RP Conditions Research Articles

Promoting retrieval practice use during self‐study in higher education: The effects of a compact strategy intervention with metacognitive support

AbstractIntensive training programs have successfully supported students in using cognitive learning strategies. This study investigated whether a compact intervention can promote students' retrieval practice use during self‐study for course‐relevant materials. In an experiment embedded in a reputation management course, students were either given strategy instructions on retrieval practice (RP condition), strategy instructions and metacognitive email support (RP++) or no support (control). Students' potential retrieval practice use during self‐study of key concepts was measured with an online learning environment. Results showed a small but significant effect on retrieval practice use for the RP++ condition as compared to control (p = .005, r = 0.39). No significant differences were found between RP++ and RP, and RP and control and no significant effects were found on a delayed performance test. With our compact intervention, we took a small step in fostering the use of retrieval practice as a learning strategy during self‐study.

An Actinobacterium Strain From Soil of Cerrado Promotes Phosphorus Solubilization and Plant Growth in Soybean Plants.

The huge biological diversity of the Brazilian Cerrado is an important source of economically interesting microbial agents. The phylum Actinobacteria plays an important role in nutrient cycling, potentially improving their availability to plants. In this study, we isolated an actinobacteria (strain 3AS4) from wheat rhizospheres of crops cultivated in the Cerrado biome. Strain 3AS4 was identified as belonging to the genus Streptomyces and had phosphorus mobilization ability, mineralizing approximately 410 μg ml–1 from phytate, 300 μg ml–1 from calcium phosphate, and 200 μg ml–1 from rock phosphate. The analysis of the actinobacteria crude extract by spectrometric techniques revealed the presence of gluconic and 2-ketogluconic acid, and a greenhouse experiment was carried out to evaluate its plant growth promotion activity in soybean. Soil in its natural condition (with no phosphorus addition), 40 kg ha–1 rock phosphate from Bayovar (RP) added to soil, and triple super phosphate (SPT) added to soil were used. Significant differences in plant height were observed at 6 weeks when the plants were inoculated with the 3AS4 strain. The growth of inoculated plants in natural condition was promoted in 17% compared with the RP and SPT non-inoculated conditions, suggesting that inoculation can enable plants to grow with lower chemical P fertilizers. In the plants that were inoculated with the 3AS4 strain in the RP condition, the plant height increased by approximately 80% and the shoot:root ratio was approximately 30% higher compared to control conditions (non-inoculated plants in natural conditions). 3AS4 has P-solubilizing potential and can be exploited as an inoculant for soybean cultivation. These results suggest that this actinobacterium is a valuable resource for sustainable agriculture and will allow the reduction of phosphate fertilization in the future.

A new way to constrain the densities of intragroup medium in groups of galaxies with convolutional neural networks

ABSTRACT Ram pressure (RP) can influence the evolution of cold gas content and star formation rates of galaxies. One of the key parameters for the strength of RP is the density of intragroup medium (ρigm), which is difficult to estimate if the X-ray emission from it is too weak to be observed. We propose a new way to constrain ρigm through an application of convolutional neural networks (CNNs) to simulated gas density and kinematic maps galaxies under strong RP. We train CNNs using 9 × 104 2D images of galaxies under various RP conditions, then validate performance with 104 new test images. This new method can be applied to real observational data from ongoing WALLABY and SKA surveys to quickly obtain estimates of ρigm. Simulated galaxy images have 1.0 kpc resolution, which is consistent with that expected from the future WALLABY survey. The trained CNN models predict the normalized IGM density, $\hat{\rho }_{\rm igm}$ where $0.0 \le \hat{\rho }_{\rm igm, n} \lt 10.0$, accurately with root mean squared error values of 0.72, 0.83, and 0.74 for the density, kinematic, and joined 2D maps, respectively. Trained models are unable to predict the relative velocity of galaxies with respect to the IGM (vrel) precisely, and struggle to generalize for different RP conditions. We apply our CNNs to the observed H i column density map of NGC 1566 in the Dorado group to estimate its IGM density.

An Exploratory Study of General Self-Efficacy and Employment in Adults with Retinitis Pigmentosa

Introduction: In this study, the author examined the association between general self-efficacy (GSE) and employment status in working-age adults with retinitis pigmentosa (RP; N = 183). The author further examined the associations between employment status and factors that were previously found to be linked to employment outcomes in individuals with visual impairments: educational attainment, mobility tool use (i.e., use of dog guide or cane), ability to drive, age, gender, and age at onset of visual impairment. Methods: Multiple logistic regression was used to analyze cross-sectional data collected online in 2015. Results: Findings indicated that individuals with RP who have a bachelor’s degree or higher had significantly higher odds of being employed ( p < .01) and that individuals with RP who use a cane or dog guide had significantly lower odds of being employed ( p < .01). Although not statistically significant, findings further indicated that individuals with RP who have higher GSE had higher odds of being employed ( p = .07) and that individuals who are able to drive had 130% higher odds of being employed ( p = .06). Discussion: Results demonstrated an association between GSE and employment status, after controlling for factors that were previously linked to employment outcomes in individuals with visual impairment. Implications for practitioners: Self-efficacy is an alterable cognitive construct and may be the target of interventions to increase employment outcomes for adults with RP or other eye conditions.

The Genetics of Anthocyanin Pigmentation (of Colour) and Chlorophylls Content of <i>G. hirsutum</i> L. Cotton Plant

In the article, the first time genes of anthocyanin pigmentation Rp and Rstv appeared in cotton plant interacting complementarily. Recessive homozygosis rprрrstvrstv conditions the development of green colour. The gen Rp conditions the development of anthocyanin in all organs of plants, Rstv only exists on the stalk and in the nerves of leaves, the flower is uncolored, the boll is green. The plants’ existence in genotype of both dominant equilocal genes (Rp, Rst) provides a high rate of biosynthesis of anthocyanin—dark red. Inheritance of the chlorophylls “a” + “b” and “a” and “b” quantity in anthocyanin coloured L-2 and L-3 lines of F1 and F2 generations. The quantity of chlorophylls in anthocyanin coloured L-3 line was defined 1.0 - 1.5 times higher and participation of the gen Rstv responsible for anthocyanin colour in chlorophylls biosynthesis was also defined. Apparently, in the line L-3 in Rstv is localized, there are gens which are responsible for the quantity of chlorophyll or Rstv has pleiotropic effects on the quantity of chlorophyll. It is proved with low quantity of chlorophyll in green coloured plants by recessive homozygote condition rprprstvrstv green colour.

Impact of orthognathic surgery on the body posture

BackgroundPostural control is classically described as being based on the visual, vestibular, and proprioceptive musculo-articular sensory systems. The influence of mandibular proprioception on postural stabilization remains controversial. Most previous studies analyzed how postural stability is influenced by partial changes in mandibular proprioception (dental occlusion and jaw position). Research QuestionIn the present experiment, we asked whether drastic mandibular changes, resulting from orthognathic surgery (including dental, joint and muscular efferents), modify postural control. MethodsThe analyzes were performed in 22 patients tested before, and 2.5 months, after orthognathic surgery for treatment of dysmorphic jaws. Experiments were performed under 4 experimental conditions: 2 visual conditions: Eyes Open (EO) and Eyes Closed (EC), and 2 occlusal conditions: Occlusion (OC: mandible positioned by the contact of the teeth), and Rest Position (RP: mandible positioned by the muscles without tooth contact). The analyses focused on head orientation in the frontal plane and on postural stabilization in a static task, consisting of standing upright. ResultsThe results show that, 2.5 months after orthognathic surgery, head orientation in the frontal plane was improved, since patient’s external intercanthal lines became closer to the true horizontal line when they were tested EC and in OC condition. Postural responses, based on the wavelet transformation data, highlight an improvement in maintaining an upright stance for all the tested sensory conditions. However, such improvement was greater in the EC and RP conditions. SignificanceThese results show, for the first time, that after drastic mandibular changes, the weight of proprioceptive cues linked to the mandibular system may be so enhanced that it may constitute a new reference frame to orient the head in space, in darkness, and improve static postural stabilization, even in the presence of visual cues.

Near-nozzle spray dynamics of 6-hole GDI injector under subcooled and superheated conditions

The flash boiling of fuel sprays can occur in engines when the fuel is injected into the ambient gas which pressure is lower than the saturation vapor pressure of the fuel. Recently, the flash boiling has attracted many engine researchers’ interest due to its superior spray atomization performance. It has been discussed that the formation of the flash boiling sprays is governed by the bubble dynamics in the fuel such as bubble nucleation, growth, and burst. However, the detailed bubble dynamics and its effects on near-nozzle spray dynamics have remained a mystery due to great difficulties in the observation of flow characteristics inside and near the nozzle. The current study investigates the near-nozzle dynamics of flash boiling sprays from a 6-hole gasoline-direct-injection injector using an X-ray imaging technique. Various Rp (ratio of saturated vapor pressure to ambient gas pressure) conditions were applied by altering the ambient pressure under the fixed fuel temperature. The results showed that the flash boiling did not alter significantly the emerging flow velocity at the nozzle exit. The center of flash-boiling sprays did not decelerate in the near-nozzle region while that of the subcooled spray showed a gradual deceleration. The radial velocity of the flash boiling sprays increased at the edge of the spray as Rp increased while that in the spray center was near zero regardless of Rp condition. The radial velocity of the flash boiling spray was solely governed by Rp regardless of injection pressure while that of the subcooled sprays was altered by the injection pressure. Based on the results, the initial formation mechanism of the flash boiling sprays and the associated bubble dynamics were thoroughly discussed.

N-Propyl-N′-2-pyridylurea-modified silica as mixed-mode stationary phase with moderate weak anion exchange capacity and pH-dependent surface charge reversal

Herein, we present a novel silica-based stationary phase modified with N-propyl-N′-2-pyridylurea selector. Due to the weakly basic properties of the pyridine selector and the presence of residual silanols after selector immobilization, a zwitterionic surface with a pI observed at approximately pH 5.5 was measured by electrophoretic light scattering in pH-dependent ζ-potential determinations. The capability of the new N-propyl-N′-2-pyridylurea-modified silica to serve as mixed-mode stationary phase was investigated. For this purpose, it was characterized under RP and HILIC conditions using test mixtures. Subsequent classification of this stationary phase in comparison to in-house and commercial benchmarks was carried by principal component analysis of resultant retention factors from chromatographic tests. The results show a relatively unique mixed-mode character amongst the tested stationary phases. The chromatographic retention characteristics of acidic compounds matched well the ζ-potential determinations. The application of anion-exchange at low pH values (e.g. pH 5) and ion exclusion chromatography at pH 7 for the separation of uridine 5′-mono-, di- and triphosphate demonstrated a pH-dependent umpolung of the stationary phase surface. The combination of these separation principles in a pH gradient from 5 to 7 gave rise to weak anion-exchange selectivity with a charge-inducted elution due to repulsive interactions at higher pH and resulted in a significant faster separation with improved peak shape under mild elution conditions.

A systematic approach for the chromatographic fractionation and purification of major steroid saponins in commercial extracts of Yucca schidigera Roezl.

Yucca schidigera Roezl. (yucca) is one of the major industrial sources of steroid saponins used as animal and human food additives. This work describes a new, systematic and reproducible three-step method by medium and high-pressure liquid chromatography (under RP, NP and RP conditions), for the isolation and purification of three groups of saponins, which were further purified in six sub-fractions, and finally into twelve individual steroid saponins previously reported in Y. schidigera. In accordance to the increasing applications of yucca extracts, further analytical, biological and physicochemical studies are still required. The presented method is applicable to the preparation of steroids saponins previously reported in commercial extracts of Y. schidigera, both as highly purified mixtures of defined composition, including twelve pure components.

Practical observations on the performance of bare silica in hydrophilic interaction compared with C18 reversed-phase liquid chromatography

The kinetic performance of a bare silica and C18 phase prepared from the same sub-2μm and 3.5μm base materials were compared in the HILIC and RP mode using both charged and neutral solutes. The HILIC column was characterised using the neutral solute 5-hydroxymethyluridine, the weak base cytosine, and the strong base nortriptyline, the latter having sufficient retention also in the RP mode to allow comparison of performance. Naphthalene was also used as a simple neutral substance to evaluate the RP column alone. The retention factors of all substances were adjusted to give similar values (k′∼5.5) at their respective optimum linear velocities. Reduced van Deemter b-coefficients (determined by curve fitting and by the peak parking method, using a novel procedure involving switching to a dummy column) were significantly lower in HILIC for all substances compared with those found under RP conditions. Against expectation, c-coefficients were always lower in RP when compared with HILIC using sub-2μm particles. While measurement of these coefficients is complicated by retention shifts caused by the influence of high pressure and by frictional heating effects, broadly similar results were obtained on larger particle (3.5μm) phases. The mechanism of the separations was further investigated by examining the effect of buffer concentration on retention. It was concluded that HILIC can sometimes show somewhat inferior performance to RP for fast analysis at high mobile phase velocity, but clearly shows advantages when high column efficiencies, using longer columns at low flow velocity, are employed. The latter result is attributable to the lower viscosity of the mobile phase in HILIC and the reduced pressure requirement as well as the lower b-coefficients.

Head-to-head comparison of udenafil vs amlodipine in the treatment of secondary Raynaud's phenomenon: a double-blind, randomized, cross-over study

RP is a reversible vasoconstriction of digital arteries that causes pain and skin discoloration. This study compared the efficacy of the new phosphodiesterase type 5 inhibitor udenafil with that of the calcium channel blocker amlodipine in the treatment of secondary RP. A total of 29 patients with secondary RP associated with connective tissue diseases were enrolled in this double-blind, randomized, cross-over study. The patients were randomized to receive udenafil 100 mg/day or amlodipine 10 mg/day for 4 weeks. After a washout period they were crossed over to the other drug for another 4 weeks. The primary outcome was RP frequency before and after treatment. The secondary outcomes were RP condition scores, RP duration, number of digital ulcers, HAQ, physician global assessment and digital artery flow before and after treatment. Amlodipine and udenafil both decreased the rate of RP attack significantly. The drugs did not differ in terms of RP frequency or any of the secondary outcomes except for digital blood flow; udenafil improved it significantly better than amlodipine (P = 0.021). Udenafil was well tolerated without serious adverse effects. Udenafil and amlodipine have comparable efficacy in improving RP attacks. In addition, udenafil improves the blood flow in digital arteries compared with amlodipine. www.clinicaltrials.gov, protocol number NCT01280266.

Thorough investigation of the retention mechanisms and retention behavior of amides and sulfonamides on amino column in hydrophilic interaction liquid chromatography

In this paper detailed analysis of a mixture of four amides (tropicamide, nicotinamide, tiracetam, and piracetam) and six sulfonamides (sulfanilamide, sulfacetamide, sulfamethoxazole, sulfafurazole, furosemide, and bumetanide) on aminopropyl column in hydrophilic interaction chromatography (HILIC) was carried out. Since, there are no papers on the topic of the assessment of the contribution of ion-exchange retention mechanism involved in the separation of the acidic compounds on aminopropyl column in HILIC mode, the authors utilized the retention data of the acidic sulfonamides for this purpose. Next, broad range of the aqueous buffer concentrations in the mobile phase was examined providing the separation under either HILIC or RP conditions. Turning points between these two mechanisms were determined and then the fitting of the experimental data in the localized and non-localized adsorption models in both RP and HILIC regions was assessed. Since not many papers in the literature were dealing with the estimation of factor influence on the retention behavior of neutral and acidic compounds on aminopropyl column in HILIC, Box–Behnken design and Response Surface Methodology were applied. On the basis of the obtained data, ten quadratic models were proposed and their adequacy was confirmed using ANOVA test. Furthermore, retention data was graphically evaluated by the construction of 3D response surface plots. Finally, good predictive ability of the suggested models was proved with five additional verification experiments.

OP0039 Head to Head Comparison of Udenafil Versus Amlodipine in the Treatment of Secondary Raynaud’s Phenomenon: A Double-Blind, Randomized Cross-Over Study

BackgroundRaynaud’s phenomenon (RP) is a reversible vasoconstriction of digital arteries that causes pain and discoloration. Calcium channel blockers (CCB) such as amlodipine are commonly used as the first-line treatment. However,...

Automated DBS Extraction Prior to Hilic/RP LC–MS/MS Target Screening of Drugs

This article describes a rapid LC–MS/MS target screening method based on an automated extraction of 5 μL dried blood spots (DBS), two 5 min chromatographic runs on orthogonal phase columns (RP and Hilic) and a data dependent acquisition (DDA) of product ions spectra for the reliable identification of the detected compounds. The extraction step was performed in 2 min by using the LC autosampler itself in 96-well plates. This procedure was evaluated using 22 model compounds frequently encountered in forensic investigations, i.e., cocaine, benzodiazepines, amphetamines, opioids, antidepressants and antipsychotics. These investigations showed that even if the extraction step was reduced to a minimum, the extraction recoveries were satisfactory (median value of 40 %) and allowed for the detection of the model compounds in their therapeutic ranges, with the exception of morphine. Moreover, the use of two different chromatographic columns broadened the number of screening targets to those that behaved poorly under RP conditions, such as amphetamines or glucuronides, while keeping chromatographic gradients very short. This procedure was applied to 34 authentic post-mortem cases. It allowed the detection of 89 % of the compounds that were quantified in the routine procedures and the formal identification of 77 % of the compounds using their product ions spectra. These results were considered more than satisfactory compared to routine screening alone (GC–MS and LC-DAD, 55 % compound identification). The method described in this article is therefore a powerful approach for a fast, reliable and efficient target screening of drugs in forensic and clinical investigations.

HPLC separation of dihydropyridine derivatives enantiomers with emphasis on elution order using polysaccharide‐based chiral columns

The separation of enantiomers of five chiral dihydropyridine derivatives was studied on five different polysaccharide-based chiral HPLC columns with various normal-phase (NP), polar organic, and reversed-phase eluents. Along with the successful separation of analyte enantiomers, the emphasis of this study was on enantiomer elution order (EEO) with various columns and mobile phase composition. The interesting phenomenon of reversal of EEO, recently reported in the case of amlodipine (AML) depending on the concentration of formic acid in acetonitrile, was also confirmed with NP eluents. Under RP conditions at relatively low water content, the EEO of AML could also be reverted by varying the concentration of formic acid in the mobile phase. However, at higher water content the same parameter did not affect the EEO, but only induced gradual decrease in resolution up to complete co-elution of enantiomers. Additionally, in organic-aqueous mobile phases retention factors decreased with increasing water content but only up to 20% (v/v), while above this concentration the expected typical RP behavior was observed. The presence of the commonly used additive diethylamine in the mobile phase seems important for observing a reversal in EEO with increasing concentration of formic acid. The reversal of the EEO was characteristic of AML only and was not observed for any of other dihydropyridines included in this study.

Efficacy of tadalafil in secondary Raynaud’s phenomenon resistant to vasodilator therapy: a double-blind randomized cross-over trial

To evaluate the efficacy of tadalafil as add-on therapy in secondary RP resistant to vasodilators. Patients with scleroderma and MCTD having four or more RP attacks per week despite being on vasodilators were randomized to receive either placebo or tadalafil (20 mg) on alternate days as add-on therapy to their current vasodilators for 6 weeks. After a 7-day washout, patients were crossed over to the other arm. Primary endpoints were improvement in the daily frequency and duration of RP episodes and RP condition score (RCS). Secondary outcome measures were healing of existing and appearance of new digital ulcers (DUs) and improvement in scleroderma-specific HAQ (SHAQ), quality of life (QoL), flow-mediated dilatation (FMD), patient and physician global assessment. Twenty-four of 25 recruited patients completed the study. All the patients were receiving calcium channel blockers and in addition 18 were receiving other vasodilators. During tadalafil therapy significant improvement in mean daily frequency, mean daily duration of RP and mean daily RCS were observed as compared with baseline and placebo. All the 24 digital lesions healed during tadalafil therapy as compared with 3/13 during the placebo treatment (P<0.0001). One new DU was reported during tadalafil therapy vs 13 during placebo therapy (P=0.0005). QoL, SHAQ, FMD, patient and physician global assessment significantly improved while on tadalafil. No serious adverse event was observed. Tadalafil as add-on therapy improves symptoms of RP, heals and prevents new DUs and improves QoL in patients with resistant secondary RP. Clinicaltrials.gov, http://clinicaltrials.gov/, identifier: NCT00626665.

Postural responses to unexpected perturbations of balance during reaching

To study the interaction between feedforward and feedback modes of postural control, we investigated postural responses during unexpected perturbations of the support surface that occurred during forward reaching in a standing position. We examined postural responses in lower limb muscles of nine human subjects. Baseline measures were obtained when subjects executed reaching movements to a target placed in front of them (R condition) and during postural responses to forward and backward support-surface perturbations (no reaching, P condition) during quiet stance. Perturbations were also given at different delays after the onset of reaching movements (RP conditions) as well as with the arm extended in the direction of the target, but not reaching (P/AE condition). Results showed that during perturbations to reaching (RP), the initial automatic postural response, occurring around 100 ms after the onset of perturbations, was relatively unchanged in latency or amplitude compared to control conditions (P and P/AE). However, longer latency postural responses were modulated to aid in the reaching movements during forward perturbations but not during backward perturbations. Our results suggest that the nervous system prioritizes the maintenance of a stable postural base during reaching, and that later components of the postural responses can be modulated to ensure the performance of the voluntary task.

Application of bromoacetate-substituted β-CD-bonded silica particles as chiral stationary phase for HPLC

Bromoacetate-substituted [3-(2-O-beta-cyclodextrin)-2-hydroxypropoxy]propylsilyl-appended silica particles (BACD-HPS), an important and useful synthetic intermediate for preparation of novel types of macrocycles-capped beta-CD-bonded silica particles including crown ether/cyclam/calix[4]arene-capped beta-CD-bonded silica particles, have been prepared and used as chiral stationary phase for HPLC. This synthetic stationary phase is characterized by means of elemental analysis. For the first time, the chromatographic behavior of BACD-HPS was systematically evaluated with several disubstituted benzenes and some chiral drug compounds under both normal and RP conditions in HPLC. The results show that BACD-HPS has excellent selectivity for the separation of aromatic positional isomers and chiral isomers of some drug compounds when used as stationary phase in HPLC.

Reading aloud: Evidence for contextual control over lexical activation.

Can readers exert control (albeit unconsciously) over activation at particular loci in the reading system? The authors addressed this issue in 4 experiments in which participants read target words aloud and the factors of prime-target relation (semantic, repetition), context (related, unrelated), stimulus quality (bright, dim), and relatedness proportion (RP; high, low) were manipulated. In the high RP condition (RP = .5), an interaction between semantic context and stimulus quality was observed in which low stimulus quality slowed unrelated targets more than related ones, replicating previous work. In contrast, the low RP condition (RP = .25) yielded additive effects of semantic context and stimulus quality. However, when low RP was examined within the context of repetition priming, context and stimulus quality once again interacted. These results are discussed in the context of a widely endorsed framework with the addition of the central assumption that there is control over feedback between various levels.

Enantioseparation of kavain on Chiralpak IA under normal‐phase, polar organic and reversed‐phase conditions

First baseline HPLC enantioseparation of kavain is described. Complete enantiodiscrimination was achieved on the immobilised-type Chiralpak IA chiral stationary phase (CSP) using pure methanol and simple methanol-water and ethanol-water mixtures as eluents. A water-dependent enantioselectivity was clearly demonstrated. Performance of the Chiralpak IA CSP in polar organic and RP conditions was compared with that of five coated polysaccharide-derived CSPs used in normal-phase mode.