6,925 research outputs found
Juvenile chronic arthritis in Chinese children: a review of the local experience
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High-throughput continuous dielectrophoretic separation of neural stem cells.
We created an integrated microfluidic cell separation system that incorporates hydrophoresis and dielectrophoresis modules to facilitate high-throughput continuous cell separation. The hydrophoresis module consists of a serpentine channel with ridges and trenches to generate a diverging fluid flow that focuses cells into two streams along the channel edges. The dielectrophoresis module is composed of a chevron-shaped electrode array. Separation in the dielectrophoresis module is driven by inherent cell electrophysiological properties and does not require cell-type-specific labels. The chevron shape of the electrode array couples with fluid flow in the channel to enable continuous sorting of cells to increase throughput. We tested the new system with mouse neural stem cells since their electrophysiological properties reflect their differentiation capacity (e.g., whether they will differentiate into astrocytes or neurons). The goal of our experiments was to enrich astrocyte-biased cells. Sorting parameters were optimized for each batch of neural stem cells to ensure effective and consistent separations. The continuous sorting design of the device significantly improved sorting throughput and reproducibility. Sorting yielded two cell fractions, and we found that astrocyte-biased cells were enriched in one fraction and depleted from the other. This is an advantage of the new continuous sorting device over traditional dielectrophoresis-based sorting platforms that target a subset of cells for enrichment but do not provide a corresponding depleted population. The new microfluidic dielectrophoresis cell separation system improves label-free cell sorting by increasing throughput and delivering enriched and depleted cell subpopulations in a single sort
Passive PT -symmetric couplers without complex optical potentials
© 2015 American Physical Society. In addition to the implementation of parity-time-(PT-) symmetric optical systems by carefully and actively controlling the gain and loss, we show that a 2×2 PT-symmetric Hamiltonian has a unitarily equivalent representation without complex optical potentials in the resulting optical coupler. Through the Naimark dilation in operator algebra, passive PT-symmetric couplers can thus be implemented with a refractive index of real values and asymmetric coupling coefficients. This opens up the possibility to implement general PT-symmetric systems with state-of-the-art asymmetric slab waveguides, dissimilar optical fibers, or cavities with chiral mirrors
Childhood acute lymphoblastic leukaemia masquerading as primary skeletal problem
Acute lymphobiastic leukaemia (ALL) usually presents with signs of bone marrow failure, Occasionally ALL in children may present with non-specific or misleading clinical features. In a retrospect analysis of 25 consecutive cases of childhood ALL, we identified three children who were initially managed and discharged as acute osteomyelitis, juvenile chronic arthritis and postinfectious arthralgia respectively. They had mild normochromic, normocytic anaemia and two had transient leucopenia. Their platelet counts were normal and none had circulating blasts. The severity of their skeletal symptoms was out of proportion to the clinical and radiological finding. They failed to respond to the initial management and diagnosis was delayed for an average of 42 days and eventually confirmed on the marrow aspirate. Complete remission was attained in all cases with standard chemotherapy and had been maintained for an average of 29 months. ALL should be considered as a differential diagnosis in children complaining of multiple or persistent joint pains, especially in the presence of atypical clinical features or poor response to treatment.published_or_final_versio
Is locking plate fixation a better option than casting for distal radius fracture in elderly people?
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The efficacy of extracorporeal shock wave lithotripsy in the treatment of ureteric stones
This study was conducted to evaluate the efficacy of in situ extracorporeal shock wave lithotripsy treatment of ureteric stones using the Dornier MFL 5000 lithotripter. From March 1991 to June 1994, 184 patients received in situ extracorporeal shock wave lithotripsy treatment. The overall success rate was 76% (77% for upper; 69% for middle; and 81% for lower ureteric stones, respectively). The level and size of the stones did not affect the final outcome significantly. An average of 1.23 sessions were required for each patient and the rate of major auxiliary intervention was 21%. We conclude that extracorporeal shock wave lithotripsy is an effective treatment for ureteric stones.published_or_final_versio
Prevalence of and Risk Factors for Childhood Asthma, Rhinitis, and Eczema in Hong Kong: Proposal for a Cross-Sectional Survey
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Invasive Acremonium falciforme infection in a patient with severe combined immunodeficiency [7]
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Management of ureteric calculi: the pendulum swings
Extracorporeal shock wave lithotripsy (ESWL) for treatment of ureteral calculi has gained wide popularity because of its non-invasive and ambulatory nature. The success rate using the Dornier MFL 5000 is about 77%, but retreatment is often required and stone clearance is gradual. Ureteroscopic lithotripsy (URSL) used to be performed as an in-patient procedure. With the introduction of Holmium laser and establishment of day surgery service, out-patient URSL carries a success rate of 93% and offers immediate stone clearance. It is an attractive alternative for low surgical risk patients as a primary treatment modality.published_or_final_versio
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