A gradient algorithm for solution of the optimal control problem for hybrid switching systems

In this article, an algorithm is presented for solving the optimal control problem for the general form of a hybrid switching system. The cost function comprises terminal, running and switching costs. The controlled system is an autonomous hybrid switching system with jumps either at some switching times or some time varying switching manifolds. The proposed algorithm is an extension of the first-order gradient method for the conventional optimal control problem. The algorithm requires a low computational effort. The system's dynamical equations together with a set of algebraic equations are solved at each iteration in order to find the descent direction. The convergence of algorithm is proved and examples are provided to demonstrate the efficiency of the algorithm for different types of hybrid switching system optimal control problems.     

A wideband PVDF-on-silicon ultrasonic transducer array with microspheres embedded low melting temperature alloy backing

A PVDF-based 8-element ultrasound transducer array (1 mm × 1 mm element size with an inter-element spacing of 1 mm) on a silicon carrier substrate is fabricated and characterized. To improve the performance of the transducer, new CMOS-compatible fabrication technologies are introduced. These include: (1) adhesive micro-contact printing on non-radiating areas, and (2) glass microspheres (7–20 μm in diameter) embedded low melting temperature alloy (LMA) for backside electrical connection. The first improvement removes the adverse effects of adhesive layer (e.g., lower sensitivity) between the PVDF and backside contact while the second one improves the pulse-echo signal quality by eliminating reflections at the backing/water interface. The fabricated array elements are tested in a water tank and their pulse-echo response are recorded. The central frequency of each element is 25 MHz with a 100% measured 6-dB bandwidth (60% 3-dB bandwidth).     

Proatherogenic high-density lipoprotein,vascular inflammation,and mimetic peptides

Atherosclerosis is an example of an inflammatory disorder. During the acute phase and under inflammatory conditions, high-density lipoprotein (HDL), which is normally anti-inflammatory, can become proinflammatory. Reactive oxygen species generated by several enzyme systems can modify phospholipids and sterols, producing oxidized phospholipids and oxidized sterols that reduce the capacity of HDL to protect against undesirable oxidative modifications of molecules. In animal models of dyslipidemia, diabetes, vascular inflammation, and chronic rejection, it is observed that reducing oxidative and inflammatory pressure will help HDL regain its protective role. One way to accomplish this is through the use of apolipoprotein A-I mimetic peptides, which remove oxidation products from lipoproteins and cell membranes, returning normal structure and function to low-density lipoprotein and HDL. These mimetic peptides markedly reduce atherosclerosis in animal models. Published studies of apolipoprotein mimetic peptides in models of inflammatory disorders other than atherosclerosis suggest that they have efficacy in a wide range of inflammatory conditions.     

Hospital readmissions following HLA‐incompatible live donor kidney transplantation: A multi‐center study

Thirty percent of kidney transplant recipients are readmitted in the first month posttransplantation. Those with donor‐specific antibody requiring desensitization and incompatible live donor kidney transplantation (ILDKT) constitute a unique subpopulation that might be at higher readmission risk. Drawing on a 22‐center cohort, 379 ILDKTs with Medicare primary insurance were matched to compatible transplant‐matched controls and to waitlist‐only matched controls on panel reactive antibody, age, blood group, renal replacement time, prior kidney transplantation, race, gender, diabetes, and transplant date/waitlisting date. Readmission risk was determined using multilevel, mixed‐effects Poisson regression. In the first month, ILDKTs had a 1.28‐fold higher readmission risk than compatible controls (95% confidence interval [CI] 1.13‐1.46; P < .001). Risk peaked at 6‐12 months (relative risk [RR] 1.67, 95% CI 1.49‐1.87; P < .001), attenuating by 24‐36 months (RR 1.24, 95% CI 1.10‐1.40; P < .001). ILDKTs had a 5.86‐fold higher readmission risk (95% CI 4.96‐6.92; P < .001) in the first month compared to waitlist‐only controls. At 12‐24 (RR 0.85, 95% CI 0.77‐0.95; P = .002) and 24‐36 months (RR 0.74, 95% CI 0.66‐0.84; P < .001), ILDKTs had a lower risk than waitlist‐only controls. These findings of ILDKTs having a higher readmission risk than compatible controls, but a lower readmission risk after the first year than waitlist‐only controls should be considered in regulatory/payment schemas and planning clinical care.     

Surgical management of contact point headaches

INTRODUCTION: Contact point headaches are caused by contact between the nasal septum and the lateral nasal wall by a mechanism of referred pain involving the trigeminal nerve. Our goal was to investigate headaches caused by the contact between the septum and the superior turbinate or medial wall of the ethmoid sinuses and not the middle turbinate. MATERIALS AND METHODS: A retrospective chart review was performed on patients who underwent septoplasty and sinus surgery for headache. The total number of patients who opted for surgery was 23. Only 12 patients met the criteria of having a contact point between the septum and medial wall of the ethmoid sinus, or septum and superior turbinate, which were demonstrated via CT scan of the sinuses. These patients underwent surgical intervention in order to relieve the contact points. RESULTS: According to the same pain questionnaire given pre- and postoperatively, 83% no longer complained of headaches, while 8% had significant relief. Forty-one percent of our patients were previously diagnosed with migraines; 80% of these patients were successfully treated by surgery. DISCUSSIONS: Contact point headaches and migraine without aura (MWOA) have similar symptoms (eg, photophobia, phonophobia, nausea and vomiting, pulsating nature). We believe contact point headaches should be considered in the patient with a diagnosis of MWOA headaches.     

The dorsal premotor cortex orchestrates concurrent speech and fingertapping movements

Human speech and hand use both involve highly specialized complex movement patterns. Whereas previous studies in detail characterized the cortical motor systems mediating speech and finger movements, the network that provides coordination of concurrent speech and hand movements so far is unknown. Using functional magnetic resonance imaging (fMRI), the present study investigated differential cortical networks devoted to speech or fingertapping, and regions mediating integration of these complex movement patterns involving different effectors. The conjunction contrasts revealing regions activated both during sole fingertapping and sole repetitive articulation or reading aloud showed contralateral regions at the border of ventral and dorsal motor cortex. In contrast, the analyses revealing regions showing a higher level of fMRI activation for concurrent movements of both effectors compared with sole hand movements or repetitive articulation or reading aloud showed distinct premotor activations, which were situated dorsal and caudal to the areas activated across speech and fingertapping tasks. These results indicate that the premotor cortex (PMC) subserves coordination of concurrent speech with hand movements. This integrative motor region is not identical with the area that shows overlapping activations for speech and fingertapping. Thus, concurrent performance of these complex movement patterns involving different effectors requires, in addition to somatotopic motor cortex activation, orchestration subserved by a distinct PMC area.