Mean Retention Research Articles

Development and validation of a chiral LC-MS method for the enantiomeric resolution of (+) and (-)-Mebeverine Hydrochloride in bulk drug by using polysaccharide-based chiral stationary phase

The aim of this study was to develop a simple, specific, sensitive and precise LC-MS method for the determination of mebeverine enantiomers in pharmaceutical formulations and it was validated as per ICH guidelines. The chromatographic separation was achieved on Phenomenex® Lux Cellulose 1 (250 mm x 4.6 mm i.d, 5μm particle size) column using mobile phase system containing acetonitrile: 10 mM ammonium acetate (85:15) at the flow rate of 0.8 mL/min. In the spectral investigation by LC-MS, the standard solution of Mebeverine showed major peak at m/z of 430.70, which was assigned to the [M+H] ion of Mebeverine. The described method was linear over the range of 15–75 ng /mL for (±) Mebeverine enantiomers with a correlation coefficient (r2 = 0.999). Detection limits and quantification limits of (+) Mebeverine and (-) Mebeverine were found to be 5 ng/mL and 15 ng/mL respectively. The recovery study of mebeverine from tablet formulation was found to be 99.16%. Mebeverine standard solution and mobile phase were found to be stable for at least 48h. The Mebeverine enantiomers were well resolved with mean retention times of about 1.16 min and 1.20 min respectively. The developed method was extensively validated and proved to be robust, accurate, precise, and suitable for analysis of Mebeverine enantiomers in tablet dosage form.

Retentive force variations in three polyamide and a polyetheretherketone denture attachments for implant-supported overdentures: An in vitro study

Statement of problemThe loss in the retentive capability of implant-supported overdenture attachments has been related to the wear of the retentive inserts. Wear of the abutment coating material when following the replacement period for the retentive inserts requires investigation. PurposeThe purpose of this in vitro study was to compare the changes in retentive force of 3 polyamide and a polyetheretherketone denture attachments under repeated insertion and removal cycles in wet conditions while following their manufacturers’ replacement time recommendations. Material and methodsFour different denture attachments (LOCKiT, OT-Equator, Ball attachment, and Novaloc) with their retentive inserts were tested. Four implants were embedded into individual acrylic resin blocks, and 10 abutments for each attachment were used. Forty metal housings with their retentive inserts were attached to polyamide screws with autopolymerizing acrylic resin. A customized universal testing machine was used to simulate insertion and removal cycles. The specimens were mounted on a second universal testing machine at 0, 540, 2700, and 5400 cycles, and the maximum retentive force was recorded. The retentive inserts for LOCKiT (light retention), OT-Equator (soft retention), and Ball attachment (soft retention) were replaced every 540 cycles, while the Novaloc (medium retention) attachments were never replaced. All the abutments were weighed with a precision scale at 0, 2700, and 5400 cycles. The surface of every abutment was examined under a stereomicroscope at ×10 magnification. Data were analyzed with descriptive statistics. Two-way repeated measures ANOVA was used to compare the mean retentive force and mean abutment mass of all groups and time evaluation points. Bonferroni corrections were made to adjust for multiple tests (α=.05). ResultsThe mean retention loss for LOCKiT was 12.6% after 6 months and 45.0% after 5 years of simulated use. The mean retention loss for OT-Equator was 16.0% after 6 months and 50.1% after 5 years of simulated use. The mean retention loss for Ball attachment was 15.3% after 6 months and 39.1% after 5 years of simulated use. The mean retention loss for Novaloc was 31.0% after 6 months and 59.1% after 5 years of simulated use. The mean abutment mass difference was statistically significant (P<.05) for LOCKiT and Ball attachment but not statistically significant (P>.05) for OT-Equator and Novaloc at baseline, 2.5 years, and 5 years. ConclusionsAll tested attachments recorded retention loss under the experimental conditions, even when their manufacturers’ recommendations for replacement time for the retentive inserts were followed. Patients should be aware that implant abutments should be replaced after a recommended period since their surfaces also change over time.

Improving students’ geography achievement using computer simulation and animation packages in flipped classroom settings

The deployment of innovative and learner-centered approaches into teaching and learning has strong potential of improving students’ learning outcomes. The study compared the effectiveness of computer simulation and animation instructional packages in flipped classroom settings on secondary school students’ achievement and retention in geography. The study adopted a pre-/post-test, non-equivalent, non-randomized quasi-experimental control group design. A sample of 126 senior secondary school class two (SS2) geography students was purposively drawn from two intact classes in Minna Metropolis, Niger State, Nigeria as participants for the study. The two intact classes were randomly assigned to experimental group I (computer simulation package, n=67) and experimental group II (computer animation package, n=59) in flipped classroom settings. A 50-item geography achievement test (GAT) was used for data collection, while computer simulation and computer animation instructional packages were administered to students as treatment in flipped classroom settings. The face and content validity of GAT was carried out using experts in the field of geography, educational technology and computer science from Federal University of Technology, Minna. GAT was further subjected to pilot testing, and a reliability coefficient of 0.85 was obtained using test re-test method and PPMC formula. Descriptive statistics of mean and standard deviation were used to answer the research questions, while inferential statistics of t-test was used to test the null hypotheses at 0.05 level of significance. Findings revealed that computer simulation (mean gain=41.70) and computer animation (mean gain=38.32) instructional packages in flipped classroom settings improved students’ achievement and retention of geography concepts. Also, no significant difference was found in the mean achievement (t=.05, df=124, p=0.63) and retention (t=2.04, df=124, p=0.82) scores of the two groups. It was therefore recommended that teachers should incorporate technology-based flipped classroom instructional strategies into teaching and learning of geography in order to improve students’ learning outcomes in the subject.

EFFECTS OF GUIDED DISCOVERY AND PROBLEM-SOLVING INSTRUCTIONAL STRATEGIES ON ACHIEVEMENT AND RETENTION OF BIOLOGY STUDENTS IN DELTA CENTRAL SENATORIAL DISTRICT, NIGERIA

This study investigated the effects of guided discovery and problem-solving instructional strategies on the achievement and retention of biology students in Delta Central Senatorial District of Delta State. Ten research questions and ten research hypotheses guided the study. The study adopted the pre-test post-test control group quasi-experimental research design. A sample size of 238 senior secondary school two (SS2) Biology students from six mixed secondary schools in Delta Central Senatorial District was used for the study. The instrument used for data collection was a biology achievement test (BAT) validated by one Biology science educator, an expert in measurement and evaluation and an experienced biology teacher. The reliability of the instrument was established using Kuder Richardson formula 21 which yielded a coefficient of 0.83. Data were collected by administering the BAT as a pre-test, post-test and follow-up test. The data collected were analyzed using mean, standard deviation, paired and independent sample t-test, ANOVA and ANCOVA. The results showed that there was a significant difference in the mean achievement scores in biology among students in guided discovery, problem-solving instructional strategies and lecture method with students in the guided discovery group scoring the highest mark followed by students in problem-solving and lecture method respectively. The result also revealed that there was a significant difference in the mean retention score among students taught with guided discovery, problem-solving instructional strategies and lecture methods. The result further showed that there was no significant interaction effect between teaching methods and sex on achievement and retention. It was recommended that biology teachers should adopt guided discovery and problem-solving instructional strategies in teaching biology concepts. Special training on how to use these teaching strategies should be organized for biology teachers to help them effectively implement guided discovery and problem-solving instructional strategies in classroom teaching.&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/soc/0005/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

A Novel Molecular Reservoir Based on Reverse Self-Assembled Liquid Crystals - A New Strategy for Prolonging the Duration in Action of Analgesics

PurposeThe aim of this study was to develop liquid crystal (LC) precursors to obtain novel long-acting analgesics for injection based on depot systems and compare the difference between the cubic and hexagonal precursors in delivering Diclofenac sodium (DS). MethodsDiclofenac sodium liquid crystal precursor injections were prepared and characterized, followed by in vitro release, pharmacodynamic, and pharmacokinetic studies. ResultsThe optimal formulations were prepared with a ratio of Phytantriol/ethanol/water as 76:19:5 for cubic LC precursors, and a ratio of Phytantriol/ethanol/water/Vitamine-E acetate as 72:18:5:5 for hexagonal, both loading various drug dosages (2.5%, 3.75% and 5%), respectively. Polarized light microscopy and small angle diffraction confirmed that the precursors were isotropic fluids and transformed into gels with Pn3m or HII framework in water. Rheological studies have shown that precursors belong to Newtonian fluids and gels to pseudoplastic fluids. The release showed that the DS in the commercial injection (DS-inj) was completely liberated within 6 h, whereas only 46.55% and 49.73% of the DS in 2.5% cubic precursors and 2.5% hexagonal precursors were freed, respectively. Pharmacodynamic studies have shown that cubic, hexagonal and DS-inj raised the pain threshold in mice by 169.4%, 157.3% and 113.79%, respectively. The mean retention times of DS in cubic and hexagonal were 3.16 and 2.67 times longer than DS-inj, respectively, according to pharmacokinetic results. ConclusionIn conclusion, cubic and hexagonal are both promising analgesic sustained release formulations. In addition, based only on the current comparison, cubic seems to have a better long-acting effect.

Effect of Animation Package on Academic Performance of Secondary School Biology Students towards Ecological Concepts in Kaduna South, Nigeria

This study entitled, Effect of Animation Package on Academic Performance of Secondary School Biology Students towards Ecological Concepts in Kaduna South, Nigeria was guided by four research questions and four corresponding research hypotheses. The study employed a quasi-experimental research design, specifically utilizing a pre-test post-test non-equivalent control group experimental design, given the use of intact classes. The study population comprised 699 SS II Biology students from Government Secondary Schools in Kaduna South LGA, with a sample size of 212 students randomly selected from two schools and an additional 150 students purposively selected from two other schools. Assessment of students' performance was conducted after they received instruction using both an animation package and conventional teaching methods. The assessment instrument used was the Ecology Performance and Retention Test (EPRT), comprising 30 items with response options A, B, C, and D, each item allocated 2 marks, resulting in a total score of 60. Validation of the EPRT was performed by two senior lecturers from the Federal College of Education, Zaria, experienced in educational tests and measurement. The reliability of the EPRT was assessed using the test-retest technique, yielding a reliability coefficient of 0.79 using Kuder-Richardson Formula 20. Data analysis was carried out using mean and t-test at a significance level of 0.05. The findings revealed differences in the mean performance scores of students taught ecology concepts using an animation package and those taught without, as well as differences in the mean retention scores of students taught Biology concepts using an animation package and those taught without it. Additionally, there were differences in the mean performance scores of male and female students taught ecology concepts using animation packages, while no significant difference was observed in the mean retention scores of male and female students taught biology concepts with the use of animation packages. Based on these findings, the study recommends that educational institutions prioritize the integration of animation packages into biology curricula to enhance student learning outcomes, among other suggestions.

Retention Evaluation of Implant-Supported Palateless Maxillary Overdentures Retained by PEEK Telescopic Attachment

Background: Retention and stabilization of implant-supported overdenture is associated with more patient satisfaction, chewing capability, and oral health-related quality of life. There are a variety of implant retention systems which can be utilized to retain an implant overdenture. Telescopic attachments provide excellent retention resulting from friction. Objective: This study evaluates the retention force and fatigue resistance of ready-made polyether ether ketone (PEEK) telescopic attachment in different numbers and positions of dental implants in palateless maxillary overdenture. Method: Five edentulous maxillary models were fabricated from cold-cure poly methyl methacrylate resin. The study models were divided into two groups; the first group (3-implant supported overdenture) and the second group (4-implant supported overdenture). Each group is subdivided into subgroups according to the different implant positions. One palateless maxillary denture was constructed over each model. Ready-made PEEK telescope attachments correspond to implant abutments embedded in the inner surface of these overdentures. Initial anterior, posterior, and central retention values of overdentures were estimated and compared with the retention after 540 cycles of insertion and removal using a digital force gauge. One-way ANOVA testing was used to compare the means of the models of group one, an Independent sample t-test was used to compare the means of the models of group two, and a comparison of retention value between the groups and Paired sample t-test was applied for determining the difference between initial and secondary retention value (p&lt;0.05). Results: The anterior retention value was significantly decreased when the dental implants were placed distally while the posterior and central retention values were significantly increased. Also, retention value increased as implant number increased; the lowest mean retention values were recorded with Group one and the highest values were with Group two. The final retention value was significantly decreased after 540 times insertion and removal. However, the values of secondary retention are still larger than the minimum retention value that was reported (5–7 N) to achieve sufficient patient satisfaction. Conclusion: The implant location and number affect the retention value of palateless maxillary overdenture. Continuous insertion and removal of the prosthesis for daily hygiene practice lead to decreases in retention values.

A pilot investigation on the effect of induced saliva flow on digestive parameters in sheep, and a comparison with cattle.

Sheep with a relatively low methane yield were observed to have shorter fluid and particle mean retention times (MRT). Because the application of pilocarpine, a saliva stimulant, was successful in reducing retention times in ruminants in previous studies, we applied this substance to sheep, expecting a reduction in MRT and methane yield. Three non-pregnant sheep (74 ± 10 kg) were fed a hay-only diet in a 3 × 3 Latin square design with oral doses of 0, 2.5 and 5 mg pilocarpine/kg body weight and day. Measurements included feed and water intake, MRT of liquid and particulate phases in the reticulorumen (RR) and total gastrointestinal tract (GIT), ruminal microbial yield (via urinary purine bases and metabolic faecal nitrogen), total tract methane emission, apparent nutrient digestibility and rumen fluid parameters. Data were investigated for linear and quadratic effects using orthogonal polynomial contrasts. The MRT of liquid and small particles in the RR and total GIT, and the short-chain fatty acid concentration in rumen fluid, linearly declined with increasing pilocarpine dosage, while no quadratic relationship was detected. Intake of feed DM and water, apparent nutrient digestibility, methane yield and microbial yield were not affected by pilocarpine. When combining the sheep data with that of a similar experiment in cattle, we found that the MRT of the liquid phase was positively associated with estimated NDF digestibility and with methane production per digested NDF, but was not associated with microbial yield or the ratio of acetate to propionate. The ratio between MRT of the particulate and the liquid phase was smaller for sheep than that for cattle, and was not affected by treatment. Differences in this ratio might explain why species reacted differently to the saliva-inducing agent, which might help to explain the discrepancy between species in the effect of induced saliva flow on digestive parameters.

Predictors of favorable outcome after pyloroplasty for gastroparesis: should response to pyloric dilation or Botox injection be used as a marker of surgical outcome?

IntroductionPyloroplasty and gastric peroral endoscopic myotomy (G-POEM) are effective surgeries for gastroparesis. The primary aim of this study was to evaluate outcomes of pyloroplasty and G-POEM in patients with gastroparesis and determine factors associated with favorable outcome. The secondary aim was to assess the utility of clinical response to preoperative pyloric dilation or botulinum toxin injection (Botox) on surgical outcome, a factor conventionally used as a favorable marker.MethodsThere were 204 patients who underwent pyloroplasty (n = 177) or G-POEM (n = 27) for gastroparesis at our institution from 2014 to 2021. Demographic and clinical parameters were analyzed to assess their impact on surgical outcome. A subgroup of patients who had pyloric dilation or Botox injection were assessed separately. Favorable outcome was defined as patient reported complete resolution of the predominant gastroparesis symptom.ResultsFavorable outcome was achieved in 78.4% of patients (pyloroplasty: 79.7% and G-POEM: 70.4%, p = 0.274). Among 61 patients where pre- and postoperative gastric emptying studies (GES) were available, mean 4-hour retention significantly improved from 33.5 to 15.0% (p < 0.001) and 77.0% of patients achieved normalization.Favorable outcome was not significantly impacted by etiology of gastroparesis (p = 0.120), GERD (p = 0.518), or primary gastroparesis symptom (p = 0.244). Age ≥ 40 was a significant predictor of favorable surgical outcome on multivariate analysis [OR: 2.476 (1.224–5.008), p = 0.012]. Among the patients who had preoperative dilation (n = 82) or Botox injection (n = 46), response to these interventions was not a predictor of favorable surgical outcome (p = 0.192 and 0.979, respectively). However, preoperative Botox injection, regardless of response to injection, was associated with favorable surgical outcome [OR: 3.205 (CI 1.105–9.299), p = 0.032].ConclusionSymptomatic improvement after pyloroplasty or G-POEM is independent of etiology of gastroparesis, GERD, and primary symptom. Response to dilation or Botox are not markers of response to surgery. However, patients who receive Botox are 3.2 times more likely to improve postoperatively.Graphical abstract

Abstract 80: Teaching Students To Teach About Stroke

Background: Inadequate stroke prevention and stroke symptom identification delays contribute to higher stroke incidence and worse outcome in African American patients and those living in disadvantaged communities. It is not known how best to improve community stroke awareness. Studies have shown effectiveness of children teaching parents about stroke. Evidence regarding students teaching other students is lacking. Primary Objective: To increase awareness of stroke risk factors and stroke signs/symptoms/call 911 in an urban high school. Secondary Objectives: 1. Teach students the principles of teaching peers. 2. Assess effectiveness of a creative versus standard teaching method. Methods: Prospective, cross-over, community-based study in which 48 sophomore students from an urban high school were taught stroke risk factors and signs/symptoms/call 911. These Student Teachers then taught these topics to peers from the same school using a creative or standard method. Student Learners were blinded to the teaching method. Pre and post-tests were used to measure teaching effectiveness with possible scores ranging from 0 to 39. Results: Forty-four Student Learners took at least one of three tests (pre, post and one-month retention). Thirty-three Student Learners took pre and post-tests, while 17 took all three. Improvements in both mean post-test scores (4.8, p &lt; 0.001) and mean retention scores (3.4, p = 0.002), irrespective of teaching method, were observed. Thirteen Student Teachers took the retention test. There was no difference in scores relative to teaching method. Scores of Student Teachers who taught stroke risk factors, compared to those who taught signs/symptoms/call 911, were better (35.4 vs. 31.0, p = 0.049). Conclusion: Awareness of stroke risk factors and signs/symptoms/call 911 improved in high school students who were taught by peers regardless of the teaching method. Limitations which impacted the results include attendance, COVID restrictions, and scheduling challenges. We will mitigate limitations in the next phase of the project.

Extrusion parameters and physical transformations of an extrudate for fish: Effect of the addition of hydrolyzed protein flour from by-products of Oncorhynchus mykiss

IntroductionThe food industries play a fundamental role in feeding for the functions of animal metabolism. Fish feed extrusion cooking includes process-independent factors such as temperature (°C), screw speed (RPM), throughput, feed, and moisture content that influence the final product's nutritional value and physical properties. The evidence suggests that the application of hydrolyzed protein flour (HPH) is a crucial step for the techno-functional properties of the product. Therefore, this work aimed to study the effect of hydrolyzed protein meal from silage of trout (Oncorhynchus mykiss) on the parameters of the extrusion system and their physical transformations.MethodsIn this study, the influence of hydrolyzed protein meals ranges between 10 and 30% as a substitute for fish meals. The physical properties of the extrudate were monitored, evaluating the hardness, durability, buoyancy, expansion index, and apparent density.ResultsConsistent with this, parameters such as feed composition, screw speed, moisture content, and extrusion process affected the composition and properties of the final product.DiscussionThe physical properties indicated that the hydrolyzed protein flour presented cohesiveness and decreased the mean retention time in the extruder barrel and the specific mechanical energy (SME). Hydrolyzed protein flour during the extrusion process produces pellets with high durability and low hardness due to the high porosity presented, which allows for obtaining nutritional characteristics in the extruded product.

Is there a difference in ruminal fermentation control between cattle and sheep? A meta-analytical test of a hypothesis on differential particle and fluid retention

Ruminant species differ in digestive physiology. The species-specific ratio of mean retention time of particles and fluid (MRTparticle/MRTfluid) in the reticulorumen has been interpreted as controlling ruminal fermentation: a higher ratio indicates of a more distinct ‘washing’ of particulate digesta by liquid. This should increase the harvest of microbes from the reticulorumen, and keep the microbiome in a state of more intense growth; at the same time, this should increase the metabolic losses of faecal nitrogen of microbial origin, leading to lower values for the apparent digestibility of crude protein (aD CP). A systematic difference has been hypothesized between cattle (higher ratio) and sheep (lower ratio), with a lower MRTfluid in cattle due to a higher saliva production. Here, we test these hypotheses in a meta-analysis, using only studies that investigated cattle and sheep simultaneously. The datasets included 12 studies on MRT (of which 11 contained information on feed intake), yielding 102 (or 89) individual data; and 26 studies on protein digestibility (of which 18 contained information on intake), yielding 349 individual data. Cattle had a higher MRTparticle/MRTfluid (2.1) than sheep (1.7), mainly due to longer MRTparticle; only if body mass was included in the model, MRTfluid was significantly shorter in cattle in the larger MRT dataset (and tended to be shorter in the slightly smaller dataset). Cattle had a significantly lower aD CP than sheep, while there was no such difference in overall (dry or organic matter) digestibility. The dataset confirms a shift in fermentation strategy towards microbial production in cattle. While this has been suggested for ruminants in general, cattle appear particularly far on an evolutionary trajectory of maximizing microbial yield from the forestomach. The application of more specific digestive physiology data (like endogenous losses) gained from sheep to cattle should be done bearing these differences in mind.

The effect of thermomechanical aging on the retention of a conometric system in a chewing simulator.

To evaluate the retention force of a novel conometric system after thermomechanical aging. In addition, the conometric system's retention force was compared with that of the cemented implant-retained crowns. Two systems to retain implant crowns were tested in this study: a conometric system and a cement-retained system. Forty-eight zirconia crowns were fabricated using computer-aided design and computer-aided manufacturing technology. Twenty-four zirconia crowns were cemented onto conometric caps with resin-modified glass ionomer cement, which were then connected with abutments. These specimens were divided into three groups, and each group was subjected to the pull-out test. A-control group: 12 specimens directly subjected to pull-out test; A-aged group: 12 specimens subjected to thermomechanical aging followed by pull-out test; A-repeat group: After the pull-out, the specimens in the aging group (A-aged) were reconnected, and the pull-out test was repeated once more. The remaining 24 zirconia crowns were cemented on standard abutments with zinc phosphate cement, and two groups were formed. C-control group: 12 specimens directly subjected to the pull-out test; C-aged group: 12 specimens subjected to thermomechanical aging followed by pull-out. Scanning electron microscope (SEM) was used to evaluate the surfaces of caps and abutments. To analyze the data, repeated measures, one-way ANOVA, and Bonferroni tests were used (p<0.05). The mean retention force value of the A-control group was 148.22±16.37N. The highest mean retention force value was measured in the A-aged group (204.93±51.67N), and the lowest mean retention force value was seen in the A-repeated group (77.02±21.48N). Thermomechanical aging had a significant influence (p<0.05) on both systems. No significant differences in retention force were found between the thermomechanical aged groups of both systems (p>0.05). SEM analysis revealed that aging had an impact on the surface of the conometric system's caps and abutments. The retention force of the conometric system increased significantly following thermomechanical aging. No crown separation occurred during the thermomechanical aging of the conometric system. There was no significant difference in the retention of the conometric and cemented systems after thermomechanical aging.

A Simple Stability-Indicating UPLC Method for the Concurrent Assessment of Paracetamol and Caffeine in Pharmaceutical Formulations

A fixed-dose combination of paracetamol (PCM) and caffeine (CAF) tablets/capsules is the most frequently used over-the-counter medicine for fever and headache. In this paper, a simple, reliable, sensitive, rapid, and stability-indicating ultra-performance liquid chromatography (UPLC) analytical method was proposed for simultaneously assessing PCM and CAF in pharmaceutical formulations. The UPLC method was developed on an Acquity UPLC® CSHTM C18 column, and the column oven temperature was maintained at 35 ± 5 °C with isocratic elution by using a solution of methanol and water (30:70, v/v). The maximum absorbance of PCM and CAF was observed at 272.5 nm. The flow rate was 0.2 mL/min, and the injection volume was 1 µL, with the total run time of 2 min for the separation of PCM and CAF. The proposed UPLC method was validated according to the ICH guidelines, and it demonstrated excellent linearity, with correlation coefficients of 0.9995 and 0.9999 over the concentration ranges of 40–400 and 7–70 ng/mL for PCM and CAF, respectively. The mean retention times of 0.82 ± 0.0 and 1.16 ± 0.02 were observed for PCM and CAF, respectively. The limits of detection and quantification were 16.62 and 3.86 for PCM, respectively, and 50.37 and 11.70 for CAF, respectively. PCM and CAF were subjected to acidic, alkali, oxidative, phytochemical, dry-heat, and wet-heat degradation. The method was found to well separate the analytes’ peaks from degradation peaks, with no alterations in retention times. The proposed method is linear, precise, accurate, specific, and robust, and it can indicate stability and be used for the quantitative assessment of pharmaceutical formulations comprising PCM and CAF within a short period of time.

DIGESTIVE AND FEEDING BEHAVIOR DIFFERENCES BETWEEN LAPPET-FACED VULTURES (TORGOS TRACHELIOTOS) AND GRIFFON VULTURES (GYPS FULVUS) EX SITU.

Appropriate diets for ex situ wildlife are essential for animal health and welfare and yet ex situ facilities are often constrained by feed ingredient availability when attempting to replicate natural diets. In obligate carnivores such as vultures, digestive strategies are likely to have evolved alongside feeding behaviors, which may differ between even sympatric species. To begin to understand the digestive strategies of two Old World vulture species (lappet-faced vulture Torgos tracheliotos, n = 3, and griffon vulture Gyps fulvus, n = 4) of similar body size but divergent feeding habits, their feeding and digestion strategies on a diet of whole rats were compared. The food intake, color of excreta, excreta consistency, and carbon and nitrogen excretion were measured. Mean retention time of the digesta was analyzed using titanium dioxide as an inert marker in a diet of chicken carcass. Lappet-faced vultures consumed significantly greater quantities of food than griffon vultures and were less selective. Lappet-faced vultures primarily produced brown excreta while griffon vultures primarily produced green excreta, with much higher carbon and nitrogen concentrations. The consistency of excreta and the mean retention time did not differ between the species but may have been too variable to detect differences. A strong positive correlation was found between food intake per metabolic weight and the proportion of brown excreta, and both were negatively correlated with green excreta, as well as excreta concentrations of nitrogen and carbon. These findings align with their reported feeding ecology, with lappet-faced vultures showing adaptations to less-digestible carcass material compared with griffon vultures. Despite their similar size and overlapping natural habitat, these results suggest a need for differentiated feed provisioning for these species when under human care.

Insoluble fibers affect digesta transit behavior in the upper gastrointestinal tract of growing pigs, regardless of particle size.

Physicochemical characteristics of dietary fibers may modulate digesta transit behavior. The present study was conducted to clarify the effect of level and particle size (PS) of insoluble fibers on digesta mean retention time (MRT) in the proximal gastrointestinal tract (mouth-ileocecal junction). Six ileal-cannulated pigs (26.8 ± 2.08 kg) were assigned to 3 dietary treatments in a 3 × 3 replicated Latin-square design. Finely ground (1 mm screen) or coarse (intact) oat husks (OH) and soybean hulls (SBH) were added (50:50, w/w) to a maize-whey protein-wheat-based diet at 50 (low) or 250 g/kg (high) inclusion levels to obtain a low-fine fiber (LF), high-fine fiber (HF), and high-coarse fiber (HC) diet. Markers to follow liquids (Co-EDTA), fine solids (Y3O2), or fibrous particles (Yb-mordanted OH and Cr-mordanted SBH) were given as a single pulse dose and marker concentrations were subsequently measured hourly in digesta for 13 h after administration. Mean retention time values were obtained from the concentration of markers in digesta observed over time by fitting a generalized Michaelis-Menten equation and calculating the time of peak. Fiber addition and fiber particle size neither affected the MRT of liquid nor solid digesta phases (P = 0.903). Segregation between solid and liquid digesta phases was observed for all diets (P < 0.0001), although the extent of segregation was greater for LF compared with HF and HC (P = 0.0220). The MRT of SBH particles, but not of OH-particles was longer for coarse vs fine PS (96 min, P < 0.05). In conclusion, digesta MRT was influenced by the dietary concentration but not by PS of insoluble fibers. The addition of insoluble fibers reduces digesta phase segregation from mouth to distal ileum in growing pigs.

Factors Associated with Attrition in a Longitudinal Cohort of Older Adults in the Community.

Retaining participants in longitudinal studies increases their power. We undertook this study in a population-based longitudinal cohort of adults with COPD to determine the factors associated with increased cohort attrition. In the longitudinal population-based Canadian Cohort of Obstructive Lung Disease (CanCOLD) study, 1561 adults > 40 years old were randomly recruited from 9 urban sites. Participants completed in-person visits at 18-month intervals and also were followed up every 3 months over the phone or by email. The cohort retention for the study and the reasons for attrition were analyzed. Hazard ratios and robust standard errors were calculated using Cox regression methods to explore the associations between participants who remained in the study and those who did not. The median follow-up (years) of the study is 9.0 years. The overall mean retention was 77%. Reasons for attrition (23%) were: dropout by participant (39%), loss of contact (27%), investigator-initiated withdrawal (15%), deaths (9%), serious disease (9%), and relocation (2%). Factors independently associated with attrition were lower educational attainment, higher pack-year tobacco consumption, diagnosed cardiovascular disease, and a higher Hospital Anxiety and Depression Scale score: adjusted hazard ratios (95% confidence interval) were 1.43(1.11, 1.85); 1.01(1.00, 1.01); 1.44(1.13, 1.83); 1.06(1.02, 1.10) respectively. Identification and awareness of risk factors for attrition could direct targeted retention strategies in longitudinal studies. Moreover, the identification of patient characteristics associated with study dropout could address any potential bias introduced by differential dropouts.

Impact of Mind-Mapping Instructional Strategy on Secondary School Students’ Achievement and Retention in Biology in Delta State

The study investigated the Impact of mind-mapping instructional strategy on Secondary School Students Achievement and Retention in Biology in Delta State. Two research questions were raised and two hypotheses were formulated to guide the study. The design for the study was pretest, posttest, and delayed test control group quasi-experimental design. The Sample for the study comprised 151 SSII Biology students sampled using simple random sampling technique. Instruments used for data collection were duly validated Biology Achievement Test (BAT). Reliability of BAT was established using Kuder-Richardson formula 21 (KR-21) which yielded a reliability coefficient of 0.81. Obtained data were analyzed using mean, standard deviation, t-test, percentage and ANOVA. The results show that there was a significant difference in the mean achievement and retention between students taught Biology using mind-mapping strategy and lecture method. It was concluded that mind-mapping strategy promotes students’ achievement and retention in Biology more than the lecture method. It was thus, recommended that biology teachers in secondary schools should adopt and integrate the use of mind-mapping strategies in the teaching and learning of Biology in Delta State.

Does High Polarity Mean High Retention on Stationary Phases in Gas Chromatography?

Stationary phase chemistry, polarity, and selectivity have been of ongoing interest since the inception of gas chromatography (GC) in the 1950s. In the early days when most analyses were performed on packed columns, there were hundreds of stationary phase materials available. Today, with modern capillary columns, most GC analyses are performed with a few stationary phases, with a wide array of choices for specialty applications. Stationary phases are often classified using the broad term polarity, with polar stationary phases recommended for separating polar analytes and nonpolar stationary phases recommended for nonpolar analytes. In this installment, we examine the idea of stationary phase polarity. We examine the assumptions inherent in the most popular stationary phase polarity evaluating systems—McReynolds constants and the polarity scale. We see that high polarity does not always mean greater retention or higher selectivity.

Jigsaw: A step toward co-operative learning among medical and nursing students

Background and Aim: To shift the paradigm from passive tutor driven tutorials to more responsible active learning by the students, a co operative teaching learning method could be a good alternative. The Jigsaw approach, a model of co operative learning, focuses on learning in groups with fellow learner co operation and reassures team work. Thus, this study was aimed at assessing the effectiveness of jigsaw strategy in comparison to tutorials in enhancing cognitive skills among the medical students in microbiology. Materials and Methods: A cross sectional study was carried out at microbiology department for 50 consenting MBBS students of professional year II and 50 consenting B.Sc nursing students of 2nd years. Students were randomly divided into two batches: Aand B of 25 students each. They were prepared for either a jigsaw (Experimental) or tutorial (Control) a week prior on predecided topics. The same groups were crossed over for another topic. Students’ performance was assessed by pretest, posttest, academic achievement level, and retention test by prevalidated multiple choice questionnaires. The student perception on TL methods was evaluated by using learning experience questionnaires. Results: Posttest scores of both groups were found to be significant at the level of P < 0.05. Among medical students, mean of posttest scores in the jigsaw is more than tutorial (12.4 v/s 9.7, crossover 13.3 v/s 11.2) and in nursing students (11.7 v/s 8.2, crossover 11.6 v/s 9.9). Mean retention tests scores and absolute achievement level were high in jigsaw groups. The students preferred jigsaw over the tutorial. Conclusion: Jigsaw strategy is a robust instructional tool, well perceived by the students to enhance cognitive skills as inferred by the results and can be tailored to the needs of varied topics across different disciplines.