Expansion in SL_d(Z/qZ), q arbitrary

Let S be a fixed finite symmetric subset of SL_d(Z), and assume that it generates a Zariski-dense subgroup G. We show that the Cayley graphs of pi_q(G) with respect to the generating set pi_q(S) form a family of expanders, where pi_q is the projection map Z->Z/qZ

Noninvasive Monitoring and Neurointerventional Management of Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is characterized by isolated rise in intracranial pressure (ICP) leading to chronic, debilitating headaches, tinnitus, and vision loss. Conventional diagnostics and monitoring primarily require the use of invasive procedure like lumbar puncture to measure ICP, while traditional management strategies involve weight reduction and medical treatment with acetazolamide. In an effort to reduce the need for invasive procedures, noninvasive methods of ICP monitoring such as optic nerve sheath diameter measurements and two-depth transcranial Doppler ultrasonography have been developed. In cases of refractory and fulminant IIH, surgical management strategies such as optic nerve sheath fenestration (ONSF), ventriculoperitoneal (VP) and lumboperitoneal (LP) shunting, and transverse venous sinus stenting are used to relieve symptoms via ICP reduction. While ONSF and VP/LP shunting exhibit utility primarily for the treatment of vision loss and headache, respectively, venous sinus stenting may prove to be an effective option in the management of all symptoms of IIH. Most importantly, consideration of the patient’s individual symptoms and values should be taken into account when choosing the optimal surgical management strategy for patients with IIH

Effects of Sex Hormones on Ocular Blood Flow and Intraocular Pressure in Primary Open Angle Glaucoma: A Review

Primary open-angle glaucoma (POAG) is a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and visual field loss. Some speculate that gender plays a role in the risk of developing POAG and that the physiologic differences between men and women may be attributed to the variable effects of sex hormones on intraocular pressure (IOP), ocular blood flow, and/or neuroprotection. Estrogen, in the form of premenopausal status, pregnancy, and post-menopausal hormone therapy is associated with increase in ocular blood flow, decrease in IOP and neuroprotective properties. The vasodilation caused by estrogen and its effects on aqueous humor outflow may contribute. On the other hand, although testosterone may have known effects in the cardiovascular and cerebrovascular systems, there is no consensus as to its effects in ocular health or POAG. With better understanding of sex hormones in POAG, sex hormone-derived preventative and therapeutic considerations in disease management may provide for improved gender-specific patient care

Tur\'an numbers for Ks,tK_{s,t}-free graphs: topological obstructions and algebraic constructions

We show that every hypersurface in $\R^s\times \R^s$ contains a large grid, i.e., the set of the form $S\times T$, with $S,T\subset \R^s$. We use this to deduce that the known constructions of extremal $K_{2,2}$-free and $K_{3,3}$-free graphs cannot be generalized to a similar construction of $K_{s,s}$-free graphs for any $s\geq 4$. We also give new constructions of extremal $K_{s,t}$-free graphs for large $t$.Comment: Fixed a small mistake in the application of Proposition

The Role of Focal Adhesion Kinase-Phosphatidylinositol 3-Kinase-Akt Signaling in Hepatic Stellate Cell Proliferation and Type I Collagen Expression

Following a fibrogenic stimulus, the hepatic stellate cell (HSC) undergoes a complex activation process associated with increased cell proliferation and excess deposition of type I collagen. The focal adhesion kinase (FAK)-phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway is activated by platelet-derived growth factor (PDGF) in several cell types. We investigated the role of the FAK-PI3K-Akt pathway in HSC activation. Inhibition of FAK activity blocked HSC migration, cell attachment, and PDGF-induced PI3K and Akt activation. Both serum- and PDGF-induced Akt phosphorylation was inhibited by LY294002, an inhibitor of PI3K. A constitutively active form of Akt stimulated HSC proliferation in serum-starved HSCs, whereas LY294002 and dominant-negative forms of Akt and FAK inhibited PDGF-induced proliferation. Transforming growth factor-beta, an inhibitor of HSC proliferation, did not block PDGF-induced Akt phosphorylation, suggesting that transforming growth factor-beta mediates its antiproliferative effect downstream of Akt. Expression of type I collagen protein and alpha1(I) collagen mRNA was increased by Akt activation and inhibited when PI3K activity was blocked. Therefore, FAK is important for HSC migration, cell attachment, and PDGF-induced cell proliferation. PI3K is positioned downstream of FAK. Signals for HSC proliferation are transduced through FAK, PI3K, and Akt. Finally, expression of type I collagen is regulated by the PI3K-Akt signaling pathway

Functional mapping of yeast genomes by saturated transposition

Yeast is a powerful model for systems genetics. We present a versatile, time- and labor-efficient method to functionally explore the Saccharomyces cerevisiae genome using saturated transposon mutagenesis coupled to high-throughput sequencing. SAturated Transposon Analysis in Yeast (SATAY) allows one-step mapping of all genetic loci in which transposons can insert without disrupting essential functions. SATAY is particularly suited to discover loci important for growth under various conditions. SATAY (1) reveals positive and negative genetic interactions in single and multiple mutant strains, (2) can identify drug targets, (3) detects not only essential genes, but also essential protein domains, (4) generates both null and other informative alleles. In a SATAY screen for rapamycin-resistant mutants, we identify Pib2 (PhosphoInositide-Binding 2) as a master regulator of TORC1. We describe two antagonistic TORC1-activating and -inhibiting activities located on opposite ends of Pib2. Thus, SATAY allows to easily explore the yeast genome at unprecedented resolution and throughput

FES-UPP: A Flexible Functional Electrical Stimulation System to Support Upper Limb Functional Activity Practice

There is good evidence supporting highly intensive, repetitive, activity-focused, voluntary-initiated practice as a key to driving recovery of upper limb function following stroke. Functional electrical stimulation (FES) offers a potential mechanism to efficiently deliver this type of therapy, but current commercial devices are too inflexible and/or insufficiently automated, in some cases requiring engineering support. In this paper, we report a new, flexible upper limb FES system, FES-UPP, which addresses the issues above. The FES-UPP system consists of a 5-channel stimulator running a flexible FES finite state machine (FSM) controller, the associated setup software that guides therapists through the setup of FSM controllers via five setup stages, and finally the Session Manager used to guide the patient in repeated attempts at the activities(s) and provide feedback on their performance. The FSM controller represents a functional activity as a sequence of movement phases. The output for each phase implements the stimulations to one or more muscles. Progression between movement phases is governed by user-defined rules. As part of a clinical investigation of the system, nine therapists used the FES-UPP system to set up FES-supported activities with twenty two patient participants with impaired upper-limbs. Therapists with little or no FES experience and without any programming skills could use the system in their usual clinical settings, without engineering support. Different functional activities, tailored to suit the upper limb impairment levels of each participant were used, in up to 8 sessions of FES-supported therapy per participant. The efficiency of delivery of the therapy using FES-UPP was promising when compared with published data on traditional face-face therapy. The FES-UPP system described in this paper has been shown to allow therapists with little or no FES experience and without any programming skills to set up state-machine FES controllers bespoke to the patient’s impairment patterns and activity requirements, without engineering support. The clinical results demonstrated that the system can be used to efficiently deliver high intensity, activity-focused therapy. Nevertheless, further work to reduce setup time is still required

The influence of left ventricular ejection fraction on the effectiveness of cardiac resynchronization therapy: MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy).

OBJECTIVES: The goal of this study was to evaluate the influence of left ventricular (LV) lead position on the risk of ventricular tachyarrhythmia in patients undergoing cardiac resynchronization therapy (CRT). BACKGROUND: Left ventricular ejection fraction (LVEF) is a surrogate marker of heart failure (HF) status and associated risk. Data on the effectiveness of cardiac resynchronization therapy with defibrillator (CRT-D) in patients with mild HF and better LVEF are limited. METHODS: In the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) study, the echocardiography core laboratory assessed baseline LVEF independent of the enrolling centers and identified a range of LVEFs, including those >30% (i.e., beyond the eligibility criteria). Echocardiographic response with CRT, defined as percent change in left ventricular end-diastolic volume (LVEDV), was analyzed in 3 prespecified LVEF groups: >30%, 26% to 30%, and 30% (in the range of 30.1% to 45.3%); 914 patients (50.5%) with LVEF 26% to 30%; and 199 patients with LVEF 30%: 22.3%; LVEF 26% to 30%: 20.1%; and LVEF 30% (hazard ratio [HR]: = 0.56 [95% confidence interval (CI): 0.39 to 0.82], p = 0.003), LVEF 26% to 30% (HR: 0.67: [95% CI: 0.50 to 0.90], p = 0.007), and LVEF 0.1). CONCLUSIONS: In MADIT-CRT, the clinical benefit of CRT was evident regardless of baseline LVEF, including those with LVEF >30%, whereas the echocardiographic response was increased with increasing LVEF, indicating that CRT might benefit patients with better LVEF. (Multicenter Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271)