Exchange-Striction Driven Ultrafast Nonthermal Lattice Dynamics in NiO.

We use femtosecond electron diffraction to study ultrafast lattice dynamics in the highly correlated antiferromagnetic (AFM) semiconductor NiO. Using the scattering vector (Q) dependence of Bragg diffraction, we introduce Q-resolved effective temperatures describing the transient lattice. We identify a nonthermal lattice state with preferential displacement of O compared to Ni ions, which occurs within ∼0.3 ps and persists for 25 ps. We associate this with transient changes to the AFM exchange striction-induced lattice distortion, supported by the observation of a transient Q asymmetry of Friedel pairs. Our observation highlights the role of spin-lattice coupling in routes towards ultrafast control of spin order.

Band structure effects in above threshold photoemission.

We have performed an angle-resolved two-photon and three-photon photoemission study of the Ag(111) surface employing ultrashort laser pulses as the excitation source. We show the presence of multi-photon resonances between electronic states at selected points of the Brillouin zone which appear in the high-order photoemission spectral region. We observe clear signatures of electronic band structure effects of the Ag crystal in above-threshold photoemission (ATP) processes, identifying two types of transitions, which either proceed via non-resonant multi-photon excitation from an occupied initial state, or involve a real intermediate state located above the vacuum level of the solid directly influencing the ATP process. For this latter class of phenomena, we suggest that electron populations created by incoherent processes give a contribution to the multi-photon transition, possibly allowing us to trace the transmission of photoexcited electrons through the crystal.

Traumatic vertebral artery aneurysm following blunt suboccipital trauma.

Traumatic vertebral artery (VA) injury has been neglected and mistaken to be innocuous. Herein, we present a rare case with a as subarachnoid hemorrhage (SAH) following blunt suboccipital trauma. Initially, it was mistaken as a saccular aneurysm and was just coincident with traumatic SAH. Surgical clipping was performed by our senior neurosurgeon and looked secure. But massive bleeding occurred before complete closure of the dura wound. Opening the wound again, blood gushed out from the junction of the aneurysm and the parent artery. Because preoperative angiography evaluation had revealed good collateral flow from the contralateral VA, the involved segment of VA was trapped. The patient recovered well with uneventful course. Blunt suboccipital trauma may result in traumatic VA injury which may cause catastrophic complications if neglected. The incidence, risk factors, the pathophysiology of traumatic VA aneurysm, and the treatments are reviewed.

High efficiency electron spin polarization analyzer based on exchange scattering at FeW(001).

We report on a compact electron spin analyzer based on exchange scattering from a magnetic surface. The heart of the detector is an Fe(001) thin film grown on W(001) with chemisorbed oxygen in the p(1 x 1) structure. The device is mounted at the exit of an energy dispersive analyzer and works at a scattering energy of about 13.5 eV. Its figure of merit is 2 x 10(-3), combined with an excellent stability of more than 2 weeks in UHV.

Suppression of fatty acid synthase in MCF-7 breast cancer cells by tea and tea polyphenols: a possible mechanism for their hypolipidemic effects.

Tea is a heavily consumed beverage world wide because of its unique aroma, less cost and broad availability. Fatty acid synthase (FAS) is a key enzyme in lipogenesis. FAS is overexpressed in the malignant human breast carcinoma MCF-7 cells and its expression is further enhanced by the epidermal growth factor (EGF). The EGF-induced expression of FAS was inhibited by green and black tea extracts. The expression of FAS was also suppressed by the tea polyphenol (-)-epigallocatechin 3-gallate (EGCG), theaflavin (TF-1), TF-2 and theaflavin 3,3'-digallate(TF-3) at both protein and mRNA levels that may lead to the inhibition of cell lipogenesis and proliferation. Both EGCG and TF-3 inhibit the activation of Akt and block the binding of Sp-1 to its target site. Furthermore, the EGF-induced biosyntheses of lipids and cell proliferation were significantly suppressed by EGCG and TF-3. These findings suggest that tea polyphenols suppress FAS expression by downregulating EGF receptor/PI3K/Akt/Sp-1 signal transduction pathway, and tea and tea polyphenols might induce hypolipidemic and antiproliferative effects by suppressing FAS.

Naltrexone shortened opioid detoxification with buprenorphine.

This double-blind, randomized, placebo-controlled clinical trial evaluated the impact on withdrawal symptoms of (i) combining naltrexone with a 4-day buprenorphine taper for short opioid detoxification (NB Group), compared to (ii) using a 4-day buprenorphine taper alone, followed by naltrexone on day 8 (PB Group). Sublingual buprenorphine was administered on days 1-4 (26 mg total). For the NB Group (n = 32) escalating doses of oral naltrexone were given on days 2-8 (placebo day 1). For the PB Group (n = 28) placebo was given on days 1-7 and naltrexone on day 8. Main outcome measures were Observed Opioid Withdrawal scores (OOW, 0-30) and use of medications to treat opioid withdrawal. Of 32 patients in the NB group, 59% experienced clinically relevant withdrawal (defined as OOW > or = 5) on day 2, but, after day 5, none experienced withdrawal. In the PB group, the number of patients experiencing withdrawal increased over time. The first naltrexone dose induced comparable withdrawal in both groups: peak OOW scores were (mean +/- SD) 5.2 +/- 3.3 on day 2 for the NB group, and 4.0 +/- 3.9 on day 8 for the PB group (NS), though, on day 2, 7 patients dropped out in the NB group and none in the PB group, while only one patient dropped out in the PB group on day 8. Throughout the 8-day study, patients in both groups received similar amount of adjunct medication: 0.64 +/- 0.07 mg (NB group) of clonidine vs 0.73 +/- 0.15 mg (PB group; NS). Only 25% of patients required use of sedatives (up to 20 mg diazepam). Starting naltrexone on day 2 appeared to abolish withdrawal symptoms after day 5 and, thus, to shorten the duration of withdrawal symptoms. Peak withdrawal symptoms after naltrexone were of moderate intensity, suggesting that naltrexone combined with buprenorphine is an acceptable and safe treatment for shortened opioid detoxification and induction of naltrexone maintenance.

Penicillium marneffei fungemia in an AIDS patient: the first case report in Taiwan.

We report a 36-year-old man with acquired immunodeficiency syndrome (AIDS), presenting systemic Penicillium marneffei (PM) infection. Fungal culture from the blood isolated PM. PM-induced enteritis was also suspected in this patient although there was no direct evidence. He also had other manifestations of immunocompromised status, including military tuberculosis and oral candidiasis. He died of respiratory failure in spite of prompt treatment for infection. This is the first confirmed case of PM infection in Taiwan.

Integration of CMAC technique and weighted regression for efficient learning and output differentiability.

Cerebellar model articulation controllers (CMAC) have attractive properties of learning convergence and speed. Many studies have used CMAC in learning control and demonstrated successful results. However, due to the fact that CMAC is a table lookup technique, a model implemented by a CMAC does not provide a derivative of its output. This is an inconvenience when using CMAC in learning structures that require such derivatives. This paper presents a new scheme that integrates the CMAC addressing technique with weighted regression to resolve this problem. Derivatives exist everywhere except on the boundaries of quantized regions. Compared with the conventional CMAC, the new scheme requires the same amount of memory and has similar learning speed, but provides output differentiability and more precise output. Compared with the typical weighted regression technique, the new scheme offers an efficient way to organize and utilize collected information.

Learning convergence of CMAC technique.

CMAC is one useful learning technique that was developed two decades ago but yet lacks adequate theoretical foundation. Most past studies focused on development of algorithms, improvement of the CMAC structure, and applications. Given a learning problem, very little about the CMAC learning behavior such as the convergence characteristics, effects of hash mapping, effects of memory size, the error bound, etc. can be analyzed or predicted. In this paper, we describe the CMAC technique with mathematical formulation and use the formulation to study the CMAC convergence properties. Both information retrieval and learning rules are described by algebraic equations in matrix form. Convergence characteristics and learning behaviors for the CMAC with and without hash mapping are investigated with the use of these equations and eigenvalues of some derived matrices. The formulation and results provide a foundation for further investigation of this technique.

A poly-HEMA based aqueous humor draining device.

An aqueous humor draining device, with size comparable to that of the Krupin tube, was constructed by using poly-HEMA material. Deposits were found on the surface of poly-HEMA when contacted in vitro with the aqueous humor of the rabbit's eye. A fibrous structure, probably composed of proteins and other macromolecules, developed on poly-HEMA surface in 15 days after the draining device was implanted into the rabbit's eye. The draining device was still in function 250 days after its implantation. SEM analysis of the retrieved poly-HEMA draining device indicated that the poly-HEMA tube opening was not blocked by any substance. These results suggest that poly-HEMA could be used as a biomaterial for construction of the aqueous humor draining device to relieve the intraocular pressure of glaucoma patients. Its long-term application awaits further investigation.