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Search Results: 1 - 10 of 42954 matches for " Young Han Kim "
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Paraplegia by Acute Cervical Disc Herniation after Shoulder Arthroscopic Surgery in Beach-Chair Position  [PDF]
Hye Young Kim, Gang Han Jung
Open Journal of Anesthesiology (OJAnes) , 2018, DOI: 10.4236/ojanes.2018.811028
Abstract: Paraplegia after non-cervical spine surgery under general anesthesia is a rare devastating postoperative complication [1]. A patient with shoulder pain was scheduled for shoulder arthroscopy due to rotator cuff repair. Arthroscopic shoulder surgery was performed with the patient in the beach-chair. Postoperatively, patients complained the weakness of both lower leg and marked numbness and tingling in the both arms. MRI showed a herniated intervertebral disc between C6 and C7 with spinal cord compression. Despite urgent discectomy, the patient remained dysesthesia of both upper extremities for 6 months. The purpose of this report is to introduce our case with a paraplegia observed after arthroscopic shoulder surgery in beach-chair position because of acute cervical herniation.
Enhanced Iontophoretic Delivery of Magnesium Ascorbyl 2-Phosphate and Sodium Fluorescein to Hairless and Hairy Mouse Skin  [PDF]
Min Young Kang, Young Kwan Sung, Moonkyu Kim, Jung Chul Kim, Insook Han, Su Hee Kim
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2012, DOI: 10.4236/jcdsa.2012.24054
Abstract:

We recently reported that L-ascorbic acid 2-phosphate (AP) stimulates the growth of human dermal papilla (DP) cells, induces secretion of IGF-1 from the DP cells to promote hair shafts elongation in cultured human hair follicles, and triggers early progression from the telogen to anagen phase in mice. Since the magnesium salt of AP (APMg) is a highly hydrophilic ionic molecule, it is not easy to deliver this reagent to the skin or hair follicles by topical application alone. In order to enhance skin penetration of APMg without changing any molecular properties, a non-invasive iontophoretic delivery method was introduced. Iontophoresis of the negatively charged APMg under the electrode bearing same charge (cathode) significantly enhanced the in vitro penetration of APMg into a Franz cell equipped with mouse dorsal skin. In contrast, iontophoretic movement with the anode inhibited APMg penetration achieved with passive diffusion alone. The effect of iontophoresis on enhancing the penetration of APMg was also found to be much higher in the skin of hairy mice (3 - 8 times) compared to hairless mice (1.5 - 2.5 times). These findings indicated that iontophoretic movement induced the transfollicular pathway more strongly and effectively than the transdermal pathway. This phenomena was also demonstrated by the in vivo iontophoretic delivery of sodium fluorescein using hairy and hairless mice. The degree of iontophoretic enhancement during APMg penetration was also dependent on various conditions such as current density and application duration.

Feedback Capacity of Stationary Gaussian Channels
Young-Han Kim
Mathematics , 2006,
Abstract: The feedback capacity of additive stationary Gaussian noise channels is characterized as the solution to a variational problem. Toward this end, it is proved that the optimal feedback coding scheme is stationary. When specialized to the first-order autoregressive moving average noise spectrum, this variational characterization yields a closed-form expression for the feedback capacity. In particular, this result shows that the celebrated Schalkwijk-Kailath coding scheme achieves the feedback capacity for the first-order autoregressive moving average Gaussian channel, positively answering a long-standing open problem studied by Butman, Schalkwijk-Tiernan, Wolfowitz, Ozarow, Ordentlich, Yang-Kavcic-Tatikonda, and others. More generally, it is shown that a k-dimensional generalization of the Schalkwijk-Kailath coding scheme achieves the feedback capacity for any autoregressive moving average noise spectrum of order k. Simply put, the optimal transmitter iteratively refines the receiver's knowledge of the intended message.
A Counterexample to Cover's 2P Conjecture on Gaussian Feedback Capacity
Young-Han Kim
Mathematics , 2005,
Abstract: We provide a counterexample to Cover's conjecture that the feedback capacity $C_\textrm{FB}$ of an additive Gaussian noise channel under power constraint $P$ be no greater than the nonfeedback capacity $C$ of the same channel under power constraint $2P$, i.e., $C_\textrm{FB}(P) \le C(2P)$.
A Coding Theorem for a Class of Stationary Channels with Feedback
Young-Han Kim
Mathematics , 2007,
Abstract: A coding theorem is proved for a class of stationary channels with feedback in which the output Y_n = f(X_{n-m}^n, Z_{n-m}^n) is the function of the current and past m symbols from the channel input X_n and the stationary ergodic channel noise Z_n. In particular, it is shown that the feedback capacity is equal to $$ \limp_{n\to\infty} \sup_{p(x^n||y^{n-1})} \frac{1}{n} I(X^n \to Y^n), $$ where I(X^n \to Y^n) = \sum_{i=1}^n I(X^i; Y_i|Y^{i-1}) denotes the Massey directed information from the channel input to the output, and the supremum is taken over all causally conditioned distributions p(x^n||y^{n-1}) = \prod_{i=1}^n p(x_i|x^{i-1},y^{i-1}). The main ideas of the proof are the Shannon strategy for coding with side information and a new elementary coding technique for the given channel model without feedback, which is in a sense dual to Gallager's lossy coding of stationary ergodic sources. A similar approach gives a simple alternative proof of coding theorems for finite state channels by Yang-Kavcic-Tatikonda, Chen-Berger, and Permuter-Weissman-Goldsmith.
Feedback Capacity of the First-Order Moving Average Gaussian Channel
Young-Han Kim
Mathematics , 2004,
Abstract: The feedback capacity of the stationary Gaussian additive noise channel has been open, except for the case where the noise is white. Here we find the feedback capacity of the stationary first-order moving average additive Gaussian noise channel in closed form. Specifically, the channel is given by $Y_i = X_i + Z_i,$ $i = 1, 2, ...,$ where the input $\{X_i\}$ satisfies a power constraint and the noise $\{Z_i\}$ is a first-order moving average Gaussian process defined by $Z_i = \alpha U_{i-1} + U_i,$ $|\alpha| \le 1,$ with white Gaussian innovations $U_i,$ $i = 0,1,....$ We show that the feedback capacity of this channel is $-\log x_0,$ where $x_0$ is the unique positive root of the equation $ \rho x^2 = (1-x^2) (1 - |\alpha|x)^2,$ and $\rho$ is the ratio of the average input power per transmission to the variance of the noise innovation $U_i$. The optimal coding scheme parallels the simple linear signalling scheme by Schalkwijk and Kailath for the additive white Gaussian noise channel -- the transmitter sends a real-valued information-bearing signal at the beginning of communication and subsequently refines the receiver's error by processing the feedback noise signal through a linear stationary first-order autoregressive filter. The resulting error probability of the maximum likelihood decoding decays doubly-exponentially in the duration of the communication. This feedback capacity of the first-order moving average Gaussian channel is very similar in form to the best known achievable rate for the first-order \emph{autoregressive} Gaussian noise channel studied by Butman, Wolfowitz, and Tiernan, although the optimality of the latter is yet to be established.
On the Feedback Capacity of Stationary Gaussian Channels
Young-Han Kim
Mathematics , 2005,
Abstract: The capacity of stationary additive Gaussian noise channels with feedback is characterized as the solution to a variational problem. Toward this end, it is proved that the optimal feedback coding scheme is stationary. When specialized to the first-order autoregressive moving-average noise spectrum, this variational characterization yields a closed-form expression for the feedback capacity. In particular, this result shows that the celebrated Schalkwijk--Kailath coding scheme achieves the feedback capacity for the first-order autoregressive moving-average Gaussian channel, resolving a long-standing open problem studied by Butman, Schalkwijk--Tiernan, Wolfowitz, Ozarow, Ordentlich, Yang--Kavcic--Tatikonda, and others.
Current Possible Drug Therapies for Ovarian Cancer  [PDF]
Jungyeob Seoung, Young-Han Park, Chaechun Rhim, Sungju Kim
Journal of Cancer Therapy (JCT) , 2014, DOI: 10.4236/jct.2014.513122
Abstract:

Ovarian cancer is the most aggressive gynecologic cancer of the heterogenous phenotypes. Development of the new chemotherapeutic agents and drug delivery mode makes better outcomes for patient treatments. Optimal cytoreductive therapy followed by molecular targeting therapy, intraperitoneal chemotherapy and dose dense chemotherapy is a hot therapeutic concept in ovarian cancers. In our review, we will introduce recent therapeutic advances in epithelial ovarian cancer patients.

NS-398 induces caspase-dependent, mitochondria-mediated intrinsic apoptosis of hepatoma cells  [PDF]
Il Han Song, Suk Bae Kim, Hyun Duk Shin, Ha Yan Kang, Eun Young Kim
Advances in Bioscience and Biotechnology (ABB) , 2012, DOI: 10.4236/abb.2012.326084
Abstract: The present study was conducted to investigate whether mitochondrial pathway of apoptosis is involved in cyclooxygenase-2 (COX-2) inhibitor-induced growth inhibition of hepatoma cells. The growth rate and pattern of NS-398 (selective COX-2 inhibitor)-treated Hep3B hepatoma cells were analyzed by microscopic examination, DNA fragmentation gel analysis and flow cytometry followed by the cleavage of down-stream caspase 3 and the release of cytosolic fraction of cytochrome c assessed by Western blot analysis. NS-398 induced the growth inhibition of hepatoma cells depending on the concentration of this COX-2 inhibitor and time sequence. Ladder patterned-DNA fragmentation and cytometric redistribution to sub-G1 phase in cell cycle were revealed in NS-398-induced growth inhibition of hepatoma cells. Cytochrome c was translocated from mitochondria to cytosol in time-dependent manner following NS-398 treatment to hepatoma cells. COX-2 inhibitor induces the growth inhibition of hepatoma cells via caspase-dependent, mitochondria-mediated intrinsic apoptosis pathway. These results strongly suggest the possibility of therapeutic implication of COX-2 inhibitor in HCC.
Double tailgut cysts (presacral and precoccygeal hamartomas) with CA 19-9 elevation  [PDF]
Ji Won Kim, Jae Woong Han, So Young Jung, Seung Chul Lee, Byung Chun Kim, Hye Kyung Ahn, Han Myun Kim
Case Reports in Clinical Medicine (CRCM) , 2013, DOI: 10.4236/crcm.2013.21002
Abstract:

Tailgut cyst, also called retrorectal hamartoma, is a rare congenital lesion and is usually located anterior to the sacrum and posterior to the rectum. We report a case of double tailgut cyst (presacral and precoccygeal hamartoma). A 62-year- old female visited the hospital complaining of anal pain and pressure in the perianal area for one month. Digital rectal examination revealed a round mass with hard consistency in the lateral and posterior part of rectum 5 cm from the anal verge. Pelvic magnetic resonance imaging showed two cystic and solid presacral masses (lateral and posterior part of rectum) compressing the rectum. The patient underwent surgical resection for pathologic diagnosis. At operation, two masses were located in the left presacral space without invasion to adjacent organs and soft tissue. Pathologic examination revealed double tailgut cysts without malignant transformation. A differential diagnosis of perirectal cystic hamartoma includes epidermal cysts, cystic teratomas, dermoid cysts, anal gland cysts, sarcoma and rectal duplications. Regional inflammatory process frequently complicates this lesion and perirectal fistula can develop. Tailgut cyst also has a malignancy potential, with development of adenocarcinomas. To establish a definite diagnosis and prevent complication, complete surgical resection is recommended.

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