Resolution of epidural hematoma related to osteoporotic fracture after percutaneous vertebroplasty

We are the first to report a case that showed spontaneous resolution of epidural hematoma which was related to a steroid-induced osteoporotic compression fracture.The patient had a painful fracture with an intravertebral cleft at L1 accompanying an epidural hematoma posteriorly.Immediate pain relief was achieved after percutaneous vertebroplasty.Complete resolution of hematoma was noted three months after procedure.We theorized that intravertebral stability after treatment might have played a role in this patient.

Balloon test occlusion of internal carotid artery: Angiographic findings predictive of results

AIM: To reveal angiographic findings to predict the re-sult of balloon test occlusion(BTO).METHODS: The cerebral angiograms of 42 consecu-tive patients who underwent cerebral angiography in-cluding both the Matas and Allcock maneuvers and BTO were retrospectively analyzed. Visualization of the an-terior cerebral artery(ACA) and the middle cerebral ar-tery(MCA) by the cross flow on the tested side during the Matas or Allcock maneuver was graded on a 5-point scale. Circle of Willis(COW) anatomy with respect to the presence/absence of a collateral path to reach the tested internal carotid artery(ICA) was classified intofour categories. A univariate logistic analysis was used to analyze the associations between each angiographic finding and the BTO result. Sensitivity, specificity, accu-racy, positive predictive value, and negative predictive value for each finding were calculated. RESULTS: Five patients(12%) were BTO-positive and the remaining 37 patients(88%) were BTO-negative. Visualizations of the ACA and MCA as well as the COW anatomy were significantly associated with the BTO re-sult(P = 0.0051 for ACA, P = 0.0002 for MCA, and P < 0.0001 for COW anatomy). In particular, good MCA vi-sualization and the presence of an anterior connection(collateral path to the tested ICA from the contralateral ICA via the anterior communicating artery) in the COW were highly predictive for negative BTO(negative pre-dictive value = 100% for both).

Stochastic and Distributed Optimal Energy Management of Active Distribution Networks Within Integrated Office Buildings

This paper proposes a stochastic and distributed optimal energy management approach for active distribution networks(ADNs)within office buildings.The proposed approach aims at scheduling office buildings fitted with heating ventilation and air conditioning(HVAC)systems,and electric vehicle(EV)charging piles,to participate in the ADN optimization.First,an energy management approach for the ADN with aggregated office buildings is proposed.And the ADN optimization model is formulated considering the detailed building thermal dynamics and the mobile behaviors of workers.Then,to consider un-certainties of photovoltaic(PV)power,scenario-based stochastic programming is integrated into the ADN optimization model.To further realize the stochastic energy management of the ADN within office buildings in a distributed manner,the alternating direction method of multipliers(ADMM)is used to solve the ADN optimization model.The original ADN optimization problem is divided into the network-side and the building-side sub-problems to effectively protect the privacy of the ADN and the office buildings.Finally,the ADN optimization model incorporating office buildings is validated in the winter by numerical studies.In addition,the impacts of comfort temperature range and expected state of charge(SOC)at departure are analyzed.Index Terms—ADN,EV,HVAC system,Office building,Stochastic and distributed energy management.

Analysis on Application of a Current-source Based DFIG Wind Generator Model

Models for simulation are vital for the authenticity of the simulation.Modeling doubly fed induction generation(DFIG)for power system stability analysis has attracted a great deal of research interests in the past few years due to the wide applications of DFIG in wind power generation.The models developed by the wind generator manufacturers are not only complicated,but also proprietary and very specific to their own products.Many simplified generic models have been proposed.Among them,the current-source based model is most widely used for power system stability analysis.The validation work on this model so far has been based on the selected simulation scenarios or limited real measurements.However,there has been no systematic and theoretic analysis on the validity of the current-source based model,which may cause inappropriate applications of this type of model in real engineering practices.This paper presents the conditions for using the current-source based model for power system stability analysis;then examines the model’s validity under symmetrical and asymmetrical fault conditions.Our practices for modeling and validating a real wind farm in North China confirm the validity analysis of this work on the current-source based DFIG model.