A vibration method for discovering density varied clusters

DBSCAN is a base algorithm for density-based clustering. It can find out the clusters of different shapes and sizes from a large amount of data, which is containing noise and outliers. However, it is fail to handle the local density variation that exists within the cluster. Thus, a good clustering method should allow a significant density variation within the cluster because, if we go for homogeneous clustering, a large number of smaller unimportant clusters may be generated. In this paper, an enhancement of DBSCAN algorithm is proposed, which detects the clusters of different shapes and sizes that differ in local density. Our proposed method VMDBSCAN first finds out the “core” of each cluster—clusters generated after applying DBSCAN. Then, it “vibrates” points toward the cluster that has the maximum influence on these points. Therefore, our proposed method can find the correct number of clusters

Acute Kidney Injury in Patients Undergoing Chronic Hepatitis C Virus Treatment With Ledipasvir/Sofosbuvir

Ledipasvir-sofosbuvir, a once-a-day, oral combination pill, was approved in 2014 for the treatment of chronic hepatitis C infection. Initial trials did not comment on nephrotoxicity; however, recent data suggest a risk of acute kidney injury (AKI) with the use of the medication. We assessed the rates of AKI in patients undergoing ledipasvir-sofosbuvir in a large, urban tertiary care center. This single-center retrospective observation study included all patients undergoing therapy from October 1, 2014, to October 1, 2015. Rates of AKI, defined by more than a 0.3 mg/dL increase in serum creatinine level, were calculated. Patients were followed 12 weeks after therapy to assess for sustained viral response as well as to assess for improvement of AKI after completion of therapy, defined by less than 0.2 mg/dL above baseline serum creatinine. In total, 197 patients were included in the final analysis who had completed ledipasvir-sofosbuvir therapy and completed laboratory values. Among the patients treated, 38 (19%) had AKI during therapy. An additional 4 (2%) had AKI at the end of therapy. Of the 38 patients who experienced AKI, 20 (53%) had improvement in serum creatinine to less than 0.2 mg/dL above their baseline. When comparing for chronic kidney disease (CKD) stage, those with CKD I or II experienced AKI 17% of the time compared with 47% of the time in CKD III or worse (P = 0.005). Conclusion: AKI was seen in nearly one-fifth of our patients, and patients with CKD stage III or worse are at increased risk. Although ledipasvir-sofosbuvir is generally safe in the general population, close monitoring of renal function is recommended

An Improvement for DBSCAN Algorithm for Best Results in Varied Densities

Density-Based Spatial Clustering of Applications with Noise (DBSCAN) is a base algorithm for density based clustering. It can find out the clusters of different shapes and sizes from a large amount of data, which is containing noise and outliers. However, it fails to handle the local density variations that exist within the cluster. In this thesis, an enhancement of DBSCAN algorithm is proposed, which detects the clusters of different shapes, sizes that differ in local density. We introduce three new algorithms. Our first proposed algorithm Vibration Method DBSCAN (VMDBSCAN) first finds out the “core” of each cluster – clusters generated after applying DBSCAN -. Then it “vibrates" points toward cluster that has the maximum influence on these points. The second proposed algorithm is Dynamic Method DBSCAN (DMDBSCAN). It selects several values of the radius of a number of objects (Eps) for different densities according to a k-dist plot. For each value of Eps, DBSCAN algorithm is adopted in order to make sure that all the clusters with respect to corresponding density are clustered. And for the next process, the points that have been clustered are ignored, which avoids marking both denser areas and sparser ones as one cluster. The last algorithm Vibration and Dynamic DBSCAN (VDDBSCAN) combines the first and second algorithms to produce best clustering results. It begins by searching for each level of density its corresponding Eps, then it will use DBSCAN to find all clusters, finally, it will use vibration method of VMDBSCAN to solve the problem of splitting clusters. Experimental results are obtained from artificial data sets and three real data sets from UCI. These data sets are of varied densities to match our goal for testing the proposed algorithms. The final results show that our algorithms get a good results with respect to the original DBSCAN algorithm and DVBSCAN algorithm. We obtain the correct number of clusters of artificial data sets. In the real data sets, the error rate is decreased when merging VMDBSCAN with DMDBSCAN and reach 9.76 % for IRIS data set, while when using DVBSCAN it was 17.22 %. For Haberman data set it reach 12.54 %, while when using DVBSCAN it was 32.65 %. For Glass data set it reach 33.43 %, while when using DVBSCAN it was 41.23 %

Incidence of cardiovascular and cerebrovascular events associated with sirolimus use after liver transplantation

BACKGROUND: Sirolimus (SRL) is an immunosuppressant often used in liver transplantation (LT) to mitigate renal insufficiency associated with calcineurin inhibitors. Sirolimus can cause hyperlipidemia, but its association with coronary artery disease (CAD) and cerebrovascular accidents (CVAs) is unclear. The purpose of this study was to assess the risk of CAD and CVAs with the use of SRL in LT recipients. METHODS: We retrospectively reviewed all of our LT recipients from 2000 to 2011. Patients with multiorgan transplant, multiple liver transplants, everolimus therapy, or survival1) 134 patients who received and tolerated SRL; 2) 604 patients who never received SRL; and 3) 65 patients who started but discontinued SRL. The primary outcome was the development of CAD or CVA beyond 4 months after transplantation with the use of time-dependent Kaplan-Meier analysis. RESULTS: In group 1, there were 6 CAD and 2 CVA events; in group 2, 27 CAD and 16 CVA events; and in group 3, 10 CAD and 2 CVA events. The event-free survival for CAD/CVA at 1, 3, and 5 years was 100%, 98.1%, and 97.2% respectively for group 1; 99.7%, 98.4%, and 96.1% for group 2; and 92.3%, 92.3%, and 85.6% for group 3. On an unadjusted basis, compared with group 2, there was no difference in CAD/CVA rates in group 1 (hazard ratio [HR] 0.92; not significant), but there was an increase in group 3 (HR 2.94; P = .0019). However, on multivariate analysis, only age at transplantation (HR 1.06; P = .001) and diabetes before transplantation (P = .011) were associated with increased CAD/CVA risk. CONCLUSIONS: Our analysis showed that patients receiving SRL after LT had no increased risk of CAD/CVA events compared with patients maintained on a calcineurin inhibitor. The risk of CAD/CVA should not be a factor in avoiding SRL

Acute Kidney Injury in Patients Undergoing Chronic Hepatitis C Virus Treatment With Ledipasvir/Sofosbuvir

Ledipasvir-sofosbuvir, a once-a-day, oral combination pill, was approved in 2014 for the treatment of chronic hepatitis C infection. Initial trials did not comment on nephrotoxicity; however, recent data suggest a risk of acute kidney injury (AKI) with the use of the medication. We assessed the rates of AKI in patients undergoing ledipasvir-sofosbuvir in a large, urban tertiary care center. This single-center retrospective observation study included all patients undergoing therapy from October 1, 2014, to October 1, 2015. Rates of AKI, defined by more than a 0.3 mg/dL increase in serum creatinine level, were calculated. Patients were followed 12 weeks after therapy to assess for sustained viral response as well as to assess for improvement of AKI after completion of therapy, defined by less than 0.2 mg/dL above baseline serum creatinine. In total, 197 patients were included in the final analysis who had completed ledipasvir-sofosbuvir therapy and completed laboratory values. Among the patients treated, 38 (19%) had AKI during therapy. An additional 4 (2%) had AKI at the end of therapy. Of the 38 patients who experienced AKI, 20 (53%) had improvement in serum creatinine to less than 0.2 mg/dL above their baseline. When comparing for chronic kidney disease (CKD) stage, those with CKD I or II experienced AKI 17% of the time compared with 47% of the time in CKD III or worse