637 research outputs found

    Simplified placement and management of cutting setons in the treatment of transsphincteric anal fistula: technical note

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    Background: We report one safe and standardized technique of seton placement and management. Conclusions: A simplified way to manage cutting setons helps to minimize manipulation and may reduce pain. In most patients our technique can be used with no additional anesthesia and in an outpatient settin

    Impact of Surgical Training on Incidence of Surgical Site Infection

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    Background: Despite availability of other training forms, tutorial assistance cannot be entirely replaced in surgical education. Concerns exist that tutorial assistance may lead to an increased rate of surgical site infection (SSI). The purpose of the present study was to investigate whether the risk of SSI is higher after surgery with tutorial assistance than after surgery performed autonomously by a fully trained surgeon. Methods: All consecutive visceral, vascular, and traumatological inpatient procedures at a Swiss University Hospital were prospectively recorded during a 24-month period, and the patients were followed for 12months to ascertain the occurrence of SSI. Using univariable and multivariable logistic regressions, we assessed the association of tutorial assistance surgery with SSI in 6,103 interventions. Results: Autonomously performed surgery was associated with SSI in univariable analysis (5.36% SSI vs. 3.81% for tutorial assistance, p=0.006). In multivariable analysis, the odds of SSI for tutorial assistance was no longer significantly lower (Odds Ratio [OR]=0.82; 95% Confidence Interval [CI]: 0.62-1.09; p=0.163). Conclusions: Surgical training does not lead to higher SSI rate if trainees are adequately supervised and interventions are carefully selected. Although other forms of training are useful, tutorial assistance in the operating room continues to be the mainstay of surgical educatio

    The Lotic Intersite Nitrogen Experiments: an example of successful ecological research collaboration

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    Collaboration is an essential skill for modern ecologists because it brings together diverse expertise, viewpoints, and study systems. The Lotic Intersite Nitrogen eXperiments (LINX I and II), a 17-y research endeavor involving scores of early- to late-career stream ecologists, is an example of the benefits, challenges, and approaches of successful collaborative research in ecology. The scientific success of LINX reflected tangible attributes including clear scientific goals (hypothesis-driven research), coordinated research methods, a team of cooperative scientists, excellent leadership, extensive communication, and a philosophy of respect for input from all collaborators. Intangible aspects of the collaboration included camaraderie and strong team chemistry. LINX further benefited from being part of a discipline in which collaboration is a tradition, clear data-sharing and authorship guidelines, an approach that melded field experiments and modeling, and a shared collaborative goal in the form of a universal commitment to see the project and resulting data products through to completion

    Active Antigen-specific Immunotherapy of Melanoma: from Basic Science to Clinical Investigation

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    Advanced-stage melanoma here dismal prognosis, and novel therapeutic approaches are urgently required. The possibility of taking advantage of the immune response of patients for its treatment has been an appealing concept for almost a century. Only during the last decade, however, has the molecular identification of tumor-associated antigens (TAAs) offered the possibility of vaccinating patients (e.g., active induction of TAA-specific immune responses). Active antigen-specific immunotherapy (AASIT) is currently being investigated in a number of clinical centers as a treatment option for advanced-stage melanoma. A large number of melanoma TAAs have been molecularly characterized and are being used in vaccination trials in various molecular forms and according to various immunization protocols. Here we provide a short overview on melanoma TAAs, the technologies currently in use to induce specific cytotoxic T-lymphocyte (CTL) responses in vivo, and their monitoring. We also propose a tentative AASIT agenda for the next few years, aiming at improving the capacity to induce and monitor TAA-specific immune responses and to verify their clinical effectivenes

    Autonomous interactive intermediaries : social intelligence for mobile communication agents

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2005.Includes bibliographical references (p. 151-167).Today's cellphones are passive communication portals. They are neither aware of our conversational settings, nor of the relationship between caller and callee, and often interrupt us at inappropriate times. This thesis is about adding elements of human style social intelligence to our mobile communication devices in order to make them more socially acceptable to both user and local others. I suggest the concept of an Autonomous Interactive Intermediary that assumes the role of an actively mediating party between caller, callee, and co-located people. In order to behave in a socially appropriate way, the Intermediary interrupts with non-verbal cues and attempts to harvest 'residual social intelligence' from the calling party, the called person, the people close by, and its current location. For example, the Intermediary obtains the user's conversational status from a decentralized network of autonomous body-worn sensor nodes. These nodes detect conversational groupings in real time, and provide the Intermediary with the user's conversation size and talk-to-listen ratio. The Intermediary can 'poll' all participants of a face-to-face conversation about the appropriateness of a possible interruption by slightly vibrating their wirelessly actuated finger rings.(cont.) Although the alerted people do not know if it is their own cellphone that is about to interrupt, each of them can veto the interruption anonymously by touching his/her ring. If no one vetoes, the Intermediary may interrupt. A user study showed significantly more vetoes during a collaborative group-focused setting than during a less group oriented setting. The Intermediary is implemented as a both a conversational agent and an animatronic device. The animatronics is a small wireless robotic stuffed animal in the form of a squirrel, bunny, or parrot. The purpose of the embodiment is to employ intuitive non-verbal cues such as gaze and gestures to attract attention, instead of ringing or vibration. Evidence suggests that such subtle yet public alerting by animatronics evokes significantly different reactions than ordinary telephones and are seen as less invasive by others present when we receive phone calls. The Intermediary is also a dual conversational agent that can whisper and listen to the user, and converse with a caller, mediating between them in real time.(cont.) The Intermediary modifies its conversational script depending on caller identity, caller and user choices, and the conversational status of the user. It interrupts and communicates with the user when it is socially appropriate, and may break down a synchronous phone call into chunks of voice instant messages.by Stefan Johannes Walter Marti.Ph.D

    Email filtering and mobile delivery

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    Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 1999.Includes bibliographical references (p. 121-122).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.This thesis is about delivering electronic messages. Active Messenger, a software system, makes it easier and more efficient. Today, there are a multitude of communication devices and channels available to exchange messages. However, each of these devices and channels has different capabilities. Additionally, the location of a user is often unknown. Current systems that decide where to send a message in a heterogeneous communication environment are complicated to customize and inefficient. The Active Messenger improves this situation. The Active Messenger is an agent that is capable of taking several steps over time to guarantee the delivery of a message, trying multiple channels and awaiting possible user reactions. It infers the location of the user by looking at her communication history and communication behavior. If a message arrives in the user's inbox, the Active Messenger decides if it is important by looking at user-specified rules, as well as correlating it with recent messages, the user's calendar, and her address book. Depending on the importance of the message and the inferred location of the user, the Active Messenger decides where to send the message, possibly to several devices in turn, monitoring the reactions of the user and the success of the delivery. For example, if a reply comes back shortly after a message is sent to a two-way capable device, the Active Messenger assumes that the user has read the message. If the primary communication device used provides no back-channel information, the Active Messenger infers whether the message has been read by monitoring other channels shortly thereafter. Depending on the status of the sender defined by the user, the Active Messenger may also give feedback to the sender about the user's location and communication behavior. The goal is to make the Active Messenger easily configurable. This thesis shows a first step towards an integration of the available communication channels.by Stefan Johannes Walter Marti.S.M

    Accuracy of Frozen Section Analysis Versus Specimen Radiography During Breast-Conserving Surgery for Nonpalpable Lesions

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    Background: Whereas specimen radiography (SR) is an established strategy for intraoperative resection margin analysis during breast-conserving surgery for nonpalpable lesions, the use of frozen section analysis (FSA) is still a matter of debate. Methods: A retrospective review was conducted of 115 consecutive operations in which the two objectives sought were the excision of nonpalpable malignant lesions and breast conservation. Breast surgery was performed in the Gynecology and the Surgery Departments at the Basel University Hospital Breast Center. Whereas one department preferably uses SR for intraoperative margin assessments of lesions involving ductal carcinoma in situ (DCIS) or atypical ductal hyperplasia, the other uses FSA to increase the rate of complete removal of these lesions with a single procedure. The respective accuracy and therapeutic impact of these two techniques are compared here. Results: Intraoperative resection margin assessments were performed with FSA in 80 and SR in 35 of a total of 115 operations performed on 111 patients with pTis, pT1, or pT2 nonpalpable breast cancer. FSA diagnostic accuracy, sensitivity, and specificity were 83.8%, 80.0%, and 87.5%, respectively, compared to 60%, 60%, and 60%, respectively, for SR. FSA tended to have a stronger therapeutic impact than SR in terms of the number of patients in whom initially positive margins were rendered margin-negative thanks to intraoperative analysis and immediate reexcision or mastectomy (27.5% vs. 14.3%; p=0.124). More importantly, significantly fewer secondary reexcisions were performed in the FSA series than in the SR series (12.5% vs. 37.1%; p=0.002). Finally, the intraoperative detection of invasive cancer with FSA led to a significantly lower number of secondary procedures for axillary lymph node staging (5% vs. 25.7%; p=0.001). Conclusions: The present results suggest that FSA may be more accurate than SR for analyzing intraoperative resection margins during breast-conserving surgery for nonpalpable lesion

    Mammotome: Less Invasive than ABBI with Similar Accuracy for Early Breast Cancer Detection

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    We performed a prospective analysis of two consecutive biopsy cohorts investigated by the same team to compare the Mammotome system with the ABBI procedure. From April 1997 to August 2003 a series of 413 nonpalpable mammographic lesions in 387 women (median age 56 years, range 30-84 years) were stereotactically biopsied in the University Hospital of Basel, Switzerland. Until October 1999 the ABBI system was applied exclusively, it was subsequently superseded by the Mammotome device in our clinic. Main outcome measures were accuracy, technical demand, and morbidity. Sensitivity (97.3%/96.8%), negative predictive value (99.2%/98.7%), and diagnostic accuracy (99.4%/99.1%) regarding the detection of malignancy were excellent for both techniques (ABBI/Mammotome). The Mammotome procedure was faster and less invasive, thus causing significantly less morbidity. The larger specimen obtained by the ABBI procedure resulted in more detailed histology. In conclusion, recommend the Mammotome system as the method of choice for detecting nonpalpable early breast cance

    Data-driven reduction of dendritic morphologies with preserved dendro-somatic responses

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    Dendrites shape information flow in neurons. Yet, there is little consensus on the level of spatial complexity at which they operate. Through carefully chosen parameter fits, solvable in the least-squares sense, we obtain accurate reduced compartmental models at any level of complexity. We show that (back-propagating) action potentials, Ca2+ spikes, and N-methyl-D-aspartate spikes can all be reproduced with few compartments. We also investigate whether afferent spatial connectivity motifs admit simplification by ablating targeted branches and grouping affected synapses onto the next proximal dendrite. We find that voltage in the remaining branches is reproduced if temporal conductance fluctuations stay below a limit that depends on the average difference in input resistance between the ablated branches and the next proximal dendrite. Furthermore, our methodology fits reduced models directly from experimental data, without requiring morphological reconstructions. We provide software that automatizes the simplification, eliminating a common hurdle toward including dendritic computations in network models
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