Analysis of linearity and frequency response of a novel piezoelectric flextensional actuator using a homodyne interferometer and the J(1)-J(4) method

Piezoelectric transducers are widely used in high-resolution positioning systems. This paper reports the experimental analysis of a novel piezoelectric flextensional actuator (PFA), which is designed by using the topology-optimization method through a low-cost homodyne Michelson interferometer. By applying the J(1) - J(4) method for signal demodulation, which provides a linear and direct measurement of dynamic optical phase shift independent of fading, the nanometric displacements of the PFA were determined. Linearity and frequency response of the PFA were evaluated up to 50 kHz. PFA calibration factor and amplification rate were determined for the PFA operating in the quasi-static regime. To confirm the observed frequencies of resonance, an impedance analyzer is also utilized to measure the magnitude and phase of the PFA admittance.

Does radioiodine therapy in patients with differentiated thyroid cancer increase the frequency of another malignant neoplasm?

Objectives. To compare the frequency of another primary malignancy in patients with differentiated thyroid carcinoma (DTC) who received radioiodine therapy or not ((131)I). Material and Methods. 168 cases of DTC patients were retrospectively evaluated as to the frequency of another neoplasia by comparing patients with and without it, taking into account clinical, laboratory, and therapeutic parameters. Results. Another primary malignancy occurred in 8.9% of patients. Of these, 53.3% showed the malignancy before (131)I and 46.7% after it. By comparing both groups, the age at the moment of diagnosis of another neoplasia was 46.1 ± 20.2 years for the group before (131)I therapy and of 69.4 ± 11.4 years for the group after it (P = 0.02). Of the 148 patients treated with (131)I, 4.7% developed another malignancy. The latter were older (61 ± 17 years) than those who did not show another cancer type (44.1 ± 14.2 years) (P < 0.05). Conclusion. The frequency of another neoplasia found after (131)I was similar to that found before (131)I.

Effect of himatanthus sucuuba in maternal reproductive outcome and fetal anomaly frequency in rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clinical study on survival rate of short implants placed in the posterior mandibular region: resonance frequency analysis

Short implants are increasingly used, but there is doubt about their performance being similar to that of regular implants. The aim of this study was to compare the mechanical stability of short implants vs. regular implants placed in the edentulous posterior mandible. Twenty-three patients received a total of 48 short implants (5 × 5.5 mm and 5 × 7 mm) and 42 regular implants (4 × 10 mm and 4 × 11.5 mm) in the posterior mandible. Patients who received short implants had <10 mm of bone height measured from the bone crest to the outer wall of the mandibular canal. Resonance frequency analysis (RFA) was performed at time intervals T0 (immediately after implant placement), T1 (after 15 days), T2 (after 30 days), T3 (after 60 days), and T4 (after 90 days). The survival rate after 90 days was 87.5% for the short implants and 100% for regular implants (P < 0.05). There was no significant difference between the implants in time intervals T1, T2, T3, and T4. In T0, the RFA values of 5 × 5.5 implants were higher than values of 5 × 7 and 4 × 11.5 implants (P < 0.05). A total of six short implants that were placed in four patients were lost (three of 5 × 5.5 mm and three of 5 × 7 mm). Three lost implants started with high ISQ values, which progressively decreased. The other three lost implants started with a slightly lower ISQ value, which rose and then began to fall. Survival rate of short implants after 90 days was lower than that of regular implants. However, short implants may be considered a reasonable alternative for rehabilitation of severely resorbed mandibles with reduced height, to avoid performing bone reconstruction before implant placement. Patients need to be aware of the reduced survival rate compared with regular implants before implant placement to avoid disappointments.

Low frequency of Y anomaly detected in Australian Brahman cow-herds

Indicine cattle have lower reproductive performance in comparison to taurine. A chromosomal anomaly characterized by the presence Y markers in females was reported and associated with infertility in cattle. The aim of this study was to investigate the occurrence of the anomaly in Brahman cows. Brahman cows (n = 929) were genotyped for a Y chromosome specific region using real time-PCR. Only six out of 929 cows had the anomaly (0.6%). The anomaly frequency was much lower in Brahman cows than in the crossbred population, in which it was first detected. It also seems that the anomaly doesn't affect pregnancy in the population. Due to the low frequency, association analyses couldn't be executed. Further, SNP signal of the pseudoautosomal boundary region of the Y chromosome was investigated using HD SNP chip. Pooled DNA of non-pregnant and pregnant cows were compared and no difference in SNP allele frequency was observed. Results suggest that the anomaly had a very low frequency in this Australian Brahman population and had no effect on reproduction. Further studies comparing pregnant cows and cows that failed to conceive should be executed after better assembly and annotation of the Y chromosome in cattle.

Breakfast frequency, adiposity, and cardiovascular risk factors as markers in adolescents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of frequency and time domain electromyography parameters in women with patellofemoral pain

Despite its high incidence, patellofemoral pain etiology remains unclear. No prior study has compared surface electromyography frequency domain parameters and surface electromyography time domain variables, which have been used as a classic analysis of patellofemoral pain. Thirty one women with patellofemoral pain and twenty eight pain-free women were recruited. Each participant was asked to descend a seven step staircase and data from five successful trials were collected. During the task, the vastus medialis and vastus lateralis muscle activities were monitored by surface electromyography. The data were processed and analyzed in four variables of the frequency domain (median frequency, low, medium and high frequency bands) and three time domain variables (Automatic, Cross-correlation and Visual Onset between the vastus medialis and vastus lateralis muscles). Reliability, Receiver Operating Characteristic curves and regression models were performed. The medium frequency band was the most reliable variable and different between the groups for both muscles, also demonstrated the best values of sensitivity and sensibility, 72% and 69% for the vastus medialis and 68% and 62% for the vastus lateralis, respectively. The frequency variables predicted the pain of individuals with patellofemoral pain, 26% for the vastus medialis and 20% for the vastus lateralis, being better than the time variables, which achieved only 7%. The frequency domain parameters presented greater reliability, diagnostic accuracy and capacity to predict pain than the time domain variables during stair descent and might be a useful tool to diagnose individuals with patellofemoral pain.

Reliable assessment of forearm photoageing by high-frequency ultrasound: a cross-sectional study

High-frequency ultrasound is a non-invasive tool used in skin ageing research to assess dermis thickness and echogenicity. This study evaluated the reliability of a range of high-frequency ultrasound parameters and tested their correlation with age and a validated clinical scale for the assessment of forearm skin photoageing; the difference between two body sites according to environmental exposition patterns was also investigated. Twenty-three volunteers aged 28-82 years were divided into three groups according to forearm photoageing degree. A 20 MHz ultrasound unit was used to obtain cross-sectional images of the skin by two trained investigators on two different sites: the dorsal forearm (chronically photoexposed skin) and the proximal medial arm (non-photoexposed skin). Several echogenicity parameters were studied for each skin compartment: total dermis, upper dermis and lower dermis, and the ratio between upper and lower dermis. The intraclass correlation coefficient (for complete agreement) between investigators was higher for upper and total dermis echogenicity measures compared with the lower dermis. At the non-photoexposed site, the upper and lower dermis parameter ratio was better correlated with age. At the photoexposed area, total dermis parameters demonstrated higher correlations with clinical score. The authors discuss the choice of parameters for forearm photoageing assessment using high-frequency ultrasound.

Morphometric relationships and indirect determination of the length frequency structure of the pirarucu, Arapaima gigas (Cuvier), in Brazilian Amazonia

The pirarucu (giant red fish), Arapaima gigas (Cuvier), (Arapaimidae) is among the diverse fish resources of Amazonia which are threatened by over-exploitation. Little is known about the biology of this species despite its commercial importance. The present paper provides indirect information about the length-frequency structure of the stock which was estimated by sampling its tongue bone in craft shops and weighing fresh manias (processed fish product) in fish markets since these were the only remaining recognizable features of the fish. The length-frequency reconstruction was carried out using a regression analysis calculated by utilizing individuals caught in experimental fishing.

Morphometric relationships and indirect determination of the length frequency structure of the pirarucu, Arapaima gigas (Cuvier), in Brazilian Amazonia

The pirarucu (giant red fish), Arapaima gigas (Cuvier), (Arapaimidae) is among the diverse fish resources of Amazonia which are threatened by over-exploitation. Little is known about the biology of this species despite its commercial importance. The present paper provides indirect information about the length-frequency structure of the stock which was estimated by sampling its tongue bone in craft shops and weighing fresh manias (processed fish product) in fish markets since these were the only remaining recognizable features of the fish. The length-frequency reconstruction was carried out using a regression analysis calculated by utilizing individuals caught in experimental fishing.

Frequency measurements of CD3OH and (CH3OH)-C-13 optically pumped far-infrared laser lines

We report the frequency measurements of 18 optically pumped far-infrared (FIR) laser lines generated from CD3OH and (CH3OH)-C-13. We use the heterodyne technique of mixing FIR laser radiations and microwave radiation on a metal-insulator-metal point-contact tunnel diode to determine the FIR laser frequencies. Two FIR laser systems, consisting of CO2 waveguide pump lasers and Fabry-Perot FIR laser cavities, were used as optical sources. (C) 1997 Optical Society of America.

Simulations of the Frequency Modulated Atomic Force Microscope (FM-AFM) nonlinear control system

The Frequency Modulated - Atomic Force Microscope (FM-AFM) is apowerful tool to perform surface investigation with true atomic resolution. The controlsystem of the FM-AFM must keep constant both the frequency and amplitude ofoscillation of the microcantilever during the scanning process of the sample. However,tip and sample interaction forces cause modulations in the microcantilever motion.A Phase-Locked Loop (PLL) is used as a demodulator and to generate feedback signalto the FM-AFM control system. The PLL performance is vital to the FM-AFMperformace since the image information is in the modulated microcantilever motion.Nevertheless, little attention is drawn to PLL performance in the FM-AFM literature.Here, the FM-AFM control system is simulated, comparing the performancefor di erent PLL designs.

Characterization of the patellofemoral pain syndrome by frequency parameters of EMG signal

Patellofemoral pain syndrome (PFPS) is the most frequent complaint in orthopedic clinics; although, its etiology remains unclear [Bolgla, 2010; Felicio, 2011]. Trying to understand its causes has been used time analysis of electromyography (EMG), but this method shows controversies. The aim of this study was to apply a method of processing the EMG signal in the frequency domain of the vastus lateralis (VL) and vastus medialis (VM) muscles for the characterization of PFPS.

Validation of a FFQ (Food Frequency Questionaire) for older people

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fire Frequency and the Vegetative Mosaic of a Spruce-Fir Forest in Northern Utah

Fire scar and vegetative analysis were used to construct a fire history for the Engelmann spruce/subalpine fir (Picea engelmannii/Abies lasiocarpa) vegetation type of the Utah State University (USU) T. W Daniel Experimental Forest. Three distinct periods of fire frequency were established-presettlement (1700-1855), settlement (1856-1909), and suppression (1910-1990). Mean fire interval (MFI) decreased during the settlement period and greatly increased during the suppression era. The difference was attributed to the influx of ignition sources during the settlement of nearby Cache Valley, located 40 km to the west. Logging and livestock grazing appear to have led to the reduced MFI, which in turn worked as a factor to create the vegetative mosaic now observed on the study area. The increase in MFI during the suppression era permitted the advancement of shade-tolerant species in the understory of the shade-intolerant lodgepole pine (Pinus contorta var. latifolia) and quaking aspen (Populus tremuloides). Continued suppression of disturbance from wildfire will allow the lodgepole pine cover type, which experienced the lowest MFI during the settlement period, to be further invaded by shade-tolerant species, decreasing spatial stand diversity and increasing the risk of more intense fires.