Unilateral spinal anaesthesia with hyperbaric bupivacaine

BACKGROUND: The dosage of local anaesthetic and the time the patient must be kept in the lateral decubitus position for a unilateral spinal anaesthesia is not known. The aim of this study was to determine the ideal dosage of hyperbaric bupivacaine and the time required for the lateral decubitus position for a unilateral spinal block. METHODS: Ninety patients who were scheduled to receive spinal block for surgery in the lower extremity were randomised into 9 groups (n = 10). The spinal block was performed through the L4-L5 intervertebral space with the patient in the lateral decubitus position. Patients in groups Ia, Ib, Ic; IIa, IIb, IIc; IIIa, IIIb, IIIc received 1.5 ml of 0.5%, 2 ml of 0.5%, and 2.5 ml of 0.5% hyperbaric bupivacaine solutions, respectively. The patients were turned to the supine position for 5 min after the injection in groups Ia, IIa, IIIa, 10 min after the injection in groups Ib, IIb, IIIb, and 15 min after the injection in groups Ic, IIc, IIIc. The onset and regression of sensory and motor block were checked and compared between the dependent and non-dependent sides in each group. RESULTS: The rate of block progression of the non-dependent side was higher in the groups receiving 2.5 ml 0.5% hyperbaric bupivacaine solution than in the other groups; at the same time the level of block was higher and the duration of block was longer. The incidence of hypotension was 10-20% in these groups. In the 2 ml 0.5% hyperbaric bupivacaine solution groups, a satisfactory block level and duration of anaesthesia for surgery was obtained. The rate of block progression to non-dependent side in the groups receiving 1.5 ml of 0.5% hyperbaric bupivacaine solution was lower than the other groups, but the duration of block was shorter and the level of block was lower than the other groups. CONCLUSION: For unilateral spinal anaesthesia in lower extremity operations, 2ml 0.5% hyperbaric bupivacaine solution for operations above the knee and 1.5 ml 0.5% hyperbaric bupivacaine solution for operations below the knee and keeping the patients for 10 min in the lateral decubitus position were found to be appropriate.     

Systematik und katalog für räumliche elementenpaareClassification of and catalog for spatial pairs of elements

Design catalogs, much used in recent years in Germany [1–3], are excellent resources for methodical mechanical design. They are a kind of information store, containing the special knowledge necessary for design engineers in a concentrated, clearly arranged and easily accessible form. A design catalog consists of three parts: (1) classification, (2) main part, and (3) charactersitic properties. The first part presents a systematic, contradiction-free subdivision of solutions in the main part. It enables a quick check of completeness and, if necessary, allows completion of the solution field. The main part contains the solution field and identifies each solution in the form of sketches, text, equations or diagrams. The third part is used to seek and select the solution that is most suitable for a given problem. Therefore this part should contain all important characteristic properties of each solution.This paper introduces a design catalog for “Spatial Pairs of Elements”. In 1876 Reuleux discovered that in the general solution of the machine problem the elementary parts of a machine are not single, but always occur in pairs. Therefore, from a kinematic point of view, the machine must be divided into pairs of elements. A catalog that includes all important spatial pairs of elements, therefore, would be a fundamental resource for the designer.The design catalog for spatial pairs of elements contains 9 point-contact, 31 line-contact, and 10 surface-contact pairs, divided according to three classification aspects: type of contact, type of spatial element, and type of surface element. The main part shows the pairs of elements with their sketches, pairing restraints, and specific axis. The third part includes the kinetic and construction properties, frequency and application fields, which render possible the selection of an optimal pair of elements for given conditions.     

A dynamic theory for polarizable and magnetizable magneto-electro thermoviscoelastic,electrically and thermally conductive anisotropic solids having magnetic symmetry

A unified dynamic theory for polarizable and magnetizable magneto-electro thermoviscoelastic. electrically and thermally conducting anisotropic solids possessing magnetic symmetry is developed for time-dependent electromagnetic fields. Considering the Chu formulation of the Maxwell equations, the balance equations of nonrelativistic continuum mechanics and the boundary conditions together with the constitutive equations for anisotropic materials are given. It is shown that the entropy, polarization. magnetization and the nondissipative part of stress are derivable from a potential while the dissipative part of stress, electric current and heat flux vectors satisfy a residual inequality. The theory developed for a general anisotropy and interaction is applied to special cases.     

Reflex sympathetic dystrophy syndrome due to arteriovenous fistula

A patient with end-stage renal disease presented with reflex sympathetic dystrophy syndrome (RSDS) on her left hand 1 month after arteriovenous fistula (AVF) surgery. Magnetic resonance angiography revealed steal syndrome at the AVF level. Bone scintigraphy revealed early-stage RSDS. We considered that arterial insufficiency because of steal phenomenon following AVF surgery and underlying occlusive arterial disease triggered RSDS development.     

Wake-up receivers for wireless sensor networks: benefits and challenges - [Accepted from open call]

For successful data delivery, the destination nodes should be listening to the medium to receive data when the sender node starts data communication. To achieve this synchronization, there are different rendezvous schemes, among which the most energy-efficient is utilizing wakeup receivers. Current hardware technologies of wake-up receivers enable us to evaluate them as a promising solution for wireless sensor networks. In this article the benefits achieved with wake-up receivers are investigated along with the challenges observed. In addition, an overview of state-of-the-art hardware and networking protocol proposals is presented. As wake-up receivers offer new opportunities, new potential application areas are also presented and discussed.     

Co-Oxidative Transformation of Piperine to Piperonal and 3,4-Methylenedioxycinnamaldehyde by a Lipoxygenase from Pleurotus sapidus

The valuable aroma compound piperonal with its vanilla-like olfactory properties is of high interest for the fragrance and flavor industry. A lipoxygenase (LOX_Psa1) of the basidiomycete Pleurotus sapidus was identified to convert piperine, the abundant pungent principle of black pepper (Piper nigrum), to piperonal and a second volatile product, 3,4-methylenedioxycinnamaldehyde, with a vanilla-like odor through an alkene cleavage. The reaction principle was co-oxidation, as proven by its dependence on the presence of linoleic or α-linolenic acid, common substrates of lipoxygenases. Optimization of the reaction conditions (substrate concentrations, reaction temperature and time) led to a 24-fold and 15-fold increase of the piperonal and 3,4-methylenedioxycinnamaldehyde concentration using the recombinant enzyme. Monokaryotic strains showed different concentrations of and ratios between the two reaction products.     

Periodic flow of a second-grade fluid induced by non-torsional oscillations of eccentric rotating disks

This paper deals with the periodic flow of a second-grade fluid caused by non-torsional oscillations of two disks rotating about non-coincident axes. While the two parallel disks are initially rotating with the same angular velocity about distinct axes, they start to execute non-torsional oscillations in their own planes and in the opposite directions. An exact solution is obtained for the components of the horizontal force per unit area exerted by the top and bottom disks on the fluid in the periodic state. The results are graphically displayed and the influence of the second-grade fluid parameter, the ratio of the frequency of oscillation to the angular velocity of the disks, the Reynolds number and the dimensionless velocity amplitudes of oscillation is discussed. It is observed that the change in the \( x \)-component of the mentioned force gets larger when the second-grade fluid parameter increases. However, an opposite effect is seen for the change in the \( y \)-component.     

Drilling detritus and the operating parameters of thermally stable PDC core bits

A single rock type was drilled using two types of thermally stable polycrystalline diamond compact (PDC) and an impregnated diamond core bit using a fully instrumented laboratory drilling rig at a fixed rotational speed, and over a range of weights on bit (WOB). Operating parameters of the bits such as WOB, rate of penetration (ROP), rotational speed (RPM), torque and drilling specific energy (SE) were continuously monitored during the drilling trials. The effects of these parameters on the performance of the bits were examined. Relations between the drilling variables are also described. At each set WOB for each bit, the drilling detritus were collected. The detritus sizes between 1180 and 53 microns were analysed using wet sieving and sub 53 micron was analysed using a Malvern particle size machine. Both data were combined to obtain a particle size distribution at set WOBs for each bit. The relations between the particle size of the drilling detritus and operating parameters, cutter size and wear of the PDC and impregnated diamond core bits, and original rock grain size were established. An increase in WOB, ROP, wear rates, pins or diamond size increased the drilling detritus size for the bits. No relation was found between the drilling detritus and the rock grain size due to the regrinding effect and the high proportion (> 30%) of matrix material in the rock.