Sensory test A-Not A rating signal detection: panel’s sensory learning and stability of decision criteria

Signal detection theory (SDT) sensory discrimination analysis using A-Not A with a two-step rating is an efficient approach to in-house sensory quality management in the food industry. For such sensory analysis using an internal panel, the panels' ability to use stable decision criteria and provide a consistent response distribution responding to "A" vs "Not A" is critical for guaranteeing the data quality. This study examined the effects of the familiarization procedure (FP) and reference presentation probability (RPP) in the SDT A-Not A rating protocol on the panels' sensory learning of samples and stability of decision criteria using SDT parameters, recognition d' (d'_Rec),criteria location (c), and discrimination d' indices. Three different protocols were compared using ice-tea samples with small differences: Control, 0.25 RPP with repeated reference tasting (FP_R); Modified-1, 0.25 RPP with reference categorization (FP_C); Modified-2, 0.5 RPP with reference categorization (FP_C). An independent sample design with three groups having equal sensitivity was used to identify the differences among the protocols. For each protocol, two sub-groups with similar decision criteria (response bias) were formed according to the results obtained from the pre-test and used for the main-test analysis. SDT analysis results indicated that the Modified-2 protocol with a higher RPP (0.5) induced the most efficient sensory learning of the reference. The protocol improved the subjects' recognition of the reference and test samples, better differentiating from the reference and stabilizing the decision criterion, resulting in higher discrimination performance (larger d'). The results showed that d'_Rec analysis, together with d' analysis using a sensory panel, is a useful tool for monitoring the panel performance and checking for the sensory data quality of the sensory difference tests. In the present paper, a detailed illustration of the A-Not A sensory test procedure and examples of how to apply the SDT indices for different business decision-making is also introduced using the design and results of the present experiment.

The Effect of Professional Oral Care on the Oral Health Status of Critical Trauma Patients Using Ventilators

Background: Oral care reduces the incidence of ventilator-associated pneumonia. In addition, it is important that critically ill patients to maintain their oral health in order to restore their quality of life and to receive adequate nutrition after recovery. Objective: The purpose of this study was to evaluate the effect of professional oral hygiene care (POHC) on the oral health status of patients using a ventilator. Methods: Fifty-seven ventilated trauma patients were admitted to a tertiary medical institution. For 5 days, the dental hygienist performed POHC every 24 h along with routine oral hygiene care (ROHC) every 8 h for the experimental group (Exp.) (n = 29), whereas only ROHC was provided the control group (Cont.) (n = 28). Oral health status was evaluated using a modified bedside oral exam (MBOE). Results: There was no significant difference between the two groups in the total MBOE score up to 48 h after admission. However, the difference between the two groups was significant for MBOE (F = 16.10, p = 0.000), gingiva (F = 6.02, p = 0.018), buccal mucosa (F = 4.21, p = 0.046), and dental plaque score after 72 h (F = 13.15, p = 0.000). Conclusion: This study confirms the importance of POHC in improving the oral health.

The influence of professional oral hygiene care on reducing ventilator-associated pneumonia in trauma intensive care unit patients

Aim This study aimed to examine the effects of professional oral hygiene care for the prevention of ventilator-associated pneumonia (VAP) and the improvement of oral hygiene among patients in the trauma intensive care unit (TICU).Materials and methods TICU patients who underwent intubation were randomly assigned to either the experimental group (n = 29) or control group (n = 28). The developed professional oral hygiene care protocol was administered to patients in the experimental group every 24 hours. Additionally, data regarding general characteristics, medical history, oral hygiene status, Clinical Pulmonary Infection Score and quantitative polymerase chain reaction were assessed.Results The incidence of VAP differed between the control group (10.58) and experimental group (0) post intervention. Post-admission bedside oral exam scores with significant differences in oral hygiene were observed in the experimental group (in contrast to the control group) from 48 hours onwards (10.69 ± 3.43, p = 0.06). Staphylococcus aureus and Klebsiella pneumoniae exhibited significant differences in count as professional oral hygiene care continued.Conclusions This study suggests a model in which different health care professionals can cooperate to reduce the incidence of VAP and improve oral health conditions.

Survival of itinerant excitations and quantum spin state transitions in YbMgGaO4 with chemical disorder

A recent focus of quantum spin liquid (QSL) studies is how disorder/randomness in a QSL candidate affects its true magnetic ground state. The ultimate question is whether the QSL survives disorder or the disorder leads to a “spin-liquid-like” state, such as the proposed random-singlet (RS) state. Since disorder is a standard feature of most QSL candidates, this question represents a major challenge for QSL candidates. YbMgGaO₄, a triangular lattice antiferromagnet with effective spin-1/2 Yb³⁺ions, is an ideal system to address this question, since it shows no long-range magnetic ordering with Mg/Ga site disorder. Despite the intensive study, it remains unresolved as to whether YbMgGaO₄ is a QSL or in the RS state. Here, through ultralow-temperature thermal conductivity and magnetic torque measurements, plus specific heat and DC magnetization data, we observed a residual κ₀/T term and series of quantum spin state transitions in the zero temperature limit for YbMgGaO₄. These observations strongly suggest that a QSL state with itinerant excitations and quantum spin fluctuations survives disorder in YbMgGaO₄.

It remains an open question as to whether the quantum spin liquid state survives material disorder, or is replaced by some spin-liquid like state. Here, Rao et al succeed in resolving a resolving a κ₀/T residual in the thermal conductivity of YbMgGaO₄ strongly suggesting the survival of the quantum spin liquid state.

Development of a competency for professional oral hygiene care of endotracheally-intubated patients in the intensive care unit: development and validity evidence

BACKGROUND

Professional oral care in the intensive care unit may reduce the incidence of Ventilator Associated Pneumonia, which increases the patient's mortality rate. This study aimed to develop a competency for professional oral hygiene care of endotracheally-intubated intensive-care patients.

METHODS

First, we developed a competency draft by reviewing the literature on oral hygiene care of patients in the intensive care unit. Next, we developed expert validity test questionnaires using this draft and conducted expert validity tests twice on 18 experts. We determined competency as a content validity index of 0.8 or more and received expert additive opinions about competency through an open-questionnaire expert validity test paper in this methodology study.

RESULTS

The content validity index ranged from 0.8 ~ 1.0 for all items. The competency of 'professionalism' comprised 2 sub-competencies with 7 behavioral indicators. 'POHC preparation' comprised 3 sub-competencies with 10 behavioral indicators. 'POHC implementation' comprised 3 sub-competencies with 6 behavioral indicators. 'POHC evaluation' comprised 2 sub-competencies with 8 behavioral indicators. Lastly 'Cooperation among experts' comprised 3 sub-competencies with 7 behavioral indicatiors.

CONCLUSIONS

To provide patients with high quality oral hygiene care, these competencies should be implemented, and oral hygiene care professionals and related medical personnel should form a cooperative system.

Magnetic ordering in the Ising antiferromagnetic pyrochlore Nd2ScNbO7

The question of structural disorder and its effects on magnetism is relevant to a number of spin liquid candidate materials. Although commonly thought of as a route to spin glass behaviour, here we describe a system in which the structural disorder results in long-range antiferromagnetic order due to local symmetry breaking. Nd₂ScNbO₇is shown to have a dispersionless gapped excitation observed in other neodymium pyrochlores belowT_N= 0.37 K through polarized and inelastic neutron scattering. However the dispersing spin waves are not observed. This excited mode is shown to occur in only 14(2)% of the neodymium ions through spectroscopy and is consistent with total scattering measurements as well as the magnitude of the dynamic moment 0.26(2)μ_B. The remaining magnetic species order completely into the all-in all-out Ising antiferromagnetic structure. This can be seen as a result of local symmetry breaking due disordered Sc⁺³and Nb⁺⁵ions about theA-site. From this work, it has been established thatB-site disorder restores the dipole-like behaviour of the Nd⁺³ions compared to the Nd₂B₂O₇parent series.

Association between sleep habits and symptoms of oral disease in adolescents: the 2017 Korea Youth Risk Behavior Web-based Survey

BACKGROUND

This cross-sectional study aimed to examine the relationship between sleep habits and oral disease symptoms in adolescents.

METHODS

Among 62,276 adolescents who participated in the 13th Korea Youth Risk Behavior Web-based Survey (2017), we selected a total of 54,766 adolescents (age, 12-18 years; male, 49.9%) for the final analysis, after excluding those who did not report their sleep duration. The 13th Korea Youth Risk Behavior Web-based Survey data were obtained from a stratified, multistage, clustered sample. Independent variables included general characteristics, oral health behavior, sleep types, sleep duration, and sleep quality; dependent variables comprised oral disease symptoms. Sleep was categorized according to bedtime astype A (bedtime < 1 a.m.) and type B (bedtime ≥ 1 a.m.). Data were analyzed using logistic regression analysis. Statistical significance was set at p < 0.05.

RESULTS

After adjusting for all covariates, adolescents with type A sleep had a higher risk of toothache on chewing (OR = 1.08, 95% CI 1.02-1.15) than adolescents with type B. Adolescents who slept for 6 h or less each night had a higher risk of pain in the tongue and buccal mucosa (OR = 1.35, 95% CI 1.18-1.54), gingival pain, and bleeding (OR = 1.31, 95% CI 1.19-1.45) than those who slept for more than 8 h. Adolescents with low quality of sleep had a higher risk of toothache or throbbing (OR = 1.70, 95% CI 1.60-1.81), toothache on chewing (OR = 1.73, 95% CI 1.65-1.82), and halitosis (OR = 1.51, 95% CI 1.41-1.59) than those with high quality of sleep.

CONCLUSIONS

Our findings indicate that some oral symptoms are related to sleep duration and quality. It is essential to inculcate good sleeping habits in adolescents by emphasizing the effects of inadequate sleep duration and quality.

Possible itinerant excitations and quantum spin state transitions in the effective spin-1/2 triangular-lattice antiferromagnet Na2BaCo(PO4)2

The most fascinating feature of certain two-dimensional (2D) gapless quantum spin liquid (QSL) is that their spinon excitations behave like the fermionic carriers of a paramagnetic metal. The spinon Fermi surface is then expected to produce a linear increase of the thermal conductivity with temperature that should manifest via a residual value (κ₀/T) in the zero-temperature limit. However, this linear in T behavior has been reported for very few QSL candidates. Here, we studied the ultralow-temperature thermal conductivity of an effective spin-1/2 triangular QSL candidate Na₂BaCo(PO₄)₂, which has an antiferromagnetic order at very low temperature (T_N ~ 148 mK), and observed a finite κ₀/T extrapolated from the data above T_N. Moreover, while approaching zero temperature, it exhibits series of quantum spin state transitions with applied field along the c axis. These observations indicate that Na₂BaCo(PO₄)₂ possibly behaves as a gapless QSL with itinerant spin excitations above T_N and its strong quantum spin fluctuations persist below T_N.

The association between Antonovsky's sense of coherence and job stress among dental hygienists in Korea

OBJECTIVE

High stress levels experienced by medical professionals are a well-established phenomenon in current literature. However, there are few studies focusing on stress experienced in the field of oral health or on the sense of coherence (SOC) that helps to actively respond to job stress. The purpose of this study was to analyse if there is an association between SOC and job stress among dental hygienists in Korea.

METHODS

A cross-sectional study was conducted on a convenience sample of 441 dental hygienists in the Seoul Gyeonggi province, Korea. The independent variable was SOC which had three dimensions: comprehensibility, manageability and meaningfulness. The dependent variable was job stress, which was evaluated using the Korean Occupational Stress Scale Short Form. Confounding factors were age, marital status, educational background, type of hospital, and work experience. The chi-square test and t test measures were used for bivariate analysis. Multiple logistic regression analysis was performed to confirm the association between SOC and job stress. The collected data were statistically analysed using SPSS version 22.0.

RESULTS

The SOC score showed a significant difference in relation to the job stress score. The SOC score was high when the job stress was low (P < .001). Overall SOC scores showed an inverse correlation with job stress.

CONCLUSION

This study reports that a higher SOC is associated with lower job stress in Korean dental hygienists. Since a higher SOC in dental hygienists indicated that they could cope with job stress more positively, it is important to increase their SOC.

Inter-rater agreement among multiple examiners for the assessment of plaque scores between quantitative light-induced fluorescence-digital and two-tone disclosing solution-stained digital images

BACKGROUND

To utilize plaque scoring indices as objective measures, a certain standard of intra-rater and inter-rater agreement must be met. Achievement of high consistency among several examiners in the assessment of images from Q-ray cam (for quantitative light-induced fluorescence-digital imaging) and digital single-lens reflex camera of stained tooth surfaces might enable more efficient undertaking of large epidemiological studies and oral tests.

METHODS

Second-year dental hygiene students and registered dental hygienists 40 examiners were randomly selected, all of whom provided informed consent. Multiple examiners assessed plaque scoring indices from the two types of images of the same 30 patients. The images were observed on a computer monitor, and the area with dental plaque was assessed using the Patient Hygiene Performance Index. The intra-class correlation coefficient was determined to evaluate the agreement among examiners and test methods for dental plaque Q-ray cam and digital single-lens reflex camera measurements were compared using a Bland-Altman plot. The intra-class correlation coefficient was analyzed using SPSS version 24 software (SPSS Inc., Chicago, IL, USA), and the exploratory graph was analyzed with MedCalc.

RESULTS

Agreement among 40 examiners was excellent with an intra-class correlation coefficient of 0.990 when the Q-ray cam was used. The intra-class correlation coefficient for the registered dental hygienists group was 0.987 and that for the dental hygiene students group was 0.980.

CONCLUSIONS

The study was high agreement in the assessment of Q-ray cam images and digital single-lens reflex camera images of stained dental plaque by multiple examiners, confirming that the two methods are validated both independently and with high mutual agreement.

Sugar-sweetened beverage consumption frequency in Korean adolescents: based on the 2015 Youth Risk Behavior Web-Based Survey

INTRODUCTION

The purpose of the present study was to investigate current sugar-sweetened beverage consumption habits in Korean adolescents in conjunction with their demo-socioeconomic characteristics, and to identify variables that affect such behaviours.

MATERIALS AND METHODS

The study was conducted via secondary analysis of data from the 2015 Youth Risk Behavior Web-Based Survey (the 11th survey). The dependent variable in the current study was the combined consumption frequency of three types of sugar-sweetened beverages (carbonated beverages, highly-caffeinated beverages, sugary beverages), and demographic (gender, academic grade, residence), sociological (father's education level, mother's education level, having experienced depression within the last 12 months) and economic (subjective economic status, weekly allowance) factors constituted the independent variables.

RESULTS

Our results showed that the amount of weekly allowance had the greatest impact on adolescents' beverage consumption of more than seven times a week. Increases in experiencing a depressed mood and allowance were associated with an increased tendency to consume ≥ 7 sugar-sweetened beverages per week.

CONCLUSION

The results of the current study suggest that families and society should work collectively to motivate adolescents to consciously choose and buy healthy snacks. Furthermore, society should reach a consensus and invest effort to resolve this issue continuously and gradually, such as by presenting a standard for consumption of sugar-added drinks and implementing regulations to ban sales to adolescents.

A pilot study of occupational exposure to pathogenic microorganisms through lip cosmetics among dental hygienists

Objectives

In dental clinics, dental hygienists are exposed to aerosolized pathologic bacteria, which can be transmitted to the oral cavity via lip cosmetics. Accordingly, such contamination poses a consistent health risk among staffs. Our study examined the bacterial contamination of lip cosmetics used by dental hygienists while in a clinic setting.

Methods

Sixteen dental hygienists were surveyed regarding their job assignments and habits associated with lip cosmetic. Subsequently, microorganisms were analyzed in collected samples of the hygienists' lip cosmetics using colony‐forming unit (CFU) assays, 16s‐rDNA polymerase chain reaction, and DNA sequencing.

Results

Notably, 81.3% of the submitted lip cosmetic samples were contaminated, with bacterial CFUs ranging from undetectable to innumerable. Many samples (43.8%) exceeded the microbial limits of cosmetic contamination. Of the lip cosmetic used for more than 6 months, 60% exceeded the microbial limit. When wearing a mask every time, only one of the six samples exceeded the microbial limit. More frequent dental mask changing was associated with a lower likelihood that the cosmetic sample would exceed the microbial limit. No samples from hygienists who changed their masks four times a day exceeded the microbial limit, compared to 33.3% from hygienists who only changed the mask when it became wet. Most isolated bacteria were gram‐positive, facultative anaerobic, asporogenic, and opportunistically pathogenic, and the most prevalent species were Staphylococcus aureus, Streptococcus salivarius, and Staphylococcus epidermidis.

Conclusion

Our findings indicate that dental staff, including dental hygienists, should exercise more careful workplace habits, particularly with regard to infection control and cosmetic use.

Item-level analysis of the relationship between orthodontic treatment need and oral health-related quality of life in Korean schoolchildren

INTRODUCTION

This study aimed to evaluate the associations between normative orthodontic treatment need and oral health-related quality of life (OHRQoL) at an item level as well as subscale and total score levels among schoolchildren.

METHODS

A cross-sectional study was conducted on 2,010 randomly selected children aged approximately 8, 10, 12, and 15 years residing in the Gyeonggi province, Korea. Children were clinically examined with the Index of Orthodontic Treatment Need (IOTN). To measure OHRQoL, the Child Oral Health Impact Profile (COHIP) was used.

RESULTS

In the physical health domain of COHIP, crooked teeth, discoloration, "food sticking," and "difficulty keeping teeth clean" were significantly associated with IOTN levels (P < 0.05), whereas pain, sensitivity and bleeding, bad breath, mouth breathing, and dry mouth were not. In addition, present and future dental health were significantly associated with IOTN levels, although self-confidence, attractiveness, and future health were not. As expected, the 5 subscale scores and total score of COHIP were significantly associated with IOTN levels after adjustment for gender, age, socioeconomic level, and caries state.

CONCLUSIONS

This study suggests the importance of in-depth investigation at the item level of OHRQoL assessment scales to better evaluate the impact of malocclusion that might be alleviated by orthodontic treatment.

Health effects from exposure to dental diagnostic X-ray

The purpose of this review is to summarize the results of studies on of the association between exposure to dental X-rays and health risk. To perform the systematic review, We searched the PUBMED, EMBASE, and MEDLINE databases for papers published before December 15, 2016. A total of 2 158 studies, excluding duplicate studies, were found. Two reviewers independently evaluated the eligibility of each study. The final 21 studies were selected after application of exclusion criteria. In terms of health outcomes, there were 10 studies about brain tumors, 5 about thyroid cancer, 3 about tumors of head and neck areas, and 3 related to systemic health. In brain tumor studies, the association between dental X-ray exposure and meningioma was statistically significant in 5 of the 7 studies. In 4 of the 5 thyroid-related studies, there was a significant correlation with dental diagnostic X-rays. In studies on head and neck areas, tumors included laryngeal, parotid gland, and salivary gland cancers. There was also a statistically significant correlation between full-mouth X-rays and salivary gland cancer, but not parotid gland cancer. Health outcomes such as leukemia, low birth weight, cataracts, and thumb carcinomas were also reported. In a few studies examining health effects related to dental X-ray exposure, possibly increased risks of meningioma and thyroid cancer were suggested. More studies with a large population and prospective design are needed to elaborate these associations further.

The nature of spin excitations in the one-third magnetization plateau phase of Ba3CoSb2O9

Magnetization plateaus in quantum magnets—where bosonic quasiparticles crystallize into emergent spin superlattices—are spectacular yet simple examples of collective quantum phenomena escaping classical description. While magnetization plateaus have been observed in a number of spin-1/2 antiferromagnets, the description of their magnetic excitations remains an open theoretical and experimental challenge. Here, we investigate the dynamical properties of the triangular-lattice spin-1/2 antiferromagnet Ba₃CoSb₂O₉ in its one-third magnetization plateau phase using a combination of nonlinear spin-wave theory and neutron scattering measurements. The agreement between our theoretical treatment and the experimental data demonstrates that magnons behave semiclassically in the plateau in spite of the purely quantum origin of the underlying magnetic structure. This allows for a quantitative determination of Ba₃CoSb₂O₉ exchange parameters. We discuss the implication of our results to the deviations from semiclassical behavior observed in zero-field spin dynamics of the same material and conclude they must have an intrinsic origin.

Frustrated magnetic materials attract significant interest because their properties can become dominated by quantum fluctuations. Here the authors show that excitations in the plateau phase of a quantum magnet can be understood semiclassically even though the ground state involves strong quantum effects.

Field-Driven Quantum Criticality in the Spinel Magnet ZnCr_{2}Se_{4}

We report detailed dc and ac magnetic susceptibilities, specific heat, and thermal conductivity measurements on the frustrated magnet ZnCr_{2}Se_{4}. At low temperatures, with an increasing magnetic field, this spinel material goes through a series of spin state transitions from the helix spin state to the spiral spin state and then to the fully polarized state. Our results indicate a direct quantum phase transition from the spiral spin state to the fully polarized state. As the system approaches the quantum criticality, we find strong quantum fluctuations of the spins with behaviors such as an unconventional T^{2}-dependent specific heat and temperature-independent mean free path for the thermal transport. We complete the full phase diagram of ZnCr_{2}Se_{4} under the external magnetic field and propose the possibility of frustrated quantum criticality with extended densities of critical modes to account for the unusual low-energy excitations in the vicinity of the criticality. Our results reveal that ZnCr_{2}Se_{4} is a rare example of a 3D magnet exhibiting a field-driven quantum criticality with unconventional properties.

Canted magnetic ground state of quarter-doped manganites R 0.75Ca0.25MnO3 (R = Y, Tb, Dy, Ho, and Er)

Polycrystalline samples of the quarter-doped manganites R _0.75Ca_0.25MnO₃ (R  =  Y, Tb, Dy, Ho, and Er) were studied by x-ray diffraction and AC/DC susceptibility measurements. All five samples are orthorhombic and exhibit similar magnetic properties: enhanced ferromagnetism below T ₁ (∼80 K) and a spin glass (SG) state below T _SG (∼30 K). With increasing R ³⁺ ionic size, both T ₁ and T _SG generally increase. The single crystal neutron diffraction results on Tb_0.75Ca_0.25MnO₃ revealed that the SG state is mainly composed of a short-range ordered version of a novel canted (i.e. noncollinear) antiferromagnetic spin state. Furthermore, calculations based on the double exchange model for quarter-doped manganites reveal that this new magnetic phase provides a transition state between the ferromagnetic state and the theoretically predicted spin-orthogonal stripe phase.

Controlled Orientation of Active Sites in a Nanostructured Multienzyme Complex

Multistep cascade reactions in nature maximize reaction efficiency by co-assembling related enzymes. Such organization facilitates the processing of intermediates by downstream enzymes. Previously, the studies on multienzyme nanocomplexes assembled on DNA scaffolds demonstrated that closer interenzyme distance enhances the overall reaction efficiency. However, it remains unknown how the active site orientation controlled at nanoscale can have an effect on multienzyme reaction. Here, we show that controlled alignment of active sites promotes the multienzyme reaction efficiency. By genetic incorporation of a non-natural amino acid and two compatible bioorthogonal chemistries, we conjugated mannitol dehydrogenase to formate dehydrogenase with the defined active site arrangement with the residue-level accuracy. The study revealed that the multienzyme complex with the active sites directed towards each other exhibits four-fold higher relative efficiency enhancement in the cascade reaction and produces 60% more D-mannitol than the other complex with active sites directed away from each other.

Magnetism and multiferroicity of an isosceles triangular lattice antiferromagnet Sr3NiNb2O9

Various experimental measurements were performed to complete the phase diagram of a weakly distorted triangular lattice system, Sr3NiNb2O9 with Ni(2+) , spin-1 magnetic ions. This compound possesses an isosceles triangular lattice with two shorter bonds and one longer bond. It shows a two-step magnetic phase transition at [Formula: see text] K and [Formula: see text] K at zero magnetic field, characteristic of an easy-axis anisotropy. In the magnetization curves, a series of magnetic phase transitions was observed such as an up-up-down phase at [Formula: see text] T with 1/3 of the saturation magnetization (M sat) and an oblique phase at [Formula: see text] T with [Formula: see text]/3 M sat. Intriguingly, the magnetic phase transition below T N2 is in tandem with the ferroelectricity, which demonstrates multiferroic behaviors. Moreover, the multiferroic phase persists in all magnetically ordered phases regardless of the spin structure. The comparison between the phase diagrams of Sr3NiNb2O9 and its sister compound with an equilateral triangular lattice antiferromagnet Ba3NiNb2O9 (Hwang et al 2012 Phys. Rev. Lett. 109 257205), illustrates how a small imbalance among exchange interactions change the magnetic ground states of the TLAFs.

Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er)

We present the structural and magnetic properties of a new compound family, Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE=Gd, we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120° structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE=Dy, LRO at 0.37 K is related to the "kagome spin ice" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE=Er, two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative XY system.

Dimerization-induced Fermi-surface reconstruction in IrTe2

We report a de Haas-van Alphen (dHvA) oscillation study on IrTe2 single crystals showing complex dimer formations. By comparing the angle dependence of dHvA oscillations with band structure calculations, we show distinct Fermi surface reconstruction induced by a 1/5-type and a 1/8-type dimerizations. This verifies that an intriguing quasi-two-dimensional conducting plane across the layers is induced by dimerization in both cases. A phase transition to the 1/8 phase with higher dimer density reveals that local instabilities associated with intra- and interdimer couplings are the main driving force for complex dimer formations in IrTe2.

Incipient ferromagnetism in Tb2Ge2O7: application of chemical pressure to the enigmatic spin-liquid compound Tb2Ti2O7

After nearly 20 years of study, the origin of the spin-liquid state in Tb2Ti2O7 remains a challenge for experimentalists and theorists alike. To improve our understanding of the exotic magnetism in Tb2Ti2O7, we synthesize a chemical pressure analog: Tb2Ge2O7. Substitution of titanium by germanium results in a lattice contraction and enhanced exchange interactions. We characterize the magnetic ground state of Tb2Ge2O7 with specific heat, ac and dc magnetic susceptibility, and polarized neutron scattering measurements. Akin to Tb2Ti2O7, there is no long-range order in Tb2Ge2O7 down to 20 mK. The Weiss temperature of -19.2(1)  K, which is more negative than that of Tb2Ti2O7, supports the picture of stronger antiferromagnetic exchange. Polarized neutron scattering of Tb2Ge2O7 reveals that liquidlike correlations dominate in this system at 3.5 K. However, below 1 K, the liquidlike correlations give way to intense short-range ferromagnetic correlations with a length scale similar to the Tb-Tb nearest neighbor distance. Despite stronger antiferromagnetic exchange, the ground state of Tb2Ge2O7 has ferromagnetic character, in stark contrast to the pressure-induced antiferromagnetic order observed in Tb2Ti2O7.

Valley-polarized interlayer conduction of anisotropic Dirac fermions in SrMnBi2

We report the valley-selective interlayer conduction of SrMnBi(2) under in-plane magnetic fields. The c-axis resistivity of SrMnBi(2) shows clear angular magnetoresistance oscillations indicating coherent interlayer conduction. Strong fourfold variation of the coherent peak in the c-axis resistivity reveals that the contribution of each Dirac valley is significantly modulated by the in-plane field orientation. This originates from anisotropic Dirac Fermi surfaces with strong disparity in the momentum-dependent interlayer coupling. Furthermore, we found a signature of broken valley symmetry at high magnetic fields. These findings demonstrate that a quasi-two-dimensional anisotropic Dirac system can host a valley-polarized interlayer current through magnetic valley control.

Quantum oscillations of the metallic triangular-lattice antiferromagnet PdCrO2

We report the electronic and transport properties of the triangular antiferromagnet PdCrO(2) at high magnetic fields up to 33 T, using measurements of the de Haas-van Alphen oscillations and the Hall resistivity. The de Haas-van Alphen oscillations below the magnetic ordering temperature T(N) reveal several two-dimensional Fermi surfaces of smaller size than those found in nonmagnetic PdCoO(2), consistent with the band structure calculations. This evidences Fermi surface reconstruction due to the 120° helical ordering of the localized Cr spins, suggesting significant coupling of the itinerant electrons to the underlying spin texture. This induces the nonlinear Hall resistivity at low temperatures via the magnetic breakdown in the reconstructed Fermi surface. Furthermore, such a coupling leads to the unconventional anomalous Hall effects near T(N) due to the field-induced spin chirality at high magnetic fields.

Successful rescue of early graft failure in pediatric patients using T-cell-depleted haploidentical hematopoietic SCT

Graft failure (GF) is a significant complication after allogeneic hematopoietic stem cell transplantation (HCT) and is associated with a high mortality rate. We performed re-transplantation using haploidentical-related donors to rescue children with early GF. Between 2008 and 2013, 10 patients received re-transplantation from haploidentical family donors. The median age at HCT was 13.5 years and the median time between transplantations was 52.5 days. Conditioning regimen with fludarabine and CY was used in seven patients, and TBI was added in three patients. All 10 patients received T-cell-depleted grafts using CD3 or CD3/CD19 MoAb. The median numbers of CD34(+) and CD3(+) cells were 5.52 × 10(6)/kg and 1.08 × 10(6)/kg, respectively. For GVHD prophylaxis, mycophenolate mofetil (MMF) and tacrolimus or MMF and CYA were used. All 10 patients achieved a sustained neutrophil engraftment and maintained a complete donor chimerism at the time of analysis (median 23 months, range 6-62 months). Nine of 10 patients were alive, and one patient with moyamoya disease with AML died of encephalopathy 7 months post transplant. This study suggests that fludarabine- and CY-based conditioning with T-cell-depleted haploidentical HCT is a feasible option to rescue pediatric patients with primary GF.

Electronic Griffiths phase in the Te-doped semiconductor FeSb2

We report on the emergence of an electronic Griffiths phase in the doped semiconductor FeSb(2), predicted for disordered insulators with random localized moments in the vicinity of a metal-insulator transition. Magnetic, transport, and thermodynamic measurements of Fe(Sb(1-x)Te(x))(2) single crystals show signatures of disorder-induced non-Fermi liquid behavior and a Wilson ratio expected for strong electronic correlations. The electronic Griffiths phase states are found on the metallic boundary between the insulating state (x = 0) and a long-range albeit weak magnetic order (x ≥ 0.075).

Successive magnetic phase transitions and multiferroicity in the spin-one triangular-lattice antiferromagnet Ba3NiNb2O9

We report the magnetic and electric properties of Ba3NiNb2O9, which is a quasi-two-dimensional spin-one triangular-lattice antiferromagnet with trigonal structure. At low T and with increasing magnetic field, the system evolves from a 120 degree magnetic ordering phase (A phase) to an up-up-down (uud) phase (B phase) with a change of slope at 1/3 of the saturation magnetization, and then to an "oblique" phase (C phase). Accordingly, the ferroelectricity switches on at each phase boundary with appearance of spontaneous polarization. Therefore, Ba3NiNb2O9 is a unique triangular-lattice antiferromagnet exhibiting both uud phase and multiferroicity.

The angular magnetothermoelectric power of a charge density wave system

The angular dependence of the magnetothermopower of a charge transfer organic salt α-(ET)(2)KHg(SCN)(4) below (4 K) and above (9 K) the phase transition temperature, T(p) = 8 K, and under fields of 15 T and 25 T, below and above the 'kinkfield', has been studied. We find that for a longitudinal thermoelectric measurement both an interlayer thermopower (the Seebeck effect), S(zz), and a transverse thermopower (the Nernst effect), S(yz), exist in all three different B-T phases (the CDW (0), CDW (x) and metallic states) with large amplitude. Both thermoelectric effects display a resonant-like behavior without a sign reversal at the angles corresponding to angular magnetoresistance oscillation minima and maxima in this compound. The resonant behavior is most evident in the CDW(0) state, indicating a mechanism involving the Fermi surface nesting. Angular dependences reveal different behaviors of the thermopower and Nernst effect in the high magnetic field (CDW(x)) state.

Chemical pressure effects on pyrochlore spin ice

A comparison among the two sets of studied pyrochlore spin ices, Ho2Sn2O7, Ho2Ti2O7, and Ho2Ge2O7 with Ho3+ spins and Dy2Sn2O7, Dy2Ti2O7, and Dy2Ge2O7 with Dy3+ spins, shows that the application of chemical pressure through each set drives the system toward the antiferromagnetic phase boundary from the spin ice region, which agrees with the prediction of the "dipolar spin ice" model of den Hertog and Gingras. Among all the studied pyrochlore spin ices, Dy2Ge2O7 has the smallest ratio of Jnn/Dnn=-0.73.

Skyrmions in a doped antiferromagnet

Magnetization and magnetoresistance have been measured in insulating antiferromagnetic La2Cu0.97Li0.03O4 over a wide range of temperatures, magnetic fields, and field orientations. The magnetoresistance step associated with a weak ferromagnetic transition exhibits a striking nonmonotonic temperature dependence, consistent with the presence of Skyrmions.

Spin liquid state in the S = 1/2 triangular lattice Ba3CuSb2O9

The synthesis and characterization of Ba3CuSb2O9, which has a layered array of Cu2+ spins in a triangular lattice, are reported. The magnetic susceptibility and neutron scattering experiments of this material show no magnetic ordering down to 0.2 K with a θ(CW) = -55  K. The magnetic specific heat reveals a T-linear dependence with a γ = 43.4  mJ  K(-2)  mol(-1) below 1.4 K. These observations suggest that Ba3CuSb2O9 is a new quantum spin liquid candidate with a S = 1/2 triangular lattice.

Synthesis and electrochemical properties of LiMPO4 (M = Fe, Mn, Co) nanocrystals in polyol medium

Olivine structured LiMPO4 (M = Fe, Mn, Co) was synthesized by the solvothermal process using a polyol medium of diethylene glycol (DEG) without any further heating as a post procedure. The synthesized LiMPO4 nanoparticles exhibited an average length of 200 approximately 400 nm, width of 200 approximately 300 nm, and thickness of 20 approximately 50 nm, and with well dispersed plate and rod morphologies. The Rietveld-refined X-ray diffraction (XRD) pattern of LiFePO4 exhibited a good fit with an olivine structure (space group: Pnma) and no undesirable impurity phases. The LiFePO4 nanocrystals showed a reversible capacity of 167 mAh/g, equating to a utilization efficiency of 98% of its theoretical capacity, with a good cyclability over an extended range up to 40 cycles.

Synthesis and electrochemical properties of LiFePO4/carbon nanocomposites in polyol medium

LiFePO4/Carbon nanocomposites with varying amounts of carbon were synthesized using polyol process without any further heating as a post step. The X-ray diffraction patterns of all samples were indexed on the basis of orthorhombic olivine-type structure. The field emission-TEM images of composites with the amount of 3 approximately 15 wt% carbon showed the average sizes of 45 approximately 80 nm with nanorod shape surrounded by carbon. The initial discharge curves of LiFePO4/Carbon show 166, 157, 142, and 119 mAh/g capacities at a current density of 0.1 mA/cm2 in the voltage range of 2.5-4.2 V, respectively, without capacity fading and excellent cycle retentions during the 20 cycles. Especially, the sample of amount of 3 wt% carbon shows the excellent high rate performances at 15 and 30 C rates with high capacity retention compared with previously reported results of high temperature processed results, due to the existence of conductive agents such as carbon which suppresses particle growth and exhibits improved electronic conductivity and lithium ion diffusivity, simultaneously.

Generation of a fast maturating red fluorescent protein by a combined approach of elongation mutagenesis and functional salvage screening

Fluorescent proteins that can be useful as indicators or reporters must have rapid maturation time, high quantum yield and photobleaching stability. A red fluorescent protein DsRed that has a high quantum yield and photostability has an innately slow maturation time when compared to other fluorescence proteins. In this study, we combined a functional salvage screen (FSS) and elongation mutagenesis to obtain a DsRed variant that maintained structural features closely linked with a high quantum yield and photostability and evolved to have a rapid maturation time. It is expected that the variant generated here, FmRed (fast maturating red fluorescent protein), will be widely used as an indicator or reporter because it maintained traits superior to that of the wild-type protein and also matured rapidly.

Light-extraction enhancement of red AlGaInP light-emitting diodes with antireflective subwavelength structures

We demonstrate the enhancement of light extraction in 633 nm AlGaInP light-emitting diodes (LEDs) with antireflective subwavelength structures (SWS). From the contour plots by the rigorous coupled wave analysis method, it is found that the reduction of the internal reflection strongly depends on the period of SWS. The Ag nanoparticles formed by thermal dewetting were used as an etch mask for dry etch process to fabricate antireflective SWS on the LED surface. The tapered pillars on the GaP were fabricated, on average, with distances below 200 nm, satisfying the required antireflection condition at the emission wavelength. The improvement in light output power by approximately 26.4% was achieved for the fabricated AlGaInP LEDs with SWS compared to the conventional LEDs due to a strongly reduced Fresnel internal reflection at the GaP/air interface. The improved directionality in the far-field pattern was also obtained due to the directional light extraction enhancement.

Enhanced production of 1,2-propanediol by tpi1 deletion in Saccharomyces cerevisiae

Saccharomyces cerevisiae was metabolically engineered to improve 1,2-propanediol production. Deletion of the tpi1 (triosephosphate isomerase) gene in S. cerevisiae increased the carbon flux to DHAP (dihydroxylacetone phosphate) in glycolysis, resulting in increased glycerol production. Then, the mgs and gldA genes, the products of which convert DHAP to 1,2-propanediol, were introduced to the tpi1-deficient strain using a multicopy plasmid. As expected, the intracellular level of methylglyoxal was increased by introduction of the mgs gene in S. cerevisiae and that of 1,2-propanediol by introduction of both the mgs and gldA genes. As a result, 1.11 g/l of 1,2-propanediol was achieved in flask culture.

Symptomatic nerve root changes on contrast-enhanced MR imaging after surgery for lumbar disk herniation

BACKGROUND AND PURPOSE

The significance of postoperative nerve root changes (enhancement, thickening, and displacement) is still a topic of debate. The purpose of this study was to evaluate the association between nerve root changes and residual or recurrent symptoms after lumbar surgery with contrast-enhanced MR imaging.

MATERIALS AND METHODS

A total of 120 patients with 140 postoperative lumbar disk lesions causing residual or recurrent pain underwent contrast-enhanced MR imaging. The levels at which diskectomies had been performed were retrospectively evaluated for nerve root enhancement (NRE), thickening, and displacement. Association between nerve root changes and corresponding clinical presentations were statistically assessed. Nerve root changes in recurrent disk herniation (RDH) and postoperative epidural fibrosis (PEF) were also evaluated with clinical symptoms.

RESULTS

Ninety-two (65.7%) of the 140 disks demonstrated NRE. Regarding the association with clinical symptoms, the sensitivity was 91.7%, the specificity was 73.2%, the positive predictive value (PPV) was 83.7%, and the negative predictive value was 85.4% (P = .000). Nerve root thickening and displacement were significantly associated with the clinical symptoms, especially when NRE was combined (PPV, 87.7% and 87.2%, respectively). When RDH was combined with all 3 nerve root changes, the PPV was increased up to 94.1%. However, in PEF, the association between nerve root changes and clinical symptoms was not significant unless all 3 nerve root changes were combined.

CONCLUSIONS

In patients with residual or recurrent pain after surgery for lumbar disk herniation, nerve root changes on contrast-enhanced MR imaging were well associated with clinical symptoms, of which NRE was the most significant finding.

TLR9 is expressed in idiopathic interstitial pneumonia and its activation promotes in vitro myofibroblast differentiation

Infectious diseases can be cofactors in idiopathic interstitial pneumonias (IIP) pathogenesis; recent data suggests that toll-like receptors 9 (TLR9) ligands contribute to experimental chronic tissue remodeling. Real-time TAQMAN and immunohistochemical analysis of IIP normal surgical lung biopsies (SLBs), primary fibroblast lines grown from both IIP and normal SLBs indicate that TLR9 is prominently and differentially expressed in a disease-specific manner. TLR9 expression was increased in biopsies from patients with IIP compared with normal lung biopsies and its expression is localized to areas of marked interstitial fibrosis. TLR9 in fibroblasts appeared to be increased by profibrotic Th2 cytokines (IL-4 and IL-13) and this was true in fibroblasts cultured from the most severe form of IIP, idiopathic pulmonary fibrosis (IPF) SLBs, in non-specific interstitial pneumonia fibroblast lines, and in normal fibroblasts. Finally, confocal microscopy studies have shown that TLR9 activation by its synthetic agonist CpG-ODN significantly increased the expression of alpha smooth muscle actin, the main marker of myofibroblast differentiation. These data indicate that TLR9 expression may drive the abnormal tissue healing response in severe forms of IIP and its activation can have a key role in myofibroblast differentiation promoting the progression of disease during the terminal phase of IPF.

Antiferromagnetic d-electron exchange via a spin-singlet pi-electron ground state in an organic conductor

Electron spin resonance reveals the spin behavior of conduction (pi) and localized (d) electrons in beta-(BDA-TTP)2MCl4 (M=Fe, Ga). Both the Ga3+(S=0) and Fe3+(S=5/2) compounds exhibit a metal-insulator transition at 113 K with the simultaneous formation of a spin-singlet ground state in the pi electron system of the donor molecules. The behavior is consistent with charge ordering in beta-(BDA-TTP)2MCl4 at the metal-insulator transition. At 5 K, the Fe3+ compound orders antiferromagnetically, even though the pi electrons, which normally would facilitate magnetic exchange, are localized nonmagnetic singlets.

Vortex dynamics and the Fulde-Ferrell-Larkin-Ovchinnikov state in a magnetic-field-induced organic superconductor

Under special conditions, a superconducting state where the order parameter oscillates in real space, the so-called FFLO state, is theoretically predicted to exist near the upper critical field, as first proposed by Fulde and Ferrell, and Larkin and Ovchinnikov. We report systematic measurements of the interlayer resistance in high magnetic fields to 45 T in the two-dimensional magnetic-field-induced organic superconductor lambda-(BETS)2FeCl4, where BETS is bis(ethylenedithio)tetraselenafulvalene. The resistance is found to show characteristic dip structures in the superconducting state. The results are consistent with pinning interactions between the vortices penetrating the insulating layers and the order parameter of the FFLO state. This gives strong evidence for an oscillating order parameter in real space.

[The determinants of adolescent smoking by gender and type of school in Korea]

OBJECTIVES

This study assessed the influences of various factors that are related to youth smoking such as gender, age and type of school, and we wanted to provide supporting data for tailored and effective policy initiatives to reduce adolescent smoking.

METHODS

A self-report survey was conducted on 14,910 teen-age students who were selected based on the nationwide distribution of students in large and small cities and counties, the gender ratio of the students and the ratio of students attending various type of school at 38 middle and high schools in six representative areas of each province. The survey was handled and managed by a health education teacher at each school. Binary and multinomial logistic regression was used in the analyses.

RESULTS

Smoking by adolescents was associated with gender, age and even height. Male high school students tended to smoke more than female high school students, but this differences was not significant for middle school students. The older the adolescents were, the more likely that they smoked, except for the female high school students. Height was meaningful for all adolescents, except for the boys at the vocational high schools. Monthly allowance was significant for all adolescents. School factors such as type of school and the students' school performance were also crucial factors. Attending a vocational high school was strongly related to smoking, especially for girls. Students' school performance and the perceived level of stress were strongly associated with smoking, especially for boys. Home factors such as the relationship with parents and conversation time with family members were closely related to smoking behavior. Knowledge about the health hazard of smoking was also found to be strongly related to adolescent smoking.

CONCLUSIONS

In conclusion, demographic factors, school factors, home surroundings and the perception on the harmfulness of smoking are strongly related to adolescent smoking behavior, but these differ from gender and type of school.

Focal interstitial CC chemokine receptor 7 (CCR7) expression in idiopathic interstitial pneumonia

BACKGROUND/AIMS

Idiopathic interstitial pneumonias (IIPs) are a diverse grouping of chronic pulmonary diseases characterised by varying degrees of pulmonary fibrosis. The triggers of the fibroproliferative process in IIP remain enigmatic but recent attention has been directed towards chemokine involvement in this process.

METHODS

The expression of two chemokine receptors, CCR7 and CXCR4, and their respective ligands, CCL19, CCL21, and CXCL12, were examined in surgical lung biopsies (SLBs) from patients with IIP. Transcript and protein expression of these receptors and their ligands was compared with that detected in histologically normal margin SLBs.

RESULTS

CCR7 and CXCR4 were detected by gene array and real time polymerase chain reaction analysis and CCR7, but not CXCR4, expression was significantly raised in usual interstitial pneumonia (UIP) relative to biopsies from patients diagnosed with non-specific interstitial pneumonia (NSIP) or respiratory bronchiolitis/interstitial lung disease (RBILD). CCR7 protein was expressed in interstitial areas of all upper and lower lobe UIP SLBs analysed. CCR7 expression was present in 50% of NSIP SLBs, and CCR7 was restricted to blood vessels and mononuclear cells in 75% of RBILD SLBs. Immune cell specific CXCR4 expression was seen in IIP and normal margin biopsies. CCR7 positive areas in UIP biopsies were concomitantly positive for CD45 (the leucocyte common antigen) but CCR7 positive areas in all IIP SLBs lacked the haemopoietic stem cell antigen CD34, collagen 1, and alpha smooth muscle actin.

CONCLUSION

This molecular and immunohistochemical analysis showed that IIPs are associated with abnormal CCR7 transcript and protein expression.