Yoonhee Lee

Staging of extrahepatic cholangiocarcinoma

Preoperative staging of extrahepatic cholangiocarcinoma is important in determining the best treatment plan. Several classification systems have been suggested to determine the operability and extent of surgery. Longitudinal tumor extent is especially important in extrahepatic cholangiocarcinoma because operative methods differ depending on the tumor extent. The Bismuth-Corlette classification system provides useful information when planning for surgery. However, this classification system is not adequate for selecting surgical candidates. Anatomic variation of the bile duct and gross morphology of the tumor must be considered simultaneously. Lateral spread of the tumor can be evaluated based on the TNM staging provided by American Joint Committee on Cancer (AJCC). However, there is a potential for ambiguity in the distinction of T1 and T2 cancer from one another. In addition, T stage does not necessarily mean invasiveness. Blumgart T staging is helpful for the assessment of resectability with the consideration of nodal status and distant metastasis as suggested by the AJCC cancer staging system. Computed tomography (CT) and magnetic resonance imaging (MRI) are the primary tools used in the assessment of longitudinal and lateral spread of a tumor when determining respectability. Diagnostic laparoscopy and positron emission tomography (PET) may play additional roles in this regard.

Valence band electronic redistribution in ion-beam-mixed PdAg alloys

Abstract The core-level binding energy shift and L2,3 absorption-edges for pure Pd, Ag, and ion-beam-mixed Pd1−xAgx (x = 0.5-0.9) alloys are measured to investigate the charge redistribution in ion-beam-mixed PdAg alloys. It is found that, in ion-beam-mixed alloys, there is a substantial decrease in the area of the Pd L2,3 white lines compared with that of pure Pd. The observed decrease in white line area was attributed to an increase in the number of d-electrons at the Pd site upon alloy formation. Using the observed core-level binding energy shifts and white line area changes, the net charge transfer at the Pd site of ion-beam-mixed PdAg alloys has been estimated on the basis of a charge compensation model. We find that the net charge transfer is very small owing to back donation of sp-like conduction electron from the Pd site. These results are compared with the self-consistent electronic structure calculation.

Analysis of familial factors using the basic and specific (BASP) classification in Korean patients with androgenetic alopecia

BACKGROUND The mechanisms and inheritance of androgenetic alopecia (AGA) have yet to be elucidated. Several clinical studies suggest that a predisposition to AGA is affected by a variety of paternal and/or maternal hereditary factors. No previous study has addressed the association of AGA with family history based on the pattern of hair loss. OBJECTIVES The purpose of this study was to investigate paternal and/or maternal genetic influences in each type of hair loss pattern using the basic and specific (BASP) classification and to explore whether the morphology of AGA tends to be inherited in family members. METHODS Between October 2007 and September 2008, 1220 Korean participants, 998 male and 222 female, were classified according to the BASP classification at 13 university dermatologic centers. Information was collected using a standard questionnaire and BASP classification sheet. RESULTS Parental influences on anterior hairline shape in men were predominantly from the paternal side, whereas these effects were less notable in women. In the absence of a family history, statistical analysis showed a higher frequency for early-onset AGA than late-onset AGA (Pearson χ(2)P < .05). Basic types of hair loss had a higher degree of inheritance from the paternal side of the family, regardless of specific type. LIMITATIONS The evaluation of hair loss pattern and family history was done by the patients. CONCLUSIONS Familial factors affecting the morphology of AGA differ between male and female individuals, and for each type of BASP classification.

Ambient-pressure bulk superconductivity deep in the magnetic state of Ce Rh In 5

Specific heat, magnetic susceptibility and electrical transport measurements were performed at ambient pressure on high-quality single crystal specimens of CeRhIn5 down to ultra-low temperatures. We report signatures of an anomaly observed in all measured quantities consistent with a bulk phase transition to a superconducting state at T{sub c}=110 mK. Occurring far below the onset of antiferromagnetism at T{sub N}=3.8 K, this transition appears to involve a significant portion of the available low-temperature density of electronic states, exhibiting an entropy change in line with that found in other members of the 115 family of superconductors tuned away from quantum criticality.

Composition and field tuned magnetism and superconductivity in Nd1 xCexCoIn5

Abstract: The Nd1-xCexCoIn5 alloys evolve from local moment magnetism (x = 0) to heavy fermion superconductivity (x =1). Magnetic order is observed over a broad range of x. For a substantial range of x (0.83 <= x <= 0.95) in the temperature - composition phase diagram we find that superconductivity may coexist with spin - density wave magnetic order at the Fermi surface. We show that a delicate balance betwen superconducting and magnetic instabilities can be reversibly tuned by both the Ce/Nd ratio and magnetic field, offering a new and unique model electronic system.

Hair Shaft Damage from Heat and Drying Time of Hair Dryer

Background Hair dryers are commonly used and can cause hair damage such as roughness, dryness and loss of hair color. It is important to understand the best way to dry hair without causing damage. Objective The study assessed changes in the ultra-structure, morphology, moisture content, and color of hair after repeated shampooing and drying with a hair dryer at a range of temperatures. Methods A standardized drying time was used to completely dry each hair tress, and each tress was treated a total of 30 times. Air flow was set on the hair dryer. The tresses were divided into the following five test groups: (a) no treatment, (b) drying without using a hair dryer (room temperature, 20℃), (c) drying with a hair dryer for 60 seconds at a distance of 15 cm (47℃), (d) drying with a hair dryer for 30 seconds at a distance of 10 cm (61℃), (e) drying with a hair dryer for 15 seconds at a distance of 5 cm (95℃). Scanning and transmission electron microscopy (TEM) and lipid TEM were performed. Water content was analyzed by a halogen moisture analyzer and hair color was measured with a spectrophotometer. Results Hair surfaces tended to become more damaged as the temperature increased. No cortex damage was ever noted, suggesting that the surface of hair might play a role as a barrier to prevent cortex damage. Cell membrane complex was damaged only in the naturally dried group without hair dryer. Moisture content decreased in all treated groups compared to the untreated control group. However, the differences in moisture content among the groups were not statistically significant. Drying under the ambient and 95℃ conditions appeared to change hair color, especially into lightness, after just 10 treatments. Conclusion Although using a hair dryer causes more surface damage than natural drying, using a hair dryer at a distance of 15 cm with continuous motion causes less damage than drying hair naturally.

Wave propagation characteristics of a figure-eight shaped nanoaperture

Wave propagation characteristics of apertures were analyzed to explain the light transmission of metallic nanoapertures. Based on Maxwell’s equations, the wave dispersion relations of wave propagation modes in nanoapertures were derived. The resonance frequency shift of the aperture and the variation of the spot size are explained with the dispersion relations. The relationship between near-field and far-field light transmission power throughput and spot size is also shown with the wave mode change predicted by the dispersion relations.

Interfacial properties of ion beam mixed Cu/SiO2 system

Abstract A thin Cu layer (35 nm) deposited on SiO 2 has been mixed with 80 keV Ar + at room temperature, 550 and 650 K. Interfacial properties of irradiated samples were investigated with Rutherford backscattering spectroscopy, grazing angle X-ray diffraction and scratch test. Adhesion of Cu films was improved by a factor of 3 at a dose of 1.5 × 10 16 Ar 4 /cm 2 in the case of ion beam mixing at room temperature, while the high temperature ion beam mixing enhanced the adhesion by a factor of 5. The ballistic mixing effects on the improvement of adhesion for the room temperature ion mixing and the creation of Cu 2 O phase at the interface, which contributes to the enhancement of adhesion induced by ion beam mixing at high temperature, are described in the present paper.

Comparison of hair shaft damage after chemical treatment in Asian, White European, and African hair

Diverse causes of extrinsic damage to the hair shaft have been documented and can be roughly divided into physical and chemical causes. Chemical causes of hair damage include bleaching, hair dyeing, and perming.

Low-fluence Q-switched 1,064-nm neodymium-doped yttrium aluminum garnet laser for the treatment of facial partial unilateral lentiginosis in Koreans

BACKGROUND Established pigment lasers have been used in partial unilateral lentiginosis (PUL) have shown unsatisfactory results. OBJECTIVE To determine the effectiveness and safety of low‐fluence 1,064‐nm Q‐switched neodymium‐doped yttrium aluminum garnet (QS Nd:YAG) laser treatment of PUL in Koreans. MATERIALS AND METHODS Ten Korean patients with facial PUL were treated with 1,064‐nm QS Nd:YAG laser, 7‐mm spot size, 1.5‐ to 2.5‐J/cm2 fluence at 2‐week intervals. Standard digital photographs were taken under the same condition at baseline and at each follow‐up visit. Independent dermatologists evaluated the photographs. All patients completed a questionnaire to assess their subjective satisfaction with the laser treatment using a 5‐point grading system. Degree of pain was assessed using a visual analog scale (0–10). Any complications and side effects were recorded at each visit. Patients were followed up every 4 weeks for 12 weeks after the last laser treatment. RESULTS Five of 10 patients (50%) had achieved excellent improvement (76–100%) at the end of treatment, and the remaining 50% had good improvement (51–75%). In patient self‐evaluation of the degree of improvement of PUL, nine (90%) assessed it as very much to much improved (>50% improvement), and 1 (10%) assessed it as moderate (50–75%). Subjects rated the pain associated with laser treatment at a mean score of 3.3 (range: 1–5) on a scale of 1 to 10. Mottled hypopigmentation developed in two patients. At follow‐up, 12 weeks after the last laser session, all of the patients had partial recurrence, which wqw resolved with one to two sessions of laser treatment. CONCLUSION Low‐fluence 1,064‐nm QS Nd:YAG laser treatment for facial PUL in Koreans showed improvement with no significant side effects. We recommend the low‐fluence 1,064‐nm QS Nd:YAG laser as a treatment option for facial PUL.