1,677 research outputs found

    Titanium germanium antiĀ­monide, TiGeSb

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    TiGeSb adopts the PbFCl- or ZrSiS-type structure, with Ti atoms (4mm symmetry) centred within monocapped square antiĀ­prisms generated by the stacking of denser square nets of Ge atoms ( m2 symmetry) alternating with less dense square nets of Sb atoms (4mm symmetry)

    The effects of photochromatic lenses on pupillary response to light

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    The percent area change under dark and light conditions was measured for subjects who wore photochromatic lenses and for subjects who wore clear glass lenses. There was no significant difference found between these two groups. There appears not to be any adaptive response of the pupil to lessen its ability to constrict, even though photochromatic lenses have taken on the role of the pupil to control the amount of light entering the eye

    A Case Report of Thalamic Infarction after Lumbar Drain: A Unique Cause of Perioperative Stroke?

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    In the case presented, a patient has an unexplained episode of hypertension during aneurysm clipping. Following the procedure, the patient was discovered to have bilateral thalamic infarctions unrelated to the vascular location of the aneurysm. After a review of the case, it becomes apparent that intracranial hypotension caused by lumbar over drainage of cerebrospinal fluid (CSF) is the likely cause of both the episode of intraoperative hypertension and the thalamic infarcts. It is often presumed that having an open dura protects against intracranial hypotension and subsequent herniation. We present this case to suggest that opening the dura might not be protective in all cases and anesthesiologists must pay particular attention to the rate of CSF drainage. Lumbar CSF drainage is a technique frequently employed during neurological surgery and it is important for anesthesiologists to understand the signs, symptoms, and potential consequences of intracranial hypotension from rapid drainage

    XUV Frequency Combs via Femtosecond Enhancement Cavities

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    We review the current state of tabletop extreme ultraviolet (XUV) sources based on high harmonic generation (HHG) in femtosecond enhancement cavities (fsEC). Recent developments have enabled generation of high photon flux (1014 photons/sec) in the XUV, at high repetition rates (>50 MHz) and spanning the spectral region from 40 nm - 120 nm. This level of performance has enabled precision spectroscopy with XUV frequency combs and promises further applications in XUV spectroscopic and photoemission studies. We discuss the theory of operation and experimental details of the fsEC and XUV generation based on HHG, including current technical challenges to increasing the photon flux and maximum photon energy produced by this type of system. Current and future applications for these sources are also discussed.Comment: invited review article, 38 page

    Tumor Recurrence Incidence Following Hand-Assisted Laparoscopic Nephroureterectomy

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    BACKGROUND AND OBJECTIVES: We evaluated the incidence of tumor recurrence following hand-assisted laparoscopic nephroureterectomy (HALNU) for the treatment of upper tract urothelial carcinoma. METHODS: The medical records of consecutive patients who underwent HALNU by a single surgeon (CW) between October 2001 and May 2005 were reviewed. The ureter was clipped before kidney dissection to prevent distal migration of tumor. Following liberation of the kidney, the bladder cuff and intramural ureter were excised by using a Collings knife under cystoscopic guidance. RESULTS: Ten patients were identified. The primary location of disease was confined to the intrarenal collecting system. Eight high-grade (HG) and 2 low-grade (LG) tumors were removed, with pT3 (6), pT2 (1), pT1 (1), and pTa (2) disease. The patient having a LG pTa urothelial carcinoma developed pulmonary metastasis 20 months following surgery and survived an additional 26 months. Two patients, each having a HG pT3 tumor, developed a urothelial carcinoma in the bladder contralateral to the site of ureteral excision. At a mean follow-up of 41 months, there has been no evidence of tumor recurrence in the pelvis. CONCLUSION: Our technique of HALNU does not appear to harbor an increased risk for urothelial carcinoma recurrence

    Advances in Landslide Nowcasting: Evaluation of a Global and Regional Modeling Approach

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    The increasing availability of remotely sensed data offers a new opportunity to address landslide hazard assessment at larger spatial scales. A prototype global satellite-based landslide hazard algorithm has been developed to identify areas that may experience landslide activity. This system combines a calculation of static landslide susceptibility with satellite-derived rainfall estimates and uses a threshold approach to generate a set of nowcasts that classify potentially hazardous areas. A recent evaluation of this algorithm framework found that while this tool represents an important first step in larger-scale near real-time landslide hazard assessment efforts, it requires several modifications before it can be fully realized as an operational tool. This study draws upon a prior work s recommendations to develop a new approach for considering landslide susceptibility and hazard at the regional scale. This case study calculates a regional susceptibility map using remotely sensed and in situ information and a database of landslides triggered by Hurricane Mitch in 1998 over four countries in Central America. The susceptibility map is evaluated with a regional rainfall intensity duration triggering threshold and results are compared with the global algorithm framework for the same event. Evaluation of this regional system suggests that this empirically based approach provides one plausible way to approach some of the data and resolution issues identified in the global assessment. The presented methodology is straightforward to implement, improves upon the global approach, and allows for results to be transferable between regions. The results also highlight several remaining challenges, including the empirical nature of the algorithm framework and adequate information for algorithm validation. Conclusions suggest that integrating additional triggering factors such as soil moisture may help to improve algorithm performance accuracy. The regional algorithm scenario represents an important step forward in advancing regional and global-scale landslide hazard assessment

    Paradoxical Emboli Secondary to Hepatic Pathology: Common or Coincidental?

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    Paradoxical cerebral emboli from cardiac and pulmonary sources are well described in the peer-reviewed literature. We outline a case with a hepatic etiology and describe diagnostic and management options. Though this paper represents the first documentation of such, we believe that transpulmonary shunting with concurrent paradoxical cerebral microemboli is more prevalent than recognized. We introduce this case report to compel practitioners to consider paradoxical emboli in selected cirrhotic patients since it can often be difficult to elicit subtle neurologic changes on clinical examination of patients with end stage liver disease

    Absence of gemin5 from SMN complexes in nuclear Cajal bodies

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    <p>Abstract</p> <p>Background</p> <p>Spinal muscular atrophy is caused by reduced levels of the survival of motor neurons (SMN) protein. SMN is found in large complexes with Sm proteins and at least eight other proteins, including seven "gemins". These complexes are involved in the assembly of snRNPs in the cytoplasm and their transport into the nucleus, but the precise roles of the individual protein components are largely unknown.</p> <p>Results</p> <p>We have investigated the subcellular distribution of gemins using novel antibodies against gemins 3ā€“7, and existing mAbs against SMN, gemin2, unrip, fibrillarin and profilin II. Most gemins were equally distributed between nuclear and cytoplasmic fractions of HeLa cells, but gemin5 and unrip were more abundant in the cytoplasm. In a cytoplasmic extract obtained by mild disruption of HeLa cells, nearly all the SMN and gemins 2ā€“4 were in large complexes, but most of the gemin5 sedimented separately with a lower S value. Most of the unrip sedimented with gemins 6 and 7 near the top of the sucrose density gradients, separate from both SMN and gemin5. Anti-SMN mAbs pulled down gemin5 from cytoplasmic extracts, but not from nuclear extracts, and gemin5 did not co-sediment with large SMN complexes in nuclear extracts. These data suggest that gemin5 is easily detached from SMN-gemin complexes in the nucleus. By immuno-histochemistry, gemin5 was rarely detectable in nuclear gems/Cajal bodies, although it was accessible to antibody and easily detectable when present. This suggests that gemin5 is normally absent from SMN complexes in these nuclear storage sites.</p> <p>Conclusion</p> <p>We conclude that SMN complexes usually exist without gemin5 in nuclear gems/Cajal bodies. Gemin5 is believed to be involved in capturing snRNA into SMN complexes in the cytoplasm for transport into the nucleus. We hypothesize that gemin5, though present in the nucleus, is no longer needed for SMN complex function during the time these complexes are stored in gems/Cajal bodies.</p
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