841 research outputs found
Comprehensive investigation of Ge-Si bonded interfaces using oxygen radical activation
In this work, we investigate the directly bonded germanium-silicon interfaces to facilitate the development of high quality germanium silicon hetero integration at the wafer scale. X-ray photoelectron spectroscopy data is presented which provides the chemical composition of the germanium surfaces as a function of the hydrophilic bonding reaction at the interface. The bonding process induced long range deformation is detected by synchrotron x-ray topography. The hetero-interface is characterized by measuring forward and reverse current, and by high resolution transmission electron microscopy. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3601355
The responsibility to protect and the use of force: remaking the procrustean bed?
The emergence of the Responsibility to Protect (R2P) owed much to the need to enhance the UN’s ability to act forcibly in the face of the most extreme cases of gross human suffering. Too often in the past such responses were emasculated or thwarted by the necessity to successfully navigate the UN Charter’s prescriptions over the use of force, by the unwillingness of member states to provide military forces, or by a combination of the two. In accepting that certain types of inhuman activity can lead to the legitimate use of force within the UN Charter framework, the adoption of R2P appeared to resolve at least some of these problems, and as such it offered hope to those wishing to see the UN adopt a more assertive response to the grossest of human rights abuses. But, using stalemate over Syria as its backdrop, this article demonstrates the dubiousness of the claim that such a normative development can ever trump the hard edged political and strategic factors which determine when states will accept and/or participate in the use of force, and it suggests a radical solution to the dangers inherent in R2P’s intimate association with military intervention
Ligity: A Non-Superpositional, Knowledge-Based Approach to Virtual Screening
We present Ligity, a hybrid ligand-structurebased, non-superpositional method for virtual screening of large databases of small molecules. Ligity uses the relative spatial distribution of pharmacophoric interaction points (PIPs) derived from the conformations of small molecules. These are compared
with the PIPs derived from key interaction features found in protein−ligand complexes and are used to prioritize likely binders. We investigated the effect of generating PIPs using the single lowest energy conformer versus an ensemble of conformers for each screened ligand, using different bin sizes for the distance between two features, utilizing triangular sets of pharmacophoric features (3-PIPs) versus chiral tetrahedral sets (4-PIPs), fusing data for targets with multiple protein−ligand complex structures, and applying different similarity measures. Ligity was benchmarked using the Directory of Useful Decoys-Enhanced (DUD-E). Optimal results were obtained using the tetrahedral PIPs derived from an ensemble of bound ligand conformers and a bin size of 1.5 Å, which are used as the default settings for Ligity. The high-throughput screening mode of Ligity, using only the lowest-energy conformer of each ligand, was used for benchmarking against the whole of the DUD-E, and a more resource-intensive, “information-rich” mode of Ligity, using a conformational ensemble of each ligand, were used for a representative subset of 10 targets. Against the full DUD-E database, mean area under the receiver operating characteristic curve (AUC) values ranged from 0.44 to 0.99, while for the representative subset they ranged from 0.61 to 0.86. Data fusion further improved Ligity’s performance, with mean AUC values ranging from 0.64 to 0.95. Ligity is very efficient compared to a protein−ligand docking method such as AutoDock Vina: if the time taken for the precalculation of Ligity descriptors is included in the comparison, then Ligity is about 20 times faster than docking. A direct comparison of the virtual screening steps shows Ligity to be over 5000 times faster. Ligity highly ranks the lowest-energy conformers of DUD-E actives, in a statistically significant manner, behavior that is not observed for DUD-E decoys. Thus, our results suggest that active compounds tend to bind in relatively low-energy conformations compared to decoys. This may be because actives - and thus their lowest-energy conformations - have been optimized for conformational complementarity with their cognate binding sites
A Learning Management System-Based Early Warning System for Academic Advising in Undergraduate Engineering
This chapter describes a design-based research project that developed an early warning system for an undergraduate engineering mentoring program. Using near real-time data from a university’s learning management system, we provided academic advisors with timely and targeted data on students’ academic progress. We discuss the development of the early warning system and detail how academic advisors used it. Our findings point to the value of providing academic advisors with performance data that can be used to direct students to appropriate sources of support.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107974/1/Krumm_etal_2014_LA.pd
The Role of Sonography in Patients with Breast Cancer Presenting as an Axillary Mass
Objective: To compare sonography and mammography in terms of their diagnostic value in breast cancer cases which initially presented as an axillary mass without a palpable mass or other clinical symptoms.
Materials and Methods : Seven patients with enlarged axillary lymph nodes who first presented with no evidence of palpable breast lesions and who underwent both mammography and sonography were enrolled in this study. In six of the seven, the presence of metastatic adenocarcinoma was confirmed preoperatively by axillary needle aspiration biopsy; in four, subsequent sonographically-guided breast core biopsy performed after careful examination of the primary site indicated that primary breast cancer was present. In each case, the radiologic findings were evaluated by both breast sonography and mammography.
Results : Breast lesions were detected mammographically in four of seven cases (57%); in three of the four, the lesion presented as a mass, and in one as microcalcification. In three of these four detected cases, fatty or scattered fibroglandular breast parenchyma was present; in one, the parenchyma was dense. In the three cases in which lesions were not detected, mammography revealed the presence of heterogeneously dense parenchyma. Breast sonography showed that lesions were present in six of seven cases (86%); in the remaining patient, malignant microcalcification was detected at mammography. Final pathologic examination indicated that all breast lesions except one, which was a ductal carcinoma in situ, with microinvasion, were infiltrating ductal carcinomas whose size ranged from microscopic to greater than 3 cm. At the time of this study, all seven patients were alive and well, having been disease free for up to 61 months after surgery.
Conclusion : In women with a palpable axillary mass confirmed as metastatic adenocarcinoma, breast sonography may be a valuable adjunct to mammography.ope
Learning-Facilitated Synaptic Plasticity at CA3 Mossy Fiber and Commissural–Associational Synapses Reveals Different Roles in Information Processing
Subregion-dependent differences in the role of the hippocampus in information processing exist. Recently, it has emerged that a special relationship exists between the expression of persistent forms of synaptic plasticity in hippocampal subregions and the encoding of different types of spatial information. Little is known about this type of information processing at CA3 synapses. We report that in freely behaving rats, long-term potentiation (LTP) is facilitated at both mossy fiber (mf)–CA3 and commissural–associational (AC)–CA3 synapses by exploration of a novel (empty) environment. Exploration of large spatial landmarks facilitates long-term depression (LTD) at mf-CA3 synapses and impairs synaptic depression at AC-CA3 synapses. Novel exploration of small environmental features does not facilitate LTD at mf synapses but facilitates persistent LTD at AC synapses. Thus, depending on the quality of the information synaptic plasticity at AC-CA3 and mf-CA3 synapses is differentially modulated. These data suggest that expression of LTP as a result of environmental change is a common property of hippocampal synapses. However, LTD at mf synapses or AC synapses may subserve distinct and separate functions within the CA3 region
Learning-Facilitated Synaptic Plasticity at CA3 Mossy Fiber and Commissural–Associational Synapses Reveals Different Roles in Information Processing
Subregion-dependent differences in the role of the hippocampus in information processing exist. Recently, it has emerged that a special relationship exists between the expression of persistent forms of synaptic plasticity in hippocampal subregions and the encoding of different types of spatial information. Little is known about this type of information processing at CA3 synapses. We report that in freely behaving rats, long-term potentiation (LTP) is facilitated at both mossy fiber (mf)–CA3 and commissural–associational (AC)–CA3 synapses by exploration of a novel (empty) environment. Exploration of large spatial landmarks facilitates long-term depression (LTD) at mf-CA3 synapses and impairs synaptic depression at AC-CA3 synapses. Novel exploration of small environmental features does not facilitate LTD at mf synapses but facilitates persistent LTD at AC synapses. Thus, depending on the quality of the information synaptic plasticity at AC-CA3 and mf-CA3 synapses is differentially modulated. These data suggest that expression of LTP as a result of environmental change is a common property of hippocampal synapses. However, LTD at mf synapses or AC synapses may subserve distinct and separate functions within the CA3 region
Severe Aortic Coarctation in a 75-Year-Old Woman: Total Simultaneous Repair of Aortic Coarctation and Severe Aortic Stenosis
Aortic coarctation is usually diagnosed and repaired in childhood and early adulthood. Survival of a patient with an uncorrected coarctation to more than 70 years of age is extremely unusual, and management strategies for these cases remain controversial. We present a case of a 75-year-old woman who was first diagnosed with aortic coarctation and severe aortic valve stenosis 5 years ago and who underwent a successful one-stage repair involving valve replacement and insertion of an extra-anatomical bypass graft from the ascending to the descending aorta
A Case of Successful Treatment of Stomal Variceal Bleeding with Transjugular Intrahepatic Portosystemic Shunt and Coil Embolization
Variceal bleeding from enterostomy site is an unusual complication of portal hypertension. The bleeding, however, is often recurrent and may be fatal. The hemorrhage can be managed with local measures in most patients, but when these fail, surgical interventions or portosystemic shunt may be required. Herein, we report a case in which recurrent bleeding from stomal varices, developed after a colectomy for rectal cancer, was successfully treated by placement of transjugular intrahepatic portosystemic shunt (TIPS) with coil embolization. Although several treatment options are available for this entity, we consider that TIPS with coil embolization offers minimally invasive and definitive treatment
Protocol for the saMS trial (supportive adjustment for multiple sclerosis): a randomized controlled trial comparing cognitive behavioral therapy to supportive listening for adjustment to multiple sclerosis
BackgroundMultiple Sclerosis (MS) is an incurable, chronic, potentially progressive and unpredictable disease of the central nervous system. The disease produces a range of unpleasant and debilitating symptoms, which can have a profound impact including disrupting activities of daily living, employment, income, relationships, social and leisure activities, and life goals. Adjusting to the illness is therefore particularly challenging. This trial tests the effectiveness of a cognitive behavioural intervention compared to supportive listening to assist adjustment in the early stages of MS.MethodsThis is a two arm randomized multi-centre parallel group controlled trial. 122 consenting participants who meet eligibility criteria will be randomly allocated to receive either Cognitive Behavioral Therapy or Supportive Listening. Eight one hour sessions of therapy (delivered over a period of 10 weeks) will be delivered by general nurses trained in both treatments. Self-report questionnaire data will be collected at baseline (0 weeks), mid-therapy (week 5 of therapy), post-therapy (15 weeks) and at six months (26 weeks) and twelve months (52 weeks) follow-up. Primary outcomes are distress and MS-related social and role impairment at twelve month follow-up. Analysis will also consider predictors and mechanisms of change during therapy. In-depth interviews to examine participants’ experiences of the interventions will be conducted with a purposively sampled sub-set of the trial participants. An economic analysis will also take place. DiscussionThis trial is distinctive in its aims in that it aids adjustment to MS in a broad sense. It is not a treatment specifically for depression. Use of nurses as therapists makes the interventions potentially viable in terms of being rolled out in the NHS. The trial benefits from incorporating patient input in the development and evaluation stages. The trial will provide important information about the efficacy, cost-effectiveness and acceptability of the interventions as well as mechanisms of psychosocial adjustment.Trial registrationCurrent Controlled Trials ISRCTN91377356<br/
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