380 research outputs found
Properties of Central Caustics in Planetary Microlensing
To maximize the number of planet detections, current microlensing follow-up
observations are focusing on high-magnification events which have a higher
chance of being perturbed by central caustics. In this paper, we investigate
the properties of central caustics and the perturbations induced by them. We
derive analytic expressions of the location, size, and shape of the central
caustic as a function of the star-planet separation, , and the planet/star
mass ratio, , under the planetary perturbative approximation and compare the
results with those based on numerical computations. While it has been known
that the size of the planetary caustic is \propto \sqrt{q}, we find from this
work that the dependence of the size of the central caustic on is linear,
i.e., \propto q, implying that the central caustic shrinks much more rapidly
with the decrease of compared to the planetary caustic. The central-caustic
size depends also on the star-planet separation. If the size of the caustic is
defined as the separation between the two cusps on the star-planet axis
(horizontal width), we find that the dependence of the central-caustic size on
the separation is \propto (s+1/s). While the size of the central caustic
depends both on and q, its shape defined as the vertical/horizontal width
ratio, R_c, is solely dependent on the planetary separation and we derive an
analytic relation between R_c and s. Due to the smaller size of the central
caustic combined with much more rapid decrease of its size with the decrease of
q, the effect of finite source size on the perturbation induced by the central
caustic is much more severe than the effect on the perturbation induced by the
planetary caustic. Abridged.Comment: 5 pages, 4 figures, ApJ accepte
Development of the Korean Academy of Medical Sciences Guideline for Rating the Impairment in the Brain Injured and Brain Diseased Persons with Motor Dysfunction
To develop an objective and scientific method to evaluate the brain injured and brain diseased persons with motor dysfunction, American Medical Association's Guides to the Evaluation of Permanent Impairment was used as an exemplar. After the motor dysfunction due to brain injury or brain disease was confirmed, active range of motion and muscle strength of affected extremities were measured. Also, the total function of extremities was evaluated through the assessment of activities of daily living, fine coordination of hand, balance and gait. Then, the total score of manual muscle test and functional assessment of impaired upper and lower extremity were added, respectively. Spasticity of upper and lower extremity was used as minus factors. Patients with movement disorder such as Parkinson's disease were assessed based on the degree of dysfunction in response to medication. We develop a new rating system based on the concept of total score
Three concurrent variations of the aberrant right subclavian artery, the non-recurrent laryngeal nerve and the right thoracic duct
We herein report a case showing three anatomical variations including the aberrant right subclavian artery (ARSA), the non-recurrent laryngeal nerve (NRLN) and the right thoracic duct in a 59-year-old male cadaver. The right subclavian artery (RSA) arose from the descending aorta next to the left subclavian artery and coursed in between the oesophagus and the thoracic vertebrae. The recurrent laryngeal nerve did not coil around the RSA but directly entered the larynx. Lastly the thoracic duct terminated into the right brachiocephalic vein. This study makes an embryological assumption that the abnormal development of the RSA had happened first and subsequently caused NRLN and the thoracic duct drainage variation. As to our knowledge, only two reports have been made previously concerning such concurrent variations. Therefore, this case report alerts anatomists and clinicians to the possibility of simultaneous occurrence of ARSA, NRLN and the right thoracic duct
Comparison of the characteristic features of bonghan ducts, blood and lymphatic capillaries
Objective: To show that the characteristic morphological and ultrastructural features
of a Bonghan corpuscle and duct presented here are consistent with the description
given in the early reports of Bonghan Kim.
Materials and Methods: We compared the morphological aspects of Bonghan ducts
with those of blood and lymphatic capillaries on the ultrastructural level to display
the manifestly distinctive nature of the Bonghan system.
Results: The walls of the ductules were observed to be composed of a single layer of
endothelial cells with characteristic rod-shaped nuclei and were not surrounded by
a basal lamina or by accessory cells, such as pericytes or smooth muscle cells. The
abluminal cell membranes of Bonghan ductules were not attached by anchoring filaments to the fibers of extracellular matrices as observed in lymphatic capillaries
Multifunctional nanoparticles as a tissue adhesive and an injectable marker for image-guided procedures
Tissue adhesives have emerged as an alternative to sutures and staples for wound closure and reconnection of injured tissues after surgery or trauma. Owing to their convenience and effectiveness, these adhesives have received growing attention particularly in minimally invasive procedures. For safe and accurate applications, tissue adhesives should be detectable via clinical imaging modalities and be highly biocompatible for intracorporeal procedures. However, few adhesives meet all these requirements. Herein, we show that biocompatible tantalum oxide/silica core/shell nanoparticles (TSNs) exhibit not only high contrast effects for real-time imaging but also strong adhesive properties. Furthermore, the biocompatible TSNs cause much less cellular toxicity and less inflammation than a clinically used, imageable tissue adhesive (that is, a mixture of cyanoacrylate and Lipiodol). Because of their multifunctional imaging and adhesive property, the TSNs are successfully applied as a hemostatic adhesive for minimally invasive procedures and as an immobilized marker for image-guided procedures.
Worse outcome of debridement, antibiotics, and implant retention in acute hematogenous infections than in postsurgical infections after total knee arthroplasty: a multicenter study
Background : We sought to determine (1) the success rate of debridement, antibiotics, and implant retention (DAIR) for acute periprosthetic joint infection (PJI) of the knee in patients with acute postsurgical infection and in those with acute hematogenous infection via a multicenter study, (2) the factors related to the failure of DAIR for overall acute PJI and acute hematogenous PJI via subgroup analysis, and (3) whether the PJI recurrence patterns differed between the two groups over time after DAIR.
Methods : This retrospective multicenter study included 101 acute knee PJI. Acute postsurgical PJI was defined as PJI diagnosed < 3 months following initial knee arthroplasty surgery. DAIR was performed for 34 cases of acute postsurgical PJIs (postsurgical group) and 67 cases of acute hematogenous PJIs (hematogenous group). The success rates between groups were compared, and factors related to DAIR failure were analyzed.
Results : The overall success rate of DAIR was 77%. The success rate tended to be higher in the postsurgical group than in the hematogenous group (p = 0.060). However, there was no significant factor related to DAIR failure in the subgroup analysis of acute hematogenous PJIs. In the postsurgical group, the recurrence of PJI occurred until 3 months, whereas in the hematogenous group, recurrence occurred for up to 2 years.
Conclusions : The failure rate tended to be higher in the acute hematogenous PJI group than in the acute postsurgical PJI group. Since acute hematogenous infections may recur for a longer period than postsurgical infections, careful follow-up is required after DAIR
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