Detection of Micrometer-Sized Virus Aerosols by Using a Real-Time Bioaerosol Monitoring System.

This study investigates a real-time handheld bioaerosol monitoring system for the detection of biological particles using UV-LED and light-induced fluorescence technology. Biological particles produce both scattering and fluorescence signals simultaneously, which can help distinguish them from general particles. The detected scattering, fluorescence, and simultaneous signals are then converted into photon signals and categorized based on predetermined criteria. A reliable biological particle generator was required to validate the performance of the system. This study explores the use of an M13 bacteriophage as a virus simulant of biological agents and employs a customized inkjet aerosol generator to produce M13 bacteriophage aerosols of a specific size by controlling the concentration of M13. We confirmed that micro-sized, narrowly dispersed M13 aerosols were efficiently generated. Additionally, we confirmed the performance of this real-time handheld bioaerosol monitoring system by detecting viruses.

Usefulness of an Additional Filter Created Using 3D Printing for Whole-Body X-ray Imaging with a Long-Length Detector.

We recently developed a long-length detector that combines three detectors and successfully acquires whole-body X-ray images. Although the developed detector system can efficiently acquire whole-body images in a short time, it may show problems with diagnostic performance in some areas owing to the use of high-energy X-rays during whole-spine and long-length examinations. In particular, during examinations of relatively thin bones, such as ankles, with a long-length detector, the image quality deteriorates because of an increase in X-ray transmission. An additional filter is primarily used to address this limitation, but this approach imposes a higher load on the X-ray tube to compensate for reductions in the radiation dose and the problem of high manufacturing costs. Thus, in this study, a newly designed additional filter was fabricated using 3D printing technology to improve the applicability of the long-length detector. Whole-spine anterior-posterior (AP), lateral, and long-leg AP X-ray examinations were performed using 3D-printed additional filters composed of 14 mm thick aluminum (Al) or 14 mm thick Al + 1 mm thick copper (Cu) composite material. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and radiation dose for the acquired X-ray images were evaluated to demonstrate the usefulness of the filters. Under all X-ray inspection conditions, the most effective data were obtained when the composite additional filter based on a 14 mm thick Al + 1 mm thick Cu material was used. We confirmed that an SNR improvement of up to 46%, CNR improvement of 37%, and radiation dose reduction of 90% could be achieved in the X-ray images obtained using the composite additional filter in comparison to the images obtained with no filter. The results proved that the additional filter made with a 3D printer was effective in improving image quality and reducing the radiation dose for X-ray images obtained using a long-length detector.

Optimizing the Sensitivity of Biological Particle Detectors through Atmospheric Particle Analysis According to Climatic Characteristics in South Korea.

Biological agents used in biological warfare or bioterrorism are also present in bioaerosols. Prompt identification of a biological weapon and its characteristics is necessary. Herein, we optimized an environmentally adaptive detection algorithm that can better reflect changes in the complex South Korean environment than the current models. The algorithm distinguished between normal and biological particles using a laser-induced fluorescence-based biological particle detector capable of real-time measurements and size classification. We ensured that the algorithm operated with minimal false alarms in any environment by training based on experimental data acquired from an area where rainfall, snow, fog and mist, Asian dust, and water waves on the beach occur. To prevent time and money wastage due to false alarms, the detection performance for each level of sensitivity was examined to enable the selection of multiple sensitivities according to the background, and the appropriate level of sensitivity for the climate was determined. The basic sensitivity was set more conservatively than before, with a 3% alarm rate at 20 agent-containing particles per liter of air (ACPLA) and a 100% alarm rate at 63 ACPLA. The reliability was increased by optimizing five variables. False alarms did not occur in situations where no alarm was unnecessary.

Two-year direct medical costs of stroke in Korea: a multi-centre incidence-based study from hospital perspectives.

BACKGROUND: Despite increasing socio-economic burden of stroke, few studies have investigated the costs associated with the stroke care in Korea. We estimated the two-year direct medical costs associated with stroke. METHODS: This was a multi-centre, incidence-based, retrospective observational study. We examined the records of all adult patients who were admitted in eight large hospitals throughout Korea due to acute stroke [I60: sub-arachnoid haemorrhage; I61: intracerebral haemorrhage; I62: other nontraumatic haemorrhage; I63: cerebral infarction, by The International Statistical Classification of Diseases and Related Health Problems (ICD)-10] between 1 November and 31 December 2006. Direct medical inpatient and outpatient cost of each patient was extracted from the medical record and the reimbursement claim data of the hospital. RESULTS: Out of 908 studied patients (14% diagnosed as I60, 18% as I61, 3% as I62, and 65% as I63), 460 (50.7%) were assessed for more than one-year. The annual average direct medical costs were Korean 8,114,471 US$8732) for the first year, and Korean 431,527 for the second year. The first year costs for haemorrhagic stroke (I60-I62) (Korean 13,090,179) were significantly higher than those associated with cerebral infarction (I63) (Korean 5,460,459), whereas the second year costs were not different. Factors independently associated with high cost were female gender, young age, and first stroke. CONCLUSIONS: Direct medical costs for stroke in Korea were determined, which seem to be lower than those of other developed countries. Female gender, young age, and first stroke were factors related to higher stroke cost.