Evaluations Of Course Research Articles

THE IMPACT OF NON-PERFORMING LOANS AND THE BI RATE ON RETURN ON ASSETS

The increase in interest rates also brings changes in the management of funding sources and distribution of funds (credit). Changes in interest rates of course not only affect the profits generated by banks, but also how banks manage the interest income earned and interest paid. This research aims to determine the effect of non-performing loans (NPL) and the Bank Indonesia Interest Rate (BI Rate) on Return on Assets (ROA). The sample used in this research is state-owned banks listed on the Indonesian Stock Exchange (BEI) for the period 2020-2022. The research method used is an associative method with a quantitive approach. The data analysis technique used is multiple linear regression. The research results show that Non Performing Loans (NPL) have a negative and significant influence on Return on Assets (ROA) and the BI Rate has a negative and insignificant influence on Return on Assets (ROA).

Courses that Impact the Terminal Efficiency in the Dentistry Career at the University of Costa Rica (2007-2014)

The main objective of this study was to determine the failure rates of the courses in the curriculum of the Dentistry degree program at the University of Costa Rica for the cohorts from 2007 to 2014. Data from 736 records were used. The variables considered were the following: gender, age at admission, nationality, marital status, children, domicile, previous high school attended, admission exam scores, and approved courses. The data were obtained from the Student Application System, physical records, and the Supreme Electoral Tribunal of Costa Rica. Descriptive, bivariate, and multivariate analyses were performed. Among the students, 98% were Costa Rican, 68% were female, 79% were admitted based on their admission exam scores, 43% were admitted at the age of 18 or younger, 50% came from public schools, 77% resided in the Greater Metropolitan Area, and 95% were single and childless. The majority of study dropouts occurred in the first four cycles of the dentistry degree. The courses with the lowest overall success rate in the curriculum were service courses: General Chemistry, Organic Chemistry, and Elemental Mathematics. Among the core courses, the Pediatric Dentistry and Orthodontics Clinic and the Endodontics Clinic had the highest failure rates. Moreover, there was a statistically significant difference between the approval rates of the physics course and the school of origin. In the Dentistry degree program at University of Costa Rica, the failure rate is high in the first four cycles of the program, which is when service courses are mainly offered. As for the core courses, the Pediatric Dentistry and Orthodontics Clinic and the Endodontics Clinic had the lowest success rates.

Undergraduate Students’ Perceptions of Professors Concerning Academic Rules and Relations: Does Sex Matter?

A common metric in appraising the classroom and educational experience is student ratings of courses and faculty. Our purpose in this study was to investigate whether the ratings of faculty in a co-educational Middle Eastern university concerning observation of university rules and policy, communication with colleagues, and communication with students differ based on sex—both that of the faculty and that of the student furnishing the ratings. Data were collected from 847 undergraduate students at Kashan University, of whom 626 had complete data. Statistically significant, though small, differences were observed for the main effect of student sex (females>males on following rules) and female faculty were rated more highly than male faculty on following rules and relationships with students. No differences by student sex or faculty sex on relationships with colleagues were noted, nor was there an interaction of student sex and faculty sex on the ratings.

A Reflective Comparison Study of Statistics Course Evaluations by Modality

Statistics for teacher evaluations in seated and online classes show a glaring difference in both quantitative and qualitative scores. The generalized analysis of the quantitative and qualitative elements of the same course, instructor, assignment as grouped by learning environment provide an opportunity to inform future practice. In this four-year study at a small, private Midwestern university (n = 316 students over 20 course sections), the seated students were much more engaged and satisfied as demonstrated by their response rates, Likert-scale ratings of course and professor, and associated comments. Reflection and best practices were employed in the online course for continuous improvement, but the numeric values for online evaluations remained consistently and significantly lower in mean value. This study concludes with a series of takeaways for enhancing connections with students and increasing their associated evaluation scores.

Impacts of college-level courses via Asynchronous Learning Networks: Some Preliminary Results

New Jersey Institute of Technology has been delivering college courses via an Asynchronous Learning Network (ALN) system called the Virtual ClassroomTM for a decade, using various media mixes. Currently, two complete undergraduate degree programs are available via a mix of video plus Virtual Classroom, the B.A. in Information Systems and the B.S. in Computer Science. This paper presents preliminary findings about impacts on students, and touches on some issues and potential impacts for faculty, individual universities, and the structure of higher education. Overall ratings of courses by students who complete ALN based courses are equal or superior to those for traditional courses. Dropout or Incomplete outcomes are somewhat more prevalent, while grade distributions for those who complete tend to be similar to those for traditional courses. For both students and faculty, more startup time devoted to solving the "logistics" of ALN delivery seems to be required at the beginning of courses. ALN delivery is not just a "different" way of doing the same thing, however; it is likely to change the nature and structure of higher education.

MOOCRC: A Highly Accurate Resource Recommendation Model for Use in MOOC Environments

With the rapid development of MOOC platforms, the online learning resources are increasing. Because learners differ in terms of cognitive ability and knowledge structure, they cannot rapidly identify learning resources in which they are interested. Traditional collaborative filtering recommendation technologies perform poorly given sparse data and cold starts. Furthermore, the redundant recommended content and the high-dimensional and nonlinear data on online learning users cannot be effectively handled, leading to inefficient resource recommendations. To enhance learner efficiency and enthusiasm, this paper presents a highly accurate resource recommendation model (MOOCRC) based on deep belief networks (DBNs) in MOOC environments. This method deeply mines learner features and course content attribute features and incorporates learner behavior features to build user-course feature vectors as inputs to the deep model. Learner ratings of courses are processed as supervised labels with supervised learning. The MOOCRC model is trained by unsupervised pretraining and supervised feedback fine tuning; moreover, the model is obtained by adjusting the model parameters repeatedly. To verify the effectiveness of the MOOCRC, an experimental analysis is conducted using learner elective data obtained from the starC MOOC platform of Central China Normal University. Real course enrollment data are used to verify the classification accuracy of the MOOCRC. The experimental results show that the MOOCRC has greater recommendation accuracy and converges more quickly than traditional recommendation methods.

The effect of switching to mandatory online course assessments on response rates and course ratings

Increasingly, student assessments of courses are being conducted online as opposed to administered in class. A growing body of research compares response rates and course ratings of courses evaluated online versus on paper. The present study extends this research by comparing student course assessments before and after the University of South Florida made online evaluations mandatory for all courses. This change only directly affected courses taught on-campus, as online courses were already being assessed online. However, we examine the effect of this change on courses taught on-campus and online, because we expect this change in policy to have differential effects. We hypothesise that by making online assessments mandatory for all courses, online assessments went from a novel method of evaluation to the norm; and, therefore, increased response rates for online courses, but had the opposite effect for on-campus courses. We find mixed support for our hypothesis.

The Relationship Between Method of Viewing Lectures, Course Ratings, and Course Timing.

Background:In recent years, medical schools have provided students access to video recordings of course lectures, but few studies have investigated the impact of this on ratings of courses and teachers. This study investigated whether the method of viewing lectures was related to student ratings of the course and its components and whether the method used changed over time.Methods:Preclinical medical students indicated whether ratings of course lectures were based primarily on lecture attendance, video capture, or both. Students were categorized into Lecture, Video, or Both groups based on their responses to this question. The data consisted of 7584 student evaluations collected over 2 years.Results:Students who attended live lectures rated the course and its components higher than students who only viewed the video or used both methods, although these differences were very small. Students increasingly watched lectures exclusively by video over time: in comparison with first-year students, second-year students were more likely to watch lectures exclusively by video; in comparison with students in the first half of the academic year, students in the second half of the academic year were more likely to watch lectures exclusively by video.Conclusions:With the increase in use of lecture video recordings across medical schools, attention must be paid to student attitudes regarding these methods.

What determines students’ perceptions in course evaluation rating in higher education? An econometric exploration

While student evaluation of courses (SEC) in higher education is an intensely researched area, the existing literature has not paid due attention to rigorous econometric analysis of the SEC data. Using the four-year (2010–2013) evaluation results for economics courses on offer at a leading Australian university, this study employed a random effects ordered probit model with Mundlak correction to identify factors influencing student ratings of courses. This represents an innovative application to educational data.Findings show that class-level, course-level, class-size, instructors’ course-specific experience and their linguistic background influence student ratings of courses. Lecturers’ prior teaching experience in a course and their English language background attracted higher rating while second and third-level courses relative to postgraduate classes, 2010 and 2012 student cohorts relative to 2013, and larger classes attracted lower ratings.Implications include specific training for instructors of non-English speaking background (NESB), teaching larger classes, and intermediate and upper undergraduate courses.This study underscores the critical importance of student-specific responses capturing student heterogeneity in preference to class-average data including students’ academic performance, discipline destination, linguistic background, age and indicators of effort-level. It raises survey instrument implications e.g., sub-scales, data on course contents providing intellectual challenges, real world applications, and problem-solving skills.

Team-Based Learning, Faculty Research, and Grant Writing Bring Significant Learning Experiences to an Undergraduate Biochemistry Laboratory Course

This biochemistry laboratory course was designed to provide significant learning experiences to expose students to different ways of succeeding as scientists in academia and foster development and improvement of their potential and competency as the next generation of investigators. To meet these goals, the laboratory course employs three different practices that support an ‘Integrated Course Design’ approach: (1) incorporating basic laboratory techniques with faculty research projects, (2) promoting team-based learning, and (3) developing, de novo, a mini-NIH grant proposal that serves as a capstone project. On course evaluations, students give the biochemistry laboratory course the highest ratings for course and teaching effectiveness, and these ratings are a higher percentage overall compared to similar chemistry laboratory courses offered in the program. Students also state that the practices of the laboratory course went beyond their prior experiences in traditional lab courses. They have reported th...

Analysis of global and hemispheric temperature records and prognosis

Climate changes are connected to long term variations of global and hemispheric temperatures, which are important for the work out of socio-political strategy for the near future. In the paper the annual temperature time series are modeled by linear multiple regression to identify important climate forcings including external climate factors such as atmospheric CO2 content, volcanic emissions, and the total solar irradiation as well as internal factors such as El Niño-Southern oscillation, Pacific decadal oscillation and Atlantic multidecadal oscillation. Adjusted temperatures were determined by removal of all significant influences except CO2. The adjusted temperatures follow a linear dependence toward the logarithm of the CO2 content, and the coefficient of determination is about 0.91. The evolution of the adjusted temperatures suggests that the warming due to CO2 from the beginning of the studied here time interval in 1900 has never stopped and is going on up to now.The global warming rate deduced from the adjusted temperatures since 1980 is about 0.14±0.02°C/decade. The warming rate reported in the IPCC assessment report 4 based on observed global surface temperature set is about 20% higher, due to the warming by the Atlantic multidecadal oscillation additional to the anthropogenic warming.The predicted temperature evolution based on long time changes of CO2 and the Atlantic multidecadal oscillation index shows that the Northern Hemispheric temperatures are modulated by the Atlantic multidecadal oscillation influence and will not change significantly to about 2040, after that they will increase speedily, just like during the last decades of the past century. The temperatures of the Southern Hemisphere will increase almost linearly and don’t show significant periodic changes due to Atlantic multidecadal oscillation. The concrete warming rates of course are strongly depending on the future atmospheric CO2 content.

Mini-Allogeneic Transplantation in Multiple Myeloma: A Single-Center Ten-Year Experience

Allogeneic stem-cell transplantation is a potential curative option in multiple myeloma (MM). Reduced-intensity conditioning regimens (allo-RIC) result in a lower transplant related mortality (TRM) compared to conventional conditioning, despite of a higher relapse rate. Several prospective studies compared single or tandem autologous stem cell transplantation (SCT) with planned tandem autologous-reduced intensity allogeneic SCT, with discordant results in overall and progression-free survival (OS and PFS). Many studies were conducted using a “mini-allo-SCT”, a regimen containing a low-dose total body irradiation (TBI) and Fludarabine (Flu). Moreover, introduction of new drugs (bortezomib, thalidomide or lenalidomide) in the first decade of 2000 changed the biological history of MM.We analyzed the results of ten-year experience with mini-allo-SCT in patients with MM in our institution.Patients, materials and methods: Between June 2000 and December 2010, 21 patients (9 M, 12 F, median age 54 – range 36-66) received a mini-allo-SCT, 17 from an HLA identical sibling donor, 4 from a MUD full-matched. The source of stem cell was the peripheral blood in all patients. All grafts were not manipulated. At the time of diagnosis, Durie-Salmon (DS) stage was I in 5 patients (23.8%), II in 3 patients and III in 13 patients (61.9%). Disease status at the time of transplant was partial response (PR) in 17 patients (81%), 13 of them in first PR, 4 in second or more PR; 4 patients received allo-SCT as salvage therapy in active ore refractory disease. Eleven patients (52.4%) underwent to transplant after one line of treatment, 5 patients after 2 lines, 5 patients after 3 or more lines. Five patients (23.8%) were treated with new drugs. Auto-SCT is included in previous lines. Nine patients received one auto-SCT before the mini-allo-SCT; ten patients (47.6%) underwent transplantation after two auto-SCT. Two patients were allo-grafted frontline. Conditioning regimen was Flu-TBI in all patients. Graft versus Host Disease (GvHD) prophylaxis consisted on cyclosporine and MMF in all.Results: Overall response rate was 76%, 5 PR and 11 complete remission (CR). One patient developed progression next allo-SCT. Four patients died in the first 100 days after allo-SCT, and they are censored for OS and PFS analyses. Of 17 pre-transplant PR, 11 achieved CR (64%), 4 maintained PR, 2 died before response evaluation. Of 4 patients who underwent allo-SCT in active disease, only 1 obtained a PR, whereas the other 3 patients developed progression or were not-valuable. Six patients (28.6%) developed acute GvHD, but no one died for complicated acute GvHD. Eleven patients (52.4%) had chronic GvHD.Follow up range was from 4 to 96 months. The median time was 19 months. The relapse/progression rate in course of follow up was 29%. Two patients progressed after PR (40%), 3 after CR (5.9%). At the time of the last follow-up 8 patients died (47%), 3 of them for progression of MM.Survival analyses: TRM at 1 and 3 years was respectively 24% and 31%. OS at five years was 51%, with a plateau trend after 3 years (Fig. 1). In univariate statistical analysis, early DS stage at diagnosis (I-II), double auto-transplant, development of chronic GvHD have a significant impact (p value <.05) on OS. PFS at 3 years was 39%, at 6 years was near 20% (Fig 1). Early DS stage at diagnosis (I-II), double auto-transplant, and development of chronic GvHD have a significant impact (p value <.05) on PFS. Both in OS than in PFS, the previous treatment with new drugs did not result in statistical significant improvement, but the curves are spaced (Fig. 3 a and b), with a better performance for patients treated with new drugs.Conclusions: Use of allogeneic transplantation in MM is limited because of high TRM. Mini-allo reduces the TRM. We observed 50% of long term survivors. DS stage at diagnosis, double auto-SCT and development of chronic GvHD impact on survival. New drugs demonstrate better trend in OS and PFS, despite the number of patients is too small to obtain a clear conclusion. This finding suggests the execution of further studies in this regard. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

An Eight-year Retrospective Study in “Flipped” Pharmacokinetics Courses

To assess the impact on student performance of increased active learning strategies in a foundational pharmacokinetics course and a clinical pharmacokinetics course over an 8-year period. A foundational pharmacokinetics course with a lecture-with-active-learning (LAL) format was redesigned to a recitation-format (REC) using smaller groups of students (ie, the class divided into thirds) and eventually to a team-based learning (TBL) format. The lecture-based clinical pharmacokinetics course was redesigned to a case-based learning (CBL) format to encourage preclass preparation with class time used for application; this course format underwent minor redesigns over an 8-year period. An analysis of covariance (ANCOVA) was performed on examination scores in the clinical course based on foundational course format changes. End-of-semester student evaluations of the course were used as a secondary measure of impact. The highest grades in the clinical course were associated with the TBL format within the foundational course compared to LAL format (effect size 0.78). The REC format in the foundational course compared to LAL was associated with higher performance in the clinical course (effect size 0.50). Examination performance in the clinical course had a small increase when the foundational course was transitioned from the REC format to the TBL format (effect size 0.27). There was a trend within the foundational course that overall student ratings of the course decreased with enhanced self-directed learning; there was no change in overall ratings of the clinical course. Increasing the amount of active learning within the foundational pharmacokinetics course increases performance in the clinical course but this increase in performance may be associated with decreases in student evaluations of the foundational course.

Influences of silicon on the work hardening behavior and hot deformation behavior of Fe–25 wt%Mn–(Si, Al) TWIP steel

The influence of silicon on mechanical properties and hot deformation behavior of austenitic Fe–25wt%Mn TWIP steel was investigated by means of the comparison research between 25Mn3Al and 25Mn3Si3Al steel. The results show that the 25Mn3Si3Al steel has higher yield strength and higher hardness than that of 25Mn3Al steel because of the solution strengthening caused by Si atoms and possesses higher uniform deformation ability and tensile strength than that of 25Mn3Al steel due to the higher work hardening ability of 25Mn3Si3Al steel. 25Mn3Si3Al steel presents a clear four-stage curve of work hardening rate in course of cold compression. Quite the opposite, the 25Mn3Al steel presents a monotonic decline curve of work hardening rate. The difference of the work hardening behavior between 25Mn3Al and 25Mn3Si3Al steel can be attributed to the decline of stacking fault energy (SFE) caused by the addition of 3wt% Si. The dislocation glide plays an important role in the plastic deformation of 25Mn3Al steel even though the mechanical twinning is still one of the main deformation mechanisms. The 3wt% Si added into the 25Mn3Al steel blocks the dislocation glide and promotes the mechanical twinning, and then the dislocation glide characteristics cannot be observed in cold deformed microstructure of 25Mn3Si3Al steel. The hot compression tests reveal that the hot deformation resistance of the 25Mn3Si3Al steel is significantly higher than that of the 25Mn3Al steel due to the solid solution strengthening of silicon atoms. The hot deformation activation energies Q for the 25Mn3Si3Al and 25Mn3Al steels are determined respectively as 406 and 365kJ/mol using hyperbolic-sine constitutive equation. The dynamic recrystallization (DRX) is the most important softening mechanism for the two steels. Furthermore, the nucleation and growth of DRX grains of Fe–25wt%Mn TWIP steels are clearly retarded by the addition of 3wt% Si, especially at low deformation temperature and high strain rate, and these effects of Si can be gradually weakened as the increasing of temperature and decreasing of strain rate.

Undocumented College Students in the United States: In-State Tuition Not Enough to Ensure Four-Year Degree Completion

Using restricted-access data from one of the largest urban public university systems in the United States—where many undocumented students are eligible for in-state tuition—we review the literature on undocumented college students in the United States and provide a comparison of the performance of undocumented students to that of U.S. citizens and other legal migrants. Overall, undocumented students perform well in the short-term, earning higher grades and higher rates of course and associate degree completion than their U.S. citizen counterparts. But undocumented students are less likely to earn their bachelor's degrees within four years. This finding suggests that, despite their earlier college successes and their access to in-state tuition rates, at some point after enrollment, undocumented students experience higher costs to completing their bachelor's degrees than they had anticipated upon enrollment. We offer a number of policy considerations for university officials and policy makers who aim to help undocumented college students succeed in postsecondary institutions.

Factors That Influence Student Completion of Course and Faculty Evaluations

To determine if there is a relationship between students' grades, gender, age, or ethnicity and their completion of course and/or faculty evaluations. Data were collected and analyzed for relationships among students' gender, age, ethnicity, and course grade on their completion rates of course and faculty evaluations. The grade a student received in a course was not related to completion rates for course or faculty evaluations. Students born in 1987 or earlier were significantly more likely to complete course or faculty evaluations. Significant differences in completion rates were also found based on the course taken and the gender and ethnicity of the students. Several demographic characteristics were identified that correlated with the completion of course and/or faculty evaluations. However, no correlation was found with the grade a student receives in a course and completion of either course or faculty evaluations. In order to improve course and faculty evaluation rates, further analysis of the influence of demographics on completion rates is warranted.

So NOT Amazing! Teach for America Corps Members’ Evaluation of the First Semester of Their Teacher Preparation Program

Background Much of the research related to Teach For America (TFA) is related to the concerns surrounding whether such teachers should assume primary teaching responsibility and whether alternatively certified teachers are effective in the classroom. This research study takes a different approach and moves the conversation into a new domain of evaluating the coursework that TFA teachers undertake to meet state-mandated certification requirements. Based on initial course evaluations at a college of education, TFA students rated their university courses and instructors more critically than did non-TFA students. Purpose of Study The purposes of this study were (1) to explore the aforementioned differences in quality ratings of courses and instructors and (2) to examine what items on the student evaluation instrument could be used to identify salient constructs that are most necessary to meet the needs of TFA students. Setting This research was conducted at a college of education at a Research I university involved with a TFA partnership through which TFA students earn master's and certification while teaching in high-needs schools. Participants Participants in this study were TFA students who were teaching on an alternative teaching certificate, as compared with traditional students who were enrolled in the same methods courses with the same instructors. Both sets of students were enrolled in their first year of their teacher preparation program. Research Design The researchers analyzed the numerical differences between student evaluation scores posted for the same instructors by different groups of students (TFA and traditional students enrolled in the same methods coursework). The researchers also analyzed survey (Likert-type and open-ended) data to evidence and explain differences. Findings/Results (1) TFA students did in fact rate their courses and instructors significantly lower than did their non-TFA peers; (2) TFA students, as practicing teachers in charge of real-time classrooms, were more critical consumers, critical in the sense that they needed—or, more appropriately, felt that they needed—coursework that provided just-in-time knowledge; and (3) TFA students did not feel as if they were treated like master's students. They wanted instructors who modeled practical teaching strategies and did not dumb down course activities, many of which they believed were irrelevant and a waste of time given their immediate needs. Conclusions/Recommendations Issues related to certification coursework are highlighted, and included are specific and immediate course improvement recommendations and a call to reexamine educational policies related to alternative teacher certification.

Perceived Improvements in Service User Involvement in Two Clinical Psychology Training Courses

In line with current developments in mental health training, the doctoral courses in clinical psychology at two UK universities, Canterbury Christ Church and Surrey, have been working together to increase service user and carer involvement. A questionnaire was constructed and sent out at two time-points, one year apart, to examine staff and trainee ratings of service user and carer involvement, the friendliness of the course towards service user and carer experiences, and barriers and opportunities in relation to involvement. Initial validation work on the questionnaire is briefly presented, along with the final questionnaire subscales and items used. There were eight subscales, of which seven had reasonable internal consistency. Response rates from staff and trainee samples on each occasion ranged between 35% and 48%. The number of trainees responding to both surveys was 44, and staff 81. Ratings of service user and carer involvement improved significantly between the two time-points. However, there was no overall change in ratings of courses' friendliness towards service user and carer experiences, or of barriers and opportunities in relation to service user involvement. Trainees rated barriers to involvement lower than did staff at both times. The questionnaire may be useful for other courses in assessing staff and trainee perceptions of service user and carer involvement.

Some Rank-Based Two-Phase Procedures in Sequential Monitoring of Exchange Rate

Financial or economic crisis of 2008 and its severe negative impact on the human race is currently one of the focal themes of financial research. During this crisis period the Indian Rupee (INR) has significantly lost its ground compared to the United States Dollar (USD). In the present paper, we address the issues identifying warning and action points in a time sequential monitoring of the exchange rate records. We developed some approximate power 1 partially sequential nonparametric tests that are based on both usual and sequential ranks. Proposed procedures necessarily help us to capitalize the best features of the two different rank procedures. We use Wilcoxon score and the idea of curved stopping boundaries as in Bandyopadhyay et al. (2008). We vividly present our numerical findings obtained by sequential Monte-Carlo procedures. We aim at controlling the type I error rate in course of structural monitoring.

Inhibition of hydroxyapatite dissolution by whole casein: the effects of pH, protein concentration, calcium, and ionic strength

Formulating drinks with reduced erosive potential is one approach for reducing dental erosion. In this study, whole casein was added to citric acid solutions representative of soft drinks, and the hydroxyapatite dissolution rate was assessed. Adding 0.02% (w/v) casein to acid solutions significantly reduced the hydroxyapatite dissolution rate by 51 +/- 4% at pH values of 2.80, 3.00, 3.20, 3.40, and 3.60, although the baseline dissolution rates of course varied as a function of pH. The protein concentration [0.002, 0.02, and 0.2% (w/v) casein] had no significant effect on dissolution inhibition. Adding both casein and calcium to citric acid resulted in a further reduction in the dissolution rate at low and intermediate calcium concentrations (5 and 10 mM) but not at higher calcium concentrations (20 and 50 mM). Ionic strength had no significant impact on the efficacy of casein. Casein also significantly reduced the hydroxyapatite dissolution rate when the hydroxyapatite was coated with a salivary pellicle. The reduction in dissolution rate is ascribed to firmly adsorbed casein on the hydroxyapatite surface, which stabilizes the crystal surface and inhibits ion detachment.