1,182 research outputs found
Fractional phenomena of the spontaneous emission of a two-level atom in photonic crystals
We suggest a better mathematical method, fractional calculus, for studying
the behavior of the atom-field interaction in photonic crystals. By studying
the spontaneous emission of an atom in a photonic crystal with one-band
isotropic model, we found that the long-time inducing memory of the spontaneous
emission is a fractional phenomenon. This behavior could be well described by
the fractional calculus. And the results show no steady photon-atom bound state
for the atomic resonant transition frequency lying in the proximity of allowed
band edge which is encountered in the previous study [J. Opt. B: Quantum
Semiclass. Opt. {\bf 5}, R43 (2003)]. The correctness of this result is
validated by the ``cut-off smoothing'' density of photon states (DOS) with
fractional calculus. By obtaining a rigorous solution without the
multiple-valued problem for the system, we show the method of fractional
calculus has logically concise property.Comment: 12 Pages, 3 figure
Pulse-power-detection analysis of incoherent O-CDMA systems under the influence of fiber temperature fluctuations
In this paper, a pulse-shift technique, which divides every time slot (or chip) into equal-width sub-chips, is used to model the effect of fiber temperature fluctuations in incoherent optical code-division multiple-access (O-CDMA) systems. With the advance in all-optical thresholding technology, power detection of ultrashort optical pulses is possible. This paper also formulates a new pulse-power-detection model for incoherent OCDMA and applies it to the analysis of the pulse-shift technique as a case study. Numerical studies and computer simulations are presented to validate the new analytical model. Our study presents a more realistic theoretical model of all-optical thresholding in incoherent O-CDMA and results in better performance than the conventional pulse-energy-detection model
Emergence of Ceftriaxone-Resistant Salmonella Isolates and Rapid Spread of Plasmid-Encoded CMY-2–Like Cephalosporinase, Taiwan
Of 384 Salmonella isolates collected from 1997 to 2000 in a university hospital in Taiwan, six ceftriaxone-resistant isolates of Salmonella enterica serovar Typhimurium were found in two patients in 2000. The resistance determinants were on conjugative plasmids that encoded a CMY-2–like cephalosporinase. During the study period, the proportion of CMY-2–like enzyme producers among Escherichia coli increased rapidly from 0.2% in early 1999 to >4.0% in late 2000. Klebsiella pneumoniae isolates producing a CMY-2–like β-lactamase did not emerge until 2000. The presence of blaCMY-containing plasmids with an identical restriction pattern from Salmonella, E. coli, and K. pneumoniae isolates was found, which suggests interspecies spread and horizontal transfer of the resistance determinant. Various nosocomial and community-acquired infections were associated with the CMY-2–like enzyme producers. Our study suggests that the spread of plasmid-mediated CMY-2–like β-lactamases is an emerging threat to hospitalized patients and the public in Taiwan
Surgical treatment for thyrotoxic hypokalemic periodic paralysis: case report
Thyrotoxic hypokalemic periodic paralysis (THPP) is a rare, potentially life-threatening endocrine emergency. It is characterized by recurrent muscle weakness and hypokalemia. Because many THPP patients do not have obvious symptoms and signs of hyperthyroidism, misdiagnosis may occur. The published studies revealed that definitive therapy for THPP is control of hyperthyroidism by medical therapy, radioactive iodine or surgery, but the long-term post-operative follow-up result was not observed. We reported two cases of medically refractory THPP with recurrent paralysis of extremities and hypokalemia, and both were combined with thyroid nodules. Both patients were treated with total thyroidectomy; the pathology revealed that one is Graves' disease with thyroid papillary carcinoma, and the other is adenomatous goiter with papillary hyperplasia. No episode of periodic paralysis was noted and laboratory evaluation revealed normal potassium level during the post-operative follow up. Our experience suggests that total thyroidectomy by experienced surgeon is an appropriate and definite treatment for medically refractory THPP, especially in cases combined with thyroid nodules
Anatomical Variations of Recurrent Laryngeal Nerve During Thyroid Surgery: How to Identify and Handle the Variations With Intraoperative Neuromonitoring
Recurrent laryngeal nerve (RLN) palsy is the most common and serious complication after thyroid surgery. Visual identification of the RLN during thyroid surgery has been shown to be associated with lower rates of palsy, and although it has been recommended as the gold standard for RLN treatment, it does not guarantee success against postoperative vocal cord paralysis. Anatomical variations of the RLN, such as extra-laryngeal branches, distorted RLN, intertwining between branches of the RLN and inferior thyroid artery, and non-recurrent laryngeal nerve, can be a potential cause of nerve injury due to visual misidentification. Therefore, intraoperative verification of functional and anatomical RLN integrity is a prerequisite for a safe thyroid operation. In this article, we review the literature and demonstrate how to identify and handle the anatomical variations of the RLN with the application of intraoperative neuromonitoring in the form of high resolution photography, which can be informative for thyroid surgeons. Anatomical variations of the RLN cannot be predicted preoperatively and might be associated with higher rates of RLN injury. The RLN injury caused by visual misidentification can be rare if the nerve is definitely identified early with intraoperative neuromonitoring
Seizure After Local Anesthesia for Nasopharyngeal Angiofibroma
We report a young male patient who experienced seizure after local injection of 3 mL 2% lidocaine with epinephrine 1:200,000 around a recurrent nasal angiofibroma. After receiving 100% oxygen via mask and thiamylal sodium, the patient had no residual neurologic sequelae. Seizure immediately following the injection of local anesthetics in the nasal cavity is probably due to injection into venous or arterial circulation with retrograde flow to the brain circulation. Further imaging study or angiography should be done before head and neck surgeries, especially in such highly vascular neoplasm
Microscopic Description of Band Structure at Very Extended Shapes in the A ~ 110 Mass Region
Recent experiments have confirmed the existence of rotational bands in the A
\~ 110 mass region with very extended shapes lying between super- and
hyper-deformation. Using the projected shell model, we make a first attempt to
describe quantitatively such a band structure in 108Cd. Excellent agreement is
achieved in the dynamic moment of inertia J(2) calculation. This allows us to
suggest the spin values for the energy levels, which are experimentally
unknown. It is found that at this large deformation, the sharply down-sloping
orbitals in the proton i_{13/2} subshell are responsible for the irregularity
in the experimental J(2), and the wave functions of the observed states have a
dominant component of two-quasiparticles from these orbitals. Measurement of
transition quadrupole moments and g-factors will test these findings, and thus
can provide a deeper understanding of the band structure at very extended
shapes.Comment: 4 pages, 3 eps figures, final version accepted by Phys. Rev. C as a
Rapid Communicatio
Comparative Geochemistry of 234Th, 210Pb, and 210Po: A Case Study in the Hung-Tsai Trough off Southwestern Taiwan
Detailed profiles of dissolved and particulate 234Th, 210Pb, and 210Po activities at three stations in the Hung-Tsai Trough off south western Taiwan were determined. The total 234Th activ ity is 20 ~ 25% deficientfrom its secular equilibrium in the entire water column. Except for an evident excess of 210Po at some depths in the mixed layer and in the pycnocline layer, total 210Po activity is also lower than total 210Pb activity. As a result of atmospheric deposition, 210Pb is about 25% in excess of its parent, 226Ra, through out the water column of the Hung-Tsai Trough. The ratios of the distribution coefficients of 234Th, 210Pb, and 210Po show that the order of particle affinity is Po > Th ~ Pb in the mixed layer and bottom layer, whereas the order changes, due to particlere generation, into Th > Pb > Po in the pycnocline layer of the Hung-Tsai Trough
Molecular typing of Mycobacterium tuberculosis isolated from adult patients with tubercular spondylitis
Background/PurposeTuberculosis (TB) is endemic in Taiwan and usually affects the lung, spinal TB accounting for 1–3% of all TB infections. The manifestations of spinal TB are different from those of pulmonary TB. The purpose of this study was to define the epidemiological molecular types of mycobacterial strains causing spinal TB.MethodsWe retrospectively reviewed the medical charts of adult patients diagnosed with spinal TB from January 1998 to December 2007. Patients with positive culture results and/or pathological findings characteristic of TB were enrolled in this study. Spoligotyping was performed to type the Mycobacterium tuberculosis isolates.ResultsA total of 38 patients with spinal TB were identified. Their mean age was 68 years, and their median duration of symptoms was 60 days (range 3–720 days). The lumbar and thoracic spine accounted for 76% of the sites involved. Thirteen specimens (from seven male and six female patients) were available for typing. Spoligotyping of these 13 specimens revealed three Beijing (23%) and 10 non-Beijing types (77%). The non-Beijing types included two EAI2 Manilla (15%), two H3 (15%), two unclassified (15%), and one each of BOVIS1, U, T2, and orphan type. No significant predominant strain was found in this study, and no drug-resistant Beijing strains were identified.ConclusionTB spondylitis was found to occur in older patients. Spoligotyping results showed that most of the TB spondylitis cases were caused by non-Beijing type Mycobacterium tuberculosis
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