The need to evaluate and compare medical journals has become an ongoing struggle. Researchers and librarians have several citation and journal metric options that can help make assessments at the journal, article, and author level.Journal Citation Report was first utilized in the 1970s [Journal Citation Report is one of the only sources of citation data on journals covering the areas of science and medicine, technology, and social sciences.While the over-reliance on any journal-level metric has its shortcomings, the impact factor, also known as journal impact factor, remains one of the most widely used indicators of journal quality. Eugene Garfield first thought of the idea in 1955, but it would be decades later when the This resource review provides a general overview of the content and features of Clarivate Analytics’ Journal Citation Reports (JCR). It explains impact factors and journal rankings, and how they are calculated and can be utilized.not a direct link to factors such as quality of peer review or quality of the content of a journals’ articles.An impact factor is a measure of the frequency with which the average article in a journal has been cited in a particular year. The higher a journal’s impact factor, the more frequently articles in that journal are cited. In this way, an impact factor can give an approximate indication of how prestigious or influential a journal is in its field. A journal’s impact factor is Impact factors for journals are sourced from several indexes in the Web of Science Core Collection published by Clarivate Analytics, such as the Science Citation Index and the Social Sciences Citation Index. As of November 2018, JCR has aggregated data from over 11,500 titles and over 230 disciplines.To be covered in Web of Science and, therefore, have a chance to be given an impact factor, journals undergo a selection process and maintenance review. More information about this process can be found on the JCR website . ClarivaEssentially, a journal’s impact factor is derived by calculating the average number of times that articles in a journal are referenced by other journals within a future period of time. Calculating the JCR impact factor uses a ratio where the numerator is the number of times an article that was published in a specific journal in the previous two years was cited. The denominator is the number of total possible citable items published in that journal .The Example Journal. For the year 2017, Clarivate scans through a set of journals covered by JCR . It counts the number of times that articles published in 2017 made reference to works published in The Example Journal in 2015 and 2016. If this number is 200, that is the numerator. Then it counts the total number of articles published by The Example Journal in 2015 and 2016. If this is 45, that is the denominator. Divide the 2 numbers to calculate the impact factor.Here is an example of a fictitious journal: The Example Journal is 4.444. Librarians and researchers are often asked what this number means. Is this a high impact factor? What is a good impact factor?The 2017 impact factor (IF) for Nature Reviews Immunology, with a 2017 impact factor of 41.982. The top ranked journal in “Economics” is the Quarterly Journal of Economics with a 2017 impact factor of 7.863. This should not be taken to mean that Nature Reviews Immunology is a higher quality journal than the Quarterly Journal of Economics. Certain disciplines lend themselves to having articles cited at higher levels than others. They are both ranked #1 in their respective categories, and this should be the key takeaway.One important thing to keep in mind is the high variation in average impact factors across different subject areas. Practically speaking, it is rarely useful to compare journals from different subject areas. Hence, JCR classifies journals into a number of subject categories. For instance, the #1 ranked journal in the category of “Immunology” is Nature Reviews Drug Discovery is listed in two categories: “Biotechnology & Applied Microbiology” and “Pharmacology & Pharmacy.”Each journal in JCR is assigned to at least one subject category. In some cases, a journal may be assigned to more than one subject category; therefore, when comparing journals across related categories, it is possible to see the same journal title in different categories. In JAMA is included in JCR, and so all the references of its appropriate articles are tracked. If a journal cites a JAMA article but that journal is not indexed, then that citation does not count toward JAMA’s impact factor or any other indicators.It is important to keep in mind the shortcomings and issues surrounding the impact factor. Coverage for tracking citations is entirely subject to those indexes that Clarivate Analytics has included. If a journal is not indexed in Web of Science, it will not be included in the scan for its references. For instance, Because it takes at least three years before an impact factor can be calculated, there is a tendency to favor older and larger journals. Such journals typically have more citations as they naturally have a larger body of previously published articles that are available to be cited.Another problem is that self-citations  can bolster a journal’s impact factor . JCR doeLikewise, since review articles typically include so many more references, journals that heavily publish review articles can influence an impact factor as well.While impact factors make up the backbone of JCR, there are several other metrics, indicators, and features provided throughout the resource that can aid in providing a fuller picture of a journal, article, or author’s influence.immediacy index measures how frequently the average article from a journal is cited within the same year as its publication. This number could be useful for evaluating journals that publish cutting-edge research.The eigenfactor score is based on the number of times that articles from the journal that were published in the past five years have been cited in the JCR year, but it also considers which journals have contributed these citations so that highly cited journals will influence the network more than lesser cited journals. References from one article in a journal to another article from the same journal are removed so that eigenfactor scores are not influenced by journal self-citation.The journal impact factor without self-cites also addresses the criticism that impact factors can be easily influenced by self-citations. It is calculated exactly the same as the journal impact factor, but with one important exception: any citations to a publication that come from the publication itself  are excluded from the numerator of the calculation.The 5-year journal impact factor is the average number of times that articles from the journal that were published in the past five years have been cited in a given JCR year. This helps show the long-term citation trend for a journal.The h-index is usually used as a measure of scientific productivity and the scientific impact of an individual scientist, but it can also be used to rank journals.The Other features include being able to compare journals by trends and quartiles. There are a number of visualization charts and graphs that assist in seeing the relationship between citing and cited journals, which helps to trace a journal’s impact over time. Data from charts and graphs can be exported to portable document format (PDF), comma-separated value (CSV), and Excel (XLS) formats.JCR is a resource meant for researchers, librarians, clinicians, institutions, publishers, authors, and readers of medical, science, and social science literature to determine a journal’s influence in its relative field. There are many times when individuals or institutions will want to know a precise impact factor. Having access to the source means not having to rely on a publisher’s website for current and accurate data.Knowing how best to use impact factors and journal rankings means acknowledging the limitations of solely relying on them to judge a journal’s scholarly worth. That said, impact factors and the journal’s ranking in its JCR category could be useful as part of a package including information such as databases where the journal is indexed. Those working in collection development and acquisitions would find JCR helpful when making purchasing decisions.This reviewer has pulled lists from the category rankings to give authors other journals to consider for publishing. There is even an option to filter to open access journals, which is sometimes an author’s goal . Users cAnyone interested in tracking bibliometric citation patterns and trends will find the JCR information as well as their visualization charts and graphs very helpful.Access depends on having a license to the JCR resource. JCR lives on the Clarivate platform, allowing thorough integration with other Clarivate resources such as Web of Science and InCites; however, a subscription to one of these resources is necessary.Searching and navigating JCR can be frustrating. It offers only basic title search functionality. A user has to input the title according to how Clarivate indexes that title for it to show up. The auto-fill is very sensitive and can miss a title, if care is not taken in typing out the journal title. Going from category data to journal rankings is clunky and nonintuitive. The hyperlink of the total number of journals must be used to get to the Journals By Rank.There are several other journal metrics and ranking systems available. Perhaps the biggest competitor is SCImago journal rank indicator. It measures the scientific influence of scholarly journals based on both the number of citations received by a journal, very similar to how impact factor is collected (except they go back three years instead of two), and the importance or prestige of the journals where such citations come from .The SCImago Journal & Country Rank is a publicly available portal, meaning there is no fee to access their information, which is a huge advantage over JCR. A limitation for this indicator is that it makes citation analyses based only on those journals that are indexed in Scopus. Likewise, JCR has a limitation of only being able to track citations of journals that are indexed in Web of Science. The difference is that Elsevier, the large publishing group, owns Scopus and could, therefore, potentially inflate the importance of its own journals.Purchasing JCR should be based on an institution’s research and publishing needs. JCR provides powerful and comprehensive bibliometric metrics from an objective source. While it has its limitations and newer metrics continually become available, JCR continues to be used globally.


Objectives: The aim is to compare the adhesion between zirconia and cements attained with melt-etching with potassium hydrogen difluoride, KHF2, with that found when such traditional surface treatments as sandblasting and ceramic stone grinding are employed.Materials and methods: Groups of zirconia crowns where treated by sandblasting (n = 6), grinding with carbide bur (n = 6) or melt-etching with KHF2 (n = 6) of the surface before cementation with a resin cement to an implant substitute made by Selective Laser Melting of a cobalt-chromium alloy. Tensile testing was performed to rupture, while measured increasing load at the zirconia-cement interface. The strength was calculated by dividing the rupture load with the contact area. The three groups were compared using one-way ANOVA.Results: The adhesion strength between the zirconia crowns and the cement resulted in significant differences between all groups (p < .05). The sandblasted group had the lowest strength (5.2 ± 0.95 MPa), the ground group significantly higher (7.3 ± 1.49 MPa) and the melt-etched group the highest values (9.8 ± 1.37 MPa).Conclusion: The adhesive strength of resin cement to zirconia can be ranked according to the surface preparation with surfaces melt-etched with KHF2 stronger than ground which is stronger than sandblasted. An in vimplants . Until reratures . The fraBonding strength to different cements has been regarded as a factor limiting the use of zirconia materials. Good bonding requires a rough surface to enable mechanical bonding. Hydrofluoric acid etching is a common procedure for silica-containing glass ceramics, but the procedure is claimed not to give a surface on zirconia rough enough to improve the adhesion strength between cements and zirconia . Another6 plasma spraying [Different surface treatments of zirconia materials have been studied in recent years for their effect on bonding to a number of cements. Tribo-chemical silica coating was introduced by 3M ESPE AG in 1989 based on silicoating techniques for silicatization of metal frameworks. This method, the Rocatec system, has been used for both alumina- and zirconia-based ceramics , SF6 plaspraying  and lasespraying  have alsspraying  found noA recently published article presented a melt-etching technique for zirconia surface treatment to enhance adhesion strength to resin cement . The preThe test method uses a modification of the equipment designed for a pull-off test performed on alumina and zirconia crowns mounted to steel models by Derand et al. .® star CL . One STL-file of this design was sent for production of 18 standardized implant substitutes in a cobalt-chromium alloy, Remanium star CL , with Se star CL .A model of tooth 36 was designed with CAD/CAM Zirkonzahn Modellier-system for making 18 standardized Prettau Zirconia crowns  for mounThe abutment substitutes were sandblasted with 110 µm alumina at an angle of 45° and a distance of 10 mm leaving circular traces as shown in n = 6), B: ground (n = 6) and C: etched (n = 6) as preparation for mounting to the cobalt-chromium implant substitutes. Group A was sandblasted for 10 s with 50 µm alumina particles at a pressure of 3.5 bars and at 45° angle to the inner surface. Group B was carefully hand milled at the inner side with a ceramic grinder tool . The crowns in Group C were filled with fine grained potassium hydrogen difluoride, KHF2 . A metal cylinder and a plastic ring with an inner diameter less than the crown margin were placed around the abutment substitutes before these were mounted in the machine and clamped . The metσ, was calculated as σ = F/A, where F was the force at rupture and A, the cemented area, calculated as a sum of the top circular area and a truncated cone with the upper radius of 3.2 mm and the margin radius of 4.0 mm and a height of 5.0 mm, i.e. 145.3 mm2 which is the same for all samples.The adhesion strength, p values <.05.The de-bonding strength data was analyzed using One Way Anova followed by the Tukey’s multiple comparisons test using Graphpad, version 6.0 with a When inspected in stereo microscope prior to cementation, the inner surface exhibited different morphologies according to group . The sanp < .05). The sandblasted group had the lowest strength values and the melt-etched group showed the highest values , only the sandblasted and ground surfaces appeared rough; the melt-etched surface looked smooth and shiny. At the higher magnification (64X), however, the melt-etched surface appeared to be matte indicating some roughness, apparently sufficient to provide a good retention. Static images of the texture of the inner curved surface taken at high magnification contained little information. However, Ruyter et al. , using sSandblasting and grinding of zirconia surfaces are associated with an energy-induced structural transformation from tetragonal to monoclinic structure which is believed to enhance hydrothermal aging when exposed to dynamic loading in humid environment as described by several authors, including Prado et al. . The melDespite claims that etching of zirconia is difficult and has a limited effect, the results of this present study show that melt-etching with potassium hydrogen difluoride has given significantly higher bond strength for resin-based cement than both sandblasted and ground surfaces. This confirms that the etching method proposed by Ruyter et al. can be successful when used on clinically designed crowns. The null-hypothesis can be rejected.There were significant differences between adhesion strength to resin cement for the sandblasted, ground and melt etched groups, with the melt etch method showing the highest strength.


Journal clubs are an important tool for critically appraising articles and keeping up-to-date with the current literature. This paper provides a critical review of the literature on the design and structure of journal clubs in residency education with a focus on preparation, topic selection, implementation, and integration of technology. Recommendations for preparation include developing clearly defined goals and objectives that are agreed upon by all journal club participants; mentorship from experienced faculty members to ensure appropriate article selection, maintenance of structure, and applicability to objectives; distribution of articles to participants 1–2 weeks prior to the scheduled session with reminders to read the articles at predetermined intervals; and the use of a structured critical appraisal tool for evaluating the articles. Recommendations for topic selection include selecting a primary objective of either critical appraisal or informing clinical practice and ensuring that the articles align with the objective; involving learners in the topic- and article-selection process; and having the article selection driven by a specific clinical question. Recommendations for implementation include hosting sessions in the evening and away from the hospital environment; providing food to participants; hosting meetings on a monthly basis at regularly scheduled intervals; mandating journal club attendance; and using theories of adult learning. Recommendations for integration of technology include using previously established, effective strategies and determining the feasibility of creating an online journal club versus joining an established journal club. It is the authors’ intention that after reading this paper readers will have new strategies and techniques for implementing and running a journal club at their home institutions. While the concept of the journal club is most commonly attributed to Cushing’s description of Sir William Osler’s meetings in 1875, the first reference dates back to 1835 when Sir James Paget would meet with a group of students near St. Bartholomew’s Hospital to review articles.5While many programs use journal clubs in their graduate medical education training, there is significant variation in the structure and goals.This article is the first in a series of evidence-based best practice reviews from the Council of Emergency Medicine Residency Directors (CORD) Best Practices Subcommittee. The first two authors independently performed a search of PubMed for articles published from inception to August 20, 2017, using the keywords “journal club.” Bibliographies of all relevant articles were reviewed for additional studies. The search was further augmented by several calls via social media to the #FOAMed and #MedEd communities requesting additional article recommendations. Articles were screened independently by two authors to evaluate for any papers addressing the following four themes, which were determined a priori: preparation for journal club; topic selection; strategies for successful implementation; and incorporation of technology. Articles were included if either author recommended inclusion.The search yielded a total of 2,102 articles, of which 67 were deemed to be directly relevant for inclusion in this review. When supporting data was not available, recommendations were made based upon the authors’ combined experience and consensus opinion. Level of evidence was provided for each statement according to the Oxford Centre for Evidence-Based Medicine criteria .8 Prior Successful journal clubs are predicated upon thorough preparation and the development of clear, specific goals and objectives. Defining and articulating the goals and objectives of any educational experience is an important pedagogical step;11Several surveys across multiple medical specialties have assessed the most common goals for a journal club. These include teaching critical appraisal skills, providing an impact on clinical practice, remaining current on medical literature, allowing residents and faculty to work together on a common project, and learning research methodology.16Another important aspect is support and mentorship from more experienced faculty members in the form of advice and technical support to resident physicians. Mentorship includes assistance in the selection of an article for critical appraisal and preparing the associated presentation.19Studies unanimously agree that selected articles should be distributed to all members of the journal club prior to the session. A systematic review by Deenadayalan and colleagues found that the preparation time for those who attended journal clubs varied widely and recommended a minimum of one week.10When participants review articles prior to the journal club, article evaluation guidelines or a critical appraisal instrument should be used. This practice has been consistently reported in the literature as a feature of successful journal clubs.Best Practice Recommendations:Develop clearly defined goals and objectives that are agreed upon by all journal club participants (Level 2a).Faculty members or more experienced clinicians should provide mentorship to ensure appropriate article selection, maintenance of structure, and applicability to objectives (Level 2a).Distribute articles to participants one to two weeks prior to the scheduled session and consider reminders to read the articles at predetermined intervals (Level 4).Use a structured critical appraisal tool when evaluating articles for journal club (Level 2a).The first consideration that should be made when selecting journal club topics are the overall objectives.17This distinction in goals may influence the topic selection methods used for the session. For example, a journal club session with a primary objective of teaching principles of evidence-based medicine might select very different articles to review than one with a primary goal of keeping participants informed on the most current literature. Alternatively, topic selection techniques focused on enhancing resident participation  may result in different learner goals, with variations in the applicability to practice or the ability to teach critical appraisal skills. Moreover, the curriculum and the impact of the selected topic may be influenced by the experience of the learner. Harris and colleagues highlighted that “a [journal club] for students or interns may include the same ingredients, but in different proportions, with more emphasis on learning the ‘rules’ of critical appraisal and the topics of clinical epidemiology and biostatistics.”As a result, some experts have suggested separating the curriculum that teaches skills in epidemiology from the curriculum that reviews the newest literature. One study found that this separation improved the ability of participants to acquire the skills and knowledge in each area.29When selecting article topics, it can be valuable to begin with a specific clinical question. These may be based upon actual cases encountered by the learner, hypothetical cases, or new literature. The use of a particular case or challenge may increase learner interest and engagement. Several authors have described the importance of a clinical problem-based article selection, though formal comparative studies are limited.33In a systematic review on journal clubs published by Honey and colleagues, nine of the 14 included articles had the participants select the topic.37It is important that the article search be performed in a structured manner to be effective. When performing a search for potential articles, learners first need to understand how to convert a clinical question into a query. They should receive structured training to be familiar with the variety of literature repositories . They should learn search strategies, such as using Boolean language and how to use MeSH terms. Training should include practice in searching article databases and feedback on their search strategy. Additionally, learners should receive instruction on which journals publish the highest quality literature in EM. Therefore, they often need to have direct mentorship in article selection techniques.29It is important to vary the types of studies included to ensure that the learner develops the skills to analyze multiple different types of articles ;4Best Practice Recommendations:Determine whether the primary objective is critical appraisal or informing clinical practice and ensure that the articles selected align with this objective. While these are not mutually exclusive, one often predominates (Level 4).Involve learners in the topic and article selection process to increase learner engagement and maximize the learner benefit (Level 3b).When possible, have the article selection driven by a specific clinical question (Level 3a).Article selection and topic selection should have active mentorship from a faculty member (Level 4).While there are numerous studies assessing different aspects of journal clubs, there is no standard process for how to implement a journal club. Review of the existing literature demonstrated that the setting of a journal club varied significantly between studies, including conference rooms, faculty members’ houses, restaurants, and the hospital. The timing also varied in the studies, with some meeting in the evening, while others met during work hours. This variation is likely dependent upon the physician type, due to the variations in schedules and work hours. For example, a study conducted in an internal medicine residency program, found meeting during the lunch hour to be the most common.6Although there are variations in the time and place of hosting a journal club, one of the most significant factors associated with successful journal clubs was the availability of food as an incentive.41The optimal frequency of journal club meetings has not yet been established. Meeting too often may result in lower attendance, while meeting infrequently may decrease the retention of evidence-based medicine concepts. Most programs meet every two to four weeks for journal club sessions.29Most journal club sessions range from one-to-two hours in length.Another important consideration is whether the journal club sessions should be mandatory. In a survey of anesthesiology residents, 63% of residents preferred voluntary attendance.20While mandatory attendance will increase the number of learners, it is equally important to ensure that the sessions align with sound educational principles. First, the learners must feel that they are in a safe learning environment. The journal club must establish an environment that is conducive to learning, which includes learners being comfortable with their own limitations, as well as feeling comfortable discussing the specific limitations of a study.46Additionally, it is valuable to incorporate adult learning theories when designing journal club sessions .34 As ad51Best Practice Recommendations:Sessions should be hosted in the evening and away from the hospital environment (Level 3b).Food should be provided to participants (Level 3b).Monthly meetings at regularly scheduled intervals are optimal for continued involvement of the residents and retention of evidence-based medicine concepts (Level 3a).Journal club attendance should be mandated by program leadership (Level 3a).Principles of adult learning theory should be upheld (Level 3b)Modern social media platforms  provide the opportunity to readily create and participate in online journal clubs.60As technology has evolved, so has the online journal club experience. Early journal clubs consisted of static webpages with experts providing summaries of articles and highlighting the applicability to other research and clinical practice without the opportunity for discussion.One of the most commonly used resources for online journal clubs is Twitter. This platform has been used as the starting platform for numerous online journal clubs, as well as individuals, specialty organizations, journals, institutions, and events by providing instantaneous discussions with a diverse group of participants. 56Twitter has rapidly become the dominant source of medical blog traffic while providing a platform for journals to tweet links to their latest papers. This initiates the community peer-review process and may predict future paper citations.58Annals of Emergency Medicine on a year-long pilot of a series of online journal clubs discussing select articles from the journal.58The rapid expansion and affordability of high-quality online video teleconferencing platforms  has created the ability to rapidly share and record journal club discussions across the globe.Other researchers have demonstrated that a hybrid model of live event and online discussions provides an adaptive and feasible educational delivery method for clinicians with limited educational time, with one study finding a positive improvement in the use of evidence-based recommendations by clinicians.59Other platforms have been used successfully including the Wikipedia software to create the Wiki journal club (WikiJC) in 2011.54Suggested keys to success for a new online journal club include starting discussions on a single platform  and then sharing the curated discussions on a blog or website; providing live discussions with the educator or author, followed by subsequent replies to learner comments across platforms; focusing on an initial small community of learners; ensuring that psychological safety is always ensured even after erroneous comments are posted; and tracking local participation and engagement.58One study of general surgery residents found that an online journal club using a combination of email, Facebook, and Twitter was very well received by learners, noting that it was easy to participate in, helpful in keeping up with the latest literature, and valuable for developing critical appraisal skills.Best Practice Recommendations:Consider using an online journal club format to increase participation and overcome the limitations of time, geography, and limited local membership (Level 4).Before creating an online journal club, review successful, established online journal clubs and use previously established, effective strategies (Level 5).Starting a new online journal club requires a significant time and resource commitment by a dedicated team. Ensure that this is feasible at your institution prior to launching an online journal club. Consider joining an existing online journal club rather than creating a new one if resources are limited (Level 5).It is important to consider several limitations with respect to this article. While we used multiple methods to identify potential relevant articles, it is possible that some articles may not have been identified by the current review; however, we used an inclusive search strategy, reviewing all articles in PubMed that populated in response to the keywords “journal club.” We also discussed this with topic experts, reviewed the bibliographies for all relevant articles, and reached out via multiple social media networks for further resources. Nonetheless, it is possible that some articles not published in PubMed or referenced in the included articles may have been missed by this search strategy.Additionally, we based article selection upon relevance to the specific themes selected. The topic of journal clubs is extensive and only specific components deemed to be most relevant to the clinician educator were selected for review in this publication. We also did not assess journal club effectiveness, as this has already been studied elsewhere.This paper provides an evidence-based review of the literature on the design and structure of journal clubs in residency education. Strategies for preparation, topic selection, implementation, and integration of technology are discussed along with recommendations for best practices. After reading this paper, it is the authors’ intention that readers will have new strategies and techniques for implementing and running a journal club at their home institution.Michael Gottlieb, MD – Co-ChairRush University Medical CenterJohn Bailitz, MD – Co-ChairNorthwestern University, Feinberg School of MedicineJeremy Branzetti, MDNew York University/BellevueRichard Byyny, MDDenver Health Medical CenterMolly Estes, MDStanford UniversityPuja Gopal, MDUniversity of Illinois in ChicagoAlbert Kim, MDWashington University in Saint LouisAndrew King, MDThe Ohio State UniversityMelissa Parsons, MDUniversity of Florida - Jacksonville


Early reperfusion of occluded arteries via recombinant tissue plasminogen activator (rtPA) administration is considered to be an effective strategy for the treatment of acute ischemic stroke. However, delayed administration of rtPA may cause severe hemorrhagic transformation (HT) and undesirable neurological outcomes. The current study aims to establish a canine HT model using rtPA administration and to investigate the potential mechanisms underlying HT. Following anesthesia, two autologous clots were injected into the middle cerebral artery (MCA) to induce ischemic stroke. To induce reperfusion, rtPA (2 mg/kg) was administrated intravenously 4.5 h after the establishment of stroke. The occurrence of HT was determined by computed tomography (CT) and by pathological assessment. Transmission electron microscopy was utilized to assess blood-brain barrier (BBB) damage. The expression of matrix metalloprotein 9 (MMP-9) was analyzed by enzyme linked immunosorbent assay (ELISA), immunofluorescence (IF), and western blot. Administration of rtPA 4.5 h after stroke induced reperfusion in 73.9% of the canines, caused evident HT, and did not improve neurological outcomes compared to canines that did not receive rtPA. There was a significant increase in expression of MMP-9 after rtPA administration, accompanied by BBB disruption. We have established a canine HT model that closely mimics human HT by using rtPA administration after the induction of middle cerebral artery occlusion (MCAO) with autologous clots. Our data suggest that a potential mechanism underlying rtPA-caused HT may be related to BBB dysfunction induced by an increase in MMP-9 expression. Acute ischemic stroke is a leading cause of death and disability worldwide . Early aExperimental models of cerebral infarction have significant limitations. Many groups have utilized an intraluminal monofilament , an injeWe recently described an endovascular canine stroke model based on MCAO with autologous clots that is highly suitable for the study of ischemic stroke . Using tin vivo Experiments).All animal-related experiments were performed according to the National Institutes of Health guide for the care and use of laboratory animals. The experimental protocols were approved by the Committee on the Ethics of Animal Experiments, Southeast University Medical School. All experiments, documentation and reporting were in compliance with the ARRIVE guidelines  were acclimatized to our animal facilities for 1 day before the initiation of experiments. Using a table of random numbers, canines were randomly divided into 3 groups: control (sham operation), MCAO, and MCAO + rtPA . AnimalsCanines were anesthetized with pentobarbital (30 mg/kg)  and maintained (dose = 1/5 of induction) via administration once every 2 h. Fentanyl (0.03 mg/kg) was used for analgesia peri-operation and post-operation. Physiological parameters, including mean arterial blood pressure (MABP) and blood gas were measured before and after rtPA administration . EndovasThread-like clots were prepared as previously described . Plasma http://www.fda.gov/Drugs/DrugSafety/ucm223966.htm). The MCAO and control groups received the same volume of saline. The endovascular procedures described above were repeated to investigate whether an effective reperfusion of the MCA was achieved after rtPA administration.RtPA  was intravenously administrated at 2 mg/kg with a 10% bolus injection and 90% continuous infusion for 60 min at 4.5 h post-stroke. In canines, the 2 mg/kg dose is considered to equivalent to the clinical dose (in humans) of 0.9 mg/kg after adjusting to the body surface area, as recommended by the Food and Drug Administration guidelines  according to the following parameters: kV: 120, mAs: 28, and slice thickness: 1.5 mm. CT images were assessed by three blinded investigators.All behavioral evaluations were performed by an interventional neuroradiologist who was blinded. A modified canine neurobehavioural scoring system was employed to assess motor function, consciousness, heading turning, circling, and hemianopsia .Hemorrhagic events were scored as follows: 0 = no blood; 1 = hemorrhagic infarction type 1 (HI-1) ; 2 = hemorrhagic infarction type 2 (HI-2) ; 3 = parenchymal hematoma type 1 (PH-1) ; 4 = parenchymal hematoma type 2 (PH-2) .Twenty-four hours after thrombolysis, the vertebral catheter was inserted into contralateral ICA, and the dogs were super selectively perfused with saline followed by 4% paraformaldehyde through the catheter. Brains were excised and fixed in 4% paraformaldehyde at 4°C for 24 h, then embedded in paraffin and cut into 50-μm-thick serial sections. Sets of five serial sections were stained with HE.3 in size were excised from the peri-infarct region, fixed in 4% glutaraldehyde at 4°C for 24 h, and postfixed in 1% osmium tetroxide for 2 h. Then, the samples were dehydrated through a graded ethanol series, exchanged through propylene oxide, and embedded in epoxy resin at 60°C for 36 h. Ultrathin sections were obtained, stained with 0.5% uranyl acetate and 3% lead citrate, and then observed with a transmission electron microscope  at 100 kV.Tissue blocks ~1 mmBlood samples were obtained at the following time points: prior to MCAO; 2, 4.5 h post-stroke; 0, 0.5, 2, 4, 6, 12, and 24 h after rtPA administration . The amount of MMP-9 in serum was quantified using an enzyme linked immunosorbent assay (ELISA) kit . Optical density (OD) was detected on a microplate reader at 450 nm and corrected at 540 nm.After fixation in 4% paraformaldehyde at 4°C for 24 h, brains were sequentially dehydrated in 15 and 30% sucrose dissolved in saline. The brains were then embedded in optimum cutting temperature compound (OTC) and sliced into 6-μm-thick coronal sections using a cryostat . Five sections from each animal were stained with anti-MMP-9 , followed by staining with secondary antibodies . Fluorescence intensities of the different groups were detected by fluorescence microscope .Western blotting analysis was performed as described previously . The folpost-hoc least significant difference (LSD) tests was performed . Results were considered to be statistically significant for P < 0.05.Data are presented as mean ± standard deviation (SD). To analyse differences between multiple groups, one-way analysis of variance (ANOVA) followed by Spontaneous reperfusion occurred in two beagles of the MCAO group and three of the MCAO + rtPA group before drug administration. The efficacy of embolization in the MCAO and the MCAO + rtPA groups was 81.8 and 90.0%, respectively. There were no significant difference in the mortality rate between the MCAO (2/11) and MCAO + rtPA groups (4/27). A total of 11 canines  were excluded from the experiments . No evidDigital subtraction angiography (DSA) clearly defined the anatomy of the cerebrovasculature . After tCT scanning was performed 24 h after rtPA administration. Low-density areas in the cerebral cortex, a typical sign of ischemic cerebral infarction, were observed in the MCAO group. There were obvious high-density regions in the MCAO + rtPA canines (9/23), which indicated the occurrence of significant HT .CT scanning is the primary strategy for the detection of significant HT in the clinic; however, it is less sensitive for the detection of benign HT, such as HI-1 and HI-2. To confirm the presence of HT, pathological analysis was used. In the control group, there was no evidence of HT assessed by the gross pathology  or by hiGross pathological assessment confirmed the occurrence of significant HT after administration of rtPA 4.5 h post-stroke . FurtherAfter recovering from anesthesia, the canines were subjected to neurological assessment using an 11-point neurobehavioral scoring system. There was a significant difference in the neurological scores between the control group and the MCAO group. All the canines in the MCAO group showed neurobehavioral deficits including circling, reduced consciousness, inability to stand, and ipsilateral hemiparesis. rtPA administration at 4.5 h post-stroke did not improve the neurological outcomes observed in the MCAO group .BBB disruption is a central feature of acute ischemic stroke , and mayMatrix metalloprotein 9 (MMP-9) is a well-recognized peptidase that digests components of the basal lamina, and may contribute to BBB damage . We analWestern blot analysis was utilized to assess MMP-9 protein expression in the peri-infarct region 24 h post-thrombolysis. The results suggested that MCAO significantly increased the MMP-9 expression in this region compared to the control group. This effect was significantly enhanced in the MCAO + rtPA group .We further analyzed MMP-9 protein expression in the peri-infarct regions by IF. MMP-9 expression was significantly higher in the MCAO group compared to the control group. In addition, MMP-9 expression was further increased after rtPA administration .To date, rtPA is the only FDA-approved drug to treat acute ischemic stroke. Unfortunately, it may cause severe complications such HT , 15. Thein situ clot formation, which was thought to be suitable for investigation of HT caused by rtPA , as detected by pathological examination, while the rest of the MCAO group exhibited mild bleeding . These results suggest that MCAO itself can lead to HT even in the absence of rtPA administration, which is consistent with the findings of Couret et al. . Our resThe current model presents various advantages. First, as a large animal with a gyrencephalic brain, the vessel size, and degree of vasospasm encountered in canines are more similar to humans compared to rodents, and it is more convenient to conduct imaging studies on canines because of their compatibility with non-specialized, clinical imaging equipment –20. SecoHT is defined as the extravasation of blood into brain tissue, and may be associated with BBB breakdown , 22. TheMMP-9, a member of the matrix metalloprotein family, is a zinc-dependent enzyme that digests the extracellular matrix. Its substrates include collagen IV, laminin, and fibronectin –27. We hThough there were no significant differences in serum MMP-9 levels between the MCAO group and the MCAO + rtPA group at 29.5 h post-stroke, the IF and western blot results confirmed an increase in MMP-9 protein levels in the peri-infarct region in the MCAO + rtPA group at this time point. Many studies have indicated that neutrophils are the main source of MMP-9 in peripheral blood –32. AccoThere are some limitations of the current study: (1) Due to the high density of bleeding and the unclear infarct boundary in CT scans, we didn't measure infarct volume in our research. To overcome this obstacle, we utilized an 11-point neurological score to assess the therapeutic effects of rtPA administration. In future studies, other methods such as multimodality magnetic resonance imaging may be utilized to resolve this deficiency. (2) To simulate clinical situation, we set rtPA administration at 4.5 h post stroke. For optimization of this model or exploration of time-dependent effects of rtPA, further studies could chose more time points for rtPA thrombolysis. (3) In order to prevent excessive animal deaths, the observation time after rtPA thrombolysis is relatively short. With an increased observation time, the occurrence HT could also increase. (4) There is a lack of specific antibodies in canines, as is the case with many large experimental animals. As a result, though complicated interactions between MMPs and tissue inhibitor of metalloproteinase have been previously described , 33, 34,In summary, we have established a reproducible and feasible canine model of HT caused by rtPA administration. BBB dysfunction caused by rtPA-induced MMP-9 expression is a candidate mechanism for HT induction by rtPA.The raw data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation, to any qualified researcher.in vivo Experiments).All animal-related experiments were performed according to the National Institutes of Health guide for the care and use of laboratory animals. The experimental protocols were approved by the Committee on the Ethics of Animal Experiments, Southeast University Medical School. All experiments, documentation, and reporting were in compliance with the ARRIVE guidelines (Animal Research: Reporting R-HJ, Q-QZ, X-QX, SL, and H-BS conceived the project and designed the experiments. R-HJ, Q-QZ, and X-QX performed experiments. BW, YD, and JW contributed to the analysis and interpretation of data. R-HJ wrote the manuscript. All authors revised the work critically and approved the final version of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Arabidopsis thaliana starch synthase III, which have modest affinity. SBSs, which are overall less widespread than SBDs, have been reported in some branching enzymes, isoamylases, synthases, phosphatases, and phosphorylases active in starch biosynthesis. SBSs appear to exert roles similar to CBMs. SBSs, however, have also been shown to modulate specificity for example by discriminating the length of chains transferred by branching enzymes. Notably, the difference in rate of occurrence between SBDs and SBSs may be due to lack of awareness of SBSs. Thus, SBSs as opposed to CBMs are not recognized at the protein sequence level, which hampers their identification. Moreover, only a few SBSs in enzymes involved in starch biosynthesis have been functionally characterized, typically by structure-guided site-directed mutagenesis. The glucan phosphatase Like SEX4 2 from A. thaliana has two SBSs with weak affinity for β-cyclodextrin, amylose and amylopectin, which were indicated by mutational analysis to be more important than the active site for initial substrate recognition. The present review provides an update on occurrence of functional SBDs and SBSs in enzymes involved in starch biosynthesis.Biosynthesis of starch is catalyzed by a cascade of enzymes. The activity of a large number of these enzymes depends on interaction with polymeric substrates via carbohydrate binding sites, which are situated outside of the catalytic site and its immediate surroundings including the substrate-binding crevice. Such secondary binding sites can belong to distinct starch binding domains (SBDs), classified as carbohydrate binding modules (CBMs), or be surface binding sites (SBSs) exposed on the surface of catalytic domains. Currently in the Carbohydrate-Active enZYmes (CAZy) database SBDs are found in 13 CBM families. Four of these families; CBM20, CBM45, CBM48, and CBM53 are represented in enzymes involved in starch biosynthesis, namely starch synthases, branching enzymes, isoamylases, glucan, water dikinases, and α-glucan phosphatases. A critical role of the SBD in activity has not been demonstrated for any of these enzymes. Among the well-characterized SBDs important for starch biosynthesis are three CBM53s of  In plantae experiments have shown that a few mutations in one of the enzymes involved in starch biosynthesis can affect the structure and functional properties of the produced polysaccharides. These mutations can be situated far from the active site and may lead to loss of carbohydrate binding ability. Some enzymes possess CBMs, i.e., non-catalytic domains with carbohydrate binding sites which are connected to catalytic modules, sometimes through polypeptide linkers. The CBMs are grouped into families in the Carbohydrate-Active enZYmes (CAZy) database based on the amino acid sequence  catalyze transfer of glucose from the soluble precursor ADP-glucose to the non-reducing end of an α-1,4-glucan primer or growing chain. SSs belong to glycosyl transferase family 5 (GT5) and contain also a GT1 domain . The GT1Arabidopsis thaliana leaves. PTST2 is an ortholog to the CBM48-containing FLOURY ENDOSPERM6 (FLO6) from rice (Oryza sativa) endosperm that influences grain starch content, granule morphology, and starch physico-chemical properties. The CBM48 of FLO6 was shown to bind to starch as well as amylopectin and amylose. FLO6 also interacts with the rice debranching enzyme isoamylase 1 that does not bind starch directly . CLg1GBSS crystallized as a trimer and on molecule B two planar electron densities corresponding to maltose was present out side the active site  was analyzed by affinity gel electrophoresis (AGE) yielding Kd of 0.49 and 0.20 mg/ml for starch and amylopectin, respectively , which causes major alterations to amylopectin architecture, is due to a catalytically inactive form of the endosperm-specific SSIIa having two amino acid substitutions (one outside the GT domains and one in the GT domains) and being unable to bind amylopectin. Thus, while wild type SSIIa has a Kd of 3.1 mg/ml for amylopectin no binding was observed of the sugary-2 mutant using AGE (SSII is thought to be important for the formation of chains with intermediate lengths (DP12–25), since SSII deficiency in numerous species results in increased frequency of short glucan chains (DP6–DP11) within amylopectin, decreased abundance of DP12 to DP25 chains, and in most instances an elevated amylose to amylopectin ratio . Furthersing AGE .A. thaliana (AtSSIII) (Osterococcus tauri (OtSSIII-A and OtSSIII-B) .SSIIIs contain one or more CBM53s and are the best studied SSs with regard to carbohydrate binding. In the CAZy database , 133 proAtSSIII) , 2011, tSSIII-B) , and SSIAtSSIII has three N-terminal CBM53s in tandem, which preferentially bind to amylose, the first CBM53 being mainly responsible for this selective binding  SSIII (HvSSIII) has been recombinantly produced and shown by glucan microarray analysis to bind to some starches, but not to any of the linear and branched oligosaccharides tested, while strong binding was observed to 3-phosphomaltose, which mimics the 3-phosphorylation of starch found in vivo (The third CBM53 from barley ( in vivo .Phaseoulus vulgaris L.) (PvSSIII), as well as its N-terminal and catalytic domains on their own, have been characterized with regard to enzymatic activity and binding to amylose and amylopectin , and the affinity of CBM48 alone with β-CD was very similar (Kd ranged from 1.7 to 4 μM). Injection of β-CD into an equimolar mixture of PTST2 and maltoheptaose resulted in similar heat changes as when PTST2 was analyzed alone, indicating that maltoheptaose and β-CD occupy different binding sites. On the other hand, when the experiment was repeated with maltodecaose together with PTST2, significant variations were observed, while the Kd was in the same range as for PTST2 alone. This suggested that the ability of maltodecaose to adopt a structure mimicking helical amylose chains is important for binding long maltooligosaccharides to CBM48 of PTST2  in complex with the inhibitor acarbose, which showed an SBS  catalyze formation of α-1,6-glucosidic linkages creating branch points in amylopectin and are crucial in determining structural and physical properties of starch granules  to a maltooligosaccharide with degree of polymerization (DP) 13 (Kd of 0.13 mM)  in complex with maltohexaose and maltoheptaose were published recently , while CyBE3 transfers short as well as long glucan chains (DP 30)  were similar, while the CyBE3 specificity was similar to that of rice BE1  . The charice BE1 .CyBE1 with maltoheptaose at the active site revealed seven additional binding sites  has a similar domain architecture to CyBE1  resembles CyBE1 in domain architecture, but does not contain the N-domain , while the remaining 6 sites are SBSs some of which  tuber starch BE1 (StBE1) described above  could bind the glucan chain entering the active site, and III and VI could bind the glucan chain exiting the active site  hydrolyze α-1,6-glycosidic linkages at branch points in amylopectin and oligosaccharides derived thereof. DBEs play a role during amylopectin biosynthesis and degradation. Two types of starch DBEs are found in plants, the isoamylase-type (EC 3.2.1.68) and the pullulanase-type (EC 3.2.1.41). While at least three isoforms exist of the isoamylase-type, the pullulanase-type occurs as a single form, known as limit dextrinase. Both belong to GH13 but are categorized into different subfamilies with distinct specificities; isoamylases are found in GH13 subfamily 11 (GH13_11), and pullulanase-type DBEs are found in GH13 subfamilies 12–14 (GH13_12–14) with the plant pullulanases being found solely in GH13 subfamily 13 . Isoamyltability .Aspergillus niger glucoamylase, suggesting that plant DBE CBM48s may be intermediates between CBM20 and CBM48  isoamylase 1 (OsISA1) does not bind starch directly, but it can interact both in vivo and in vitro with the CBM48-containing FLO6 protein . Hence, FLO6 might assist binding of OsISA1 to starch  has a C-terminal catalytic domain and two CBM45s: CBM45-1 located at the N-terminal next to the chloroplast transit peptide and CBM45-2 at the center of the sequence, and large areas of the sequence were unmapped . Such low affinity may be a prerequisite for a dynamic interaction of GWD1 with the starch granule facilitating a necessary tight control of the starch metabolism  has a single CBM20 appended at the N-terminus and a C-terminal GWD catalytic domain, while the function of the ∼700 amino acid residues long segment in between these two domains is unknown  as determined by SPR  and CBM48 domains   Figure . Of thes) Figure . Using A amylose . LSF2 sp amylose , which a amylose . The hig amylose . Unexpecectively . Remarkaectively .As the presence of either CBMs or SBSs in several cases has been crucial for correct starch biosynthesis, the recent focus on non-catalytic sites can potentially open new promising routes to obtain useful modified starches.Current insights on CBM53s from SSIIIs and their interaction with starch may be useful for manipulating catalytic efficiency of SSIII by altering the active site structure without modifying the catalytic module. Determination of the structure of a CBM53 would take the knowledge to the next level and improve understanding of the protein–carbohydrate interactions, maybe to deduce a mechanism for how the different CBM53s can alter activity of SSIII .PTST gene has been demonstrated to be essential for amylose synthesis in A. thaliana leaves and could be useful in obtaining amylose-free starches, which find extensive applications in food and non-food industrial products (ptst2 A. thaliana mutant had larger starch granules, but with similar morphology to wild type granules, while much smaller granules were observed in the ptst2 overexpression lines (SBSs in BE1s appear to define the length of transferred branch chains , which cproducts . CBM48 oon lines . Furtheron lines .Notably, these various examples evidently demonstrate that properties of starch can be modified by altering the enzyme–substrate interaction during starch biosynthesis. Yet, the impact of especially SBSs on the function of the starch biosynthetic enzymes is still to be further explored. However, the challenge is that they are not easily recognized based on bioinformatics analysis, like the carbohydrate binding sites of CBMs.MM, CW, and BS conceptualized the manuscript, which was written by CW and MM with invaluable input from BS.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Conclusions: After a one-year simulation of chewing activity, irrespective of preparation geometry, zirconia copings did not show any sign of t–m transformation, either in the load application areas or at the margins. Consequently, manufacturing milling even in thin thickness did not cause any structural modification of zirconia ceramics “as received by manufacturers” both before and after chewing simulation.Objectives: Stresses produced during the fabrication of copings and by chewing activity can induce a tetragonal-to-monoclinic (t–m) transformation of zirconia. As a consequence, in the m-phase, the material is not able to hinder possible cracks by the favorable mechanism known as “transformation toughening”. This study aimed at evaluating if different marginal preparations of zirconia copings can cause a premature phase transformation immediately after manufacturing milling and after chewing simulation. Methods: Ninety copings using three commercial zirconia ceramics  were prepared with deep-chamfer, slight-chamfer, or feather-edge finish lines (n = 10). Specimens were tested in a chewing simulator  under cyclic occlusal loads simulating one year of clinical service. Raman spectra were acquired and analyzed for each specimen along the finish lines and at the top of each coping before and after chewing simulation, respectively. Results: Raman analysis did not show any t–m transformation both before and after chewing simulation, as the typical monoclinic bands at 181 cm IC = 9–10 MN/m3/2), and flexural strength (>1 GPa) [Due to patients increasing demand for aesthetics, as well as the introduction of the latest innovative dental technologies, the use of high-strength polycrystalline ceramics has become fairly widespread in the last decade ,3,4,5,6.Zirconia is an allotropic metastable material, which can be present in different crystallographic structures with the same chemical composition ,10. StruThe transformations from cubic to tetragonal (c–t) and from tetragonal to monoclinic (t–m) under cooling are described as “martensitic”, ; in the t–m transformation a volume expansion of about 5 vol.% occurs (when unconstrained) . The thrTo date, most zirconia restorations are fabricated by means of CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) or copy-milling techniques . During For zirconia core prostheses, the manufacturers recommend chamfer or round shoulder preparations, as they are considered to have the best precision, resistance, and aesthetics ,14,15,16Framework fractures were reported as mechanical complications of zirconia restorations in several clinical studies ,12,19,20The margin of a single crown framework is a key point where stresses accumulate ,8,26. ItMicro-Raman spectroscopy was used as a qualitative technique for the spectroscopic characterization of zirconia for biomedical applications. This technique was used to evaluate zirconia metastability, and visualize patterns of phase-transformation and related residual stresses on the surface of zirconia samples ,30,31,32To date, there is little information on the integrity and mechanical reliability of zirconia cores with different marginal finish lines ,7,8. ThuThree standardized stainless steel abutments ,36,37 weThree zirconia available on the market were selected: NobelProcera Zirconia, , Lava Classic , and Lava Plus . Thirty zirconia copings for each material were prepared with a deep-chamfer, slight-chamfer, or feather-edge finish line (n = 10 per group). All copings had a thickness of 0.6 mm . Groups Zirconia copings were placed on their proprietary stainless steel abutments used for their preparation before impression. One drop of paraffin gel was used between the copings and the stainless steel abutments to avoid minor movements during the simulated chewing process.A chewing simulator (CS) was used to simulate occlusal loading  . The devAccording to data reported in literature ,42,43,44−1 with an average spectral resolution of 5 cm−1 [A modular research spectrograph  connected to an optical microscope  was used to investigate the crystalline configuration of zirconia. A near-infrared diode laser operating at 785 nm was used to induce the Raman scattering effect. The spectral coverage ranged from 100 to 3450 cm−1 (zirconia fingerprint region), and the exposure time for each scan was 40 s. Acquired data were then analyzed with a spectrographic analysis software .Twenty spectra for each specimen were acquired, before and after chewing simulation, along the marginal finish line and 5 at the top of each coping, thus where the load was distributed and applied, respectively, to assess if phase-transition of the zirconia occurred. The spectral range was set between 100 and 700 cm−1  did not show the typical bands of monoclinic zirconia at 181 cm−1 and 192 cm−1. None of the Raman spectra acquired at the margins and on the top of the copings showed the presence of monoclinic zirconia in the pre-chewing situation, irrespective of the different margin geometry. Moreover, when the spectra acquired before and after chewing simulation were compared, no changes were detected in any group, at both magnifications, as showed representatively in No significant differences either in the shape of the spectra and in the height and width of the peaks were observed in all the tested specimens, both as received by manufacturers and after chewing simulation .Micro-Raman spectroscopy was used to qualitatively identify possible crystallographic phase transformation of zirconia, but since no changes were detected in any spectra, no statistical analyses were performed.Zirconia is a restorative material widely used in dentistry and extensively tested for mechanical properties , fracturThe present investigation was not conceived as a load-to-fracture study but as a qualitative evaluation of the possible phase transformation induced only by fabrication processes of zirconia copings as received by manufacturers. As the micro-Raman analyses were performed not only on the occlusal surfaces but also at the level of the prosthetic margins, it was necessary to remove the copings from the abutments so as to analyze the inner part of the finish lines. The use of conventional cements would have made such analyses impossible, so it was decided that a stabilizing medium would be used to avoid minor movements during the dynamic load of the copings. Indeed, the present investigation was designed to include the minimum possible number of study variables so as to detect the influence of milling procedures on possible zirconia phase transformation solely.The results of the Raman spectroscopic analyses performed in this investigation showed that the machining processes needed to obtain the complex framework crown shaping did not generate the phenomenon of “transformation toughening”, either on the top or at the margins of the restorations. Similarly, specimens that underwent an in vitro occlusal loading challenge  showed monoclinic zirconia neither on the top of the dental framework (where the load was applied) nor at the margins. Thus, both the experimental hypotheses tested were accepted since (1) different marginal preparations  did not produce a t–m phase transformation of zirconia cores and (2) phase transformation did not occur on specimens prepared with different prosthetic geometries after 1 year of fatigue load simulation. These results are remarkable since it was reported that zirconia under wear can show up to 40% vol of m-zirconia , so the 2O3), as disclaimed by manufacturers; LAVA Classic and LAVA Plus are single-phase tetragonal zirconia polycrystals doped with yttrium (Y-TZP) as deduced by their composition. Zirconia for dental use is available in three formulations: (1) dispersion-toughened ceramic, in which t-zirconia particles are dispersed in alumina ; (2) mullite  as partially stabilized zirconia (PSZ), in which zirconia is stabilized in the t and c phase by addiction of dopants ; (3) tetragonal zirconia polycrystals (TZP) that contain almost 98% of t-zirconia grains, which are so fine to need only a small amount of dopants (3 mol% of yttrium oxide) . Among t2 to m-ZrO2, the monoclinic crystals being larger than the tetragonal ones. In fact, the energy dissipation mechanism determines a 3%–5% volume increase of the crystals, constrained by the surrounding ones, resulting in a favorable compressive stress that acts as a crack limiter. Such a stress-induced t–m phase transformation of zirconia crystals under load is known as “phase transformation toughening” (PTT) and remarkably increases the fracture toughness and the flexural strength of the material, much higher than in other ceramics for dental use [Thanks to the presence of dopants, during the processing of zirconia frameworks or monolithic crowns, zirconia polycrystals remain in the tetragonal polymorph phase (TZP), metastably retained when the temperature decreases . Such a ntal use ,15,21. Antal use ,52,54. Nntal use ,51. Thisntal use ,31,55 an−1 and 192 cm−1 [Previous studies used X-ray diffractometry (XRD) to detect the crystallographic changes of zirconia but this technique is limited by its inability to detect the monoclinic zirconia if its content is lower than 5%, making it unsuitable to identify the start of the transformation ,57. For 192 cm−1 . In a re192 cm−1 . Current manufacturers’ recommendations and literature suggest that shoulder, chamfer, or slight-chamfer marginal finish lines should be prepared for zirconia restorations ,60, espePrevious in vitro studies focused on the role of finish line preparation in determining marginal adaptation and fracture load resistance of zirconia crowns ,18,64,65irrespective of preparation geometry, the manufacturing processes needed to obtain different marginal finish lines  did not generate the phenomenon of “transformation toughening” either in the load application areas or at the margins of the restorations in the analyzed brands of zirconia;after wear-simulation of one year of chewing (fatigue cyclic load), monoclinic zirconia was not found either on the top or at the margins of the copings;manufacturing milling, even in thin thickness, did not cause any structural modification of zirconia ceramics “as received by manufacturers” both before and after chewing simulation;further laboratory studies and RCTs are needed to investigate if longer chewing time can produce negative effects on zirconia.According to the results and within the limits of this in vitro study, the following conclusions can be drawn:


JHPS inhabits, are at times frightening.For the past 6 months I have been learning to be a journalist, a future chosen path, as I have reached a certain age. For sure it has been interesting training, but the similarities between the world outside, and the scientific bubble of academic publishing that Freelance text journalists will have a lower chance of an unsolicited submission being published than any scientific author, and they will be paid a pittance for their efforts. Few have retired wealthy from writing. Publishers are going to the wall more frequently than is comfortable, while the internet is making significant inroads to their profits. Advertising is harder to find—many publications rely on it—which means standards can be allowed to lapse and articles can be commissioned, or accepted, simply to ensure that advertising income follows.Take a look at the next travel article you read in a mainstream publication and decide for yourself if you think it has been written with advertising in mind, or for a genuine desire to tell an original story. Faced with these frustrations, self-publishing, now called independent publishing, has taken off remarkably. It is now the way of things. Right now, >50% of new e-books are independent, a number that is set to increase further. No wonder the larger publishers are worrying.There is a problem, too, as the headlong dash for independent publishing runs the risk of compromising quality. Whole conferences are dedicated to being noticed, how to sell, how to feature on social media. Not once have I attended a meeting, in the great wide world of writing, and I attend plenty of them, where anyone has even mentioned elegance of the prose.Enter at this point, academic publishing. The subscription journals are struggling because advertising is harder to find, so they are forced to think continually how best to ensure their survival. No longer are readers loyal. We are like sheep in a field, grazing here and there. We take a piece of information from one journal, another from somewhere different, we then undertake an internet search and might also look at social media. This is the way it is done these days. No longer do we trust one journal alone and rely on it to offer everything we need, both as a source of information, but also as an outlet for our research. We look around and shop around. It is simply the way we do it.JHPS readers will receive regular requests to write for journals based in far-flung lands, or to present at conferences that seem to have no focus. Some of these invitations are a privilege to receive and are unquestionably above board and valid. Others are more dubious. I sometimes ask myself the question, is this journal, is this conference, after my money or my expertise? Sadly, and all too often, it can be the former. Money, not expertise. But their existence dilutes an already overstuffed market.If subscription journals are struggling, then so is Open Access, as its simplicity allows so many players to compete. I am certain JHPS we are blessed by incredible editorial support, without which we simply could not function. I realize that I acknowledge, and appreciate, its role repeatedly. That is intentional.This makes it hard for any credible journal to compete, be it subscription, Open Access, or a combination. There is a temptation to lower standards, increase acceptance rates, select papers that may encourage advertising—all manner of tricks to keep a journal afloat. It is the role of the Editor, Deputy Editors and Editorial Board to ensure this does not happen. At JHPS remains in the forefront of hip preservation surgery. It reached that point in record time. We need it to stay there in perpetuity. Without authors submitting, and submitting decent work, a journal will ultimately fail. I rely on us all to be sure that does not happen to our journal.But top of the list for our journal’s success must be the authors and, of course, our readers who cite what we publish. Right now, we are doing brilliantly, and I am grateful for your support. But we need to keep it that way in the face of challenges from many sectors. We need to be sure that JHPS.When it comes to improving your chances of being accepted, there are two simple rules I would encourage. They apply as much to work in the wider world of writing, as they do to First, have a clear message. Be specific. If you cannot summarize your work in a single sentence, the chances are your submission will be too vague. For example, do not say something to your trainee like, ‘Let’s have a look at my last 50 osteotomies’. Make it clearer, such as, ‘Let’s have a look at the rehabilitation of my last 50 osteotomies’. Be as focussed as you can.Second, and as a writer the most important, never submit your first effort. Finish your work, at least think you have finished, but at that moment do not click ‘Send’. Wait a few days, preferably a fortnight, and revisit what you have done. I wager you will think your first effort was futile and you will edit and edit again. This editorial, for example, has been edited multiple times. Even so, I feel I could have done better. Remember also, Thomas Jefferson. It was he who said, ‘The most valuable of all talents is that of never using two words when one will do’. There is always room for making things shorter.JHPS first, last, and continually.So, keep ‘em coming! Please think of JHPS, issue 5.3, was splendid. Yet again I was spoiled for choice. I was especially interested to read the two review articles on venous thromboembolism associated with hip preservation surgery, one by Rezaie, Azboy and Parvizi [et al. [Turning more specifically to our journal. I thought our last issue of  Parvizi  where a  [et al.  agreed tet al. [et al.[And for this issue, our latest, issue 5.4, which papers especially appeal? All of them of course, otherwise they would not have been accepted, although two in particular stand out. There is that by Krueger et al.  on injecJHPS. It is published for you, the hip preservation practitioner, and is filled from cover to cover with brilliance. I commend this issue to you in its entirety.So, as ever, please enjoy this issue of My very best wishes to you all.


To compare the efficiency and safety of steep-axis one-handed phacoemulsification with steep-axis two-handed phacoemulsification.  Patients with cataracts underwent steep-axis one-handed (steep-axis one-handed group) or steep-axis two-handed (steep-axis two-handed group) phacoemulsification with a 2.4 mm clear corneal incision (CCI) under the guidance of the Verion Image-Guided System. Intraoperative phacoparameters, such as visual acuity, surgically induced astigmatism (SIA), total corneal astigmatism (TCA), angle of error (AE), corneal volume (CV), and corneal endothelial cells, were compared. p < 0.05) but not at 1 month and 3 months postoperatively. TCAs were significantly decreased in both groups at 1 and 3 months postoperatively . There were no significant differences at any follow-up points in both groups . At 3 months postoperatively, the SIA was 0.95 ± 0.44 D in the steep-axis one-handed group and 1.01 ± 0.50 D in the steep-axis two-handed group; there was no significant difference between the groups. The AE was 39.45 ± 26.53° in the steep-axis one-handed group and 49.75° ± 26.23° in the steep-axis two-handed group, which were significantly different (p=0.005). Endothelial cell loss was significantly lower in the steep-axis one-handed group than that in the steep-axis two-handed group at all follow-up points .  There were no significant differences in the intraoperative phacoparameters between the two groups. The visual outcomes were significantly better in the steep-axis one-handed group than in the two-handed group at 1 week postoperatively (all  Both the steep-axis one-handed and the steep-axis two-handed techniques could significantly decrease TCA. Compared with the steep-axis two-handed technique, the steep-axis one-handed technique has the advantage of decreasing the AE and reducing trauma to the cornea in soft-to-moderate nuclei. Currently, cataract surgery has entered the era of refractive surgery, and the intraoperative correction of corneal astigmatism is a necessary requirement for refractive cataract surgery (RCS). Many methods are available to correct preexisting astigmatism of the cornea, such as single clear corneal incision (CCI) or paired opposite CCI at the steepest meridian –4, limbaCurrently, there are two kinds of phacoemulsification: one-handed phacoemulsification and two-handed phacoemulsification. Our previous studies have found that the one-handed technique had the advantage of reduced trauma to the cornea compared with the two-handed technique for cataract patients with a soft-to-moderate nucleus , 9. The This prospective nonrandomized comparative study comprised patients with age-related cataract (ARC) who received phacoemulsification at the Department of Ophthalmology, Affiliated Hospital of Nantong University, Jiangsu, China, from September 2017 to May 2018. All patients agreed to participate, met the inclusion criteria, chose a surgical technique according to the patient's wishes, and signed an informed consent agreement before undergoing any procedure, and the eye conditions were matched between two groups. The study was performed in accordance with the ethical principles of the Declaration of Helsinki and approved by the Affiliated Hospital of Nantong University's ethics committee.The Lens Opacities Classification System III (LOCS III) was used for cataract classification . InclusiAll patients underwent a complete ophthalmologic measurement. Visual acuity included uncorrected and corrected distance visual acuity (UDVA and CDVA) and uncorrected and corrected near visual acuity (UNVA and CNVA). Biometry, such as axial length, WTW, and CCT, was performed using a Lenstar noncontact optical low-coherence reflectometer . Corneal volume (CV) and TCA were obtained using a Pentacam . Anatomic landmarks of the eye were obtained using the Verion Image-Guided System .The anatomic image was transferred onto a USB drive inserted into the Verion digital marker monitor screen, which was used to guide the different positions of steep-axis CCI. The 2.4 mm CCI was selected for the steep axis, which was chosen according to the steepest corneal meridian of the TCA. The triangle representing the target incision appeared both on the monitor and through the oculars on the microscope .All operations were performed under topical anesthesia with 0.5% proparacaine hydrochloride  by the same experienced surgeon (H.G.). Pupillary dilation was achieved with the instillation of one drop of 0.5% compound tropicamide  every 10 minutes until the pupil diameter was greater than 7 mm before surgery. In all cases, sodium hyaluronate gel  was used as an ophthalmic viscosurgical device (OVD) and balanced salt solution (BSS) as the infusion fluid. All phacoemulsifications were performed using a phacoemulsification machine . Phacoemulsification was performed using OZil Intelligent Phaco (IP) software. The ultrasound and fluid settings were as follows: bottle height: 105 cm, power: 60%, vacuum: 500 mmHg, and aspiration flow: 32 cc/min.A 2.4 mm single-plane CCI was created at the steep axis of the cornea under the guidance of the Verion Image-Guided System with a diamond keratome. Continuous curvilinear capsulorhexis (CCC) was performed with capsular forceps under the protection of an OVD. After CCC, hydrodissection and hydrodelineation were performed, and nuclear emulsification was performed using the one-handed technique . All phaA 2.4 mm single-plane CCI was created at the steep axis of the cornea, and a 1.0 mm cornea side incision was set at the limbus far from CCI (at approximately 115°) in the two-handed group, under the guidance of the Verion Image-Guided System. CCC was performed with capsular forceps under protection of an OVD. After CCC, hydrodissection and hydrodelineation were performed, and nuclear emulsification was performed using the two-handed technique . The resThe following intraoperative phacoparameters were recorded: cumulative dissipated energy (CDE), ultrasonic total time, and total surgical time .All patients underwent ophthalmologic measurements at follow-up appointments: 1 week, 1 month, and 3 months postoperatively. Visual acuity included uncorrected and corrected distance visual acuity (UDVA and CDVA) and uncorrected and corrected near visual acuity (UNVA and CNVA), CV within the central 10 mm zone (10-mm CV), TCA, and central endothelial cell measurements. SIA and angle of error (AE) at 3 months postoperatively were analyzed by vector analysis according to the Alpins method .t-tests for two independent samples were used. The chi-square test was used for comparison of the type of corneal astigmatism. For the comparison of preoperative and postoperative data, Student's t-test of paired samples was used. The level of statistical significance was always p < 0.05.Statistical analysis was performed using SPSS for Windows software . The homoscedasticity of the data was studied with Levene's test. For the comparison of steep-axis one-handed and steep-axis two-handed group data, Student's p > 0.05).The study evaluated 209 eyes of 185 patients: 104 eyes of 96 patients in the steep-axis one-handed group and 105 eyes of 96 patients in the steep-axis two-handed group. Seven patients underwent steep-axis one-handed phacoemulsification in one eye and two-handed phacoemulsification in the other eye. Patients' demographics and preoperative ophthalmic measurements are provided in p > 0.05).The surgical parameters in both groups are summarized in p < 0.001). At 1 week postoperatively, UDVA, CDVA, UNVA, and CNVA in the steep-axis one-handed group were significantly improved compared with those in the steep-axis two-handed group . However, the abovementioned differences were ameliorated at 1 and 3 months postoperatively . Compared with baseline, TCAs were improved at 1 week postoperatively in both groups, but there were no significant differences . At 1 and 3 months postoperatively, TCAs were significantly decreased in both groups . There were no significant differences in TCA at all follow-up points in both groups . At 3 months postoperatively, the SIA was 0.95 ± 0.44 D in the steep-axis one-handed group and 1.01 ± 0.50 D in the steep-axis two-handed group; this difference was not statistically significant (p=0.363). The AE was 39.45° ± 26.53° in the steep-axis one-handed group and 49.75 ± 26.23° in the steep-axis two-handed group, which was a significant difference (p=0.005).p < 0.001) and 1 month postoperatively ; the values returned to preoperative levels at 3 months postoperatively . The between-group difference was statistically significant at 1 week postoperatively (p=0.005) but not at 1 month (p=0.467) or 3 months postoperatively (p=0.736). In both groups, the mean ECD was significantly decreased postoperatively , and no significant difference was observed between the 2 groups at any follow-up points . Endothelial cell loss (ECL) was significantly lower in the steep-axis one-handed group than in the steep-axis two-handed group at all follow-up points . In both groups, the mean percentages of hexagonal cell (HEX%) were significantly decreased postoperatively , and no significant differences were observed between the 2 groups at any follow-up points .μm (range: 449 to 619 μm), the WTW was 11.59 ± 0.31 mm, (range: 10.86 to 12.32 mm), and the SIA at 3 months postoperatively was 0.95 ± 0.44 D. There was no significant correlation between CCT and SIA  but significant negative correlation between WTW and SIA . In the steep-axis one-handed phacoemulsification group, the CCT was 530.13 ± 32.27 μm (range: 482 to 615 μm), and the WTW was 11.61 ± 0.32 mm (range: 10.90 to 12.38 mm) The SIA at 3 months postoperatively was 1.01 ± 0.50 D. There was significant negative correlation between CCT and SIA  but no significant correlation between WTW and SIA at 3 months .In the steep-axis one-handed phacoemulsification group, the CCT was 525.45 ± 31.24 Improvements in surgical techniques and instruments have propelled CCI into the current trend of phacoemulsification . In RCS,The efficiency of both techniques was evaluated by the amount of CDE and total ultrasound time in two groups. In our study, the CDE and total ultrasound time were slightly higher and longer in the steep-axis one-handed group than that in the steep-axis two-handed group, but the differences were not statistically significant, which was in accordance with our previous study , 9; thusp=0.03) [p < 0.005).Previous studies hypothesized that CCI at the steep axis could flatten the steep meridian and steepen the flat meridian so as to reduce corneal astigmatism , 12. Borp=0.84) with a 2.4 mm transconjunctival single-plane sclerocorneal incision. Koç et al. [μm, and SIA was approximately 0.6 D with a 2.7 mm CCI). Theodoulidou et al. [r = −0.54; p=0.585) but significant negative correlation between WTW and SIA  in the steep-axis one-handed phacoemulsification group. There was significant negative correlation between CCT and SIA , but no significant correlation between WTW and SIA at 3 months . Our CCT was thinner than that observed by Woo and Lee [The SIA is an integral component of refractive surgery, and personalized SIA power has been advocated in the planning of cataract surgery. SIA is influenced by the incision numbers, size (width and length), configuration , and location  , 12–14. ç et al.  reportedç et al.  reportedu et al.  reported and Lee , and our and Lee . These dp=0.005).AE is the angle difference between the SIA and TIA. Positive and negative values of angle of error refer to mean counterclockwise and clockwise rotation from its intended axis, respectively . The AE p < 0.001). At 1 week postoperatively, visual outcomes in the steep-axis one-handed group were statistically better than those in the steep-axis two-handed group. The improvement of early visual acuity is associated with corneal trauma. Given that endothelial cellular injury alters the pumping activity of this corneal layer, resulting in increased stromal hydration [The improvement in visual acuity is an important goal of a successful cataract surgery. Visual acuity was significantly improved at all follow-up points in both groups (all ydration , CV is cydration . In our At present, corneal endothelial injury after phacoemulsifcation is generally assessed by specular microscopy in terms of changes in corneal endothelial cells. In our study, no significant difference in ECD was noted between the 2 groups at any follow-up point, but the mean ECL in the steep-axis one-handed group was significantly decreased compared with that in the steep-axis two-handed group. These findings were in accordance with our previous study that the one-handed technique had the advantages of less trauma to the cornea than the two-handed technique for cataract patients with a soft-to-moderate nucleus , 9.In conclusion, our results indicate that both the steep-axis one-handed and the steep-axis two-handed techniques could significantly decrease TCA. Compared with the steep-axis two-handed technique, the steep-axis one-handed technique has the advantage of decreasing the AE and reducing trauma to the cornea in a soft-to-moderate nucleus.


Incidence of cornea melting or perforation is commonly seen in variety of cornea conditions. It can cause debilitating vision loss and impair patient's daily activity. Several techniques have been described to surgically treat cornea perforation and melting. In this article, a series of corneal diseases treated with corneal patch graft are highlighted to relate different approach of cornea patch graft surgery. Post-operative management and complications are discussed. Cornea patch graft has been advocated as the surgical procedure to treat variety of anterior segment pathologies. It involves patching the affected area with full thickness or partial thickness corneal donor tissue. The aim is to restore globe integrity and prevent further inflammation that could lead to devastating complications such as endophthalmitis. Cornea perforation and melting can occur in infectious keratitis, autoimmune diseases such as rheumatoid arthritis, ocular trauma and ocular surface disorder.Patch graft materials are derived from cornea, sclera, pericardium and dura mater . ScleralCornea patch graft has been indicated in cases of corneal perforation, cornea thinning , scleralA 32-year-old gentleman, presented to eye casualty with sudden onset left eye redness and discomfort. He had history of foreign body entering into his left eye while hammering 1 week prior to that. Examination revealed deeply seated rust ring on the anterior cornea stroma. Failure to remove the rust ring completely resulted in corneal ulceration 1 week later. Topical antibiotics and lubricants were initiated. However, he started to develop cornea thinning. Despite being treated with intensive antibiotics and lubricants, the cornea thinning progressed to cornea perforation with flat anterior chamber (AC) . He undeA 38-year-old gentleman with underlying diabetes mellitus (DM) type I, hypertension, end stage renal failure (ESRF), right eye pseudophakia presented with right eye blurring of vision associated with photophobia and watery eye for 1 month. Examination revealed right eye vision of 6/60 pinhole 6/36. He had a furrow cornea thinning from 12 to 5 o'clock with overhanging edge where there's only Descemet remaining. There's adjacent cornea epithelial defect but no cornea perforation seen .Systemic examination and blood investigations were normal. He was diagnosed having Mooren's ulcer. Topical corticosteroid and antibiotic, systemic immunosuppressant and collagenase inhibitor were commenced. He underwent conjunctival resection and cryotherapy twice and amniotic membrane patch graft once before a banana shaped corneal lamellar patch graft was performed . His visA 46-year-old Malay gentleman, without any comorbid, presented with progressively worsening left eye vision associated with pain and redness for 1 year duration. Symptoms started to appear 6 months post pterygium excision. His left eye vision on hand motion only. On examination, there was a crescent shape peripheral corneal thinning from 4 to 1 o'clock. The remaining cornea with its overhanging edge remains oedematous. Examination of fellow eye was normal.He was investigated for underlying autoimmune or related diseases. A diagnosis of Mooren's ulcer were made and he was started on systemic and topical immunosuppression therapy. Despite this treatment, 3 months later, his eyes showed disease progression where there was continuous cornea melting to almost 360 degree  for whicA 42-year old gentleman with underlying DM, hypertension with history of Steven Johnson Syndrome (SJS) 10 years ago presented with left progressive blurring of vision with occasional eye redness and discomfort. He had history of bilateral myopic laser refractory surgery done 3 years prior to this.Examination revealed right eye vision 6/24 and left eye counting finger. Both eyes showed presence of extensive peripheral cornea thinning. Peripheral edge of left cornea had slow leak but with deep anterior chamber . Other eSeries of investigation were taken to rule out autoimmune related diseases. He was diagnosed as Mooren's ulcer. He was started on systemic immunosuppressant, collagenase inhibitor and topical corticosteroid and antibiotic. He was scheduled for left eye cornea banana-shaped patch graft . Post opA 32-year-old Myanmar lady, complained of right eye discomfort with recurrent eye redness for the past 2 years. The eye redness usually resolve temporarily with over the counter eye drop. She noticed the presence of bluish discoloration at the right nasal conjunctiva for the past 1 year which was increasing in size. Her vision on both eyes were 6/6. She had history of trauma to right eye during childhood.Right eye examination showed two locations of scleral thinning with visible uveal tissue at inferonasal quadrant with adjacent cornea scarring . Other oShe underwent cornea patch graft for the scleral thinning . Post-opA 15-year-old boy with congenital right eye temporal limbal dermoid  was seenHe underwent excision of the limbal dermoid and corneal patch graft surgery . Post-opCornea melting is a sequelae of progressive keratolytic process. Untreated cases can lead to cornea perforation. Application of corneal patch graft is another way to address this issue. Corneal patch graft use when the cornea defect is too large until the application of cyanoacrylate tissue adhesive is not recommended (perforation of >1 mm)  or when In this series, the decision for patch graft was made due to many reasons. The author attempted corneal patch graft as patients were not responding to pharmacological management.Small cornea perforation as in case 1, was initially managed with cyanoacrylate glue, however, this method was not fruitful in this case. Application of corneal patch graft helped to seal off the perforation and maintained the anterior chamber. Post-operatively this patient had persistent epithelial defect because of uneven surface. This results in unequal distribution of tear film which can result in persistent epithelial defect. The patient underwent graft re-suturing twice before he responded well. A round trephined corneal patch graft was used in this patient had minimal effect on visual axis .Case 2, 3 and 4 involves the usage of corneal patch graft in Mooren's ulcer. Stepwise approach involving; conjunctival resection, amniotic membrane graft and corneal patch graft with concurrent systemic and topical immunosuppressant, manage to control the disease activity. Conjunctival resection is known to remove the presence of complements, immunoglobulins and inflammatory cells . Two patScleral thinning has been shown to respond well with corneal patch graft. As in case 5, the usage of corneal patch graft can be cosmetically acceptable as the curvature of cornea was able to cover large area of scleral bed defect . ConjuncCorneal patch graft similarly used in post limbal dermoid excision. It has proven to consume less time and labor force . The cosAll patients who underwent this cornea patch graft surgery were treated with topical corticosteroid and topical antibiotic. The author advocate the usage of topical prednisolone acetate 1% and topical levofloxacin 0.5% along with adequate lubricants. Systemic corticosteroid; oral prednisolone was started peri-operatively to control the ocular inflammatory process. Apart from oral corticosteroid, systemic immunosuppressant such as oral azathioprine was given in cases where the patients were treated for Mooren's ulcer.Corneal patch graft has evidence to improve the outcome in treating anterior segment disorders especially involving cornea and sclera. Its advantages have made it possible to produce good post-operative result; be it functionally or cosmetically.