Low household income increases the risk of tuberculosis recurrence: a retrospective nationwide cohort study in South Korea

OBJECTIVES

We assessed the impact of household income on tuberculosis (TB) recurrence and the long-term impact of TB on household income.

STUDY DESIGN

This was a retrospective nationwide cohort study of patients with drug-susceptible TB (DS-TB) and TB recurrence.

METHODS

Using the South Korean national TB cohort database, we identified a sub-set cohort of patients with newly diagnosed drug-susceptible TB between 2013 and 2016 and tracked their TB recurrence and longitudinal income data from 2007 to 2018. Income levels were evaluated as 'Medical aid' and quintile categories. To assess risk factors associated with TB recurrence, we used a sub-distribution hazard model, adjusting for the competing risks of death.

RESULTS

Of 66,690 patients successfully treated with DS-TB, 2095 (3.1 %) experienced recurrence during a median follow-up of 39 months. The incidence of TB recurrence was 982.1/100,000 person-years, with 50.3 % of the recurrences occurring within 1 year of treatment completion. The risk of TB recurrence increased with decreasing income levels, with the highest risk observed in the lowest income group. The effect of income on TB recurrence was prominent in males but not in females. Overall, patients with TB recurrence experienced a linear decline in income levels, compared with those without recurrence.

CONCLUSIONS

Household income during the initial TB episode was an important risk factor for TB recurrence, particularly in males.

Full-range stress-strain curve estimation of aluminum alloys using machine learning-aided ultrasound

Full-range stress-strain (SS) curves are crucial in understanding mechanical properties of a material such as the yield strength, ultimate tensile strength, and elongation. In this study, a full-range SS-curve was nondestructively estimated by applying machine learning to the ultrasonic amplitude-scan signal propagated through the material. The performance of the developed technique was validated using five-hundred aluminum alloy specimens with a wide spectrum of mechanical properties. The analyses of various ultrasonic properties, including nonlinearity and attenuation, with respect to the elements in the SS curves revealed how ultrasonics can be used to predict the SS curves without conventional destructive tensile testing. The proposed technique has significant potential for new applications in the fields of materials science and engineering, such as inline SS curve estimation during manufacturing.

Optical polarization perturbed by shear strains of ultrasonic bulk waves in anisotropic semiconductors: Multiphysics modeling and optoacoustic validation

Characterization of lattice properties of monocrystalline semiconductors (MS) has been rapidly advanced. Of particular interest is the use of shear strains induced by optoacoustic-bulk-waves. However, this technique has been hindered owing to the lack of quantitative correlations between optoacoustic-bulk-waves-induced shear strains and anisotropic photoelasticity of MS. Motivated by this, a multiphysics model is developed to interrogate the coupling phenomena and interaction between optical polarization and shear strains in MS. With the model, perturbation to the polarization of a monochromatic laser beam, upon interacting with optoacoustic waves in MS, is scrutinized quantitatively. Experimental results are in agreement with those from the model, both revealing the polarization perturbed by shear strains quantitatively depends on the crystal orientation and crystal-structure-related symmetry, which are jointly governed by mechanical/photoelastic/optical anisotropies of MS. The approach has paved a new way for selectively acquiring high-sensitivity shear components of optoacoustic-ultrasonic-waves for in situ, high-definition characterization of anisotropic MS.

To Test or Not? Xpert MTB/RIF as an Alternative to Smear Microscopy to Guide Line Probe Assay Testing for Drug-Resistant Tuberculosis

Xpert MTB/RIF (Xpert) revolutionized tuberculosis (TB) diagnosis. Laboratory decision making on whether widely-used reflex drug susceptibility assays (MTBDRplus, first-line resistance; MTBDRsl, second-line) are conducted is based on smear status, with smear-negative specimens often excluded. We performed receiver operator characteristic (ROC) curve analyses using bacterial load information (smear microscopy grade, Xpert-generated semi-quantitation categories and minimum cycle threshold [CTmin] values) from Xpert rifampicin-resistant sputum for the prediction of downstream line probe assay results as "likely non-actionable" (no resistance or susceptible results generated). We evaluated actionable-to-non-actionable result ratios and pay-offs with missed resistance versus LPAs done universally. Smear-negatives were more likely than smear-positive specimens to generate a non-actionable MTBDRplus (23% [133/559] versus 4% [15/381]) or MTBDRsl (39% [220/559] versus 12% [47/381]) result. However, excluding smear-negatives would result in missed rapid diagnoses (e.g., only 49% [264/537] of LPA-diagnosable isoniazid resistance would be detected if smear-negatives were omitted). Testing smear-negatives with a semi-quantitation category ≥ "medium" had a high ratio of actionable-to-non-actionable results (12.8 or a 4-fold improvement versus testing all using MTBDRplus, 4.5 or 3-fold improvement for MTBDRsl), which would still capture 64% (168/264) and 77% (34/44) of LPA-detectable smear-negative resistance, respectively. Use of CTmins permitted optimization of this ratio with higher specificity for non-actionable results but decreased resistance detected. Xpert quantitative information permits identification of a smear-negative subset in whom the payoffs of the ratio of actionable-to-non-actionable LPA results with missed resistance may prove acceptable to laboratories, depending on context. Our findings permit the rational expansion of direct DST to certain smear-negative sputum specimens.

The Unknown Abnormal Condition Monitoring Method for Pumped-Storage Hydroelectricity

Pumped-storage hydroelectricity (PSH) is a facility that stores energy in the form of the gravitational potential energy of water by pumping water from a lower to a higher elevation reservoir in a hydroelectric power plant. The operation of PSH can be divided into two states: the turbine state, during which electric energy is generated, and the pump state, during which this generated electric energy is stored as potential energy. Additionally, the condition monitoring of PSH is generally challenging because the hydropower turbine, which is one of the primary components of PSH, is immersed in water and continuously rotates. This study presents a method that automatically detects new abnormal conditions in target structures without the intervention of experts. The proposed method automatically updates and optimizes existing abnormal condition classification models to accommodate new abnormal conditions. The performance of the proposed method was evaluated with sensor data obtained from on-site PSH. The test results show that the proposed method detects new abnormal PSH conditions with an 85.89% accuracy using fewer than three datapoints and classifies each condition with a 99.73% accuracy on average.

Understanding patient-level costs of weekly isoniazid-rifapentine (3HP) among people living with HIV in Uganda

BACKGROUND: Twelve weeks of weekly isoniazid and rifapentine (3HP) prevents TB disease among people with HIV (PWH), but the costs to people of taking TB preventive treatment is not well described.METHODS: We surveyed PWH who initiated 3HP at a large urban HIV/AIDS clinic in Kampala, Uganda, as part of a larger trial. We estimated the cost of one 3HP visit from the patient perspective, including both out-of-pocket costs and estimated lost wages. Costs were reported in 2021 Ugandan shillings (UGX) and US dollars (USD; USD1 = UGX3,587)RESULTS: The survey included 1,655 PWH. The median participant cost of one clinic visit was UGX19,200 (USD5.36), or 38.5% of the median weekly income. Per visit, the cost of transportation was the largest component (median: UGX10,000/USD2.79), followed by lost income (median: UGX4,200/USD1.16) and food (median: UGX2,000/USD0.56). Men reported greater income loss than women (median: UGX6,400/USD1.79 vs. UGX3,300/USD0.93), and participants who lived further than a 30-minute drive to the clinic had higher transportation costs than others (median: UGX14,000/USD3.90 vs. UGX8,000/USD2.23).CONCLUSION: Patient-level costs to receive 3HP accounted for over one-third of weekly income. Patient-centered approaches to averting or defraying these costs are needed.

Continuous Structural Displacement Monitoring Using Accelerometer, Vision, and Infrared (IR) Cameras

With the rapid development of computer vision, vision cameras have been used as noncontact sensors for structural displacement measurements. However, vision-based techniques are limited to short-term displacement measurements because of their degraded performance under varying illumination and inability to operate at night. To overcome these limitations, this study developed a continuous structural displacement estimation technique by combining measurements from an accelerometer with vision and infrared (IR) cameras collocated at the displacement estimation point of a target structure. The proposed technique enables continuous displacement estimation for both day and night, automatic optimization of the temperature range of an infrared camera to ensure a region of interest (ROI) with good matching features, and adaptive updating of the reference frame to achieve robust illumination-displacement estimation from vision/IR measurements. The performance of the proposed method was verified through lab-scale tests on a single-story building model. The displacements were estimated with a root-mean-square error of less than 2 mm compared with the laser-based ground truth. In addition, the applicability of the IR camera for displacement estimation under field conditions was validated using a pedestrian bridge test. The proposed technique eliminates the need for a stationary sensor installation location by the on-site installation of sensors and is therefore attractive for long-term continuous monitoring. However, it only estimates displacement at the sensor installation location, and cannot simultaneously estimate multi-point displacements which can be achieved by installing cameras off-site.

Cost to perform door-to-door universal sputum screening for TB in a high-burden community

BACKGROUND: Population-based active case-finding (ACF) identifies people with TB in communities but can be costly.METHODS: We conducted an empiric costing study within a door-to-door household ACF campaign in an urban community in Uganda, where all adults, regardless of symptoms, were screened by sputum Xpert Ultra testing. We used a combination of direct observation and self-reported logs to estimate staffing requirements. Study budgets were reviewed to collect costs of overheads, equipment, and consumables. Our primary outcome was the cost per person diagnosed with TB.RESULTS: Over a 28-week period, three teams of two people collected sputum from 11,341 adults, of whom 48 (0.4%) tested positive for TB. Screening 1,000 adults required 258 person-hours of effort at a cost of US$402,000, 70% of which was for GeneXpert cartridges. The estimated cost per person screened was $36 (95% uncertainty range [95% UR] 34-38), and the cost per person diagnosed with Xpert-positive TB was $8,400 (95% UR 8,000-8,900). The prevalence of TB in the underlying community was the primary modifiable determinant of the cost per person diagnosed.CONCLUSION: Door-to-door screening can be feasibly performed at scale, but will require effective triage and identification of high-prevalence populations to be affordable and cost-effective.

Spectral noise and data reduction using a long short-term memory network for nonlinear ultrasonic modulation-based fatigue crack detection

This paper presents a spectral noise and data reduction technique based on long short-term memory (LSTM) network for nonlinear ultrasonic modulation-based fatigue crack detection. The amplitudes of the nonlinear modulation components created by a micro fatigue crack are often very small and masked by noise. In addition, the collection of large amounts of data is often undesirable owing to the limited power, data storage, and data transmission bandwidth of monitoring systems. To tackle the issues, an LSTM network was applied to ultrasonic signals to reduce the noise level and the amount of data. The proposed technique offers the following benefits: (1) spectral noise reduction using the LSTM network for ultrasonic signals and (2) data reduction without compromising the spectral density amplitude of the existing nonlinear modulation components. Finally, the performance evaluation was conducted using the data obtained from complex geometry and real structure under external noises, indicating that the proposed method can be applied to various structures.

Cubic nonlinearity parameter measurement and material degradation detection using nonlinear ultrasonic three-wave mixing

Early detection of accumulated damage or material degradation in structures is important to ensure their structural safety. Nonlinear ultrasonic techniques are widely used to measure the quadratic nonlinearity parameter that represents the third-order elastic constants of materials for material degradation detection. In addition, there are ongoing efforts to exploit both the third- and fourth-order elastic constants that describe the cubic nonlinearity parameter to detect material degradation. This study develops a nonlinear ultrasonic three-wave mixing technique to generate and measure third-order combined harmonics (TOCH) in plate-like structures and to measure cubic nonlinearity parameter. The proposed three-wave mixing technique generates three primary Lamb waves in the target structure and measures the TOCH produced by nonlinear cross-interaction of the primary Lamb waves. A theoretical model is developed to describe the generation of TOCH in a nonlinear elastic and homogeneous plate, and the effectiveness of the theoretical model is validated experimentally. Measurements of the TOCH are conducted for intact and degraded aluminum specimens with different degradation levels. Because inherent material nonlinearity and material degradation alter the third- and fourth-order elastic constants of a structure, the three-wave mixing technique for measuring the TOCH can be used to identify the inherent material nonlinearity and material degradation. In particular, the experimental results indicate that the proposed technique is more sensitive to early-stage material degradation than existing nonlinear ultrasonic techniques such as two-wave mixing, and third harmonic generation techniques.

Determining the value of TB active case-finding: current evidence and methodological considerations

Active case-finding (ACF) is an important component of the End TB Strategy. However, ACF is resource-intensive, and the economics of ACF are not well-understood. Data on the costs of ACF are limited, with little consistency in the units and methods used to estimate and report costs. Mathematical models to forecast the long-term effects of ACF require empirical measurements of the yield, timing and costs of case detection. Pragmatic trials offer an opportunity to assess the cost-effectiveness of ACF interventions within a 'real-world´ context. However, such analyses generally require early introduction of economic evaluations to enable prospective data collection on resource requirements. Closing the global case-detection gap will require substantial additional resources, including continued investment in innovative technologies. Research is essential to the optimal implementation, cost-effectiveness, and affordability of ACF in high-burden settings. To assess the value of ACF, we must prioritize the collection of high-quality data regarding costs and effectiveness, and link those data to analytical models that are adapted to local settings.

Multifunctional Smart Ball Sensor for Wireless Structural Health Monitoring in a Fire Situation

A variety of sensor systems have been developed to monitor the structural health status of buildings and infrastructures. However, most sensor systems for structural health monitoring (SHM) are difficult to use in extreme conditions, such as a fire situation, because of their vulnerability to high temperature and physical shocks, as well as time-consuming installation process. Here, we present a smart ball sensor (SBS) that can be immediately installed on surfaces of structures, stably measure vital SHM data in real time and wirelessly transmit the data in a high-temperature fire situation. The smart ball sensor mainly consists of sensor and data transmission module, heat insulator and adhesive module. With the integrated device configuration, the SBS can be strongly attached to the target surface with maximum adhesion force of 233.7-N and stably detect acceleration and temperature of the structure without damaging the key modules of the systems even at high temperatures of up to 500 °C while ensuring wireless transmission of the data. Field tests for a model pre-engineered building (PEB) structure demonstrate the validity of the smart ball sensor as an instantly deployable, high-temperature SHM system. This SBS can be used for SHM of a wider variety of structures and buildings beyond PEB structures.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries

BACKGROUND

The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients.

METHODS

We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step.

RESULTS

A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana.

CONCLUSIONS

Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

A Real-Time, Non-Contact Method for In-Line Inspection of Oil and Gas Pipelines Using Optical Sensor Array

Corrosion is considered as one of the most predominant causes of pipeline failures in the oil and gas industry and normally cannot be easily detected at the inner surface of pipelines without service disruption. The real-time inspection of oil and gas pipelines is extremely vital to mitigate accidents and maintenance cost as well as to improve the oil and gas transport efficiency. In this paper, a new, non-contact optical sensor array method for real-time inspection and non-destructive evaluation (NDE) of pipelines is presented. The proposed optical method consists of light emitting diodes (LEDs) and light dependent resistors (LDRs) to send light and receive reflected light from the inner surface of pipelines. The uniqueness of the proposed method lies in its accurate detection as well as its localization of corrosion defects, based on the utilization of optical sensor array in the pipeline, and also the flexibility with which this system can be adopted for pipelines with different services, sizes, and materials, as well as the method's economic viability. Experimental studies are conducted considering corrosion defects with different features and dimensions to confirm the robustness and accuracy of the method. The obtained data are processed with discrete wavelet transform (DWT) for noise cancelation and feature extraction. The estimated sizes of the corrosion defects for different physical parameters, such as inspection speed and lift-off distance, are investigated and, finally, some preliminary tests are conducted based on the implementation of the proposed method on an in-line developed smart pipeline inspection gauge (PIG) for in-line inspection (ILI) application, with resulting success.

Cost-effectiveness of contact screening strategies for tuberculosis among high-school adolescents in South Korea

BACKGROUND

Effective latent tuberculous infection (LTBI) control among adolescents is a critical component of tuberculosis (TB) elimination in Korea.

OBJECTIVE

To compare the cost-effectiveness of the following contact screening strategies for LTBI among high-school adolescents after TB outbreaks: QuantiFERON®-TB Gold In-Tube (QFT-GIT), the tuberculin skin test (TST), or TST/QFT-GIT (two-step strategy).

METHOD

The costs of post-TB outbreak screening strategies were calculated using a mixed (top-down and bottom-up) cost analysis method and expressed in 2015 US dollars. Cost-effectiveness was evaluated using a decision analysis model from the health system perspective, comparing cumulative health care costs and the total number of TB cases averted.

RESULTS

In a hypothetical cohort of 1000 students, screening using the TST-alone strategy averted 1.6 TB cases at a total cost of US$52 566. The QFT-GIT-alone strategy helped avert 2.0 TB cases, but was associated with a much higher total cost (US$108 435), resulting in an incremental cost-effectiveness ratio of US$140 933/TB case averted. The two-step TST/QFT-GIT strategy was worse than the TST-alone strategy, averting 1.3 TB cases at US$75 267.

CONCLUSION

The TST-alone strategy was the most cost-effective; the QFT-GIT-alone strategy averted the greatest number of TB cases but incurred the highest cost in contact investigation for school TB outbreaks.

Costs and operation management of community outreach program for tuberculosis in tribal populations in India

Objective

To evaluate costs of an active case finding (ACF) program with tuberculosis (TB) treatment delivery and monitoring, which targeted a rural tribal population in India.

Method

A time and motion study was conducted to evaluate operations and workload. Costs from the program perspective were assessed using both the bottom-up and top-down costing methods, exclusive of routine TB care costs. The impact of ACF on routine TB laboratory workloads was measured based on the changes in available staff time per smear at nine designated microscopy centers before and after program implementation.

Results

A majority (53.2%) of the community health-care worker's time was spent in traveling to communities, with an average of 22 TB patients (95% CI 19.14-24.94) seen per day per person. Costs (at 2015 $US rates) were US$1.85-US$2.42 per patient screened and submitting sputum, US$2.51-US$4.74 per person diagnosed with TB, and US$22.52-US$34.13 per TB patient completing treatment. Total smear volumes increased significantly after the ACF program, with more than a 15% reduction in available staff time per sputum smear test in most laboratories.

Conclusion

This low-cost, ACF program has the potential to be highly cost-effective in addressing gaps in TB care problems in rural India.

Study on effect of laser-induced ablation for Lamb waves in a thin plate

In this paper, the effect of ablation on the shape of elastic waves generated by laser excitation is studied numerically and experimentally. Laser-induced ultrasound has been widely used in the nondestructive testing (NDT) field because it has the advantage that the sensor does not have to be directly attached to the target structure. In the safety assessment process, low energy excitation is used, and thus the structure is not damaged. Most studies related to laser ultrasound have focused on the method of detecting cracks within the elastic range, and there have been few studies on the effect of ablation. This research consists of experiments and numerical analyses. In experiments, elastic waves were generated in an aluminum plate by projecting laser pulses with different energy intensities. The velocities in the thickness direction were measured using a Laser Doppler Velocimeter (LDV) at a point 135 mm away from the excitation point. In the numerical study, two numerical simulations were carried out using heat flux and normal stress input to mimic laser pulse excitation. A thermo-mechanical simulation by heat flux was conducted to simulate thermal expansion by the laser pulse, and the normal stress was applied to reflect the effect of radiation pressure by ablation, respectively. Waveforms were synthesized by using different magnitude ratios of the obtained numerical responses and were compared with the experiment results. It is found that the effect of radiation pressure should not be neglected if the energy intensity is large although the effect of radiation pressure decreases as the energy intensity decreases. At the energy intensity with which ablation occurs, the effects of thermal expansion and radiation pressure exist simultaneously, and the contribution to the response depends on the energy intensity.

A graphene mesh as a hybrid electrode for foldable devices

A graphene mesh with arrays of micro-holes was fabricated on a polymer substrate using photolithography for use as an electrode in flexible devices. The optimal mesh structure with high optical transmittance and electrical conductivity was designed using a finite element method, in which the conductivity of the mesh was simulated as a function of structure, size, and periodicity of the hole array. The sheet resistance of the graphene mesh was lowered to that of a graphene monolayer by chemical doping and found to be 330 Ω Sq^-1 at 98.5% transparency. The figure of merit of the doped graphene mesh was calculated to be 106 at 98% transmittance, a value that has not yet been reported for any conventional transparent electrode material. Due to strong bonding between the polymer and substrate, the hybrid electrode composed of a silver nanowire (AgNW)/graphene mesh coated with an over-coating layer exhibited more stable electrical characteristics during mechanical fatigue deformation compared to a hybrid film composed of a AgNW/graphene sheet. The AgNW/graphene sheet underwent breakdown at less than 20 000 cycles in cyclic bending tests with 6.5% strain, but the AgNW/graphene mesh showed a 38% increase in resistance at 20 000 cycles and no breakdown even at 100 000 cycles. Therefore, in this study, we propose a hybrid structure composed of a AgNW/graphene mesh, which is optically and mechanically superior to AgNW/graphene sheets, and therefore suitable for application as a transparent electrode in foldable devices with long-term stability.

A Reference-Free and Non-Contact Method for Detecting and Imaging Damage in Adhesive-Bonded Structures Using Air-Coupled Ultrasonic Transducers

Adhesive bonded structures have been widely used in aerospace, automobile, and marine industries. Due to the complex nature of the failure mechanisms of bonded structures, cost-effective and reliable damage detection is crucial for these industries. Most of the common damage detection methods are not adequately sensitive to the presence of weakened bonding. This paper presents an experimental and analytical method for the in-situ detection of damage in adhesive-bonded structures. The method is fully non-contact, using air-coupled ultrasonic transducers (ACT) for ultrasonic wave generation and sensing. The uniqueness of the proposed method relies on accurate detection and localization of weakened bonding in complex adhesive bonded structures. The specimens tested in this study are parts of real-world structures with critical and complex damage types, provided by Hyundai Heavy Industries^® and IKTS Fraunhofer^®. Various transmitter and receiver configurations, including through transmission, pitch-catch scanning, and probe holder angles, were attempted, and the obtained results were analyzed. The method examines the time-of-flight of the ultrasonic waves over a target inspection area, and the spatial variation of the time-of-flight information was examined to visualize and locate damage. The proposed method works without relying on reference data obtained from the pristine condition of the target specimen. Aluminum bonded plates and triplex adhesive layers with debonding and weakened bonding were used to examine the effectiveness of the method.

Development of a High Precision Displacement Measurement System by Fusing a Low Cost RTK-GPS Sensor and a Force Feedback Accelerometer for Infrastructure Monitoring

A displacement measurement system fusing a low cost real-time kinematic global positioning system (RTK-GPS) receiver and a force feedback accelerometer is proposed for infrastructure monitoring. The proposed system is composed of a sensor module, a base module and a computation module. The sensor module consists of a RTK-GPS rover and a force feedback accelerometer, and is installed on a target structure like conventional RTK-GPS sensors. The base module is placed on a rigid ground away from the target structure similar to conventional RTK-GPS bases, and transmits observation messages to the sensor module. Then, the initial acceleration, velocity and displacement responses measured by the sensor module are transmitted to the computation module located at a central monitoring facility. Finally, high precision and high sampling rate displacement, velocity, and acceleration are estimated by fusing the acceleration from the accelerometer, the velocity from the GPS rover, and the displacement from RTK-GPS. Note that the proposed displacement measurement system can measure 3-axis acceleration, velocity as well as displacement in real time. In terms of displacement, the proposed measurement system can estimate dynamic and pseudo-static displacement with a root-mean-square error of 2 mm and a sampling rate of up to 100 Hz. The performance of the proposed system is validated under sinusoidal, random and steady-state vibrations. Field tests were performed on the Yeongjong Grand Bridge and Yi Sun-sin Bridge in Korea, and the Xihoumen Bridge in China to compare the performance of the proposed system with a commercial RTK-GPS sensor and other data fusion techniques.

Isolated, well-defined organovanadium(iii) on silica: single-site catalyst for hydrogenation of alkenes and alkynes

Well-defined, isolated, single-site organovanadium(iii) catalyst on SiO₂ for unprecedented liquid- and gas-phase hydrogenation of alkenes and alkynes under mild conditions.

Numerical simulation of damage detection using laser-generated ultrasound

Laser ultrasonic techniques have been widely investigated due to its high spatial resolution and capacity for remote and noncontact measurement. In this study, the laser induced ultrasonic wave on an aluminum plate is simulated, and a nonlinear feature is used to detect a micro crack introduced in the plate model. A multi-physics simulation is conducted and optimized considering the effect of thermal diffusion. A nonlinear feature, called Bhattacharyya Distance (BD), is calculated to show the crack-induced geometric difference among the state space attractors obtained from closely spaced measurement points near the crack. First, a 3D model is built, and its simulation result is compared with an experiment performed using a noncontact laser ultrasonic measurement system. Then, by creating a micro crack in the model, BD is extracted and the crack is successfully detected and visualized. Finally, the effects of BD parameters, such as embedding dimension and frequency band, on damage visualization are investigated.

Fatigue crack localization using noncontact laser ultrasonics and state space attractors

A fatigue crack and its precursor often serves as a source of nonlinear mechanism for ultrasonic waves, and the resulting nonlinear features are often much more sensitive to the fatigue crack than their linear counterparts. Among various nonlinear ultrasonic techniques, the proposed laser nonlinear wave modulation spectroscopy (LNWMS) is unique in that (1) it utilizes a pulse laser to exert a single broadband input instead of conventional two distinctive sinusoidal waves, and (2) a complete noncontact measurement can be realized based on LNWMS. Under a broadband excitation, a nonlinear source exhibits modulations due to interactions among various input frequency components. These modulations are often weak and can be hardly directly detected. In this paper, a damage feature called Bhattacharyya distance is extracted from the ultrasonic time signal corresponding to a pulse laser input and used to quantify the degree of damage-induced nonlinearity and localize the crack. This feature is a measure of a statistical distance used to detect the geometrical changes between state space attractors reconstructed before and after damage formation. It has been successfully used for localizing fatigue cracks in metallic plates.

Treatment of pseudohypoparathyroidism with 1 alpha-hydroxyvitamin D3

A maintenance dosis of 2 microgram/day of 1 alpha-OH-D3 could keep the level of serum calcium normal in all 5 cases with pseudohypoparathyroidism, in contrast with 4.0 +/- 1.26 microgram/day needed for the 11 cases with hypoparathyroidism (8 idiopathic and 3 postoperative). The conspicuous effect of 1 alpha-OH-D3 on pseudohypoparathyroidism is likely to be attributed to the fact that the unresponsiveness of bone tissue to parathyroid hormone is corrected by the action of active vitamin D.

Mechanical impedance measurement and damage detection using noncontact laser ultrasound

This Letter proposes a mechanical impedance (MI) measurement technique using noncontact laser ultrasound. The ultrasound is generated by shooting a pulse laser beam onto a target structure, and its response is measured using a laser vibrometer. Once ultrasound propagation converges to structural vibration, MI is formed over the entire structure. Because noncontact lasers are utilized, this technique is applicable in harsh environments, free of electromagnetic interference, and able to perform wide-range scanning. The formation of MI and its feasibility for damage detection are verified through thermo-mechanical finite element analysis and lab-scale experiments.

A comparison of inflammatory mediator expression between palmoplantar pustulosis and pompholyx

BACKGROUND

Both palmoplantar pustulosis (PPP) and pompholyx are clinically characterized by acute eruptions of vesicles or pustules on the palms or soles.

OBJECTIVES

This study aims to compare the expression of certain inflammatory mediator genes and proteins between patients with PPP and pompholyx using skin tissue samples.

METHODS

Skin biopsies obtained from lesional skin from patients with PPP (n = 7) and pompholyx (n = 5) were analysed by quantitative RT-PCR to measure the mRNA levels of nine genes, including IL-4, IL-8, IL-9, IL-17, IL-22, IFN-γ, CCL-20, granzyme and perforin. For immunohistochemical analysis, 34 paraffin-embedded skin specimens (PPP, n = 22; pompholyx, n = 12) were stained with anti-IL-8, IL-17A, IL-22 and granzyme B antibodies.

RESULTS

Of genes analysed, IL-8 and IL-17A mRNA expression levels were significantly higher in the PPP group than the pompholyx group (P = 0.012 in both), whereas the mRNA expression of granzyme B was significantly higher in pompholyx when compared with PPP (P = 0.004). Regarding the IL-17A immunohistochemical staining, tissue from the PPP lesions contained significantly more IL-17A(+) cells in both the epidermis and papillary dermis when compared with pompholyx (P < 0.001 and P = 0.019 respectively). Moreover, the intensity of the IL-8 immunoreactivity was also greater in the PPP skin lesions than the pompholyx tissue (P < 0.001).

CONCLUSIONS

IL-8 and IL-17A, both are increased in PPP tissue, may represent important immunologic mediators that help to differentiate this clinical entity from pompholyx. This study may provide useful clues in distinguishing PPP from pompholyx, as well as helping to understand the pathogeneses of these two diseases.

Reference-free damage detection, localization, and quantification in composites

In this study, a reference-free damage characterization technique is developed not only to identify but also to locate and quantify damage in composite structures subject to varying temperature conditions. First, damage is characterized in terms of a damage index (m-value) defined as the ratio of damage size to the wavelength of the A0 mode within the damage. Then, a feasible solution space defining all possible combinations of the damage location and size are estimated without using any prior baseline data obtained from the pristine condition of a structure or different paths. When additional information such as the A0 mode group velocity within the pristine region of the structure becomes available, the estimates for the damage location and size are updated with better accuracy. The uniqueness of this study lies in that damage localization and quantification as well as identification are all performed without comparing current Lamb wave signals with the ones obtained from the pristine condition of the target structure, making the proposed technique more attractive for online monitoring. Numerical and experimental tests are presented to demonstrate the effectiveness of the proposed damage detection technique under varying temperature.

Comparative cost and performance of light-emitting diode microscopy in HIV-tuberculosis-co-infected patients

Light-emitting diode (LED) microscopy has recently been endorsed by the World Health Organization (WHO). However, it is unclear whether LED is as accurate and cost-effective as Ziehl-Neelsen (ZN) microscopy or mercury vapour fluorescence microscopy (MVFM) in tuberculosis (TB)-HIV-co-infected subjects. Direct and concentrated sputum smears from TB suspects were evaluated using combinations of LED microscopy, ZN microscopy and MVFM. Median reading time per slide was recorded and a cost analysis performed. Mycobacterial culture served as the reference standard. 647 sputum samples were obtained from 354 patients (88 (29.8%) were HIV-infected and 161 (26%) were culture-positive for Mycobacterium tuberculosis). Although overall sensitivity of LED compared with ZN microscopy or MVFM was similar, sensitivity of all three modalities was lower in HIV-infected patients. In the HIV-infected group, the sensitivity of LED microscopy was higher than ZN microscopy using samples that were not concentrated (46 versus 39%; p = 0.25), and better than MVFM using concentrated samples (56 versus 44; p = 0.5). A similar trend was seen in the CD4 count <200 cells · mL(-1) subgroup. Median (interquartile range) reading time was quicker with LED compared with ZN microscopy (1.8 (1.7-1.9) versus 2.5 (2.2-2.7) min; p ≤ 0.001). Average cost per slide read was less for LED microscopy (US$1.63) compared with ZN microscopy (US$2.10). Among HIV-TB-co-infected patients, LED microscopy was cheaper and performed as well as ZN microscopy or MVFM independent of the staining (ZN or auramine O) or processing methods used.

Piezoelectric transducer self-diagnosis under changing environmental and structural conditions

Surface-mountable wafer-type piezoelectric transducers using lead zirconate titanate (PZT) are widely used to generate and sense guided waves for nondestructive evaluation and structural health monitoring applications. However, little attention has been paid to monitoring PZT transducer integrity, despite possibly being the weakest link in the entire monitoring system. In this study, PZT transducer self-diagnostic techniques, which enable a single PZT transducer to examine its own integrity, are developed based on a time-reversal process; the effects of temperature and structural condition variations are explicitly considered. Two PZT self-diagnosis indices are proposed which allow debonded and cracked PZT conditions to be identified and distinguished from changing environmental and structural conditions. First, the proposed self-diagnosis schemes are theoretically formulated, and then the feasibility of the proposed schemes is validated through simulations and experimental tests under varying temperature and structural conditions.

Development of dual PZT transducers for reference-free crack detection in thin plate structures

A new Lamb-wave-based nondestructive testing (NDT) technique, which does not rely on previously stored baseline data, is developed for crack monitoring in plate structures. Commonly, the presence of damage is identified by comparing "current data" measured from a potentially damaged stage of a structure with "baseline data" previously obtained at the intact condition of the structure. In practice, structural defects typically take place long after collection of the baseline data, and the baseline data can be also affected by external loading, temperature variations, and changing boundary conditions. To eliminate the dependence on the baseline data comparison, the authors previously developed a reference-free NDT technique using 2 pairs of collocated lead zirconate titanate (PZT) transducers placed on both sides of a plate. This reference-free technique is further advanced in the present study by the necessity of attaching transducers only on a single surface of a structure for certain applications such as aircraft. To achieve this goal, a new design of PZT transducers called dual PZT transducers is proposed. Crack formation creates Lamb wave mode conversion due to a sudden thickness change of the structure. This crack appearance is instantly detected from the measured Lamb wave signals using the dual PZT transducers. This study also suggests a reference-free statistical approach that enables damage classification using only the currently measured data set. Numerical simulations and experiments were conducted using an aluminum plate with uniform thickness and fundamental Lamb waves modes to demonstrate the applicability of the proposed technique to reference-free crack detection.

Induction of cell death in human macrophages by a highly virulent Korean Isolate of Mycobacterium tuberculosis and the virulent strain H37Rv

Recent studies have suggested that virulent strains of Mycobacterium tuberculosis induce apoptosis in macrophages less often than do attenuated strains. K-strain, which belongs to the Beijing family, is the most frequently isolated clinical strain of M. tuberculosis in Korea. In this study, we investigated the differential induction of cell death in human monocytic THP-1 cells by K-strain and H37Rv, a virulent but laboratory-adapted strain of M. tuberculosis. Although no significant difference in growth rate was observed between the cells exposed to K-strain and those exposed to H37Rv, the levels of protective cytokines such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-12p40 were lower in K-strain-infected cells than in H37Rv-infected cells. Cell viability assays showed that both K-strain and H37Rv, but not heat- or streptomycin-killed bacteria, induced THP-1 cell death in a TNF-independent manner. In contrast, double staining with fluorochrome-labelled inhibitors of caspase and propidium iodide and lactate dehydrogenase release assays revealed that K-strain induced significantly higher levels of necrotic cell death, rather than apoptosis, in THP-1 cells than did H37Rv. Anti-apoptotic Bcl-2, Mcl-1, Bfl-1 and Bcl-xL in the cells were significantly upregulated following infection with K-strain compared with H37Rv, whereas Bax was slightly upregulated in response to infection with both H37Rv and K-strain. These results suggest that the highly virulent K-strain keeps cellular apoptosis as a host defense mechanism to a minimum and induces necrosis in macrophages.

Fluorescence microscopy is less expensive than Ziehl-Neelsen microscopy in Thailand

Ziehl-Neelsen (ZN) microscopy is the primary method for acid-fast bacilli examination in resource-limited settings, including Thailand. Despite its considerably improved diagnostic performance, conventional fluorescent microscopy (FM) is rarely used due to its perceived high cost. An evaluation in Thailand found that the total cost of FM operated in the National Tuberculosis Reference Laboratory (NTRL) in Bangkok, Thailand, is similar to that of ZN performed in the NTRL and in four regional Thai laboratories. FM is therefore a cost-effective alternative to ZN in resource-limited settings.

Obesity should not influence the management of appendicitis

BACKGROUND

Obesity implies an adverse effect on outcome after appendectomy. This study aimed to determine whether obese patients with appendicitis should be managed differently than nonobese patients.

METHODS

After appendectomy, all patients were enrolled in a prospective clinical pathway and followed from initial presentation to full outpatient recovery.

RESULTS

In 1 year, 272 adults underwent appendectomy, 55 (22%) of whom were obese. The obese patients were slightly older (35 vs 33 years; p < 0.001). The time to diagnosis (8.5 vs 8.6 h), and the need for computed tomography (CT) scanning (40% vs 49%) was similar in both populations. The obese patients had similar rates of perforation (35% vs 35%) and laparoscopy (47% vs 41%). The median hospital length of stay (LOS) (2 days) and complications, including wound complications (9.1% vs 10.9%) and intraabdominal abscesses (3.6% vs 3.1%), were similar. Subgroup analysis showed a longer LOS for the obese patients with perforation than for the nonobese patients (6 vs 5.5 days; p = 0.036).

CONCLUSION

Obese patients had no greater delay in diagnosis, had no greater need for CT scan, gained no additional benefit from laparoscopy, and did not incur significantly worse outcomes after appendectomy except for an increased LOS among those with perforation.

Induction chemotherapy followed by concurrent chemoradiotherapy (CCRT) versus CCRT alone for unresectable stage III non-small cell lung cancer (NSCLC): Randomized phase III trial

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Background: We conducted a prospective randomized phase III trial comparing induction chemotherapy followed by concurrent chemoradiotherapy (CCRT) versus immediate CCRT to evaluate whether the addition of induction chemotherapy would result in improved survival. Methods: Patients with unresectable stage III NSCLC, ECOG PS 0–1, and weight loss up to 10% were eligible. They were randomized to receive either induction chemotherapy followed by CCRT (arm A) or immediate CCRT (arm B) after stratification for stage (T4N0–2, T1–3N3, T4N3, and stage IIIA), histology (squamous vs non-squamous), and SCLN positivity. Induction chemotherapy consisted of two cycles of gemcitabine (1,000 mg/m2 D1, D8) and cisplatin (70 mg/m2 D1) q 21days. Chemotherapy during CCRT consisted of 6 cycles of weekly paclitaxel (50 mg/m2) and cisplatin (20 mg/m2). Radiation therapy performed with hypofractionated scheme (2.2 Gy/fraction, once a day) and total dose was 66 Gy. Irradiated volume encompassed gross tumor plus 1.0 cm margin. Results: Between March 2003 and June 2006, 134 patients were enrolled. 92% of patients were male and 60% were age 60 or older. Objective tumor response was obtained in 38% after induction chemotherapy. Response rates after completion of CCRT were 72% (95% CI, 61%–83%) on arm A and 79% (95% CI, 69%–89%) on arm B. Grade 3/4 toxicities during induction chemotherapy consisted mainly of neutropenia (11%/3%). During CCRT, grade 3/4 neutropenia was noted in 8%/5% (arm A) versus in 8%/0% (arm B), grade 3 anemia was 8% vs 0%, grade 3 thrombocytopenia 5% vs 0%, and grade 3 esophagitis 16% vs 16%. At median follow-up of 28 months, median survival was 12.6 months (95% CI, 8.6–16.7 months) on arm A versus 18.2 months (95% CI, 11.7–24.8 months) on arm B (P=0.18). Two year survival estimates was 25% (15%–35%) and 43% (31%–55%), respectively. Median progression free survival was 7.5 months (95% CI, 5.6–9.4 months) on arm A and 11.6 months (95% CI, 9.6–13.6 months) on arm B (P=0.04). Conclusions: The addition of induction chemotherapy to CCRT failed to increase the survival of unresectable stage III NSCLC over immediate CCRT. Moreover, the progression free survival was inferior to immediate CCRT.

No significant financial relationships to disclose.

Phase I/II study of combination chemotherapy with S-1 and cisplatin every 3 week schedule in patients with metastatic or recurrent gastric cancer

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Background: S-1 plus cisplatin has been reported to be highly active in advanced gastric cancer (AGC). The objectives of this study were to define the maximal-tolerated dose (MTD) of S-1, given for 2 weeks separated by 1 week rest, with a fixed dose of cisplatin, and to determine the activity and safety of this combination regimen at the recommended dose (RD) when used as the first line treatment of AGC. Methods: Cisplatin was fixed at a dose of 60 mg/m2 on D1 and the starting dose of S-1 was 30 mg/m2 bid (level I) on D1 to D14 every 3 weeks. The dose of S-1 was increased by 5 mg/m2 bid up to 50 mg/m2 bid (level V) unless MTD was achieved. At every level, a cohort of 3 patients (pts), which could be expanded to 6 pts, was studied. Dose-limiting toxicities (DLTs) were assessed for the first 2 cycles. Results: From February 2004 to January 2006, 62 eligible pts were enrolled. In phase I (N=21), DLTs occurred at level V (S-1 50 mg/m2 bid), with 2 of 3 pts developing G3 diarrhea or febrile neutropenia. The RD was determined at level IV (45 mg/m2 bid) because only 1 DLT occurred out of 6 pts at this level. After the first 20 pts (series I) were enrolled in phase II, the protocol was amended; the S-1 dose was reduced down to 40 mg/m2 bid (level III, series II, N=23) because of poor bone marrow recovery and resultant treatment delay. At the time of analysis, a total of 272 cycles of chemotherapy were administered. The median age was 52 years (28–70) and ECOG PS was 0/1 in 98% of pts. The objective response was observed in 20(47%; 95% CI, 36–66%) of 43 pts. SD was achieved in 15 (35%) pts. With a median FU of 12.1 months (range 9.8–23.3) for all survivors, median PFS was 5.3 months (95% CI, 4.6–6.0 months) with a median OS of 10.0 months (95% CI, 5.1–14.8 months). G3–4 toxicities included neutropenia (33%), anemia (31%), anorexia (24%), and asthenia (14%); however severe febrile neutropenia, abdominal pain, and stomatitis were never observed. Conclusions: The cisplatin plus S-1 regimen incorporating 2-weeks on and 1-week off is highly active against gastric adenocarcinoma with favorable toxicitiy profiles in Korean patients.

No significant financial relationships to disclose.