Structural and histological observations on the male reproductive system of adult red poplar leaf beetle Chrysomela populi Linnaeus, 1758 (Coleoptera: Chrysomelidae)

This study described the anatomy and histology of the male reproductive system in Chrysomela populi, which is an economically important species belonging to the family Chrysomelidae. Therefore, reproductive biology has been studied to combat this insect. As well as, the characters associated with the reproductive tract have been potential to discuss aspects of the system and to better understand the reproductive dynamics. The male reproductive system of C. populi has a pair of testes, a pair of vas efferentia and deferentia, a pair of seminal vesicles, a pair of accessory glands, an ejaculatory bulb, an ejaculatory duct, and an aedeagus. The testis consists of two flower-shaped lobes. Each testis has 20 sperm tubules (testicular follicles) containing cysts of germ cells at various developmental stages within the light orange peritoneal sheath. Testicular follicles are composed of three different (growth, maturation, and differentiation) zones. In the middle region of each testis joins with the vas efferens. The testis is attached to the seminal vesicle by a small stalk like vas efferens. In the lumen of the vas efferens, seminal vesicle, and vas deferens, sperms form clumps in the form of thin threads. The proximal end of the vas deferens is connected to the common ejaculatory duct. It joins with the ejaculatory bulb. Around the ejaculator bulb, there is a pair of convoluted, flat-surface tubular structure accessory glands. Posterior ejaculatory duct joins with the aedeagus.     

Wide band resonant ultrasound spectroscopy of spheroidal modes for high accuracy estimation of Poisson coefficient of balls

An original inversion method specifically adapted to the estimation of Poisson coefficient of balls by using their resonance spectra is described. From the study of their elastic vibrations, it is possible to accurately characterize the balls. The proposed methodology can create both spheroidal modes in the balls and detect such vibrations over a large frequency range. Experimentally, by using both an ultrasonic probe for the emission (piezoelectric transducer) and a heterodyne optic probe for the reception (interferometer), it was possible to take spectroscopic measurements of spheroidal vibrations over a large frequency range (100 kHz-45 MHz) in a continuous regime. This method, which uses ratios between wave resonance frequencies, allows the Poisson coefficient to be determined independently of Young's modulus and the ball's radius and density. This has the advantage of providing highly accurate estimations of Poisson coefficient (+/-4.3 x 10(-4)) over a wide frequency range.     

Modeling and simulation of joint clearance effects on mechanisms having rigid and flexible links

In this study, kinematic and dynamic characteristics of a planar four-bar mechanism having joint clearance and link flexibility are investigated. Assuming that joint clearance as a virtual massless link, artificial clearances are developed at crank-coupler and coupler-follower joints. Contact model in joints with clearance is established using the nonlinear spring-damper model and the friction effect is considered using the Coulomb friction model. Then the simulation is implemented and the kinematic and dynamic characteristics of model mechanism are investigated. The computational methodology can predict the effects of clearance on planar mechanism having rigid and flexible links. The results are evaluated for the case of stationary phase, and naturally show that extreme values occur in output of the mechanism with clearances. Due primarily to the suspension effect of the flexible link, values of these peaks in the flexible mechanism decrease relative to that of the rigid mechanism. In addition, the flexibility has a significant effect on the vibration response of the mechanism with joint clearance.     

Surface treatment of glass fiber and carbon fiber posts: SEM characterization

Morphology, etching patterns, surface modification, and characterization of 2 different fiber posts: Gfp, Glass fiber post; and Cfp, carbon fiber were investigated by SEM analysis, after different surface treatments. Thirty fiber posts, being 15 Gfp and 15 Cfp were divided into a 5 surface treatments (n = 3): C-alcohol 70% (control); HF 4%-immersion in 4% hydrofluoric acid for 1min; H(3) PO(4) 37%-immersion in 37% phosphoric acid for 30s; H(2) O(2) 10%-immersion in 10% hydrogen peroxide for 20 min; H(2) O(2) 24%-immersion in 24% hydrogen peroxide for 10 min. Morphology, etching patterns, surface modification and surface characterization were acessed by SEM analysis. SEM evaluation revealed that the post surface morphology was modified following all treatment when compared with a control group, for both type of reinforced posts. HF seems to penetrate around the fibers of Gfp and promoted surface alterations. The Cfp surface seems to be inert to treatment with HF 4%. Dissolution of epoxy resin and exposure of the superficial fiber was observed in both post groups, regardless the type of reinforcing fiber, H(2) O(2) in both concentrations. Relative smooth surface area was produced by H(3) PO(4) 37% treatment, but with similar features to untreated group. Surface treatment of fiber post is a determinant factor on micromechanical entanglement to resin composite core. Post treatment with hydrogen peroxide resulted strength of carbon and glass/epoxy resin fiber posts to resin composite core.     

The magnetic-distortion probe: velocimetry in conducting fluids

A new type of velocimeter, capable of local velocity measurements in conducting fluids, is introduced. The principle of the "magnetic-distortion probe" is based on the measurement of the induced magnetic field by the flow of a conducting fluid in the vicinity of a localized magnetic field. The new velocimeter has no moving parts, and can be enclosed in a sealed cap, easing the implementation in harsh environments, such as liquid metals. The proposed method allows one to probe both the continuous part and fluctuations of the velocity, the temporal and spatial resolution being linked to the actual geometric configuration of the probe. A prototype probe has been tested in a gallinstan pipe flow and in a fully turbulent flow of liquid gallium generated by the counter rotation of two coaxial impellers in a cylinder. The signals have been compared to a reference potential probe and show very good agreement both for time-averaged velocities and turbulent fluctuations. The prototype is shown to detect motion from a few cm s(-1) to a few m s(-1). Moreover, the use of the magnetic-distortion probe with large-scale applied magnetic field is discussed.     

Description of the immatures of workers of the ant Linepithema micans forel (Hymenoptera: Formicidae)

Linepithema micans Forel is a poorly studied species that is now considered a pest in vineyards in South Brazil. Larval characters have been used in a few phylogenetic studies, and their importance greatly depends in the amount of available information on different species. This study presents a complete panorama on the external morphology of the immatures of L. micans based on observations by light and scanning electron microscopy. The number of larval instars was estimated as three based on the frequency distribution of head widths of 965 larvae. Larvae of L. micans were similar to other Linepithema Mayr in the general format of body and mandibles, presenting a dorsal abdominal protuberance, nine pairs of spiracle, and unbranched hairs. On the other hand, L. micans was unique for having shorter hairs, predominantly denticulate, intraspecific variation in the number of antennal sensilla and in the types of sensilla on the labial palps were reported. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.     

Effects of irrigation solutions on the surface of protaper instruments: A microscopy study

The aim of this study was to evaluate the effects of sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX), and mixture of tetracycline, citric acid, and detergent (MTAD) solutions on the surfaces of nickel titanium (NiTi) rotary files with scanning electron microscopy (SEM) and atomic force microscopy (AFM). Irrigation solutions including 2.5% NaOCl, 5% NaOCl, 2% CHX, and MTAD were used. Four new ProTaper rotary NiTi files (F3) were immersed in each four irrigation solutions for 10 min, separately. One untreated NiTi file was used as a control specimen. The surface analysis was performed with SEM and AFM. The surface analysis in AFM was performed on 12 different regions located between first and second millimeters from the tip. SEM images were taken with different magnifications. No surface alteration was recorded under SEM evaluation. AFM revealed that the root mean square (RMS) values of all treated specimens were statistically higher than the control sample (P < 0.05). The sample which was treated with CHX showed lowest RMS values in test groups. All tested solutions caused surface alterations. CHX demonstrated limited surface alterations when compared to the other tested solutions. Microsc. Res. Tech. © 2012 Wiley Periodicals, Inc.     

Effective stress law for the permeability of a limestone

The effective stress law for the permeability of a limestone is studied experimentally by performing constant-head permeability tests in a triaxial cell with different conditions of confining pressure σ and pore pressure p_f. Test results show that a pore pressure increase and a confining pressure decrease both result in an increase of the permeability, and that the effect of the pore pressure change on the variation of the permeability is more important than the effect of a change of the confining pressure. A power law is proposed for the variation of the permeability with the effective stress (σ′=σ–n_kp_f). The permeability-effective stress coefficient n_k increases linearly with the differential pressure and is greater than unity as soon as the differential pressure exceeds few bars. The test results are well reproduced using the proposed permeability-effective stress law. A conceptual pore-shell model based on a detailed observation of the microstructure of the studied limestone is proposed. This model is able to explain the experimental observations on the effect of the total stress and of the pore pressure on the permeability of the limestone. Effective stress coefficients for the stress-dependent permeability which are greater than one are obtained. It is shown that the controlling factor is the ratio of the different bulk moduli of the various constituents of the rock. This ratio is studied experimentally by performing microhardness tests.     

Biomonitoring of the adverse effects induced by the chronic exposure to lead and cadmium on kidney function: usefulness of alpha-glutathione S-transferase

A successful prevention of renal diseases induced by occupational exposure to lead (Pb) and/or cadmium (Cd) largely relies on the capability to detect nephrotoxic effects at a stage when they are still reversible or at least not yet compromising renal function. Hence, the aim of this cross-sectional study was to evaluate the usefulness of a set of early biological markers of oxidative stress or nephrotoxicity for the biomonitoring of workers occupationally exposed to Pb and/or Cd in a non-ferrous metal smelter, and gender, age, socioeconomic status, smoking habits, and drug use-matched control individuals. In exposed subjects, mean levels of Pb in blood and urine were also 387.1+/-99.1 microg Pb/L (1.868+/-0.478 micromol Pb/L) and 217.7+/-117.7 microg Pb/g creatinine (1.051+/-0.568 micromol Pb/g creatinine), and mean levels of Cd in blood and urine were 3.26+/-2.11 microg Cd/L (0.029+/-0.019 micromol Cd/L) and 2.51+/-1.89 microg Cd/g creatinine (0.022+/-0.017 micromol Cd/g creatinine), suggesting thereby relatively low occupational exposure levels. Statistically significant variations in zinc protoporphyrin, malondialdehyde, retinol binding protein, alpha-glutathione S-transferase, and urinary protein levels were reported between the two groups, and were closely correlated with Pb and/or Cd exposure levels. Variations in alphaGST levels were closely associated with Pb exposure. Taken together, these results suggest the use of alpha-glutathione S-transferase excretion in urine as a hallmark of early changes in the proximal tubular integrity.