National prevalence of atopic dermatitis in Korean adolescents from 2009 to 2022.

Previous studies have examined the prevalence of allergic diseases in adolescents 1-2 years after the emergence of the COVID-19 pandemic. However, more data is needed to understand the long-term impact of COVID-19 on allergic diseases. Thus, we aimed to examine the trend of the atopic dermatitis prevalence in Korean adolescents before and during the COVID-19 pandemic across 14 years. Additionally, we analyze the risk factors of atopic dermatitis (AD) based on the results. The Korean Disease Control and Prevention Agency conducted the Korea Youth Risk Behavior Web-based Survey from 2009 to 2022, from which the data for this study were obtained. Prevalence trends were compared across subgroups, and the ß difference (ßdiff) was calculated. We computed odds ratios to examine changes in the disease prevalence before and during the pandemic. This study included a total of 917,461 participants from 2009 to 2022. The prevalence of atopic dermatitis increased from 6.79% (95% CI 6.66-6.91) in 2009-2011 to 6.89% (95% CI 6.72-7.05) in 2018-2019, then decreased slightly to 5.82% (95% CI 5.60-6.04) in 2022. Across the 14 years, middle school student status, low parent's highest education level, low household income, non-alcohol consumption, non-smoker smoking status, no suicidal thoughts, and no suicide attempts were associated with increased risk of atopic dermatitis, while female sex, rural residence, high BMI, low school performance, low household income, and no feelings of sadness and despair was associated with a small increase. This study examined the prevalence of atopic dermatitis across an 18-year, and found that the prevalence increased in the pre-pandemic then decreased during the start of the pandemic and remained constant throughout the pandemic. This trend could be explained mainly by the large scale social and political changes that occurred during the COVID-19 pandemic.

Why is Superlubricity of Diamond-Like Carbon Rare at Nanoscale?

Hydrogenated diamond-like carbon (HDLC) is a promising solid lubricant for its superlubricity which can benefit various industrial applications. While HDLC exhibits notable friction reduction in macroscale tests in inert or reducing environmental conditions, ultralow friction is rarely observed at the nanoscale. This study investigates this rather peculiar dependence of HDLC superlubricity on the contact scale. To attain superlubricity, HDLC requires i) removal of ≈2 nm-thick air-oxidized surface layer and ii) shear-induced transformation of amorphous carbon to highly graphitic and hydrogenated structure. The nanoscale wear depth exceeds the typical thickness of the air-oxidized layer, ruling out the possibility of incomplete removal of the air-oxidized layer. Raman analysis of transfer films indicates that shear-induced graphitization readily occurs at shear stresses lower than or comparable to those in the nanoscale test. Thus, the same is expected to occur at the nanoscale test. However, the graphitic transfer films are not detected in ex-situ analyses after nanoscale friction tests, indicating that the graphitic transfer films are pushed out of the nanoscale contact area due to the instability of transfer films within a small contact area. Combining all these observations, this study concludes the retention of highly graphitic transfer films is crucial to achieving HDLC superlubricity.

Shear-activation of mechanochemical reactions through molecular deformation.

Mechanical stress can directly activate chemical reactions by reducing the reaction energy barrier. A possible mechanism of such mechanochemical activation is structural deformation of the reactant species. However, the effect of deformation on the reaction energetics is unclear, especially, for shear stress-driven reactions. Here, we investigated shear stress-driven oligomerization reactions of cyclohexene on silica using a combination of reactive molecular dynamics simulations and ball-on-flat tribometer experiments. Both simulations and experiments captured an exponential increase in reaction yield with shear stress. Elemental analysis of ball-on-flat reaction products revealed the presence of oxygen in the polymers, a trend corroborated by the simulations, highlighting the critical role of surface oxygen atoms in oligomerization reactions. Structural analysis of the reacting molecules in simulations indicated the reactants were deformed just before a reaction occurred. Quantitative evidence of shear-induced deformation was established by comparing bond lengths in cyclohexene molecules in equilibrium and prior to reactions. Nudged elastic band calculations showed that the deformation had a small effect on the transition state energy but notably increased the reactant state energy, ultimately leading to a reduction in the energy barrier. Finally, a quantitative relationship was developed between molecular deformation and energy barrier reduction by mechanical stress.

Rapid and Easy Detection of Microcystin-LR Using a Bioactivated Multi-Walled Carbon Nanotube-Based Field-Effect Transistor Sensor.

In this study, we developed a multi-walled carbon nanotube (MWCNT)-based field-effect transistor (MWCNT-FET) sensor with high sensitivity and selectivity for microcystin-LR (MC-LR). Carboxylated MWCNTs were activated with an MC-LR-targeting aptamer (MCTA). Subsequently the bioactivated MWCNTs were immobilized between interdigitated drain (D) and source (S) electrodes through self-assembly. The top-gated MWCNT-FET sensor was configured by dropping the sample solution onto the D and S electrodes and immersing a Ag/AgCl electrode in the sample solution as a gate (G) electrode. We believe that the FET sensor's conduction path arises from the interplay between the MCTAs, with the applied gate potential modulating this path. Using standard instruments and a personal computer, the sensor's response was detected in real-time within a 10 min time frame. This label-free FET sensor demonstrated an impressive detection capability for MC-LR in the concentration range of 0.1-0.5 ng/mL, exhibiting a lower detection limit of 0.11 ng/mL. Additionally, the MWCNT-FET sensor displayed consistent reproducibility, a robust selectivity for MC-LR over its congeners, and minimal matrix interferences. Given these attributes, this easily mass-producible FET sensor is a promising tool for rapid, straightforward, and sensitive MC-LR detection in freshwater environments.

Water Adsorption Isotherm and Surface Conductivity of Boroaluminosilicate Glasses.

The surface resistivity of boroaluminosilicate display glasses, which may affect the downstream display panel manufacturing, varies with the relative humidity (RH) of the environment, but the origin of this RH dependence has not been well understood. We have measured the water adsorption behavior on Corning Eagle XG (Glass-E) and Lotus NXT (Glass-L) glass panels using Brewster angle transmission infrared spectroscopy. The IR spectra of adsorbed water were analyzed to obtain the effective thickness of adsorbed water, the distribution of hydrogen-bonding interactions among the adsorbed water molecules, and the isosteric heat of water adsorption. These characteristics were compared with the electrical conductivity (inverse of resistivity) of these two glasses [Appl. Surf. Sci. 2015, 356, 1189]. This comparison revealed the correlation between the conductivity and the water layer structure, which could explain the surface resistivity difference between Glass-E and Glass-L as a function of RH. This study also disputed the previous hypothesis that the water adsorption isotherm would be governed by the areal density of the surface hydroxyl group; instead, it suggested that the network modifier ions may also play a critical role, especially in the intermediate RH regime.

National Trends and Prevalence of Atopic Dermatitis and Pandemic-Related Factors among Korean Adults, 2007-2021.

INTRODUCTION: Previous studies have variably reported inconclusive trends in the prevalence of atopic dermatitis (AD) among adults, and there are limited data on the impact of the COVID-19 pandemic. We aimed to investigate the national trends and age-stratified prevalence of AD among adults from 2007 to 2021 in South Korea, focusing mainly on the impact of the COVID-19 pandemic-related factors. METHODS: A nationwide cross-sectional study was conducted using the Korea National Health and Nutrition Examination Survey data from 2007 to 2021. Overall and age-stratified prevalence for AD were assessed using weighted beta coefficients or odds ratios. RESULTS: A total of 83,566 adults over 20 years (male, 49.40%) were included. During the observation period, the prevalence of AD was stable in the overall population from 2.61% (95% CI, 2.29-2.93) in 2007-2009 to 2.15% (1.68-2.63) in 2020 and 2.38% (1.81-2.95) in 2021. However, the weighted prevalence of AD in adults aged 40-59 years old decreased during the pre-pandemic era, and the prevalence of AD in adults aged above 60 years significantly decreased during the pandemic, with a significant decline observed after the initial outbreak. From age-stratification analysis, the adults aged 40-59 years showed a significant increase after the pandemic outbreak which was evident in specific variables: individuals with rural residence, lower education, and lower household income quartiles. Adults aged above 60 years showed a significant decrease in the slope after the outbreak, evident in specific variables: individuals of female, rural residence, lower education, and lower household income quartiles. CONCLUSION: We observed a stable overall prevalence of AD throughout the 15-year observation period. However, the age-stratified analysis suggested significantly different trends according to age-stratified groups and the impact of the COVID-19 pandemic on the prevalence of AD.

Dupilumab Reduces Asthma Disease Burden and Recurrent SCS Use in Patients with CRSwNP and Coexisting Asthma.

Purpose: Dupilumab significantly reduced the requirement for systemic corticosteroids (SCS) in patients with severe chronic rhinosinusitis with nasal polyps (CRSwNP). Patients with CRSwNP and coexisting asthma typically have a higher disease burden and have more difficulty in managing disease. Here, we report an analysis of asthma outcomes and SCS use in patients with CRSwNP and coexisting asthma. Patients and Methods: This was a post hoc analysis of the randomized, placebo-controlled SINUS-24 and SINUS-52 studies (NCT02912468/NCT02898454) in patients with severe CRSwNP and coexisting asthma (patient self-reported) from the pooled intention-to-treat population randomized to dupilumab 300 mg every 2 weeks or placebo. On-treatment SCS use was estimated using Kaplan-Meier analysis. Forced expiratory volume in 1 s (FEV1), percent predicted FEV1, and the 6-item Asthma Control Questionnaire (ACQ-6) were assessed at baseline and Week 24 (pooled SINUS-24/52) in patients with/without history of asthma exacerbation or prior SCS use. Results: Of 337 patients with coexisting asthma, 88 (26%) required on-treatment SCS use. The requirement for on-treatment SCS use for any reason was significantly lower with dupilumab (20/167 patients; 12%) vs placebo (68/170; 40%); hazard ratio (95% confidence interval) 0.248 (0.150-0.409); p < 0.0001. The most frequent reasons for SCS use were nasal polyps (dupilumab 3% and placebo 27%) and asthma (2% and 9%, respectively). FEV1, percent predicted FEV1, and ACQ-6 were all significantly improved at Week 24 with dupilumab vs placebo irrespective of history of asthma exacerbation or prior SCS use (all p < 0.01). Conclusion: Dupilumab significantly reduced the requirement for SCS and improved asthma outcomes irrespective of history of asthma exacerbation or prior SCS use vs placebo in patients with CRSwNP and coexisting asthma, demonstrating concomitant reduction of SCS use and asthma disease burden in these patients.

Tissue-specific directionality of cellulose synthase complex movement inferred from cellulose microfibril polarity in secondary cell walls of Arabidopsis.

In plant cells, cellulose synthase complexes (CSCs) are nanoscale machines that synthesize and extrude crystalline cellulose microfibrils (CMFs) into the apoplast where CMFs are assembled with other matrix polymers into specific structures. We report the tissue-specific directionality of CSC movements of the xylem and interfascicular fiber walls of Arabidopsis stems, inferred from the polarity of CMFs determined using vibrational sum frequency generation spectroscopy. CMFs in xylems are deposited in an unidirectionally biased pattern with their alignment axes tilted about 25° off the stem axis, while interfascicular fibers are bidirectional and highly aligned along the longitudinal axis of the stem. These structures are compatible with the design of fiber-reinforced composites for tubular conduit and support pillar, respectively, suggesting that during cell development, CSC movement is regulated to produce wall structures optimized for cell-specific functions.

Effects of protective step training on proactive and reactive motor adaptations in Parkinson's disease patients.

The aim of this study was to investigate to what extent PD affects the ability to walk, respond to balance perturbations in a single training session, and produce acute short-term effects to improve compensatory reactions and control of unperturbed walking stability. Understanding the mechanism of compensation and neuroplasticity to unexpected step perturbation training during walking and static stance can inform treatment of PD by helping to design effective training regimens that remediate fall risk. Current rehabilitation therapies are inadequate at reducing falls in people with Parkinson's disease (PD). While pharmacologic and surgical treatments have proved largely ineffective in treating postural instability and gait dysfunction in people with PD, studies have demonstrated that therapy specifically focusing on posture, gait, and balance may significantly improve these factors and reduce falls. The primary goal of this study was to assess the effectiveness of a novel and promising intervention therapy (protective step training - i.e., PST) to improve balance and reduce falls in people with PD. A secondary goal was to understand the effects of PST on proactive and reactive feedback responses during stance and gait tasks. Multiple-baseline, repeated measures analyses were performed on the multitude of proactive and reactive performance measures to assess the effects of PST on gait and postural stability parameters. In general, the results indicate that participants with PD were able to use experiences with perturbation training to integrate and adapt feedforward and feedback behaviors to reduce falls. The ability of the participants with PD to adapt to changes in task demands suggests that individuals with PD could benefit from the protective step training to facilitate balance control during rehabilitation.

Regiospecific Cellulose Orientation and Anisotropic Mechanical Property in Plant Cell Walls.

Cellulose microfibrils (CMFs) are a major load-bearing component in plant cell walls. Thus, their structures have been studied extensively with spectroscopic and microscopic characterization methods, but the findings from these two approaches were inconsistent, which hampers the mechanistic understanding of cell wall mechanics. Here, we report the regiospecific assembly of CMFs in the periclinal wall of plant epidermal cells. Using sum frequency generation spectroscopic imaging, we found that CMFs are highly aligned in the cell edge region where two cells form a junction, whereas they are mostly isotropic on average throughout the wall thickness in the flat face region of the epidermal cell. This subcellular-level heterogeneity in the CMF alignment provided a new perspective on tissue-level anisotropy in the tensile modulus of cell wall materials. This finding also has resolved a previous contradiction between the spectroscopic and microscopic imaging studies, which paves a foundation for better understanding of the cell wall architecture, especially structure-geometry relationships.

DFT-Based Calculation of Molecular Hyperpolarizability and SFG Intensity of Symmetric and Asymmetric Stretch Modes of Alkyl Groups.

Vibrational sum frequency generation (SFG) spectroscopy has been extensively used for obtaining structural information of molecular functional groups at two-dimensional (2D) interfaces buried in the gas or liquid medium. Although the SFG experiment can be done elegantly, interpreting the measured intensity in terms of molecular orientation with respect to the lab coordinate is quite complicated. One of the main reasons is the difficulty of determining the hyperpolarizability tensors of even simple molecules that govern their SFG responses. The single-bond polarizability derivative model has been proposed to estimate the relative magnitude of SFG-active hyperpolarizability by assuming that the perturbation associated to each vibration is negligible. In this study, density functional theory was used to calculate the polarizability and dipole derivative tensors of the CH3 stretch mode of CH3I, CH3CH2I, CH3OH, and CH3CH2OH. Then, the hyperpolarizability tensors of symmetric and asymmetric vibration modes were calculated considering the Boltzmann distribution of representative conformers, which allowed us to theoretically calculate their SFG intensities at all polarization combinations as a function of the tilt angle of the CH3 group with respect to the surface normal direction. Then, the ratios of the calculated SFG intensities for the CH3 symmetric and asymmetric stretch peaks used in experimental studies for the CH3 tilt angle determination were compared. This comparison clearly showed that the effect of vibrational coupling among neighboring functional groups is significant and cannot be assumed to be negligible. This study presents new parameters that can be used in determining the average tilt angle of the CH3 group at the 2D interface with SFG measurements as well as limitations of the method.

Effect of Dupilumab on Type 2 Biomarkers in Chronic Rhinosinusitis With Nasal Polyps: SINUS-52 Study Results.

OBJECTIVES: Chronic rhinosinusitis with nasal polyps (CRSwNP), asthma, and non-steroidal anti-inflammatory drug-exacerbated respiratory disease (NSAID-ERD) are frequent coexisting conditions and share type 2 inflammatory pathophysiology, with interleukin (IL)-4 and IL-13 as key cytokines. Dupilumab is a monoclonal antibody that blocks the shared receptor for IL-4 and IL-13. The objective of this analysis was to evaluate dupilumab's effect on type 2 inflammation biomarkers in patients with CRSwNP with/without coexisting asthma or NSAID-ERD from the SINUS-52 (NCT02898454) study. METHODS: Patients received treatment with dupilumab or placebo for 52 weeks. Blood and urinary biomarkers were evaluated through 52 weeks, and nasal secretions and mucosa brushings through 24 weeks. RESULTS: Of 447 patients, 60% had coexisting asthma and 27% had coexisting NSAID-ERD. At baseline, blood eotaxin-3, eosinophils, and periostin, nasal secretion eotaxin-3, and urinary leukotriene E4 were significantly higher in patients with coexisting NSAID-ERD than without. Dupilumab reduced eotaxin-3, thymus and activation-regulated chemokine, periostin, and total immunoglobulin E in blood, eotaxin-3, periostin, IL-5, and eosinophil cationic protein in nasal secretions, and leukotriene E4 in urine. Reductions were generally similar or greater in the subgroups with asthma and NSAID-ERD than without. Dupilumab also reduced MUC5AC and mast cell counts in nasal mucosa brushings. CONCLUSION: Dupilumab reduced local and systemic type 2 inflammatory biomarkers in patients with CRSwNP, including mast cells in nasal mucosa and cysteinyl leukotrienes in urine. These findings provide insight into the processes driving CRSwNP and the mechanisms of dupilumab's therapeutic effects. CLINICAL TRIAL REGISTRY NAME: SINUS-52 https://www.clinicaltrials.gov/ct2/show/NCT02898454. CLINICALTRIALS.GOV IDENTIFIER: NCT02898454.

Tribochemistry of Diamond-like Carbon: Interplay between Hydrogen Content in the Film and Oxidative Gas in the Environment.

The lubricity of hydrogenated diamond-like carbon (HDLC) films is highly sensitive to the hydrogen (H) content in the film and the oxidizing gas in the environment. The tribochemical knowledge of HDLC films with two different H-contents (mildly hydrogenated vs highly hydrogenated) was deduced from the analysis of the transfer layers formed on the counter-surface during friction tests in O2 and H2O using Raman spectroscopic imaging and X-ray photoelectron spectroscopy (XPS). The results showed that, regardless of H-content in the film, shear-induced graphitization and oxidation take place readily. By analyzing the O2 and H2O partial pressure dependence of friction of HDLC with a Langmuir-type reaction kinetics model, the oxidation probability of the HDLC surface exposed by friction as well as the removal probability of the oxidized species by friction were determined. The HDLC film with more H-content exhibited a lower oxidation probability than the film with less H-content. The atomistic origin of this H-content dependence was investigated using reactive molecular dynamics simulations, which showed that the fraction of undercoordinated carbon species decreased as the H-content in the film increased, corroborating the lower oxidation probability of the highly-hydrogenated film. The H-content in the HDLC film influenced the probabilities of oxidation and material removal, both of which vary with the environmental condition.

Fiber reinforced hydrated networks recapitulate the poroelastic mechanics of articular cartilage.

The role of poroelasticity on the functional performance of articular cartilage has been established in the scientific literature since the 1960s. Despite the extensive knowledge on this topic there remain few attempts to design for poroelasticity and to our knowledge no demonstration of an engineered poroelastic material that approaches the physiological performance. In this paper, we report on the development of an engineered material that begins to approach physiological poroelasticity. We quantify poroelasticity using the fluid load fraction, apply mixture theory to model the material system, and determine cytocompatibility using primary human mesenchymal stem cells. The design approach is based on a fiber reinforced hydrated network and uses routine fabrication methods (electrohydrodynamic deposition) and materials (poly[ɛ-caprolactone] and gelatin) to develop the engineered poroelastic material. This composite material achieved a mean peak fluid load fraction of 68%, displayed consistency with mixture theory, and demonstrated cytocompatibility. This work creates a foundation for designing poroelastic cartilage implants and developing scaffold systems to study chondrocyte mechanobiology and tissue engineering. STATEMENT OF SIGNIFICANCE: Poroelasticity drives the functional mechanics of articular cartilage (load bearing and lubrication). In this work we develop the design rationale and approach to produce a poroelastic material, known as a fiber reinforced hydrated network (FiHy™), that begins to approach the native performance of articular cartilage. This is the first engineered material system capable of exceeding isotropic linear poroelastic theory. The framework developed here enables fundamental studies of poroelasticity and the development of translational materials for cartilage repair.

Overexpression of a gibberellin 20-oxidase gene in poplar xylem led to an increase in the size of nanocellulose fibrils and improved paper properties.

Cellulose, the major component of secondary cell walls, is the most abundant renewable long-chain polymer on earth. Nanocellulose has become a prominent nano-reinforcement agent for polymer matrices in various industries. We report the generation of transgenic hybrid poplar overexpressing the Arabidopsis gibberellin 20-oxidase1 gene driven by a xylem-specific promoter to increase gibberellin (GA) biosynthesis in wood. X-ray diffraction (XRD) and sum frequency generation spectroscopic (SFG) analyses showed that cellulose in transgenic trees was less crystalline, but the crystal size was larger. The nanocellulose fibrils prepared from transgenic wood had an increased size compared to those from wild type. When such fibrils were used as a reinforcing agent in sheet paper preparation, the mechanical strength of the paper was significantly enhanced. Engineering the GA pathway can therefore affect nanocellulose properties, providing a new strategy for expanding nanocellulose applications.

Understanding and Preventing Lubrication Failure at the Carbon Atomic Steps.

Two-dimensional (2D) lamellar materials are normally capable of rendering super-low friction, wear protection, and adhesion reduction in nanoscale due to their ultralow shear strength between two basal plane surfaces. However, high friction at step edges prevents the 2D materials from achieving super-low friction in macroscale applications and eventually leads to failure of lubrication performance. Here, taking graphene as an example, the authors report that not all step edges are detrimental. The armchair (AC) step edges are found to have only a minor topographic effect on friction, while the zigzag (ZZ) edges cause friction two orders of magnitude larger than the basal plane. The AC step edge is less reactive and thus more durable. However, the ZZ structure prevails when step edges are produced mechanically, for example, through mechanical exfoliation or grinding of graphite. The authors found a way to make the high-friction ZZ edge superlubricious by reconstructing the (6,6) hexagon structure to the (5,7) azulene-like structure through thermal annealing in an inert gas environment. This will facilitate the realization of graphene-based superlubricity over a wide range of industrial applications in which avoiding the involvement of step edges is difficult.

FBXO11 governs macrophage cell death and inflammation in response to bacterial toxins.

Staphylococcus aureus causes severe infections such as pneumonia and sepsis depending on the pore-forming toxin Panton-Valentine leukocidin (PVL). PVL kills and induces inflammation in macrophages and other myeloid cells by interacting with the human cell surface receptor, complement 5a receptor 1 (C5aR1). C5aR1 expression is tighly regulated and may thus modulate PVL activity, although the mechanisms involved remain incompletely understood. Here, we used a genome-wide CRISPR/Cas9 screen and identified F-box protein 11 (FBXO11), an E3 ubiquitin ligase complex member, to promote PVL toxicity. Genetic deletion of FBXO11 reduced the expression of C5aR1 at the mRNA level, whereas ectopic expression of C5aR1 in FBXO11-/- macrophages, or priming with LPS, restored C5aR1 expression and thereby PVL toxicity. In addition to promoting PVL-mediated killing, FBXO11 dampens secretion of IL-1ß after NLRP3 activation in response to bacterial toxins by reducing mRNA levels in a BCL-6-dependent and BCL-6-independent manner. Overall, these findings highlight that FBXO11 regulates C5aR1 and IL-1ß expression and controls macrophage cell death and inflammation following PVL exposure.

Nasal allergen challenge (NAC): Practical aspects and applications from an EU/US perspective-a Work Group Report of the AAAAI Rhinitis, Rhinosinusitis and Ocular Allergy Committee.

Nasal allergen challenge (NAC) is applied in a variety of settings (research centers, specialty clinics, and hospitals) as a useful diagnostic and research tool. NAC is indicated for diagnosis of seasonal and perennial allergic rhinitis, local allergic rhinitis, and occupational rhinitis; to design the composition of allergen immunotherapy in patients who are polysensitized; and to investigate the physio-pathological mechanisms of nasal diseases. NAC is currently a safe and reproducible technique, although it is time- and resource-consuming. NAC can be performed by a variety of methods, but the lack of a uniform technique for performing and recording the outcomes represents a challenge for those considering NAC as a clinical tool in the office. The availability of standardized allergens for NAC is also different in each country. The objective of this workgroup report is to review the current information about NAC, focusing on the practical aspects and application for diagnosis of difficult rhinitis phenotypes (eg, local allergic rhinitis, occupational rhinitis), taking into account the particular context of practice in the United States and the European Union.

Optimal sampling for positive only electronic health record data.

Identifying a patient's disease/health status from electronic medical records is a frequently encountered task in electronic health records (EHR) related research, and estimation of a classification model often requires a benchmark training data with patients' known phenotype statuses. However, assessing a patient's phenotype is costly and labor intensive, hence a proper selection of EHR records as a training set is desired. We propose a procedure to tailor the best training subsample with limited sample size for a classification model, minimizing its mean-squared phenotyping/classification error (MSE). Our approach incorporates "positive only" information, an approximation of the true disease status without false alarm, when it is available. In addition, our sampling procedure is applicable for training a chosen classification model which can be misspecified. We provide theoretical justification on its optimality in terms of MSE. The performance gain from our method is illustrated through simulation and a real-data example, and is found often satisfactory under criteria beyond MSE.