ORIGINAL ARTICLES DERIVED FROM RESEARCH

CHARACTERIZATION OF DENTISTRY RESEARCH GROUPS REGISTERED IN COLCIENCIAS TO DECEMBER 2012

¹ PhD Candidate in Public Health, Universidad Nacional de Colombia. Magister in Epidemiology, Universidad Industrial de Santander. Specialist in Health Education and Communication, Universidad Industrial de Santander. Dentist, Universidad Santo Tomás. Professor, School of Dentistry, Universidad Santo Tomás, Bucaramanga, Colombia. Email address: sococosavila@gmail.com

² Doctor of Dentistry, Universidad de Valencia. Magister in Economics and Health Management. Specialist in Dental Public Health, Universidad de Chile. Dentist, Universidad Santo Tomás. Professor, School of Dentistry, Universidad Santo Tomás, Bucaramanga, Colombia

³ Candidate for Master's Degree in Epidemiology, Universidad Industrial de Santander. Specialist in Pediatric Dentistry and Preventive Orthodontics, Universidad CES. Dentist, Pontificia Universidad Javeriana. Professor, School of Dentistry, Universidad Santo Tomás, Bucaramanga, Colombia

SUBMITTED: FEBRUARY 19/2013-APPROVED: SEPTEMBER 21/2013

Concha SC, Pieschacón MP, Rodríguez MJ. Characterization of dentistry research groups registered in Colciencias to December 2012. Rev Fac Odontol Univ Antioq 2014; 25 (2):.

ABSTRACT

INTRODUCTION: the goal is to characterize the dentistry research groups registered in Colciencias. METHODS: this was a descriptive observational study using the institutional platform to find information on groups, researchers, and the products of research projects. The information was systematized in Excel and processed in Stata 9.0. The univariate statistical analysis calculated summary measures according to the nature of variables. The bivariate statistical analysis related the "categorization of groups" output variable with the other variables, by means of the X² test and Fisher's exact test for the qualitative variables, and the ANOVA test or Kruskal-Wallis test for the quantitative ones, considering a level of significance of p < 0.05. RESULTS: 52 groups were identified; 13.5% of them belonged to category A and 34.6% to category D. 63.4% of the groups have focused on clinical areas, and scientific articles were the most commonly used means for knowledge dissemination. CONCLUSION: dentistry research groups have reached a good level of development in Colombia, considering the bibliometric indicators defined by Colciencias. However, they tend to be traditional in terms of the topics they approach. Their impact on the needs of oral health of Colombian population is questioned, especially concerning those populations in situations of vulnerability. In addition, the categorization of groups was strongly influenced by the economic trends in scientific production and the dental market dominating the profession.

Key words: research groups, dentistry, Colombia.

INTRODUCTION

Research is described as one of the pillars for economic, social, and cultural development at the global, regional, national, and local contexts, as well as at the institutional level. Also, for a discipline to achieve its purposes it needs to support its developments on research, and higher education institutions are responsible for promoting the development of the various disciplines. Universities are therefore unique environments for the evolution of knowledge, since research is one of their essential functions, along with teaching and community outreach. Currently, research is carried out by groups of researchers who interact among themselves promoting knowledge development.

Usually, these groups prioritize topics that are of interest to some of their members or that are part of their expertise, forming the so-called lines of research. This paves the way to other forms of understanding the object of study of dentistry, going beyond the barriers of existing knowledge, and producing new technologies and new ways to approach or understand knowledge¹

In Colombia, the Administrative Department of Science, Technology and Innovation (Colciencias) is the body that organizes and promotes most groups, researchers and their products. The work of this institution seeks to categorize research standards as well as the progress made by the groups through applications that exhibit the resume of research groups (GrupLAC), member researchers (CvLAC), and journals on the various fields of knowledge (Publindex), which follow internationally established publication standards. All this allows identifying trends, areas, lines, and research topics in Colombia.²

It is believed that the dental profession has founded its progress on research. In the national and international context, numerous researchers, groups, institutions, and universities are currently promoting the development of knowledge in dentistry to the point that we can say that to date knowledge in dentistry has made progress. However, these advances have not been monitored and the trends of this research activity are unknown; therefore, it is necessary to know how much the research in this field has advanced in Colombia.³

Since 1983, the Research Division of Asociación Colombiana de Facultades de Odontología (ACFO) has been encouraging the development of research among the various Schools of Dentistry in the country, through the production and dissemination of research. This association have strengthened research groups and promoted the interaction of researchers and groups in order to develop an academic community interested in the advancement of knowledge and to strengthen the fundamentals that determine the profession's progress. The specialized literature illustrates ACFO's process; actually, one publication describes the research activity and the research groups on dentistry in Colombia. This publication points out that in 2010 there were 37 research groups (according to the group classifications defined by Colciencias in a bottom-down, level of development, there are five groups in category A, six in category B, 8 in category C, 13 in category D, and four groups are registered). By that time, 19% (7) of the groups focused their attention on comprehensive or interdisciplinary dentistry and 11% (4) equally centered their efforts on craniofacial growth and development, public health and public policies, or epidemiology and management.⁴

By the year 2012, Colciencias' ScienTi platform listed 52 groups in the program of Science, Technology and Innovation in Health² in the specific area of dentistry, and it shows the need of characterizing the way dentistry research groups are classified and what issues they study. It is also important to know the education level of researchers belonging to the groups and their research products and, even more important, to recognize the possible trends of dentistry research projects in the country and their impact on the population's life and health conditions. All this activity is intended to identify aspects that can be strengthened or modified, in order to promote dental research in the country. It must be taken into account, however, the potential limitations of bibliometric studies due to their orientation towards quantification rather to assessment of indicators that can promote structural transformations.

Despite the active dynamics of dentistry in Colombia in recent years, the only evidence in the scientific literature is the report by Lafaurie in the 2010,⁴ which attempts to illustrate the categorization and the areas of interest of research groups. This report, however, does not address other aspects that may be crucial in defining thematic and methodological aspects, as well as the application of knowledge for the transformation of the oral conditions of Colombians.

Furthermore, in order to create new schools, specializations, advanced training programs (master's degrees and doctorate programs), research groups, and research products, it is necessary to identify the trends, the degree of advancement of knowledge, the existing gaps, and the new developments on which dentistry research must focus. This knowledge will provide ethical and responsible solutions to the great social and professional needs in dentistry at the local, national, regional, and global levels.5 All this reasoning leads to the objective of the present article: to characterize the dentistry research groups registered in the Colciencias platform.

METHODS

This was a descriptive observational study, based on dentistry research groups' information located in the Colciencias' ScienTi-Colombia platform, during the second quarter of 2012. ⁶ The output variable was group categorization, and explanatory variables included: name of group, years of existence, leader's name and level of education, leader's area of specialization, name of the institution where the group was formed, the institution's geographic location, department and city were the group is located, number of members of the group, institution that sponsors the group, nature of this institution, and lines of research. Other variables included the number of members with postdoctoral, PhD, master's and specialization degrees, number of foreign researchers, number of articles published, number of articles published in international journals, number of published articles on basic sciences, number of published articles on clinical areas, number of papers presented, number of books or book chapters published, total number of projects, area of emphasis of the research group production, among others. These variables are adapted from the information included in Colciencias' GrupLAC and CvLAC, as important aspects that allow characterizing groups and researchers. This information is mandatory for groups and researchers registered on the platform of the institution.

Procedure

The information for this study was obtained from the Colciencias' ScienTi platform (http://www. Colciencias.gov.co/scienti), by selecting "Groups" under the "Services" title. On the next page (http://201.234.78.173:8083/ciencia-war/ ) the criterion "Group by area of knowledge" was selected (http://201.234.78.173:8083/ciencia-war/BusquedaGrupoXArea.do), obtaining nine Health Sciences-related areas. Finally, we chose the "dentistry" field (http://201.234.78.173:8083/cienciawar/BusquedaGruposXAreaDetalles.do?codAreaConocimiento=0000000000&codRh=40200000 ), identifying 52 research groups.

The GrupLAC registration and the CvLAC of the researchers reported by each group were reviewed.² The information was then organized in an Excel worksheet which included the variables previously listed; the data were processed in STATA 9.0. To this end, summary measures were calculated according to the variables' nature: proportions were calculated for the qualitative variables, and the quantitative ones included measures of central tendency (mean and median) and dispersion (standard deviation, ranges, and percentiles). The bivariate analysis related the group category variable with other variables, by applying the Χ² test and Fisher's exact test to the qualitative variables, and one-way analysis of variance (ANOVA) test or the Kruskal-Wallis test for the quantitative ones.⁷ A value of p < 0,05 was considered.

This study was conducted taking into account the ethical regulations established by Resolution 008430 of 1993 by Colombia's Ministry of Health, concerning the preservation of anonymity in relation to groups, researchers, and their supporting institutions,⁸ considering that this information is of public domain and available to those who wish to consult the Colciencias databases.

RESULTS

Univariate analysis

The platform of Colciencias showed 52 research groups in the field of dentistry, in the program in Science, Technology and Innovation in Health. 90.2% (46) of the groups were registered under health as their primary program and 53.9% (28) reported no secondary program. 44.2% (23) of the groups were headed by a leader with a degree of specialization degree in basic sciences, clinical sciences or public health. In terms of area of education, 13.7% (7) were epidemiologists, 9.8% (5) had a degree on pediatric dentistry and 7.8% (4) in public health at different levels such as specialist, master or PhD.

It is important to note that about 55% of the leaders did not have a dental specialty. The institution in which the groups' leaders had been educated were primarily Universidad Nacional, 18.4% (9), and Universidad de Antioquia, 12.2% (6). Also, 75.5% of the leaders obtained their degrees in Colombian institutions. 34.6% (18) of the groups were classified by Colciencias in the D category and 28.9% (15) were listed as registered (they had entered the system but had not been assigned a category). None of the groups was listed in the A1 category, and 13.5% of the groups were classified in category A. The universities sponsoring the greatest amount of groups were Universidad Nacional, with 13.5% (7), Universidad de Antioquia, with 11.5% (6), and Universidad del Valle, with 9.6% (5). Private institutions sponsored thirty groups (57.7%). Bogotá was home to 46.2% of the groups; 55.8% are not multidisciplinary groups and 63.4% of the groups focused primarily on clinical aspects (table 1).

(table 1)

The groups had about ten years of existence on average, ranging between 1 and 22 years. During the course of their existence, they have had an average of 23 members, but interestingly enough, in accordance with their dynamic, currently the average number of active researchers in the groups dropped nearly in half (thirteen). The groups recorded, on average, about four lines of research. Approximately, two of the members of each group had received education at an international education institution, and the members with a specialization were predominant, with an average of 5.5 members.

Regarding the groups' scientific production, we found more scientific articles (an average of 36 articles) than papers (an average of 22.4 presentations), books (on average two books), chapters (on average four chapters) and they recorded, on average, 23.5 research projects. The areas with the greatest amount of production are the clinical sciences in any of the aforementioned formats, with an average of 18.5 articles, followed by papers presented in conferences (11.1), chapters (2.5) and projects (12.6) (table 2).

Regarding the lines of research reported by the groups, it is important to point out that they are consistent with the prevalence of works on clinical sciences within the groups. Accordingly, 57% of the research lines focus on this aspect, and by analyzing the percentages in detail, we found out that these are the priorities: biomaterials (8.4%), diagnosis (7.4%), pathology (6.4%) and biotechnology and innovation (6%). However, these topics are not separated by specialty, because the lines are not being reported under this modality and several specialties can be grouped in a single line, which impedes finding tendencies under this criterion. Public health prioritizes management-related issues (6.9%) and few studies focus on the social determinants of health (1.5%). In the area of basic sciences, the emphasis is on biology, anatomy, physiology, and pharmacology (6%) (figure 1).

Bivariate analysis

By analyzing the relationship between the Group category variable and other criteria, we noted that some variables showed statistically significant values (table 3). It is important to highlight that when analyzing the Group category variable including total of members, in the groups classified under the A category the number of members was twice as much with respect to the ones under the B and C categories, three times higher with respect to the D groups, and five times higher than those classified as registered.

(table 3)

The analysis of category of group and number of researchers with training outside the country showed that the average of these members is three times higher in A groups when compared with those classified as D or registered. In terms of scientific production, the publication of scientific articles in groups categorized as A is twice as much compared to the C groups, six times higher when compared with the groups listed under the D category, and ten times higher than the registered ones. The A groups produced six times more international articles (i.e. published in journals that are not Colombian) than C groups, and 33 times more than the registered groups. Articles in the clinical areas are doubled in A groups with respect to B groups, and multiply by five with respect to the groups classified as C and D. It was interesting to note that, concerning other formats of production, the differences between the groups with higher rank and the lower-level groups are not so clear.

Concerning the area of emphasis in the A groups, the overall production in the clinical area is a little more than twice as much as that of C and D groups, and nearly seven times higher with respect to registered groups. It should be noted that in this latter area is where we observed statistically significant differences with respect to the total production, and it did not occurred in basic sciences or in public health.

DISCUSSION

Research is not an optional supplement in the dental profession; the day we stop researching in our profession we will stop monitoring the social needs caused by inadequate practices in the field. A responsible dental profession is the one that makes clinical research on human subjects and basic research on biological and human functioning, but it requires the understanding of phenomena that affect the oral health status of groups and communities³

Each area of the dental profession responds to specific needs of individuals and communities, and so each should be promoted if the profession is to appropriately respond to oral health-related problems. Nevertheless, the results of this study reveal that the clinical area has been prioritized, and therefore the research conducted is insufficient to produce changes in the oral health field, since all the areas complement each other to respond to oral health problems.

In agreement with the interest of this work to recognize current changes and trends in dental research, it demonstrated that while dental research groups conduct research in basic sciences, clinical sciences, and public health science, the dominant tendency is towards research in the clinical areas, consistent with the education processes taking place in schools of dentistry in Colombia. This type of education is supported by positivist paradigms, market trends, the economic profit of the clinical areas, and the potential support provided by commercial companies to clinical research in order to promote their products and to limit the potential impact of the dental profession on public health or basic sciences.

In this sense, it is important to compare these results with those obtained in other fields of knowledge, because according to Jaramillo and Lopera, the production of scientific articles on basic sciences was five times higher than on public health in 2007.⁹ However, in 2012 this tendency did not seem to continue, since the scientific production in basic sciences and public health was very similar, disagreeing with Red Colombiana de Investigación en Políticas y Sistemas de Salud in 2005, which reported that, in terms of health research, more researchers focused their studies on basic sciences (28%) closely followed by clinical research (27%) and public health (25%).¹⁰ In the present study, clinical research in the dental field represented an emphasis of 63% of the groups, while public health and basic sciences captured the attention of 19.2% and 17.3% of the groups respectively.

Another relevant aspect in this analysis has to do with the dynamics of creation and consolidation of groups, because according to Lafaurie's report,⁴ in 2010 there were 37 research groups, and only two years later there was an increase of 40% (fifteen new groups). This may be the effect of this dynamics on the development of dental research, but it may also be attributed to the process of categorization and re-categorization of groups in 2011 by Colciencias. The importance of characterizing the groups again lies on the great changes recently happening in both the number of groups and their production in a short period. In addition, the aforementioned study did not deeply analyze aspects such as the location of groups, the focus areas, or the trends in production, which could produce changes in the groups towards a better understanding of them within the framework of the National System of Science and Technology.

In this sense, it is also important to highlight the group categorization changes in 2010 in relation to that of 2012 (table 4). This behavior may be attributed to the introduction of many groups that did not meet the requirements for categorization according to Colciencias' platform, or that the classification criteria became more rigorous, making it difficult to the newly-formed groups to achieve a better category.¹¹

Considering the information provided by the Observatorio de Ciencia y Tecnología in 2010, which describes the categorization of all the research groups in the Colciencias' platform (from the ones with greater development, classified as A groups, to the least developed, referred to as category C) and those connected to the Program of Science and Health Technology, and by comparing it with the reports of the present study concerning dentistry research groups, a higher proportion of A groups was found in the dentistry field if compared with the total proportion of groups categorized in the same level within all the programs of Colciencias' platform.

In the context of the Program of Science and Health Technology, it is evident that there are about 4% more dentistry groups classified as A in comparison with other health sciences. Additionally, we found out that there was 12% and 5% less groups in category D, respectively, when compared with all of the groups and with those registered in the Science and Health Technology Program.¹¹ This could indicate a good level of research development in the dental area, in relation to the research activity of all the programs and Colciencias' Program of Science and Health Technology..

It is currently clear that the quantification of research results is highly interested in establishing or defining research policies. Furthermore, the country's investment in research makes it necessary to assess the benefit provided by this activity, especially in terms of its social contributions. It is also necessary to clarify that research investment in Colombia is low, not exceeding 0.4% of its gross domestic product, below the average in Latin America. In addition, investments in health, specifically in dentistry, are even lower, which affects the development of research in this area.

In addition to this, evaluating the impact of dental research, especially in terms of Colombian population oral health, is not easy. It is necessary to emphasize that knowledge in our field is a cumulative and intangible good, and its results are usually evident after a long period. This situation triggers the tendency to explore bibliographic production through the quantification of articles, papers, books, and other forms of dissemination of research results. Thus, Colciencias' databases represent a potential source of bibliometric indexes of the scientific activity and a way to characterize groups and the research they perform in the dental area in Colombia.¹² Based on this characterization of dental research groups, it is possible to generate databases to promote the transformation of research in order to respond with greater relevance and appropriateness to the oral needs of individuals and communities, seeking the reconfiguration of formation processes and the paradigms that support teaching, research and care.

The advantage of this alternative is the possibility of describing the characteristics of these groups and their production, based on secondary sources (GrupLAC and CvLAC) which are available to the public and disclose the historical processes of groups and researchers, as well as the groups' dynamics in knowledge production.⁹ However, this process encountered certain difficulties that must be expressed in order to identify the potential limitations of the present study; such difficulties have to do with the way the information is systematized and updated in the GrupLAC and CvLAC applications of the ScienTi platform, implying the existence of possible inconsistencies between what actually is and what appears in the system.

On the other hand, there are potential errors in the way information is entered, producing uncertainties on the amount of research products that were taken from the ScienTi platform for their analysis. Accordingly, it is important to mention the difficulty of debugging the products referred to in the applications of Colciencias, in order to avoid possible inconsistencies, because this is a task that can only be done by the leaders of the research groups.

By analyzing each group in the overall context, we noted that the indicators for classifying groups under the A or B categories have to do primarily with the amount of published articles, in particular with the ones appearing in international journals.^{9, 11} Despite this finding, it is important to mention that one group achieved a B classification based on the production of eleven research books, without reporting other forms of generating knowledge. This factor suggests a simple interest of Colciencias to set some breakpoints, without generating deeper evaluation processes that reflects a dynamic to promote research groups and their actions to generate new knowledge intended to improve oral health and the quality of life of people. This background demonstrates the need for generating other indicators to assess the transformation of epidemiological profiles, the social appropriation of knowledge and the use of knowledge for policymaking aimed at decision makers. In addition, it is necessary to develop innovation processes in the field of dentistry with greater impact and lower costs, and a new way of seeing oral health, all of this as strategies that go beyond the production of scientific papers.

It is important to mention that there are differences between the current database information and the one used during the analysis in this study, due to Colciencias' continuous updates. This issue clarifies the dynamics of dental research and justifies the development of this type of studies, as a strategy for monitoring research development in our profession and for identifying areas, fields and lines in different regions of the country that require to be strengthened, due to the tendency of groups and research projects to focus on the cities with the greatest economic development in the country.

Currently, Colciencias reports in its platform 51 groups classified as registered in the field of dentistry, modifying the process the institution had been implementing since the first decade of this century. This might be due to the interest of generating other ways to visualize the dynamics of research and development inside the groups; however, it is also an effect of the criticisms by some authors to the developed scheme, which prioritizes the groups following positivist positions, supporting their evaluation in economic indicators validated by the market.^{11, 13}

In terms of quantity and interdisciplinarity of groups' members, and its potential effect on the process of categorization, they basically related with its possible contribution in terms of the amount of research products that they can offer to the group in view of its categorization. Similarly, it is important to recognize that the process of interaction between researchers from different disciplines, with diverse experiences and levels of training, can generate an environment that encourages research and which can be powered by attitudes and skills of the research groups' leaders, as they become key persons in the development of the group and its scientific production.⁹

In terms of themes, in 2010 nearly 19% (7) of the groups focused their attention on comprehensive or interdisciplinary dentistry, and 11% (4) worked equally on craniofacial growth and development, public health and public policies, or epidemiology and management.⁴ In 2012, there was prevalence of the clinical areas over issues related to public health and administration, just as in 2010. Also, aspects related to basic sciences, such as biology, immunology, and pharmacology, were the least covered by the groups, and in 2010 they were not even mentioned.

The research trends seem to suggest that traditional themes still dominate the field of dental research in either basic sciences, clinical sciences, or public health. It should be noted that in the latter the study of the social determinants of health represents only a small fraction of research in dentistry and public health (27.1%), not even reaching 1.5% of the public health issues addressed by the groups. This aspect seems to indicate that the challenge proposed by the World Health Organization and Collective Health to address inequalities and inequities has been poorly considered by dental researchers in Colombia.^14-16 This is the result of education processes that emphasize biological and clinical aspects and the fragmented understanding of health-disease-care-oral care process, which requires not only more public health professionals, but also researchers who approach oral health from different paradigms of thought, as well as the possibility of better understanding the difference of the dynamics between biological and social disciplines.

When analyzing the cities and universities that concentrate the dental research groups, it becomes evident that several studies showed a tendency to focus health research in cities such as Bogotá, Medellín, and Cali, and universities such as Universidad Nacional, Universidad de Antioquia and Universidad del Valle. This tendency is influenced by research traditions and by the opportunities, considering the levels of training obtained by researches in these institutions, showing the need to promote advanced education and interaction between researchers from different universities.^{12, 17}

This study evaluated the amount of research projects in the field of dentistry as reported in the platform, but it did not assess the quality of their products nor their potential social, political or economic impact because it would require to resort to other sources, such as databases and search engines, and to interview researchers from different research groups, moving away from the objective of the present work. Some of these aspects were evaluated in a work carried out by Lara et al concerning dental research in Mexico, and by Ramírez-Vélez et al in the field of physical therapy in Colombia.^{18, 19}

Lara et al analyzed the types and the amount of scientific articles published by Mexican dentists in national and international journals, and classified these publications according to their object of study and field of specialty, concluding that less than half of the publications they analyzed contributed to the generation of knowledge; therefore, they insist in the need of promoting dental research in Mexico.¹⁸ On the other hand, Ramírez-Vélez et al analyzed the scientific and research capacity of Colombian physical therapy practitioners and showed the areas of interest in which research groups developed their scientific activities, their products and their quality. They concluded that scientific production in physical therapy is insufficient, and that quality must be improved; they also mentioned the need to implement measures to solve this situation..¹⁹

It is important to understand the findings of the present work within the framework of dental research worldwide and in Latin America. According to the reports in the SCImago system of categorization, Colombia holds the position 42 among 151 countries included in this classification system, with 176 documents published on the subject in journals internationally recognized, between 1996 and 2011. At the Latin American level, our country ranks seventh in the production of scientific literature in the field of dental research, within the group led by Brazil and followed by Cuba, Mexico, Argentina, Chile, and Venezuela.

In the present study, we identified 266 articles published in scientific journals, 72 of them in international journals. This information suggests that dental scientific publication in Colombia must be strengthened, with a view to a better level. However, there are no indicators to assess the impact of this research, and they limited to analyzing the effect in terms of citation. In terms of citation of scientific production in dentistry, Colombia ranks 37 in the world, and third in Latin America, after Brazil and Chile, closely followed by Mexico and Argentina. You might think that, in the scientific world in Latin America, Colombian dental research is accepted and has credibility.²⁰

In the present study, we identified 266 articles published in scientific journals, 72 of them in international journals. This information suggests that dental scientific publication in Colombia must be strengthened, with a view to a better level. However, there are no indicators to assess the impact of this research, and they limited to analyzing the effect in terms of citation. In terms of citation of scientific production in dentistry, Colombia ranks 37 in the world, and third in Latin America, after Brazil and Chile, closely followed by Mexico and Argentina. You might think that, in the scientific world in Latin America, Colombian dental research is accepted and has credibility.

CONCLUSIONS

In synthesis, one could conclude that dental research groups have reached a good level of development in Colombia, according to the bibliometric indicators defined by Colciencias. However, the groups tend to be traditional in terms of the issues addressed, and their real impact on the needs of oral health of the population may be questioned, especially considering those who are in situations of vulnerability, perhaps, however, with greater impact on the clinical practice—which has been the focus of our dental research—. The categorization of groups was strongly influenced by the economic trends in scientific production and by the dental market, which dominate the profession and end up directing more researchers towards the publication of scientific articles instead of the well-being and oral health of the population.

Based on the results of this work, the authors would recommend:

CONFLICTS OF INTEREST

the authors declare to have no conflict of interest regarding this study; no institution had influence in the design of the study, in the process of collection, analysis and interpretation of data, or in the preparation, review, or approval of the manuscript.

APPENDIX

Appendix A,B,C

(Appendix A)

(Appendix B)

(Appendix C)

REFERENCES