Mean Retention Research Articles

The Effect of Post Dam and Border Replacement by a Flexible Acrylic on Denture Retention

Purpose: to study the effect of using thermo-elastic acrylic resin borders and post-dam on retention of conventional heat cured acrylic resin. Material and Methods: Fifteen completely edentulous patients were selected from the out-patient Clinic of the Removable Prosthodontics Department; Faculty of Oral and Dental Medicine for Girls, Al- Azhar University. On the day of the delivery each patient received maxillary and mandibular complete dentures made of conventional heat cured acrylic resin (Heat cured acrylic resin, Vertex-B. V, Netherlands). A duplicate cast was made for the maxillary complete denture. 15 patients were divided into 3 groups, 5 patients each. The first group wore the conventional heat cured acrylic complete dentures unchanged all the time, for the second group 2-3mm of the entire maxillary denture borders were removed and replaced with the flexible denture base material (Versacryl), without replacing the post dam area, while for the third group only the post dam area was replaced by the flexible denture base material (Versacryl). Results: Pair-wise comparisons between the groups revealed that borders group showed the statistically significant highest mean retention value. Conclusion: Thermo-elastic heat cured acrylic resin (Versacryl) modified dentures exhibit more retention than that of the conventional heat cured acrylic denture.

Upflow Filtration System Using Fiber-Ball Filter Media for the Treatment of Nonpoint Pollution

Objectives : The objective of this study is to investigate the performance of the fiber-ball media upflow filtration system for non-point pollutants treatment.Methods : The additional air backwashing nozzle were installed between upper and lower fliter media cartridge. The effect of feed SS concentration, surface overflow rate, retention time, head loss on the removal efficiency were investigated respectively. Particle size distribution, SEM, and backwashing effect were also analyzed.Results and Discussion : The operated of upflow filter mean retention time, mean head loss were 1.99 min, 7.2 cm. On condition of SOR 480 m<sup>3</sup>/m<sup>2</sup>/day, results indicate that the range of removal efficiency of turbidity and SS were 76.8 ~ 93.21% (mean 88.3%) and 85.4 ~ 97.9% (mean 92.7%), respectively. The effluent turbidity and SS were under 15 NTU, 20 mg/L, respectively.Conclusions : Since turbidity can be continuously monitored in a filtration non-point pollution treatment system, turbidity can be used as a operation factor in evaluating operating conditions. The particle size the effluent larger than the influent was due to bonding, collision and adsorption between particles in the pores of the filter media. SEM analysis showed that after backwashing, very fine particles in the filter medium were not removed but adhered to the fiber yarn and remained. The average recovery rate of fiber-ball media filtration was 88.7%, which is evaluated as excellent in backwashing.

Nutrient mass balance of a large riverine reservoir in the context of water residence time variability.

The excessive input of nitrogen (N) and phosphorus (P) from anthropogenic activities is the main reason behind the cultural eutrophication and algal blooms in freshwater ecosystems. Here, I present a comprehensive budget of N, P for a large reservoir (Lake Diefenbaker) within a highly cultivated watershed. I constructed a 4-year nutrient budget from 2011 to 2014, using grab samples and daily flow data, and a multi-decadal (1978 through 2014) budgeting to examine the effect of inter-annual variability of water residence time on retention of N and P, and if retention of N and P is affected differently. The 4-year budget showed that the reservoir was a net source of total nitrogen (TN) during 2011 and 2014, but a net sink during 2012 and 2013. This resulted in retention coefficients of - 35% and - 4% in 2011 and 2014, respectively. With respect to the total phosphorus (TP) budget, the reservoir acted as a net sink in all 4 years, with a mean retention coefficient of 87%. Consistent with findings of the 4-year budget, the results of the multi-decadal budgeting showed that the reservoir was a net sink for TP during the period of record with a mean retention of 81% (1583 t/year). Regarding TN, the mean retention was lower (49%, 4836 t/year) and more variable relative to TP over the long term. Unlike TP, the results showed that the retention of TN has been decreasing noticeably since 1978. Overall, the retention of TP in this lake is primarily controlled by in-lake sedimentation and most likely does not change substantially in response to inter-annual variation of hydraulic variables such as water residence time. For TN, the role of sedimentation could be minor in retention process in this reservoir (or similar reservoirs elsewhere), but in-lake biological processes could play a more important role. These findings are useful for understanding the role of larger reservoirs with water residence time of 1-3 years in nutrient retention and how changes in flow and water residence time due to climate variability and water management can influence the nutrient retention efficiency.

Adaptation and withdrawal of feeding dried Aspergillus oryzae fermentation product to dairy cattle and goats on in vitro NDF digestibility of selected forage sources.

Nutritional fermentation aids [dried Aspergillus oryzae fermentation product (AO)] are used in livestock production to increase nutrient digestion and production efficiency. The objective was to determine AO impact on neutral detergent fiber (NDF) degradation of selected forage sources (FS). A series of in vitro fermentation experiments were conducted using rumen fluid (RF) from rumen fistulated dairy heifers or dairy goats evaluating AO at 0.0, 0.3, or 0.6 g/L inclusion rates. In experiment I, the optimum AO concentration using alfalfa hay (AH), Bermuda grass (BG) hay, and peanut skins (PS) was determined via 48-h in vitro neutral detergent fiber digestion (IVNDFd). In experiment II, 0.0 g/L and 0.3 g/L AO were used to determine in vitro dry matter digestion (IVDMD), in vitro organic matter digestion (IVOMD), IVNDFd, and NDF digestion kinetics. In experiment III, in vivo AO ruminal adaptation (AD) and withdrawal (WD) times were determined for both dairy heifers and goats on IVDMD, IVOMD, IVNDFd, and NDF digestion kinetics. In experiment I, IVNDFd was similar using RF from dairy heifers or goats with IVNDFd being increased 10%, 28%, and 23% for AH, BG, and PS, respectively, at 0.3 g/L of AO compared with 0.0 g/L AO, while adding 0.6 g/L AO reduced IVNDFd among all FS. In experiment II, IVNDFd was greater when adding 0.0 g/L AO compared with 0.3 g/L AO using dairy goat RF (26.7% and 37.6%, respectively) among all FS. The mean retention time and 50% digestion times were greater, while digestion rate was lower for PS compared to AH and BG. In vitro dry matter (DM) and organic matter (OM) digestibilities were greater with AO for AH and BG compared to PS but varied with RF donor source. In experiment III, in vitro DM digestibility increased then decreased with adaptation time, while AO withdrawal increased digestion of DM, OM, and NDF. The NDF digestion kinetics were similar across all FS (AH, BG, and PS), which resulted in no clear determination of AO adaptation and withdrawal times needed for AO efficacy. The optimal AO inclusion rate was determined to be 0.3 g/L for improving in vitro NDF digestion, but subsequent experiments could not confirm that inclusion rate. Inclusion rates greater than 0.3 g/L depressed NDF degradation, which should be avoided due to depression of NDF digestion. Sourcing ruminal fluid from dairy heifers or goats for conducting in vitro fermentations resulted in similar DM, OM, and NDF digestion and NDF degradation kinetics.

Spatial patterns of weed dispersal by wintering gulls within and beyond an agricultural landscape

Abstract Non‐frugivorous waterbirds disperse a wide variety of plants by endozoochory, providing longer‐dispersal distances than other mechanisms. Many waterbirds visit both agricultural and natural landscapes during their daily movements, but potential bird‐mediated dispersal of weed plants within and from agricultural landscapes to other habitats is commonly overlooked. Gulls (Laridae) are expanding in numbers and increasingly exploiting anthropogenic habitats worldwide, with possible growing implications for the spread of weeds. Yet, to date, there are no studies on the spatial distribution of weed dispersal by waterbirds. We developed a plant dispersal model based on movements of 19 Larus fuscus using ricefields, via GPS telemetry. We combined daily movements with two curves estimating the retention times of plant seeds in their guts: (a) an experimental curve based on retention time in captivity for four weeds with dry fruits known to be dispersed by gulls: Juncus bufonius, Cyperus difformis, Polypogon monspeliensis and the alien Amaranthus retroflexus; (b) a theoretical curve based on the interspecific scaling relationship between body mass and mean retention time. Median dispersal distances of weed plant seeds by gulls ranged between 690 and 940 m, but maximum distances exceeded 150 km. The theoretical retention time model showed higher median dispersal distances than the experimental retention time model. Spatial patterns of weed deposition were very similar between retention time methods, and most strongly depended on gull movements. Variation between individual gulls had little influence on seed shadows. About 92% of all seeds (>10,000 intact seeds per day) were dispersed within the ricefield area of 370 km2. The remaining 8% of seeds were deposited beyond ricefields into other habitats, 42% of which reached moist environments (other irrigated agriculture, rivers and natural wetlands) presumably suitable for weed establishment. Synthesis. Gulls can disperse weed plants over long distances across a mosaic of habitats. This implies exchange of weed plant species between human‐dominated and natural areas by waterbirds as dispersal vectors. This spatial study highlights the importance of non‐frugivorous birds for long‐distance plant dispersal, which is generally an overlooked mechanism in studies aiming to predict and manage expansion of weed plants.

Isolated pectin (apple) and fruit pulp (mango) impact gastric emptying, passage rate and short chain fatty acid (SCFA) production differently along the pig gastrointestinal tract

Addition of fibre hydrocolloids to diets is expected to result in altered rates of digesta passage due to structuring effects, and the localised production of short chain fatty acids (SCFA) as fermentation products. However, it is not known whether these effects are similar for extracted and intrinsic plant cell wall fibre types. The purpose of this study was to determine the effect of isolated (apple) pectin and fruit (mango) pulp on gastric emptying (GE), passage rate, and SCFA production along the porcine gastrointestinal (GI) tract. Thirty pigs were fed a starch-based diet with or without addition of either pectin or mango pulp over a 21-day intervention trial. Indigestible solid phase constant markers as well as solid and liquid phase pulse markers (fed 2, 4 or 6 h prior to sampling) were fed to measure apparent mean retention time (aMRT) and GE, respectively. The GI tract was divided into nine sections and analysed for digesta contents, marker recovery and SCFA production. The control diet showed significantly faster GE of the liquid digesta phase compared to solid phase, while the addition of pectin significantly delayed GE of the solid phase. The addition of pectin and mango pulp each increased digesta water content, and the pectin diet significantly decreased aMRT along the small intestine. SCFA content was increased significantly in both isolated pectin and mango pulp diets, particularly in the caecum and large intestine, with the isolated pectin diet favouring butyrate production and the mango pulp diet favouring propionate production.

Training non-intensivist doctors to work with COVID-19 patients in intensive care units.

BackgroundDue to an expected surge of COVID‐19 patients in need of mechanical ventilation, the intensive care capacity was doubled at Rigshospitalet, Copenhagen, in March 2020. This resulted in an urgent need for doctors with competence in working with critically ill COVID‐19 patients. A training course and a theoretical test for non‐intensivist doctors were developed. The aims of this study were to gather validity evidence for the theoretical test and explore the effects of the course.MethodsThe 1‐day course was comprised of theoretical sessions and hands‐on training in ventilator use, hemodynamic monitoring, vascular access, and use of personal protective equipment. Validity evidence was gathered for the test by comparing answers from novices and experts in intensive care. Doctors who participated in the course completed the test before (pretest), after (posttest), and again within 8 weeks following the course (retention test).ResultsFifty‐four non‐intensivist doctors from 15 different specialties with a wide range in clinical experience level completed the course. The test consisted of 23 questions and demonstrated a credible pass–fail standard at 16 points. Mean pretest score was 11.9 (SD 3.0), mean posttest score 20.6 (1.8), and mean retention test score 17.4 (2.2). All doctors passed the posttest.ConclusionNon‐intensivist doctors, irrespective of experience level, can acquire relevant knowledge for working in the ICU through a focused 1‐day evidence‐based course. This knowledge was largely retained as shown by a multiple‐choice test supported by validity evidence. The test is available in appendix and online.

The effect of lizards on the dispersal and germination of Capparis spinosa (Capparaceae).

Seed dispersal is a key component of the interactions between plants and animals. There is little research on the effects of lizard seed dispersal, which is more common on islands than elsewhere. In this study, the effects of the passage of Capparis spinosa seeds through Teratoscincus roborowskii lizard digestive tracts on the seed coats, water uptake rates and germination rates were investigated. In addition, the spatial patterns of fecal deposition by lizards in various microhabitats were assessed. Our results showed that the mean retention time (MRT) of mealworms was significantly longer than that of C. spinosa seeds in both adult and juvenile lizards. The defecation rate of C. spinosa tended to be lower than that of mealworms, which might be beneficial for seed dispersal. It was determined that the longer MRT of C. spinosa seeds enhanced the permeability of the seed coats, which promoted fast water uptake, broke seed dormancy and increased the seed germination rate. Furthermore, the seeds that passed through the digestive tracts of lizards were deposited in favorable germination microhabitats. By enhancing seed germination and depositing intact and viable seeds in safe potential recruitment sites, the lizard T. roborowskii acts, at least qualitatively, as an effective disperser of C. spinosa.

Pharmacokinetics of a New Analgesic on the Basis of Hexaazaisowurtzitane Derivative.

We studied pharmacokinetics of a new analgesic based on a hexaazaisowurtzitane derivative (thiowurtzine, TWZ). A method for measuring TWZ in organs and tissues by HPLC/MS/MS was developed and validated. The sensitivity of the method under conditions of intragastric administration of TWZ to rats in a dose of 100 mg/kg is 0.5 ng/ml (calibration curve 0.5-400 ng/ml). The concentrations of the substance (Cmax) in the plasma, organs, and tissues of animals were 20-100 ng/ml, the time to reach the maximum concentration after a single dose (Tmax) was 2 h. The mean retention time of the substance in the body ranged from 5.67 to 17.15 h after administration. The highest concentrations were found in excretory organs (liver and kidneys), the substance also actively penetrated into muscle tissue. The medium concentrations were found in the brain and adipose tissue. The tropism to the heart tissues was minimal.

Improving Breviscapine Oral Bioavailability by Preparing Nanosuspensions, Liposomes and Phospholipid Complexes.

Breviscapine (BVP), a flavonoid compound, is widely used in the treatment of cardiovascular and cerebrovascular diseases; however, the low oral bioavailability and short half-life properties limit its application. The aim of this study was to investigate the three preparations for improving its oral bioavailability: nanosuspensions (BVP-NS), liposomes (BVP-LP) and phospholipid complexes (BVP-PLC). In vitro and in vivo results suggested that these three could all significantly improved the cumulative released amount and oral bioavailability compared with physical mixture, in which BVP-PLC was the most optimal preparation with the relative bioavailability and mean retention time of 10.79 ± 0.25 (p < 0.01) and 471.32% (p < 0.01), respectively. Furthermore, the influence of drug-lipid ratios on the in vitro release and pharmacokinetic behavior of BVP-PLC was also studied and the results showed that 1:2 drug-lipid ratio was the most satisfactory one attributed to the moderate-intensity interaction between drug and phospholipid which could balance the drug loading and drug release very well.

Formulation and optimization of gastroretentive bilayer tablets of calcium carbonate using D-optimal mixture design

Abstract Gastroretentive bilayer tablets of calcium carbonate (CC) were developed using D-optimal mixture design. The effect of formulation factors such as levels of HPMC K100 M (X1), sodium bicarbonate (X2), and HPMC E15 LV (X3) on responses like floating lag time (R1) and release of CC at 1 h (R2) and 6 h (R3) was elucidated. The optimized formulations developed by numerical optimization technique were found to have short floating lag time (2.85 ± 0.98 min), minimum burst release (27.02 ± 1.18%), and controlled yet near complete release (88.98 ± 2.75%) at 6 h. In vivo radiographic studies in rabbits indicated that optimized batch displayed a mean gastric retention time (GRT) of 5.5 ± 1 h which was significantly prolonged (P &lt; 0.05) compared to the conventional tablets that displayed a GRT of less than 1 h. The studies proved that the gastroretentive tablets can be a promising platform to improve bioavailability of nutrients having absorption window in upper gastrointestinal tract.

Fostering Students’ Retention in Photosynthesis Using Concept Mapping and Cooperative Mastery Learning Instructional Strategies

&lt;p style="text-align: justify;"&gt;The performance in biology at the secondary level has not been as good as expected. This has been a matter of concern. Thus, there has been a continuous focus on exploring newer innovative learner-centered and friendly instructional strategies to enhance understanding and retention in biology. This study, therefore, determined the effects of Concept Mapping (CM) and Cooperative Mastery Learning (CML) on fostering retention in photosynthesis among secondary schools in Nyamagabe district, Rwanda. A pre-test and post-test non-equivalent control group quasi-experimental design was used. Data were obtained from 151 students taught with CM, 144 students taught with CML, and 154 students taught with Conventional Teaching Methods (CTM). The Photosynthesis Retention Test (KR-21= 0.82) was used for data collection. The data were mainly analyze d using mean and Analysis of Covariance (ANCOVA). The results showed that the CM and CML treatment groups outperformed the CTM group in retention in photosynthesis. There was a statistically significant difference in favor of the CM between the two experimental groups. The male and female students taught using CM retained equally in photosynthesis while gender difference was revealed in the mean retention scores of the students exposed to the CML, with females retained significantly higher than males. The study concluded that the CM and CML strategies were more effective than CTM. It was suggested, among other things, that teachers should be encouraged to apply CM and CML strategies when teaching biology.&lt;/p&gt;

Effect of Multiple Intelligences Instructional Strategy on Achievement and Retention in Mole Concept Among Chemistry Students in Abuja, Nigeria

This study examined the Effect of Multiple Intelligences Instructional Strategy (MIIS) on Achievement and Retention in Mole Concept among Chemistry Students in Abuja, Nigeria. Quasi experimental, pre-test, post-test, and post post-test control group design was adopted for this study. Two research questions guided the study and two hypotheses were tested at 0.05 level of significance. The population of the study was senior secondary school chemistry students in Abuja, Nigeria. The sample for the study was two co-educational schools. One served as the experimental group and the other served as the control group. Mole Concept Achievement Test (MCAT) (KR-21 = 0.70) was used for data collection. Descriptive statistics of mean and standard deviation was used to answer the research question, while null hypotheses were tested using ANCOVA at 0.05 level of significance. The result of the study reveals that, there was significant difference between the mean achievement scores of students taught the mole concept using multiple intelligences instructional strategy (MIIS) and those taught using lecture method. There was a significant difference between the mean retention scores of chemistry students taught the mole concept using MIIS and conventional method. Based on the findings of this study, the following recommendations have been made; there is a need for curriculum developers to develop appropriate curriculum that will make provision for the teacher to adopt various activities that will appeal to each students’ learning style or intelligence to enable them learn effectively

Comparison of gastrointestinal transit times in stabled Thoroughbred horses fed freshly cut pasture and three conserved forage-based diets

Context The type of forage offered to horses varies in physical form, moisture content and nutrient quality, and these variables could affect the intake, passage rate and digestibility of the forage consumed. Aims To investigate the changes in passage rate of digesta through the gastrointestinal tract in horses fed four different forage-based diets (diet effect). Methods Thoroughbred mares (n = 6) were stabled in loose boxes for 6 weeks. During Weeks 1, 3 and 5 (washout periods), all horses were fed freshly cut pasture, either in restricted quantities (Week 1) or ad libitum (Weeks 3 and 5). Using a 3 × 3 Latin square design during Weeks 2, 4 and 6, each pair of horses was abruptly transitioned to one of three conserved forage-based diets (chopped ensiled forage fed exclusively or with oats, or perennial ryegrass hay with oats) fed ad libitum. At the beginning of each week, indigestible polyethylene markers (n = 200) were administered to the horses via a nasogastric tube, followed immediately by transition to the new diet. Key results There was a significant diet effect on the daily dry-matter intake of feed (P &lt; 0.0001), percentage of time spent eating (P &lt; 0.001), frequency of voiding faeces (P &lt; 0.05) and quantity of faeces voided (P &lt; 0.0001). There was a significant horse effect on the daily dry-matter intake of feed (P &lt; 0.0001) and quantity of faeces voided (P &lt; 0.0001), but no differences in the percentage of time spent eating or the frequency of voiding faeces. There were significant diet and horse effects on the time to recovery of the first marker in the faeces (P &lt; 0.01 and P &lt; 0.01 respectively) and the mean retention time of markers in the gastrointestinal tract (P &lt; 0.05 and P &lt; 0.001 respectively). Mean retention time was negatively correlated with feed intake and quantity of faeces voided (r2 = –0.51 and r2 = –0.64 respectively). Conclusions Longer mean retention time was associated with a greater fibre content in the diet and a restricted feed supply, thus supporting the hypothesis that horses alter mean retention time on the basis of a nutrient absorption optimisation model. Implications Feed composition, but also the quantities offered, may alter measurement of apparent feed digestibility in horses.

O-Ring Attachments on One-Piece Mini Dental Implants: In Vitro Analysis of Retention Force Reproducibility Using Different Pristine Matrix-O-Ring Combinations

To analyze the influence of pristine matrix and O-ring dimensions on retention force and reproducibility in single one-piece mini dental implants (MDIs) with ball patrices under in vitro conditions. Three different matrix and O-ring combinations (MH1-MH3) were evaluated (n = 50 per group) on 1.8-mm-diameter implants. The matrices were manually mounted on the implants and were subsequently removed in a vertical linear manner using a metal pin with two strain gauges, recording the maximum force during disconnection. After five disconnections, the O-rings were exchanged, and the mean retention force was calculated, resulting in 50 values for each matrix and O-ring combination. Mean retention forces, SDs, and 95% CI were calculated. Analysis of variance was used to test the global differences, and post hoc pairwise comparisons were subsequently applied. The level of significance was set to P < .05. ANOVA (global P < .0001) and pairwise comparisons (all P < .0001) demonstrated statistically significant differences among the three different matrix and O-ring combinations, with mean values of 5.18 N (MH 1), 6.73 (MH 2), and 9.08 (MH 3). Within each combination, retention force variations of > 1 N could not be demonstrated; ie, by exchanging O-rings, a similar retention force can be reestablished. Matrix and O-ring dimensions have a significant influence on retention forces in one-piece MDIs. Pristine O-rings demonstrated highly reproducible initial retention forces in all matrices.

Residue depletion and histopathological alterations in gilthead sea bream (Sparus aurata) after oral administration of oxytetracycline

ABSTRACT Aquaculture is a key component of the animal food industry, but intensive farming conditions increase the incidence of infectious diseases. Oxytetracycline (OTC) plays a major role for infectious diseases in fishes. Its MRLs include their 4-epimers, so in this trial, the depletion of residues of OTC and 4-epioxytetracycline in muscle and liver have been evaluated in gilthead sea bream (Sparus aurata) after oral administration. Hepatotoxicity has been investigated with histopathological effects on target tissues. A validated DAD-HPLC with SPE extraction has been applied. Residual levels in muscle and liver depleted with a similar k el, but mean retention time and t ½ß resulted longer in muscle than in liver because of different vascularization. The OTC concentrations were below the LMR at 48 h after dosing. No analytical peaks ascribable to 4-epi-OTC or other derivatives were detected, while histopathology of liver showed degenerated parenchymal hepatocytes, nuclear pyknosis, focal necrosis and inflammatory leucocytes infiltration. It can be concluded that the assessment of pharmacokinetic and residual depletion of antibiotics result fundamental to determine the most suitable therapeutic regime and to minimize the toxic effects in fish species.

Comparative study for the effect of two different types of attachment on supporting structures in implant retained mandibular complete overdenture

Objective: To compare between implant retained overdenture with two different attachments (Magnet and locator) by measuring the following: Retention. Bone changes by radiographic evaluation. Subjects and Methods: Eight completely edentulous patients were selected from the Outpatient Clinic of the Prosthodontic Department; Faculty of Dental medicine, Al Azhar University and classified into two equal groups. Each patient in two groups received two implants placed in the mandibular canine-premolar region bilaterally. Group (1): four patients received two implants with using locator attachments. Group (2): four patients received two implants with using magnet attachments. Results: Results revealed that, there was no statistically significant difference in bone loss between locator and magnet during the follow up period, and there were no statistically significant mean retention values in the two groups at base line and after 3 months. But 6 months; Magnet attachment showed statistically significantly lower mean retention values than Locator attachment. By time there was a statistically significant decrease in mean retention values of magnet rather than locator attachment. Conclusion: The use of locator and magnet attachments with two implant supported mandibular overdentures leads the same amount of bone resorption around the implants. At the beginning the two attachment have the same retention quality by time magnet attachment loss some of its retention rather than locator attachment due to poor corrosive resistance of magnets within oral fluid requires encapsulation within a new hybrid material. Keywords: Dental Implants, Overdenture, Attachment, Retention

Biological and mechanical effect of different types of attachments on supporting structures in implant retained mandibular overdenture a Randomized clinical study

Objective: To compare between implant retained overdenture with two different attachments by measuring : Retention. Bone changes by radiographic evaluation. Subjects and Methods: Eight completely edentulous patients were selected from the Outpatient Clinic of the Prosthodontic Department; Faculty of Dental medicine, Al Azhar University and classified into two equal groups. Each patient in two groups received two implants placed in the mandibular canine-premolar region bilaterally. Group (1): four patients received two implants using equator attachments. Group (2): four patients received two implants with using magnet attachments. and the study was randomized controlled trial with Calculated samples. type of randomization in that study was Block randomization and The out comes was assessor blinded as the investigators didn’t know the type of the attachment before measuring retention or amount bone resorption Results: Results revealed that, there was no statistically significant difference in bone loss between equator and magnet during the follow up period, and there were no statistically significant mean retention values in the two groups at base line and after 3 months. But 6 months; Magnet attachment showed statistically significantly lower mean retention values than Equator attachment. By time there was a statistically significant decrease in mean retention values of magnet rather than locator attachment. Conclusion: The use of equator and magnet attachments with two implant supported mandibular overdentures leads the same effect on crestal bone resorption. At the beginning the two attachment have the same retention quality by time magnet attachment loss some of its retention rather than locator attachment

Methodical considerations when estimating nutrient digestibility in horses using the mobile bag technique

Total collection of faeces is considered the golden standard for estimating apparent total tract digestibility (ATTD) in horses. However, the evaluation of individual feedstuffs is limited and determination of nutrient digestibility in different segments of the gastrointestinal tract (GIT) is excluded. The rationale for performing this study was that the mobile bag technique (MBT) can provide information on individual feedstuffs' degradation, and the use of fistulated animals does provide additionally information regarding degradation in individual segments of the GIT. Recommendations for using the MBT in ruminants are well established, but limited methodical studies have been published with horses. The objective of this study was to evaluate the MBT by comparing the ATTD with the nutrient disappearance and degradation kinetics of hay in horses. It was hypothesised that DM degradation as estimated by the MBT is equal to the ATTD of the DM. Furthermore, we hypothesised that bag size has no effect on nutrient disappearance but increasing the feed to surface area (FSA) decreases the DM disappearance. Five caecum cannulated horses were fed a hay-only diet (6.7 kg DM/day) with 14 days of adaptation followed by four consecutive days of total faeces collection. Three bag sizes (height × length × side, cm; 1.2 × 10 × 2, 3 × 4 × 2, 1 × 6 × 2) and three FSAs (10.4, 20.8 and 41.7 mg/cm2) were administrated at each meal (3 meals/day) on days 1 and 2 of the collection. Faeces were checked for bags every 6th h, the collection time was noted and the DM disappearance together with the transit time (TT) for each bag type was estimated. Dry matter disappearance from the individual bags was fitted to degradation profiles, and the effective degradability (ED) and degradation (Dt) were determined. The results of the study showed that the ATTD of DM, organic matter (OM), NDF and ADF can be predicted based on their disappearance from the mobile bags, but that ash and CP are overestimated in comparison to the ATTD. The TT for the bags was 29.2 h, and when using a mean retention time of 30 h to predict ED and Dt, it was clear that ED was underestimated, whereas Dt reflected the ATTD of DM. In conclusion, the MBT can be used to estimate the degradability of DM, OM and fibre as these nutrients resemble the ATTD. The bag size did not affect the DM disappearance, but the FSA should be kept below 20 mg/cm2 as higher levels might limit the degradation kinetics.

Gut passage time and viability of seeds consumed by Australian marsupials

Many Australian mammals consume seeds, but their role in seed dispersal has not been well explored. Here, we investigated the mean retention time and the postconsumption germination capacity of Australian seeds (Acacia acuminata, Dodonaea viscosa and Gastrolobium calycinum) likely to be consumed by quenda (Isoodon fusciventer) and woylies (Bettongia penicillata ogilbyi). Mean excretion times were 14h for quenda and 24h for woylies, but some seeds were retained in their digestive passages for up to 39.5 and 55.5h, respectively. Viable seeds of all plant species were retrieved from both species’ scats and only G. calycinum seeds ingested by quenda had a significantly higher germination percentage (62%) than control seeds (34%). Our results show that viable seeds are deposited in the scats of quenda and woylies, indicating that these species may play a role in seed dispersal.