Superior electroadhesion force with permittivity-engineered bilayer films using electrostatic simulation and machine learning approaches.

Electroadhesive forces are crucial in various applications, including grasping devices, electro-sticky boards, electrostatic levitation, and climbing robots. However, the design of electroadhesive devices relies on speculative or empirical error approaches. Therefore, we present a theoretical model comprising predictive coplanar electrodes and protective layers for analyzing the electrostatic fields between an object and electroadhesive device. The model considers the role of protective layer and the air gap between the electrode surface and the object. To exert a higher electroadhesive force, the higher permeability of the protective layer is required. However, a high permeability of the protective layer is hard to withstand high applied voltage. To overcome this, two materials with different permeabilities were employed as protective layers-a low-permeability inner layer and a high-permeability outer layer-to maintain a high voltage and generate a large electroadhesive force. Because a low-permeability inner layer material was selected, a more permeable outer layer material was considered. A theoretical analysis revealed complex relationships between various design parameters. The impact of key design parameters and working environments on the electroadhesion behavior was further investigated. This study reveals the fundamental principles of electroadhesion and proposes prospective methods to enhance the design of electroadhesive devices for various engineering applications.

CCA: Cost-Capacity-Aware Caching for In-Memory Data Analytics Frameworks.

To process data from IoTs and wearable devices, analysis tasks are often offloaded to the cloud. As the amount of sensing data ever increases, optimizing the data analytics frameworks is critical to the performance of processing sensed data. A key approach to speed up the performance of data analytics frameworks in the cloud is caching intermediate data, which is used repeatedly in iterative computations. Existing analytics engines implement caching with various approaches. Some use run-time mechanisms with dynamic profiling and others rely on programmers to decide data to cache. Even though caching discipline has been investigated long enough in computer system research, recent data analytics frameworks still leave a room to optimize. As sophisticated caching should consider complex execution contexts such as cache capacity, size of data to cache, victims to evict, etc., no general solution often exists for data analytics frameworks. In this paper, we propose an application-specific cost-capacity-aware caching scheme for in-memory data analytics frameworks. We use a cost model, built from multiple representative inputs, and an execution flow analysis, extracted from DAG schedule, to select primary candidates to cache among intermediate data. After the caching candidate is determined, the optimal caching is automatically selected during execution even if the programmers no longer manually determine the caching for the intermediate data. We implemented our scheme in Apache Spark and experimentally evaluated our scheme on HiBench benchmarks. Compared to the caching decisions in the original benchmarks, our scheme increases the performance by 27% on sufficient cache memory and by 11% on insufficient cache memory, respectively.

Simultaneous separation and determination of 20 potential adulterant antigout and antiosteoporosis pharmaceutical compounds in herbal food products using LC with electrospray ionization MS/MS and LC with quadrupole-time-of-flight MS.

An analytical method for the simultaneous and reliable determination of 20 antigout and antiosteoporosis pharmaceutical compounds in adulterated health food products was developed using liquid chromatography with electrospray ionization tandem mass spectrometry and liquid chromatography with quadrupole-time-of-flight mass spectrometry. The method was validated through the determination of specificity, linearity, limit of detection, and limit of quantification, method detection limit, method quantitation limit, precision, accuracy, recovery, and stability. The matrix effect was also determined. The validation results of the developed method are as follows: for solid and liquid blank samples, limits of detection ranged from 0.05 to 5.00 ng/mL and limits of quantification ranged from 0.15 to 15.00 ng/mL. Linearity was acceptable, and the correlation coefficients (R2 ) were ≥0.99 for all target compounds. Both intra and interday precision were less than 9.16% RSD, and accuracies ranged from 95.31 to 116.68%. Mean recoveries for different types of dietary supplements classified as powders, liquids, tablets, and capsules were found to be 80.81 to 117.62% with less than 15.00% relative standard deviation. The stability of the standard mixture solution was less than 11.72% relative standard deviation after 48 h. By the proposed method, the presence of dexamethasone was determined in seized herbal food products at concentrations that ranged from 126 to 215 µg/g.

Development of a specific fragmentation pattern-based quadrupole-Orbitrap™ mass spectrometry method to screen drugs in illicit products.

Over the past decade, illicit drugs have been founded in marketed products, which pose a risk to public health. In particular, newly designed analogues synthesized by chemical modification of parent compounds to avoid detection by authorities are frequently detected worldwide. Although many analytical methods for determination of drugs have been reported, analytical methods using high-resolution mass spectrometry, which has the advantage of rapid screening and accurate identification of new substances, are necessary to control illicit drugs in marketed products. In this study, a rapid analytical method using an Orbitrap™ mass spectrometer for identification of illicit drugs in marketed products was developed. The 32 drugs were classified as benzodiazepine-, synthetic cannabinoid-, amphetamine- and benzylpiperazine-type drugs according to their chemical structures, and from their fragmentation patterns in tandem mass spectrometry spectra of an established method. The method validation gave a limit of detection of 0.06-5.30 ng/mL and a limit of quantification of 0.18-16.50 ng/mL, high linearity (R2 > 0.994) and mean recoveries of spiked matrix-blank samples ranging from 83.7% to 117.1%. Approximately 71% of 21 samples collected over 3 years were found to individually contain one of four types of benzodiazepines or two different synthetic cannabinoids. In one case, levels as high as 827.2 mg/g were measured suggesting adulteration at high levels, which suggests that potential illicit products containing drugs should be regularly screened to protect public health.

Simultaneous determination of illegal drug substances in dietary supplements for gout and osteoporosis using ultra-performance liquid chromatography and liquid chromatography-quadrupole-time-of-flight mass spectrometry.

The aim of this study was to simultaneously determine the presence of unauthorized drug substances in health foods and herbal products used in the treatment of conditions such as gout and anti-osteoporosis. Therefore, we developed and optimised a rapid and accurate method to simultaneously measure 20 anti-gout and anti-osteoporosis drug substances using an ultra-high-performance liquid chromatography (UPLC) system equipped with a photodiode array (PDA) detector. The method was validated to fully meet internationally accepted standards. LODs and LOQs spiked in solid and liquid negative samples were ranged from 0.12 to 1.50 µg/mL, and ranged from 0.36 to 4.50 µg/mL. Linearities (R2> 0.999), stabilities (RSD ≤ 2.92%), accuracies (84.25∼106.62%, intra-day; 84.56∼105.85%, inter-day), precisions (RSD ≤ 3.71% on the intra-day; RSD ≤ 3.47% on the inter-day), recoveries spiked in various type of blank samples such as powder, liquid, tablet, and capsule were determined within 81.20-116.20 %, respectively. From a confirmation of matrix effects (88.06∼110.50% in solid blank; 89.16∼110.52% in liquid blank), it was confirmed that this method was not significantly affected by a sample matrix. The validated method was used to analyse 116 samples containing health foods, herbal products, and seized forensic samples advertised to be effective anti-gout and anti-osteoporosis agents. Of the 20 drug substances screened, dexamethasone was detected and confirmed by comparing the tandem mass spectrometry (MS/MS) fragment ion patterns of a reference standard and the sample using LC-quadrupole-time-of-flight (Q-TOF)/MS. The concentrations of adulterants in seized forensic samples ranged from 0.013 to 0.022 %.

Application of screening methods for weight-loss compounds and identification of new impurities in counterfeit drugs.

With the increasing prevalence of obesity, the use of counterfeit drugs for weight loss is widespread owing to their easy and rapid availability. Since counterfeit weight-loss drugs are not prepared under the rigorous standard of Good Manufacturing Practice (GMP), they pose a risk to public health and cause significant side effects. To counteract the risk posed by counterfeit drugs, we investigated counterfeit weight-loss drugs seized by the Incheon Customs Services using UHPLC-PDA. Five of 23 confiscated samples with distinctive pink-coloured coating contained levothyroxine, sennoside A and B, and phenolphthalein in amounts ranging from 0.03-132.40 mg/g. In addition, three unknown compounds in one of the adulterated samples containing phenolphthalein were structurally elucidated by several analytical techniques. Their accurate masses corresponded to molecular formula of C34H22O7, C34H20O6, and C20H12O3, respectively. These compounds were identified as impurities, possibly produced during the synthesis of phenolphthalein or by improper removal during purification. These impurities were detected for the first time in counterfeit drugs.

Development of a specific fragment pattern-based quadrupole-Orbitrap mass spectrometry method to screen adulterated products of phosphodiesterase-5 inhibitors and their analogues.

Recently, adulterated supplements with phosphodiesterase-5 inhibitors (PDE-5i) have frequently observed. New synthetic analogues obtained from the chemical modification of parent compounds are frequently found in illicit products despite continuous efforts to inspect for these adulterants. A rapid and accurate method based on quadrupole-Orbitrap mass spectrometry was developed for simultaneously confirming and quantifying 85 PDE-5i and derived analogues present in illicit products for erectile dysfunction (ED). Common ions of PDE-5i according to their similar structures were proposed based on MS/MS fragmentations. These common ions could be an important diagnosis of their presence targets or new emerging analogues in supplements. Several validation parameters were employed, resulting in a limit of detection and quantification of 0.09-8.55 ng/mL and 0.24-17.10 ng/mL, respectively. The linear correlation coefficient (r2) was higher than 0.995, and mean recoveries of target compounds were in the range of 82-118%. A total of 187 illicit products, obtained from on/offline markets over a period of 3 years (2015-2017), were screened by the established method. Approximately 53% of them were adulterated with PDE-5i or derived analogues at concentrations of 0.1-726.0 mg/g in the illicit products. In the interests of public health, this study describes a rapid and accurate method to determine PDE-5i and new emerging analogues in adulterated products.

Isolation and characterisation of a novel sildenafil analogue adulterant, desmethylpiperazinyl propoxysildenafil, in a dietary supplement.

A new sildenafil analogue was detected during routine screening of dietary supplements suspected to be adulterated with an erectile dysfunction drug(s) using HPLC-DAD. The UV spectrum of this compound was highly similar to that of sildenafil and almost identical to that of desmethylpiperazinyl sildenafil. The analogue was purified by using semi-preparative HPLC and structurally elucidated by performing mass spectrometric and NMR spectroscopic experiments. The spectral data revealed that this sildenafil analogue bears an n-propoxy group instead of an ethoxy group and possesses no methylpiperazinyl moiety. The isolated compound, structure of which was further confirmed by spectral comparison with synthetic one, was thus named as desmethylpiperazinyl propoxysildenafil.

Determination of illegal adulteration of dietary supplements with synthetic hair-growth compounds by UPLC and LC-Q-TOF/MS.

In this study, we developed a UPLC-PDA and LC-Q-TOF/MS method to identify and measure the following prohibited substances that may be found in dietary supplements:triaminodil, minoxidil, bimatoprost, alimemazine, diphenylcyclopropenone, α-tradiol, finasteride, methyltestosterone, spironolatone, flutamide, cyproterone, dutasteride, and testosterone 17-propionate.The method was validated according to International Conference on Harmonization guidelines in terms of specificity, linearity, accuracy, precision, LOD, LOQ, recovery, and stability. The method was completely validated showing satisfactory data for all method validation parameters. The linearity was good (R2 > 0.999) with intra- and inter-day precision values of 0.2-3.4% and 0.3-2.9%, respectively. Moreover, the intra- and inter-day accuracies were 87-102% and 86-103%, respectively, and the precision was better than 9.4% (relative standard deviation).Hence, the proposed method is precise and has high quality,and can be utilised to comprehensively and continually monitor illegal drug adulteration in various forms of dietary supplements. Furthermore, to evaluate the applicability of the proposed method, we analysed 13 hair-growth compounds in 78 samples including food and dietary supplements. Minoxidil and triaminodil were detected in capsules at concentrations of 4.69 mg/g and 6.54 mg/g. In addition, finasteride was detected in a tablet at 13.45 mg/g. In addition, the major characteristic fragment ions were confirmed once again using LC-Q-TOF/MS for higher accuracy.

Pneumatization Pattern of the Frontal Recess: Relationship of the Anterior-to-Posterior Length of Frontal Isthmus and/or Frontal Recess with the Volume of Agger Nasi Cell.

OBJECTIVES: We analyzed the pneumatization pattern of the frontal recess (FR) in a Korean population. We also determined the correlation between the volume of the agger nasi cell (ANC) and the anterior-to-posterior (A-P) length of the frontal isthmus (FI) and FR. METHODS: Multiplanar paranasal sinus computed tomography (CT) images from 105 patients who underwent endoscopic sinus surgery were reviewed. The prevalence of frontal recess cells (FRCs), thickness of the frontal beak (FB), volume of the ANC, A-P length of the FI, and FR were evaluated. RESULTS: The ANC was identified in 96% of the patients and frontal cells (FCs) in 32% (FC type 1, 24.2%; type 2, 4.2%; type 3, 3.1%; and type 4, 0%). The prevalences of frontal bullar, suprabullar, supraorbital ethmoidal, and interfrontal sinus septal cells were 10%, 7.8%, 3.6%, and 6.8%, respectively. The A-P lengths of the FR and FI were 10.1+/-3.1 and 8.4+/-2.9 mm, respectively. The thickness of the FB was 7.8+/-1.8 mm and the volume of the ANC averaged 394.1+/-240.5 mm(3). The thickness of the FB did not correlate with the volume of the ANC. In contrast, the A-P length of the FI and FR were positively correlated with the volume of the ANC. CONCLUSION: ANCs and FCs were found in 96% and 32% of the cases in this series. FC type 4 was not seen. What appeared to be FC4 on conventional CT was identified as FBC from reconstructed parasagittal images. A large ANC increased the A-P length of the FI and FR, regardless of the thickness of the FB.

Indinavir increases glucose production in healthy HIV-negative men.

In the absence of HIV infection, changes in adipose tissue and lipid levels, HIV protease inhibitor therapy increases fasting glucose levels,suggestive of hepatic insulin resistance. After 4 weeks of indinavir treatment in nine HIV-negative healthy men, fasting glucose production and glycogenolysis were significantly increased. During the euglycemic hyperinsulinemic clamp, indinavir blunted the ability of insulin to suppress glucose production. Therefore, indinavir worsens hepatic insulin sensitivity, increasing endogenous glucose production.

Use of stable isotopically labeled benzene to evaluate environmental exposures.

The use of stable, isotopically labeled compounds in controlled exposure experiments at environmentally relevant levels allows for the distinguishing of urinary metabolites associated with known exposure from background levels generally present in the urine. Exposures of volunteers to (13)C-benzene for 2 h at 40+/-10 p.p.b. were conducted after obtaining informed consent, and urinary phenol, catechol, hydroquinone and trans,trans- muconic acid were measured. Each isotopically labeled urinary metabolite was determined in the presence of significantly higher concentrations of the unlabeled metabolite. Following exposure, free and acid hydrolyzed phenol, acid hydrolyzed catechol and hydroquinone, and free trans,trans-muconic acid were determined by GC/MS. The percentage of trans,trans-muconic acid excreted was higher than reported following exposure at occupational levels. The use of isotopically labeled compounds has the potential to investigate the metabolism of common environmental contaminants for validation of toxicokinetic models and improve risk extrapolation from high concentration occupational exposures and animal studies to environmentally relevant pollutant levels.