Clustering Information Retrieval Search Outputs

Users are known to have difficulties in dealing with information retrieval search outputs especially if the outputs are above a certain size. It has been argued by several researchers that search output clustering can help users in their interaction with IR systems. Clustering may provide users an overview of the output by exploiting the topicality information that resides in the output but has not been used in the retrieval stage. It can enable them to find the relevant documents more easily and also help them to form an understanding of the different facets of the query that have been provided for their Inspection. This project aimed to investigate the viability of using clustering as a way of mediating users’ interaction with search outputs and attempted to identify its possible benefits. Can&Ozkarahan’s(90) C3M algorithm was used to test the effectiveness of clustering as a way of search output presentation. C3M is a relatively simple, non-hierarchical method that has been shown to give compatible or superior results to best-known hierarchical methods. The method was implemented in TCL and linked to the department’s experimental IR system Okapi. Implementation included a procedure of term selection for document representation which preceded the clustering process and a procedure involving cluster representation for users’ viewing following the clustering process. After some tuning of the implementation parameters for the databases used, several experiments were designed and conducted to assess whether clusters could group documents in useful ways. One group of experiments aimed to assess the ability of the implementation to bring together topically related documents. It was quite difficult to gather data for such an assessment, but the existence of a set of data generated for TREC Interactive track(1996) enabled us to design experiments that at least approximately satisfied our objective. TREC provided a set of queries, and groups of relevant documents with facet assignments made by expert users. It was thus possible to make an Inference by measuring the correlation between the clusters relevant documents were assigned to and the facet assignments made for the documents by TREC experts. The utility of this data set was limited for various reasons discussed in the related chapters, however, it can be concluded that clusters cannot be relied on to bring together relevant documents assigned to a certain facet. While there was some correlation between the cluster and facet assignments of the documents when the clustering was done only on relevant documents, no correlation could be found when the clustering was based on results of queries defined by City participants to the Interactive track. Another group of experiments was conducted to compare output clustering with relevance ranking as a search output representation method. This comparison was necessary as an immediate consequence of clustering search output would be the loss of relevance ranking. It had to be assessed whether clustering could help users to find the relevant documents more easily than by relevance ranking, before any clustering solution could be proposed as an alternative to relevance ranked output. For this purpose, two sets of user experiments(n=20 and n=57) were conducted based on the users’ own information needs. While changes have been made to the implementation between the first and the second set of experiments, the experimental design was almost the same in both runs. Users were first asked to rank clusters formed from the search output(top 50 documents) and then make relevance judgements for the individual documents for the same output. The precision of cluster(s) marked best by the users were then compared to precision values that would be attained by relevance ranking at comparable thresholds. The results from the 1st group of user experiments were not conclusive(in some part due to the smallness of the data set), but they drew our attention to the importance of representation of clusters and documents for users’ viewing. After some changes to the implementation, mainly related to representation issues, and an intermediate set of 10 experiments to assess two new representation formats, a set of 57 user experiments were conducted to measure and compare precision values attainable by clustering versus relevance ranking. These experiments revealed no significant precision difference between clustered outputs and ranked lists. The number of cases where one method achieved better than the other was slightly higher for the ranked lists at the top cluster level and slightly higher for the clustered representation at the top two clusters level. However the overall average precision values were higher for the ranked list at both levels. As such, clustering did not appear to be preferable to ranked lists especially as It also represented overheads in both computing time and resources involved in creation of the clusters, and the time and effort taken by the users to inspect them. An interesting outcome of the user experiments was the ability of the users to identify clusters that do not include relevant information. There were less relevant documents among the clusters marked last by the users as compared to the documents ranked last at similar threshold levels. This brought out the possibility of using clusters as an exclusion tool to improve the precision of ranked lists. After exclusion of documents from the last cluster, ranked lists performed significantly better than the clusters at the top cluster level. There was also some evidence (consisting of observation of users during the experiments and a few user comments) that clusters could be used to provide the users with a glimpse of the search results, in order to decide whether to inspect the search results or initiate a new query straight away. In summary, cumulative experiment results imply that clustering cannot outperform relevance ranking, and seems to deserve only a secondary role in users’ interaction with IR systems. However, it should also be noted that the experiment results are not representative of the whole set of possible user types and search situations and it may be possible to Identify search situations where clustering can be more beneficial than relevance ranking

Wyniki leczenia uszkodzenia nerwu strzałkowego na wysokości kolana: doświadczenie oddziału szpitala wo¡skowego

Background and purpose We investigated the management outcome of common peroneal nerve decompression at the knee level between the years 2005 and 2009. Material and methods Thirty consecutive patients with knee-level peroneal nerve injury who underwent decompression surgery and external neurolysis at our institution were evaluated preoperatively and postoperatively by electrophysiological studies and motor examination (Medical Research Council grading). Results Twenty-eight of the cases were male and 2 were female. Mean age was 31.1 for males and 57.5 for females. Physical activity during military training (overstretch/contusion) was the cause of nerve lesion in the majority of the patients (n = 28, 93%). Mean time interval between the diagnosis and the surgery was 5 months. Follow-up time ranged from 3 to 48 months (mean: 14 months). Twenty-nine of 30 (97%) patients recovered totally or near totally in foot/toe dorsiflexion. Conclusions Early decompression and neurolysis of the common peroneal nerve (CPN) at knee level after strenuous physical activity offers excellent functional recovery. Additionally, for knee-level CPN injuries, in order to minimize the postoperative scar, pain and delay in wound healing, we strictly advocate short ‘lazy S-shaped incision’ around the fibular head in supine position unlike the classical extensive opening up to the superior border of the popliteal fossa in prone position.Wstęp i cel pracy Autorzy ocenili wyniki chirurgicznego odbarczenia nerwu strzałkowego wspólnego na wysokości kolana, wykonywanego w latach 2005–2009. Materiał i metody Przedoperacyjnej i pooperacyjnej ocenie klinicznej (w skali Medical Research Council) oraz elektrofizjologicznej poddano 30 kolejnych pacjentów z uszkodzeniem nerwu strzałkowego na wysokości kolana, u których wykonano odbarczenie chirurgiczne z zewnętrzną neurolizą. Wyniki Wśród leczonych było 28 mężczyzn (średnia wieku: 31,1 roku) i dwie kobiety (średnia wieku: 57,5 roku). U zdecydowanej większości pacjentów (n = 28, 93%) przyczyną uszkodzenia nerwu była aktywność fizyczna w czasie szkolenia wojskowego (nadmierne rozciągnięcie/stłuczenie). Średnia czasu od rozpoznania do operacji wyniosła 5 miesięcy. Obserwacja po zabiegu trwała od 3 do 48 miesięcy (średnia: 14 miesięcy). U 29 na 30 chorych (97%) uzyskano pełny lub prawie pełny powrót zgięcia grzbietowego stopy/palców. Wnioski Wczesne chirurgiczne odbarczenie i neuroliza nerwu strzałkowego wspólnego na wysokości kolana w leczeniu urazu powstałego wskutek nadmiernej aktywności fizycznej daje możliwość znakomitej poprawy czynnościowej. Ponadto w przypadku uszkodzeń nerwu strzałkowego wspólnego na wysokości kolana w celu zminimalizowania blizny pooperacyjnej, nasilenia bólu i opóźnienia w gojeniu się rany pooperacyjnej autorzy usilnie zalecają krótkie cięcie w kształcie wydłużonej litery „S” wokół głowy strzałki u chorego w pozycji leżącej na plecach zamiast klasycznego otwarcia aż do górnej granicy dołu podkolanowego w pozycji leżącej na brzuchu

Clinical results of carotid artery stenting versus carotid endarterectomy

Objective: To review our results of carotid artery stenting (CAS) and carotid endarterectomy (CEA). Methods: We evaluated the medical records of patients undergoing carotid artery revascularization procedure, between 2001 and 2013 in Baskent University Hospital, Ankara, Turkey. Carotid artery stenting or CEA procedures were performed in patients with asymptomatic carotid stenosis (=70%) or symptomatic stenosis (=50%). Demographic data, procedural details, and clinical outcomes were recorded. Primary outcome measures were in 30-day stroke/transient ischemic attacks (TIA)/amaurosis fugax or death. Secondary outcome measures were nerve injury, bleeding complications, length of stay in hospital, stroke, restenosis (ICA patency), and all-cause death during long-term follow-up. Results: One hundred ninety-four CEA and 115 CAS procedures were performed for symptomatic and/or asymptomatic carotid artery stenosis. There is no significant differences 30-day mortality and neurologic morbidity between CAS (13%) and CEA procedures (7.7%). Length of stay in hospital were significantly longer in CEA group (p=0.001). In the post-procedural follow up, only in symptomatic patients, restenosis rate was higher in the CEA group (p=.045). The other endpoints did not differ significantly. Conclusions: Endovascular stent treatment of carotid artery atherosclerotic disease is an alternative for vascular surgery, especially for patients that are high risk for standard CEA. The increasing experience, development of cerebral protection systems and new treatment protocols increases CAS feasibility

Serum neurofilament light chain – A potential biomarker for polyneuropathy in type 2 diabetes?

AimsTo investigate the relationship between neurofilament light chain (NfL) and the presence and severity of diabetic polyneuropathy (DPN).MethodsWe performed cross-sectional analysis of data from 178 participants of the ADDITION-Denmark cohort of people with screen-detected type 2 diabetes and 32 healthy controls. Biobank serum samples were analyzed for NfL using single-molecule array. DPN was defined by Toronto criteria for confirmed DPN. Original and axonal nerve conduction study (NCS) sum z-scores were used as indicators of the severity of DPN and peripheral nerve damage.Results39 (21.9%) participants had DPN. Serum NfL (s-NfL) was significantly higher in participants with DPN (18.8 ng/L [IQR 14.4; 27.9]) than in participants without DPN (15.4 ng/L [IQR 11.7; 20.1]). There were no unadjusted s-NfL differences between controls (17.6 ng/L [IQR 12.7; 19.8]) and participants with or without DPN. Higher original and axonal NCS sum z-scores were associated with 10% higher s-NfL (10.2 and 12.1% [95% CI’s 4.0; 16.8 and 6.6; 17.9] per 1 SD). The AUC of s-NfL for DPN was 0.63 (95% CI 0.52; 0.73).ConclusionsS-NfL is unlikely to be a reliable biomarker for the presence of DPN. S-NfL is however associated to the severity of the nerve damage underlying DPN

Bidirectional lipid droplet velocities are controlled by differential binding strengths of HCV Core DII protein

Host cell lipid droplets (LD) are essential in the hepatitis C virus (HCV) life cycle and are targeted by the viral capsid core protein. Core-coated LDs accumulate in the perinuclear region and facilitate viral particle assembly, but it is unclear how mobility of these LDs is directed by core. Herein we used two-photon fluorescence, differential interference contrast imaging, and coherent anti-Stokes Raman scattering microscopies, to reveal novel core-mediated changes to LD dynamics. Expression of core protein’s lipid binding domain II (DII-core) induced slower LD speeds, but did not affect directionality of movement on microtubules. Modulating the LD binding strength of DII-core further impacted LD mobility, revealing the temporal effects of LD-bound DII-core. These results for DII-core coated LDs support a model for core-mediated LD localization that involves core slowing down the rate of movement of LDs until localization at the perinuclear region is accomplished where LD movement ceases. The guided localization of LDs by HCV core protein not only is essential to the viral life cycle but also poses an interesting target for the development of antiviral strategies against HCV

The effect of glutamate and aspartate on myocardial protection at cardiopulmonary bypass

Objective: To determine whether glutamat and aspartat enriched cold crystalloid cardioplegia which was given in antegrade way has any effect on the myocardial protection during cardiopulmonary bypass. Material and Methods: Thirty-four patients who were electively undergone open heart surgery at Osmangazi University Faculty of Medicine, thoracic and cardiovascular surgery department, between March 2001 and May 2001 were included in this study. The patients were divided in two groups, each consisting of 17 patients. In group 1 coronary artery bypass surgery (CABG) was performed in 11 patients, mitral valve replacement (MVR) in 3 patients, aortic valve replacement (AVR) in 1 patient and AVR and MVR in 2 patients. While in group 2 CABG was performed in 13 patients and MVR was done in 4 patients. Group 1 patients received antegrade glutamat and aspartat (15 mmol/L) enriched cold crystalloid cardioplegia and group 2 patients were given cold crystalloid cardioplegia by antegrade route. Age, gender, diabetes mellitus, hypertension, preoperative myocardial infarction, smoking, ejection fraction, aortic cross-clamp time, need to defibrillation, inotropic support, and intraaortic balloon pump were recorded. The levels of cardiac troponin I (cTI) and creatine kinase myocardial band fraction (CK-MB) were measured in arterial blood samples at five different times. Statistical analysis was performed using Student's t-test and Chi-square test. Results: There were no statistically significant differences in cTI and CK-MB values in blood samples taken at 5 different times pre and postoperatively between group 1 and group 2. Conclusion: It is concluded that glutamat and aspartat enriched cold crystalloid cardioplegia does not have any effect on myocardial protection

The effect of glutamate and aspartate on myocardial protection at cardiopulmonary bypass

Objective: To determine whether glutamat and aspartat enriched cold crystalloid cardioplegia which was given in antegrade way has any effect on the myocardial protection during cardiopulmonary bypass. Material and Methods: Thirty-four patients who were electively undergone open heart surgery at Osmangazi University Faculty of Medicine, thoracic and cardiovascular surgery department, between March 2001 and May 2001 were included in this study. The patients were divided in two groups, each consisting of 17 patients. In group 1 coronary artery bypass surgery (CABG) was performed in 11 patients, mitral valve replacement (MVR) in 3 patients, aortic valve replacement (AVR) in 1 patient and AVR and MVR in 2 patients. While in group 2 CABG was performed in 13 patients and MVR was done in 4 patients. Group 1 patients received antegrade glutamat and aspartat (15 mmol/L) enriched cold crystalloid cardioplegia and group 2 patients were given cold crystalloid cardioplegia by antegrade route. Age, gender, diabetes mellitus, hypertension, preoperative myocardial infarction, smoking, ejection fraction, aortic cross-clamp time, need to defibrillation, inotropic support, and intraaortic balloon pump were recorded. The levels of cardiac troponin I (cTI) and creatine kinase myocardial band fraction (CK-MB) were measured in arterial blood samples at five different times. Statistical analysis was performed using Student's t-test and Chi-square test. Results: There were no statistically significant differences in cTI and CK-MB values in blood samples taken at 5 different times pre and postoperatively between group 1 and group 2. Conclusion: It is concluded that glutamat and aspartat enriched cold crystalloid cardioplegia does not have any effect on myocardial protection

Pathological femoral neck fracture caused by an echinococcus cyst of the vastus lateralis - case report

<p>Abstract</p> <p>Background</p> <p>Musculoskeletal hydatid cysts are rare, but being locally invasive, can potentially cause significant deformity or pathological fracture.</p> <p>Case presentation</p> <p>A 39 y.o. male presented to our orthopaedic outpatient clinic complaining of severe right hip pain, and inability to ambulate. Symptoms were not preceded by trauma. Subsequent imaging confirmed a large, 17 × 3 × 5 cm echinococcus cyst in the vastus lateralis, causing erosion of the proximal metaphysis of the femur. As a consequence the patient suffered a non-traumatic pathological intertrochanteric femur fracture. The patient was treated with an en-bloc excision of the lesion - the affected soft tissue envelope containing the large cyst - and as a second surgical step a cemented total hip replacement (THR) was implanted under the same anaesthetic.</p> <p>The manuscript reviews the literature regarding musculoskeletal hydatid disease.</p