease activity that are comparable to DAS28-ESR. The cut-off values of each tool derived in this study might be useful for routine monitoring and therapeutic decision-making in Korean RA patients.

Improved Productivity of Naringin Oleate with Flavonoid and Fatty Acid by Efficient Enzymatic Esterification.

Naringin is a flavonoid found in citrus fruits. It exhibits biological activities, such as anticancer and antioxidant effects, but it suffers from low solubility and low stability in lipophilic systems. These drawbacks lead to difficulties in the commercial application of naringin, but they can be overcome through esterification. In this study, naringin oleate was synthesized by enzymatic esterification and optimal conditions for the reaction were investigated. Experiments were conducted focusing on the following parameters: enzyme type, enzyme concentration, molar ratio of naringin to oleic acid, reaction temperature, and reaction solvent. We further confirmed the degree of esterification based on the difference in the initial and the final naringin concentrations. A conversion of 93.10% was obtained under optimized conditions (Lipozyme TL IM 10 g/L, molar ratio 1:20, reaction temperature 40 °C, acetonitrile as solvent, and 48 h reaction time). Thus, naringin oleate, a high value-added material that overcomes the low hydrophobicity of naringin and enhances its performance, was obtained through esterification of naringin using oleic acid. This study presented a method for the efficient enzymatic synthesis that could ensure high conversion within a shorter reaction time compared with that required in previously reported methods.

User-demand fast-curable ocular glues enforced by multilength tunable networks.

Achieving fast and secure wound closure without ocular foreign body sensation is highly desired in ophthalmologic surgery. Sutureless approaches using tissue adhesives are gaining popularity, but their practical use is limited by the difficulty in controlling adhesion time and satisfying safety standards without compromising adhesive performance. Herein, we report user-demand hydrogel-forming ocular glues based on multilength photo-crosslinkable hyaluronic acid (HA), achieving firm tissue adhesion under wet and dynamic conditions and possessing cornea-like optical transparency. The HA-based photocurable glue (HA photoglue) quickly seals wounds upon nontoxic low-energy light exposure (320-500 nm, < 5 s, < 1 J cm-2), and its mechanical and adhesive properties are improved by introducing short and long crosslinkable moieties into HA through one-step synthesis, forming multilength networks. Furthermore, the HA photoglue provides stable sealing in wet environments like ocular mucous surface, a clear vision with a light transmittance of more than 95% over the entire visible range, and a lubricating surface with minimal ocular sensation (generating less than 10% frictional force than suture groups). In a rabbit corneal incision model, the HA photoglue showed improved wound healing efficacy based on histological evaluation compared to control groups.

Low-Temperature Multiple Micro-Dispensing on Microneedles for Accurate Transcutaneous Smallpox Vaccination.

Smallpox is an acute contagious disease caused by the variola virus. According to WHO guidelines, the smallpox vaccine is administrated by scarification into the epidermis using a bifurcated needle moistened with a vaccine solution. However, this invasive vaccination method involving multiple skin punctures requires a special technique to inoculate, as well as a cold chain for storage and distribution of vaccine solutions containing a live virus. Here, we report a transcutaneous smallpox vaccination using a live vaccinia-coated microneedle (MN) patch prepared by a low-temperature multiple nanoliter-level dispensing system, enabling accurate transdermal delivery of live vaccines and maintenance of bioactivity. The live vaccinia in hyaluronic acid (HA) solutions was selectively coated on the solid MN tips, and the coating amount of the vaccine was precisely controlled through a programmed multiple dispensing process with high accuracy under low temperature conditions (2-8 °C) for smallpox vaccination. Inoculation of mice (BALB/C mouse) with the MN patch coated with the second-generation smallpox vaccine increased the neutralizing antibody titer and T cell immune response. Interestingly, the live vaccine-coated MN patch maintained viral titers at -20 °C for 4 weeks and elevated temperature (37 °C) for 1 week, highlighting improved storage stability of the live virus formulated into coated MN patches. This coated MN platform using contact dispensing technique provides a simple and effective method for smallpox vaccination.

Injectable Self-Crosslinkable Thiolated Hyaluronic Acid for Stem Cell Therapy of Atopic Dermatitis.

Stem cell therapies offer great promise in regenerative medicine to reinstate the normal function of diseased tissue, thereby avoiding the need for replacement. In stem cell therapies, damaged cells are replaced or restored by regulating inflammation and the immune system. However, the low survival rate and local retention of transplanted cells pose a significant challenge. In this study, injectable self-crosslinkable hydrogels using thiol-functionalized hyaluronic acid (HA-SH) were developed to improve the efficacy of mesenchymal stem cells (MSCs) for treating atopic dermatitis (AD)-related inflammatory lesions. The gelation kinetics and mechanical properties of HA-SH hydrogels were easily tuned by varying the concentration of the polymer in the precursor solution before injection. The MSC-laden HA-SH hydrogels exhibited high cell viability (>80%) for 1 week and good in vivo biocompatibility after implantation beneath the mouse skin. Moreover, the MSC-laden HA-SH hydrogel showed increased expression of anti-inflammatory cytokines, which can alleviate the immune response. In an AD animal model, a reduction in epidermal thickness and mast cell infiltration was achieved by applying a self-crosslinkable HA-SH solution including MSCs. This HA-based injectable hydrogel represents a potential carrier of stem cells, and its strong immunomodulation capabilities can be utilized for treating inflammation-related diseases.

Evaluation of an autoencoder as a feature extraction tool for near-infrared spectroscopic discriminant analysis.

The utility of an autoencoder (AE) as a feature extraction tool for near-infrared (NIR) spectroscopy-based discrimination analysis has been explored and the discrimination of the geographic origins of 8 different agricultural products has been performed as the case study. The sample spectral features were broad and insufficient for component distinction due to considerable overlap of individual bands, so AE enabling of extracting the sample-descriptive features in the spectra would help to improve discrimination accuracy. For comparison, four different inputs of AE-extracted features, raw NIR spectra, principal component (PC) scores, and features extracted using locally linear embedding were employed for sample discrimination using support vector machine. The use of AE-extracted feature improved the accuracy in the discrimination of samples in all 8 products. The improvement was more substantial when the sample spectral features were indistinct. It demonstrates that AE is expandable for vibrational spectroscopic discriminant analysis of other samples with complex composition.

Odorless Glutathione Microneedle Patches for Skin Whitening.

Glutathione is a natural anti-aging substance that prevents the oxidation of protein thiols from reactive oxygen species. In the pharmaceutical industry, reduced glutathione (GSH) has been widely used for skin whitening due to its ability to inhibit tyrosinase. However, its poor permeability and foul odor limit its use in skin applications. Herein, we report a GSH-loaded dissolving microneedle (MN) patch prepared with hyaluronic acid (HA) that enables enhanced permeation across the skin and reduces the foul odor of GSH. HA was selected to prepare odorless GSH solutions and used for MN fabrications as a carrier of GSH. GSH-loaded MN (GSH-MN) arrays prepared from MN-forming solution containing up to 10% GSH showed good pattern uniformity and appropriate mechanical properties for insertion into the skin. The GSH-MNs with a loading capacity of 17.4% dissolve within 10 min following insertion into porcine skin and release the loaded GSH without being oxidized. This new approach combines functional biopolymers to reduce the characteristic GSH odor and advanced transdermal delivery based on MN technology to enhance skin permeation without pain. We believe this technique could expand the application of GSH in many cosmeceutical fields.

Transdermal delivery of Minoxidil using HA-PLGA nanoparticles for the treatment in alopecia.

BACKGROUND: Alopecia has become a very common disease that many people around the world are suffered. Minoxidil (MXD) is the most well-known commercialized drug in its treatment. However, in the case of MXD administration, there are some problems with low efficiency of transdermal delivery and additional side effects. METHOD: MXD and Rhodamine B (Rho B) are encapsulated in poly(Lactide-co-Glycolide) grafted hyaluronate nanoparticles (HA-PLGA/MXD NPs, HA-PLGA/Rho B NPs) which is prepared with W/O/W solvent evaporation method. After then, the investigation is carried out to confirm the feasibility of NPs in alopecia treatment. RESULTS: Both of HA-PLGA/MXD NPs and HA-PLGA/Rho B NPs are successfully prepared. In addition, it is confirmed that HA-PLGA NPs sufficiently delivered to cells without any significant cytotoxicity by cell viability, cellular uptake and skin permeation test. CONCLUSION: Taken together, HA-PLGA NPs as a transdermal delivery carrier to hair follicle cells can be exploited to develop the efficient and effective platform of transdermal drug delivery for the treatment of various diseases.

Change in ALT levels after administration of HMG-CoA reductase inhibitors to subjects with pretreatment levels three times the upper normal limit in clinical practice.

AIM: Prescription of statins to patients with chronic liver disease whose alanine transaminase (ALT) is over three times the upper normal limit (UNL) is not recommended. In this study, we attempted to evaluate patients with baseline ALT levels > 3 ×  UNL who were prescribed statins without ethical problems, using electronic medical records. METHODS: We enrolled subjects with ALT levels > 3 ×  UNL. The patients were divided into three groups consisting of those who had been taking agents affecting liver function (HEPA) and continued to do so after the statin prescription (HepCon), those who had not previously taken HEPA and began doing so after statin prescription (HepNew), and those who had never taken HEPA (HepNo). All ALT levels were determined within 3 months of statins administration, and changes were monitored. RESULTS: From January 2009 to December 2012, 61 patients with baseline ALT levels > 3 ×  UNL were prescribed statins for the first time. During the 3-month ALT monitoring, levels of the HepCon, HepNew, and HepNo groups decreased by 45 ± 8%, 64 ± 10%, and 42 ± 8%, respectively; however, intergroup differences were not significant (P = .386). All the subjects who were administered statins showed improvement or maintained their ALT levels, except for two subjects, which showed deterioration. However, the ALT levels of the two subjects subsequently remained stable. CONCLUSION: It is not clear whether it is safe to prescribe statins to patients with ALT > 3 times the UNL. Our study showed that prescription of statins in combination with HEPA did not cause deleterious effects, suggesting that ALT levels > 3 times the UNL do not have harmful effects.

A variable selection procedure for X-ray diffraction phase analysis.

The X-ray diffraction method has been widely used for qualitative and quantitative phase abundance analysis of crystalline materials. We propose the use of partial least squares when building the calibration model for a quantitative phase analysis based on X-ray diffraction spectra. We also propose a variable selection procedure to reduce the measurement points in terms of angles as an alternative to using the whole pattern. The proposed method is based on the variable importance in projection derived from the partial least squares and it considers some practical issues regarding the angle measurement. The method was particularly applied to the simultaneous determination of weight fractions of some iron oxides. It was found that the number of measurement points can be reduced to 30 percent of the total number of points with a small sacrifice in prediction error.

The influence of game genre on Internet gaming disorder.

Background and aims Although Internet gaming disorder (IGD) has been investigated in detail, minimal research has been conducted regarding the influence of different game genres on IGD. The aim of this study is to compare the characteristics of members of game genre-specific groups with IGD and to identify factors associated with IGD status in each group in a large sample of adults. Methods Internet games were categorized into four genres: real-time strategy games, massive multiplayer online role-playing games (MMORPG), sport games, and first-person shooter (FPS) games. Participants (n = 2,923) who usually played one of these games completed an anonymous online survey that collected sociodemographic, game usage pattern, and psychopathological assessment data. Results MMORPG and FPS game players more frequently met the criteria for IGD than participants in the other two groups. Differences between the IGD-suspected gamers within the genre-specific groups were observed for a few items, such as average game-playing time and the subscales of the behavioral activation system; however, the factors that contributed to the development of IGD within each game genre-specific group were found to be considerably different. Discussion and conclusions The findings of this study suggest that IGD is a stable psychiatric diagnosis encompassing users of a broad range of game genres. In addition, the development of strategies for the prevention of and early intervention on individuals at high risk for developing IGD may require consideration of the distinct characteristics identified as effective predictors of IGD in users of each game genre.