SL Range Research Articles

The transition away from chemical flocculants: Commercially viable harvesting of Phaeodactylum tricornutum

Harvesting can contribute up to 15% of the total production cost for microalgal biomanufacturing. Using flocculants is potentially a cost-effective approach but there has been considerable debate on the efficacy, cost, toxicity to the cell and environment, and the effect on the biomass further downstream. In this study, a range of biobased flocculants (chitosan from crab shells, Moringa oleifera seed extract, pectin from bananas, tannic acid-based derivatives from Acacia tree bark and egg shell powder) were compared with traditional chemical flocculants (aluminium sulphate, iron chloride and sodium hydroxide) for harvesting the diatom Phaeodactylum tricornutum. It was concluded that Tanac’s tannin based Tanfloc 8025 (SL range) was the most promising, requiring a low concentration (10.4 kg ton−1 biomass), at low cost ($27.04 ton−1 microalgal biomass). The flocculant was effective over a wide pH (7.5–10.0) and temperature (15–28 °C) range and harvesting (>85% efficiency) occurred in 10 mins, which resulted in a biomass concentration factor of ≥ 5.69.

Predictive value of the sentinel lymph node procedure in the staging of non-metastatic colorectal cancer.

Despite the recent growing interest of the scientific community, there is still no consensus on the actual applicability and effectiveness of sentinel lymph node (SL) procedure in colon cancers. This study aims to quantify feasibility, detection rate, negative predictive value, and accuracy of the SL identified with fluorescent dye in early colon cancers (ECC). This study conducted a consecutive sampling of 95 patients with non-metastatic colorectal cancer who have been treated with laparoscopic colon resection and complete mesocolic excision after a 25-mg indocyanine green peritumoral laparoscopic injection and SL identification with a near-infrared camera. The SL was later isolated and sent to ultra-staging. Ninety-five patients with an average age of 71 (range 37-90) and a mean BMI of 25 (range 18-39) have been recruited. On the patient sample (92 Pts), an average of 1.49 SL (range 1-5) and a mean time of 4 min were identified. The detection rate was 96.8% and the negative predictive value and accuracy rates were 96.2% and 93.4%, respectively. Mapping the SL with fluorescent dye can play an important role in the treatment of colon cancers, particularly those at early stages, and can lead to ultra-conservative surgery.

Comparing Hip and Wrist Accelerometer Estimates of Moderate-Vigorous Physical Activity Across Activity Domains

PURPOSE: Both hip/thigh and wrist-worn accelerometers are used to estimate moderate-vigorous intensity physical activity (MVPA). Few studies have directly compared these MVPA estimates in free-living environments across distinct activity domains. The purpose of this study was to compare AG wrist estimates of MVPA to AG-hip and the thigh-worn AP in five activity domains. METHODS: Fifteen adults (10F and 5M; age 18-36y) participated in two, 2-hr sessions that were categorized by activity domains; household (H, N=5), active leisure (AL, N=8), sedentary leisure (SL, N=6), work (W, N=7), and transportation/errands (TE, N=4). Participants were given general instructions (e.g., at least 45 min spent on household- related behaviors), but sessions took place in the participants’ natural environment. During the sessions, participants wore AG (non-dominant wrist, right hip) and AP on the right thigh. MVPA was estimated for AG-hip using machine learning (S3x), Freedson (F), Crouter (C2), and Sasaki (VM) methods. The AG-wrist data was processed using a random forest (RF). Pearson correlations and paired t-tests were used to compare MVPA estimates across methods. Linear mixed effects models were used to test if there was a significant difference in MVPA estimates between wrist and hip methods across activity domains. P-values <0.05 were considered statistically significant. RESULTS: Correlation between wrist RF and the hip methods ranged from R=0.63-0.66, while hip/thigh methods were all highly correlated (R=0.94-0.99). The AL domain had the highest time spent in MVPA (between method range: 50.7-60.6 min), while SL (range: 1.3-15.8 min), and W (range: 2.0-23.5 min) were the lowest. Wrist estimates of MVPA were significantly higher than the S3x (+10.8 min), F (+15.3 min), AP (+12.7 min), and VM (+12.1 min), all p<0.01. The estimates of MVPA from the RF were not significantly different than C2, p=0.11. Agreement between methods did not differ by activity domain (p>0.05). CONCLUSIONS: The wrist RF method was moderately correlated with hip/thigh measures and consistently produced higher estimates of MVPA compared to hip/thigh algorithms, across all activity types. Future research using direct observation as a criterion measures is needed. Supported by Bill and Linda Frost Fund.

Effectiveness of insecticidal nets on uncomplicated clinical malaria: a case-control study for operational evaluation.

BackgroundIn a context of large-scale implementation of malaria vector control tools, such as the distribution of long-lasting insecticide nets (LLIN), it is necessary to regularly assess whether strategies are progressing as expected and then evaluate their effectiveness. The present study used the case–control approach to evaluate the effectiveness of LLIN 42 months after national wide distribution. This study design offers an alternative to cohort study and randomized control trial as it permits to avoid many ethical issues inherent to them.MethodsFrom April to August 2011, a case–control study was conducted in two health districts in Benin; Ouidah–Kpomasse–Tori (OKT) in the south and Djougou–Copargo–Ouake (DCO) in the north. Children aged 0–60 months randomly selected from community were included. Cases were children with a high axillary temperature (≥37.5 °C) or a reported history of fever during the last 48 h with a positive rapid diagnostic test (RDT). Controls were children with neither fever nor signs suggesting malaria with a negative RDT. The necessary sample size was at least 396 cases and 1188 controls from each site. The main exposure variable was “sleeping every night under an LLIN for the 2 weeks before the survey” (SL). The protective effectiveness (PE) of LLIN was calculated as PE = 1 − odds ratio.ResultsThe declared SL range was low, with 17.0 and 27.5 % in cases and controls in the OKT area, and 44.9 and 56.5 % in cases and controls, in the DCO area, respectively. The declared SL conferred 40.5 % (95 % CI 22.2–54.5 %) and 55.5 % (95 % CI 28.2–72.4 %) protection against uncomplicated malaria in the OKT and the DCO areas, respectively. Significant differences in PE were observed according to the mother’s education level.ConclusionIn the context of a mass distribution of LLIN, their use still conferred protection in up to 55 % against the occurrence of clinical malaria cases in children. Social factors, the poor use and the poor condition of an LLIN can be in disfavour with its effectiveness. In areas, where LLIN coverage is assumed to be universal or targeted at high-risk populations, case–control studies should be regularly conducted to monitor the effectiveness of LLIN. The findings will help National Malaria Control Programme and their partners to improve the quality of malaria control according to the particularity of each area or region as far as possible.

Fishery biology of Catfish (Chrysichthys auratus, Family: Bagridae) from Damietta branch of the River Nile, Egypt

The study of fishery biology of Chrysichthys auratus from Damietta branch, Egypt showed that the population has SL range of 7–20cm, L′=11.85cm. Males represent 45.90% and females 53.98% of the population. Length–length and length–weight relationships were analyzed for males, females and combined sexes. It was: SL=−0.6231+0.8402 TL and LogW=−1.6253+2.9832 LogSL for combined sexes, respectively. The highest values of condition factor were obtained in July, August and September for both sexes. The mean value of (K) for males was higher than those of females in all different lengths. Age was assessed by Bhattacharya’s (1967) method from length frequency data to estimate the von Bertalanffy growth parameters (L∞=26.53cm, K=0.214 and to=−1.569). The individuals of this species live for about 4years and the first age dominates the population. The growth performance index in length (ФL) and weight (Фwt) was estimated as 2.18 and 1.11, respectively. The mortalities were computed as: Z=1.44, M=0.60 and F=0.84. The exploitation rate was estimated as Ecur=0.58. Length at first capture (Lc) was 9.66cm at age 0.54years. Length at recruitment (Lr) was 8.49cm and age 0.35years. It was found that the stock of Chrysichthys auratus in Damietta branch was rationally exploited.

Critical Thermal Maximum of Juvenile Spotted Seatrout (Cynoscion nebulosus) Reared for Summer Stocking in Texas

The critical thermal maximum of juvenile spotted seatrout (SL range 18–33 mm) was determined using a temperature increase of +0.26°C per hour. The critical thermal maximum (water temperature that was lethal to 50% of the test fish [LT50]) for trial 1 was LT50 = 38.8°C, LT50 = 39.4°C for trial 2, and LT50 = 38.9°C for trial 3. Critical thermal maximums differed significantly (P < 0.05) between trials 2 and 3, whereas trial 1 did not differ among trials. This difference correlated with body size, where fish in trial 2 were significantly larger (P < 0.05) (mean = 27.6 ± 2.0 mm in SL) (mean ± SE) than the fish of trials 1 (mean = 23.1 ± 0.5 mm in SL) and 3 (mean = 21.5 ± 0.7 mm in SL), suggesting positive size dependence in the critical thermal maximum.

Sexual Dimorphism in Alligator Gar

AbstractThe Alligator Gar Atractosteus spatula is currently imperiled due to habitat alterations and overharvest within much of this species’ range. Recent interest in improving management for this species within the USA and Mexico has spurred new creel restrictions, spawning area closures, and stocking programs, along with increased research on life history and population dynamics. These management and research measures can be improved by a noninvasive method for determining sex. Previous methods have required sacrificing the fish (for internal anatomy confirmation) or using costly and time‐consuming assays from a specialized laboratory. Evidence from other gar species suggests that sex determination is possible by examining sexually dimorphic external characters. We evaluated the utility of 13 morphological measurements for determining the sex of Alligator Gars of known gender (n = 117; SL range, 591–1,255 mm). Discriminate analysis identified two influential variables (snout length and caudal peduncle height) as sexually dimorphic. Univariate analyses identified three variables as sexually dimorphic (head length, snout length, and anal fin base length). Sexually dimorphic variables were used with SL to develop a method using serial body ratios (SL/snout length) followed by (snout length/anal fin base length) to identify sex in Alligator Gar to 93% accuracy in males and 72% accuracy in females.Received April 1, 2013; accepted June 3, 2013

Effect of Shortening Titin's Proximal IG Segment on Passive Cellular Mechanics

Titin is widely considered the main contributor to passive stiffness of cardiac myocytes. To test this we studied a novel mouse model, in which a large fraction of titin's proximal tandem Ig segment is deleted (we refer to the model as IG KO; for details on model, see Chung et al poster). The proximal tandem Ig segment extends greatly under physiological conditions and shortening the tandem Ig segment is predicted to increase titin-based passive tension. We first studied passive tension in skinned cardiac myocytes by stretching cells in relaxing solution with a velocity of 1 base-length/s (∼in vivo speed during diastole), and determining stiffness from the slope of the passive stress - SL relation in the physiological SL range of 1.95-2.10 μm. Cellular stiffness was significantly increased in the IG KO by ∼50%. Using a sinusoidal analysis, the elastic moduli at physiological SLs were found to be increased in the IG KO but the viscous moduli were not different. This shows that the tandem Ig segment is a pure elastic spring. Currently we are investigating intact myocytes using a carbon-fiber based system for attaching cells and measuring force. We conclude that theproximal Ig segment of titin's I band region is a pure elastic spring and that shortening of this spring element increases titin-based cellular stiffness in the physiological SL range. Increased titin-based stiffness is found in patients with heart failure with preserved ejection fraction (HFpEF) and the IGKO is well-suited to study the effect of increased titin-based stiffness on heart function (see poster by Chung et al).

Displacement, velocity preference, and substrate use of three native California stream fishes in simulated pulsed flows

We studied whether juvenile fishes were able to maintain swimming speed and position during simulated river pulsed flows in a laboratory flume. We used a glass flume (15.24×0.6 m) with river- rock substrate to determine the longitudinal displace- ment, movement distances and frequencies, velocity selection, and substrate use of juvenile (SL range: 6.1± 0.2 cm) hardhead Mylopharodon conocephalus (n=13), rainbow trout Oncorhynchus mykiss (n=11), and Sacra- mento sucker Catostomus occidentalis (n=12) during a 100-min flow pulse, as velocity changed from slow to medium, fast, medium, and slow. Fish were capable of maintaining swimming speed and position up to the maximum flume velocity of 0.46 m·s −1 , except for one hardhead that impinged on the rear fish screen. Fish swam faster in the flume during the medium and fast intervals than the slow intervals, but fish speeds were similar among the medium and faster intervals, when some fish took cover behind the rock substrate. In comparison with a Brett-type swim-tunnel, fish showed less increase in mean swimming speed as the flume velocity increased. Fish in the flume were able to use the rock substrate as hydraulic cover, decreasing the encoun- tered water velocity, and, presumably, conserving energy.

Experimental study on general correlation of turbulent burning velocity at high pressure

Turbulent burning velocities for lean C2H4-air and C3H8-air mixtures were measured for Bunsen-type turbulent premixed flames stabilized in a high-pressure chamber keeping the chamber pressure constant. The experiments were performed for a pressure range up to 1.0 MPa and for u′/SL range up to 25. The effects of equivalence ratio, Lewis number, and pressure exponent of laminar burning velocity were examined.

One-Dimensional Simulations of Freely Propagating Turbulent Premixed Flames

The propagation rate and the structure of freely propagating premixed turbulent flames are investigated using a one-dimensional simulation model based on a new version of the linear-eddy model (LEM) of Kerstein (1991, 1992). This model explicitly includes thermo-diffusive, finite-rate kinetic, and heal release effects. Reasonably good quantitative agreement in predictions of turbulent flame speed with fan-stirred bomb experiments of Abdel-Gayed el at. (1984a) is obtained over most of the reported u’/SL range. LEM predicts a rapid increase in ut/SL with u’/SL for low u’ followed by a bendiny slope of ut/SL with increasing u’ that was also observed in the experiments. Here, ut and SL are, respectively, the turbulent and stretch free planar laminar flame speeds and u’ is the r.m.s. turbulence intensity. Comparisons with an earlier model based on the G-equation (Menon and Kerstein, 1992) for flamelet combustion are also made. The resulting propagation speeds are also in good agreement. Comparisons with weak-swirl burner experiments of stationary flames by Bedat and Cheng (1995) show that the model under-predicts the reported ut/SL with u’/SL. However, progress variable probability density functions at different locations within the flame reveal the onset of distributed combustion which is predicted by the location of the flame on the Borghi combustion phase diagram (Bedat and Cheng, 1995). Finally, constant Reynolds number simulations for a range in SL/u’ compare well with experiments by Abdel-Gayed et al. (1979) for low u’, but predict a plateau in uJSL as u’ increases, and decreasing utSL with further decrease in St/u’. This behavior is interpreted as correct based on physical arguments.

Monte Carlo calculations of electron beam parameters for three Philips linear accelerators

Electron beams from three linear accelerators manufactured by Philips (SL75-20, SL75-14/N and SL15) have been simulated using the EGS4 Monte Carlo code. The linear accelerators demonstrate the change in design from the SL75 range to the SL range. The agreement between experimental and calculated central-axis depth-dose curves is good for all three machines. The calculated energy spectra are shown to be very sensitive to the design of the collimating system. Actual beam energies and those calculated from several range-energy formulae are compared and are closer for the more modern machines. Various levels of sophistication in the models for calculating the central-axis depth-dose curve in the phantom were tested for the SL15 12 MeV beam.

Observations on the Food of Macquarie Perch, Macquaria australasica (Pisces : Percichthyidae), in Victoria

The basic food of 204 Macquarie perch taken from Hughes Creek, the Seven Creeks River System (tributaries of the Goulburn River), and the Mitta Mitta River, Victoria, consisted of Coleoptera, Diptera (particularly Chironomidae), Ephemeroptera and Trichoptera. Secondary food comprised Crustacea, Hemiptera, Odonata and Mollusca; other items were considered incidental. Items of terrestrial origin formed an insignificant part of the diet. Large numbers (up to 1530) of food organisms were frequently found in the stomachs and many different food types were usually present in any one stomach. Large fish (SL range 115-287 mm) fed on a greater diversity of food types than small fish (SL range 46-65 mm). Laboratory observations indicate that Macquarie perch ingest food by a sucking action.

Dependence of loudness growth on skirts of excitation patterns

Loudness growth spanning a SL range of 50 dB was measured for a 100‐Hz tone in a noise band 200 to 9600 Hz wide. The noise was varied in intensity along with the tone so that during a given listening session the signal‐to‐noise ratio remained constant at either 0 or −10 dB. Listeners judged the loudness of the tone by loudness matching, magnitude estimation, and magnitude production. The noise markedly decreased the rate of loudness growth of the tone but not the range over which loudness grows. The overall decrease in steepness of the 100‐Hz loudness function was found to be greater than that previously reported at higher frequencies. It is suggested that, in contrast to similar measurements at higher frequencies, the excitation spread of a 100‐Hz tone to both low and high frequencies has been experimentally contained. While it appears that stimulation produced by the entire excitation pattern is necessary to obtain the expected growth rate of loudness, the loudness growth range may not depend on excitation produced by low‐ and high‐frequency skirts. Supportive data for this hypothesis are given by measures of intensity discrimination at 100 Hz. [Work supported by NIH.]

Reaction Time as a Measure of Suprathreshold Masking

Reaction time (RT) to pure tones masked by white noise was determined with two observers. At least five noise intensities, covering a 0–80 dB SL range, were selected; the tone intensity range was similarly divided. Seven tone frequencies from 250 Hz to 8 kHz were investigated. Finger-withdrawal RTs to tone onset were taken on 30 successive light-cued trials at a given combination of frequency and tone and noise intensities, presented monaurally. Noise was present continuously; tone duration was 1 sec, and foreperiod was variable. Data were obtained for intensity pairs yielding less than 1 sec RTs. Noise intensities were run in increasing order; tone intensities varied randomly within a given noise level. At equal signal-to-noise ratios for a given frequency, functions relating RT to tone and noise intensity appeared similar. Equal RT contours showed threshold shifts as a function of noise intensity. Comparison of these results with threshold masking data illustrated the use of RT as a measure of suprathreshold masking.