Improvement of the pre-deployment net closure procedure used with opening/closing plankton nets

The construction of a closing device to be used during the deploymentof phyto-zooplankton nets utilizing General Oceanics-type opening/closingmechanisms is described. This device (the cowl) decreases systemset-up time, decreases contamination from ambient particleswhile waiting for deployment, protects the net from mechanicaltears during descent, and increases system reliability. ¹This research is supported by the National Science FoundationGrant No. OCE-8003200     

A retrospective of plankton pumping systems, with notes on the comparative efficiency of towed nets

Contributing studies in the advent and utilization of planktonpumping systems are compared and evaluated. Basic terminologyand design considerations are discussed, and related to thehistorical use of pump systems, as well as to criteria for futuredesigns Such in situ considerations are also applied to theuse of towed nets, and are used as a basis of comparison forfishing efficiency and practicality.     

The use of drop traps to estimate the efficiency of two beam trawls commonly used for sampling juvenile flatfishes

The efficiencies of a 2-m and a 1·5-m beam trawl for catching newly settled flatfish and brown shrimp were compared with that of a 1-m² drop trap that was assumed to be 100% effective. Low and variable trawl efficiencies were recorded but the trawls were not size selective within the size range of individuals captured.     

A comparative analysis of the time-dependent antiproliferative effects of daunorubicin and WP631.

Jurkat T lymphocytes were treated with daunorubicin and WP631, a daunorubicin-based DNA binding agent, in experiments aimed to analyze cellular uptake of these drugs and their effect on cell viability. WP631 was taken up more slowly than daunorubicin, but laser confocal microscopy and spectrofluorometric quantification showed that the drug accumulated in the cells. Despite the slow uptake rate, the antiproliferative capacity of WP631 (measured as IC50 after a 72-h continuous treatment) was greater than that of daunorubicin. The propensities of daunorubicin and WP631 to promote apoptosis were compared. Our results indicate that the major effect of WP631 was a G2/M arrest followed, after about 72 h of treatment, by polyploidy and mitotic (reproductive) death. In contrast, daunorubicin induced a rapid response with classic features of apoptosis.     

A comparative study between two citrus rootstocks: Effect of nitrate on the root morpho-topology and net nitrate uptake

Root morpho-topology and net nitrate uptake of two citrus seedlings, Volkamer Lemon and Carrizo Citrange, grown at two nitrogen supplies (NO₃-N 5 M and 1000 M, respectively) were studied. Root morphological and topological parameters were gauged by an image-specific analysis system (WinRHIZO). Net nitrate uptake was estimated using the nitrate depletion method. The main findings showed that Carrizo seedlings had a dichotomous branching root system characterized by high root tip numbers and long 2^nd order lateral roots. Conversely, Volkamer root systems had a herringbone structure with a long tap root and 1^st order lateral root. Nitrate treatment did not seem to affect the pattern of the two genotypes, except for the 2^nd order lateral roots (Carrizo more than Volkamer) and root/shoot ratio and root mass ratio (Volkamer more than Carrizo) that were significantly different at low nitrate supply. Nitrate treatments induced a diverse net nitrate uptake regulation between citrus rootstocks. Indeed, at low nitrate supply, Carrizo showed a more efficient nitrate acquisition process in terms of: 1) higher net nitrate uptake maximum of the inducible high affinity transport system or full induction (A), (2) higher cumulative nitrate uptake (A_t) and (3) lower t₁ parameter defined as the half time of the net nitrate uptake rate of the inducible transport system during the induction phase, compared to Volkamer. Conversely, at the high nitrate level, only the genotypical difference of the t₁ parameter was maintained. The results suggested that, at the low nitrate level, the morphological root traits such as higher 2^nd order lateral roots and greater root tip numbers of the Carrizo compared with Volkamer seedlings, enhance the capacity to absorb nitrate from nutrient solution.     

Comparison of the epipelagic zooplankton samples from a U-Tow and the traditional WP2 net

The performance of a new mesozooplankton sampler, the U-Tow,was compared to that of the traditional WP2 net. The U-Tow significantlyunderestimated species abundance, but gave a very good representationof species composition and community size structure. WP2 netsamples could be used to calibrate the U-Tow, allowing absoluteabundance to be determined. It is recommended that the U-Tow,in its current configuration, be used in conjunction with WP2net samples to give measures of abundance, or as a tool to identifyareas of change in plankton communities.     

Dosimetric comparison between two MLC systems commonly used for stereotactic radiosurgery and radiotherapy: A Monte Carlo and experimental study

In this work dosimetric parameters of two multi-leaf collimator (MLC) systems, namely the beam modulator (BM), which is the MLC commercial name for Elekta “Synergy S” linear accelerator and Radionics micro-MLC (MMLC), are compared using measurements and Monte Carlo simulations. Dosimetric parameters, such as percentage depth doses (PDDs), in-plane and cross-plane dose profiles, and penumbras for different depths and field sizes of the 6 MV photon beams were measured using ionization chamber and a water tank. The collimator leakages were measured using radiographic films. MMLC and BM were modeled using the EGSnrc-based BEAMnrc Monte Carlo code and above dosimetric parameters were calculated. The energy fluence spectra for the two MLCs were also determined using the BEAMnrc and BEAMDP. Dosimetric parameters of the two MLCs were similar, except for penumbras. Leaf-side and leaf-end 80–20% dose penumbras at 10 cm depth for a 10 × 10 cm² field size were 4.8 and 5.1 mm for MMLC and 5.3 mm and 6.3 mm for BM, respectively. Both Radionics MMLC and Elekta BM can be used effectively based on their dosimetric characteristics for stereotactic radiosurgery and radiotherapy, although the former showed slightly sharper dose penumbra especially in the leaf-end direction.     

Comparative study of the transfection efficiency of commonly used viral vectors in rhesus monkey (Macaca mulatta) brains

Viral vector transfection systems are among the simplest of biological agents with the ability to transfer genes into the central nervous system.In brain research,a series of powerful and novel gene editing technologies are based on these systems.Although many viral vectors are used in rodents,their full application has been limited in non-human primates.To identify viral vectors that can stably and effectively express exogenous genes within nonhuman primates,eleven commonly used recombinant adeno-associated viral and lentiviral vectors,each carrying a gene to express green or red fluorescence,were injected into the parietal cortex of four rhesus monkeys.The expression of fluorescent cells was used to quantify transfection efficiency.Histological results revealed that recombinant adeno-associated viral vectors,especially the serotype 2/9 coupled with the cytomegalovirus,human synapsin Ⅰ,or Ca2+/calmodulin-dependent protein kinase Ⅱ promoters,and lentiviral vector coupled with the human ubiquitin C promoter,induced higher expression of fluorescent cells,representing high transfection efficiency.This is the first comparison of transfection efficiencies of different viral vectors carrying different promoters and serotypes in non-human primates (NHPs).These results can be used as an aid to select optimal vectors to transfer exogenous genes into the central nervous system of non-human primates.     

A comparative assessment of non-laboratory-based versus commonly used laboratory-based cardiovascular disease risk scores in the NHANES III population

Background

National and international primary CVD risk screening guidelines focus on using total CVD risk scores. Recently, we developed a non-laboratory-based CVD risk score (inputs: age, sex, smoking, diabetes, systolic blood pressure, treatment of hypertension, body-mass index), which can assess risk faster and at lower costs compared to laboratory-based scores (inputs include cholesterol values). We aimed to assess the exchangeability of the non-laboratory-based risk score to four commonly used laboratory-based scores (Framingham CVD [2008, 1991 versions], and Systematic COronary Risk Evaluation [SCORE] for low and high risk settings) in an external validation population.

Methods and Findings

Analyses were based on individual-level, score-specific rankings of risk for adults in the Third National Health and Nutrition Examination Survey (NHANES III) aged 25–74 years, without history of CVD or cancer (n = 5,999). Risk characterization agreement was based on overlap in dichotomous risk characterization (thresholds of 10-year risk >10–20%) and Spearman rank correlation. Risk discrimination was assessed using receiver operator characteristic curve analysis (10-year CVD death outcome). Risk characterization agreement ranged from 91.9–95.7% and 94.2–95.1% with Spearman correlation ranges of 0.957–0.980 and 0.946–0.970 for men and women, respectively. In men, c-statistics for the non-laboratory-based, Framingham (2008, 1991), and SCORE (high, low) functions were 0.782, 0.776, 0.781, 0.785, and 0.785, with p-values for differences relative to the non-laboratory-based score of 0.44, 0.89, 0.68 and 0.65, respectively. In women, the corresponding c-statistics were 0.809, 0.834, 0.821, 0.792, and 0.792, with corresponding p-values of 0.04, 0.34, 0.11 and 0.09, respectively.

Conclusions

Every score discriminated risk of CVD death well, and there was high agreement in risk characterization between non-laboratory-based and laboratory-based risk scores, which suggests that the non-laboratory-based score can be a useful proxy for Framingham or SCORE functions in resource-limited settings. Future external validation studies can assess whether the sex-specific risk discrimination results hold in other populations.     

Problems in the application of gel filtration to the desalting of organic compounds: retardation of aromatic and heteroaromatic anions by commonly used salts.

On Bio-Gel P-2 columns, certain inorganic salts elute considerably later than nucleotides and other anionic compounds of similar molecular weight when they are run separately. This would suggest that such compounds should be readily desalted by gel filtration. With some salts (e.g., NaCl, KI, KSCN) this is indeed the case. With others, however(K₂HPO₄, CH₃COONa, HCOONH₄), there is complete overlap between the peaks of the salt and the organic compound. Studies with different organic compounds and salts suggest that this entrapment within the salt peak may be due to opposing electrostatic and hydrophobic influences on the mobility of organic anions.     

A comparative study of brain Ca2+-ATPases.

1. Particulate brain ATPases from various vertebrates were optimally activated by Ca2+, Mg2+ or Mn2+. 2. Specific enzyme activity with AT32P as substrate was low in lower vertebrates and increased on the evolutionary scale. 3. The properties of the brain ATPases suggested that most of the activity was associated with plasma membrane ecto-ATPase.     

A comparative study of the phytochemistry of two African Rain Forests

A comparative analysis of aspects of the secondary chemistry of plants from the Kibale Forest, Uganda, and the Douala-Edea Forest Reserve, Cameroon (93 species in all) has shown mean concentrations of tannins and other phenolics to be significantly greater in both young and mature foliage from Douala-Edea than in comparable taxa from Kibale. The differences remain significant when analysis was restricted to common species only. Chromatographic analysis confirmed that the proportion of species from Douala-Edea yielding tannin breakdown products was significantly greater than that from Kibale. In contrast, the proportion of species whose leaves gave definite alkaloid-positive Dragendorff reactions was significantly higher in the Kibale site. Within each site, mature leaves of the great majority of species yielded either tannins or alkaloids but the presence of detectable quantities of both types of compound was rare. In each site distributions of the two classes relative to one another departed significantly from independence at the O < 0.005 level. Nutrient analyses of vegetation also showed striking differences between the two sites; the Ugandan material appearing to be more nutrient-rich. The distribution patterns of nutrients and of secondary metabolites between the two sites are discussed in relation to current hypotheses concerning strategies of defence chemistry among plant communities. The data suggest that in Douala-Edea, which is characterized by very sandy and acid soils, the common elements of the flora invest heavily in the production of high concentrations of tannins and other phenolics. According to current hypotheses, these are the class of secondary compounds whose characteristics are most suitable to defence of vegetation growing on poor soils, and/or in species-poor stands, and in which leaves are likely to be long-lived.     

The structure of two fast-white myosin heavy chain promoters. A comparative study

Two complete myosin heavy chain genes were isolated from chicken genomic libraries, and shown to code for fast-white isoforms. Isoform specific probes were developed from the 5' nontranslated regions of the two genes and used to identify the developmental stages at which each of the genes are expressed. One of the genes is transcribed in the embryo and the other only in the adult. The 5' flanking regions of the two genes were sequenced along with the first three exons. The 5' untranslated sequences in both genes are not contiguous, one intron is present in the adult gene while the embryonic gene contains two. The promoters of both genes contain the conserved CAAT and TATA box elements observed in other eucaryotic genes. A computer assisted comparison was performed on the two genes at the nucleotide and amino acid levels. No homology could be detected in the 5' flanking regions of the genes except in and around the CAAT and TATA elements, however, structural sequences at the 5' ends were highly conserved as well as the position of the first three introns. The amino acids in and around the ATP binding site are completely conserved between the two isoforms.     

A quantitative method to evaluate the donor corneal tissue quality used in a comparative study between two hypothermic preservation media

To standardize a new evaluation technique for calculating the overall quality (OQ) of the donor cornea and validate it using a comparative study of corneas preserved in Optisol-GS and Cornea Cold^®. Thirty pairs of donor corneas were selected for a 4 week in vitro comparative study using masked observers. Physiological parameters like thickness, transparency, viable endothelial cell density (VECD) and morphology were transformed to numerical range (0–4) to obtain the OQ. Microbiological examination was performed using Bactec instrument. Students t test showed statistically better results (p < 0.05) from week 3 for thickness, week 2 for transparency and week 1 for morphology and VECD; statistical significance (p < 0.05) was found for OQ from week 2 for the corneas preserved in Cornea Cold^® compared to Optisol-GS. Epithelial quality was similar regardless of the medium. Microbiological examination showed absence of aerobic and anaerobic microorganisms in both media. OQ method is efficient, consistent and easy, now validated for comparative studies. Further refinement is necessary for its use at eye-banks, bio-banks and research or transplantation purposes. Cornea Cold^® is a promising hypothermic corneal storage medium with preservation time ≤21 days. This permits higher flexibility, evaluation accuracy, longer duration for surgical preparation and ease of transportation.     

A morphometric and comparative study of the malleus.

This study has attempted to research, in detail, the dimensions and form of the malleus, and to indicate possible differences with regard to race, sex and side of origin (left or right). The ossicles were obtained from 75 adult cadavers and the dimensions were determined with the aid of a reflection microscope. Clear statistically significant differences were found between the Negroid and Caucasoid races, as well as between the right and left ossicles. No meaningful differences were determined between male and female ossicles.     

A comparative study of the parasites in two populations of white-tailed deer

The study compares parasite prevalence in two geographically separated populations of white-tailed deer in central Pennsylvania. Differences in prevalence were found for certain of the parasites studied. Characteristics of curves comparing prevalence with host-age group, however, were remarkably similar for individual parasites from both populations. Prevalence increased with host age for certain species of parasite and decreased or remained constant for others. Some of the underlying biological properties of the infections which may be responsible for the characteristics of the age specific prevalence curves are discussed.