JCHS accepts all suitable reviews that are within the scope of the journal. If you wish to enquire further about the suitability of your article, you can email the Editorial office of JCHS.

Criteria
Reviews are summaries of insights or advances in specific research areas within the scope of JCHS. Key aims of the reviews are to provide timely, systematic and substantial coverage of a mature topic, to evaluate progress in specified areas, and/or to provide critical assessments of emerging technologies.

Reviews should provide a balanced overview of the field and not to focus on the authors’ own work or that of their close colleagues.

Submission process
Manuscripts must be submitted by one of the authors of the manuscript, and should not be submitted by anyone on their behalf. The corresponding author takes responsibility for the article during submission and peer review.

To facilitate rapid publication and to minimize administrative costs, JCHS only accepts online submission. The main manuscript should be in Microsoft Word (DOC, DOCX) file formats. Tables and figures should be submitted as separate files.

During submission provide a cover letter explaining why your manuscript should be published in the journal, elaborate on any issues relating to our editorial policies and declare any potential competing interests.

Preparing main manuscript text
General guidelines of the journal's style and language are given below.

Length of article
Reviews should not exceed 5000 words (excluding references).

Overview of manuscript sections for Reviews
Manuscripts for Reviews submitted to JCHS should be divided into the following sections (in this order):

• Title page
• Abstract
• Keywords (10 words)
• Introduction
• Review
• Conclusions
• Competing interests
• Acknowledgements
• References
• Illustrations and figures (if any)
• Tables and captions (if any)
• Preparing additional files

The Accession Numbers of any nucleic acid sequences, protein sequences or atomic coordinates cited in the manuscript should be provided, in square brackets and include the corresponding database name; for example, [EMBL:AB026295, EMBL:AC137000, DDBJ:AE000812, GenBank:U49845, PDB:1BFM, Swiss-Prot:Q96KQ7, PIR:S66116].

The title page should:

- provide the title of the article
- list the full names, institutional addresses and email addresses for all authors
- indicate the corresponding author
- abbreviations within the title should be avoided

A short, unstructured, single paragraph summary, no more than 250 words, of the major points raised, making evident the key work highlighted in the article.

Ten keywords representing the main content of the article.

This section should put the subject matter in adequate context and should be comprehensible to non-experts.

This should contain the body of the article, and may also be broken into subsections with short, informative headings.

This should state clearly the main conclusions of the review and give a clear explanation of their importance and relevance.

A competing interest exists when your interpretation of data or presentation of information may be influenced by your personal or financial relationship with other people or organizations. Authors must disclose any financial competing interests; they should also reveal any non-financial competing interests that may cause them embarrassment were they to become public after the publication of the manuscript.

Authors are required to complete a declaration of competing interests. All competing interests that are declared will be listed at the end of published articles. Where an author gives no competing interests, the listing will read 'The author(s) declare that they have no competing interests'.

When completing your declaration, please consider the following questions:

Financial competing interests

• In the past three years have you received reimbursements, fees, funding, or salary from an organization that may in any way gain or lose financially from the publication of this manuscript, either now or in the future? Is such an organization financing this manuscript? If so, please specify.
• Do you hold any stocks or shares in an organization that may in any way gain or lose financially from the publication of this manuscript, either now or in the future? If so, please specify.
• Do you hold or are you currently applying for any patents relating to the content of the manuscript? Have you received reimbursements, fees, funding, or salary from an organization that holds or has applied for patents relating to the content of the manuscript? If so, please specify.
• Do you have any other financial competing interests? If so, please specify.

Non-financial competing interests

Are there any non-financial competing interests (political, personal, religious, ideological, academic, intellectual, commercial or any other) to declare in relation to this manuscript? If so, please specify.

If you are unsure as to whether you, or one your co-authors, has a competing interest please discuss it with the editorial office.

Authors' contributions
In order to give appropriate credit to each author of a paper, the individual contributions of authors to the manuscript should be specified in this section.

According to ICMJE guidelines, An 'author' is generally considered to be someone who has made substantive intellectual contributions to a published study. To qualify as an author one should 1) have made substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) have been involved in drafting the manuscript or revising it critically for important intellectual content; 3) have given final approval of the version to be published; and 4) agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Each author should have participated sufficiently in the work to take public responsibility for appropriate portions of the content. All authors should have read and approved the final manuscript.

All contributors who do not meet the criteria for authorship should be listed in an acknowledgements section. Examples of those who might be acknowledged include a person who provided purely technical help, writing assistance, a department chair who provided only general support, or those who contributed as part of a large collaboration group.

Please acknowledge anyone who contributed towards the article by making substantial contributions to conception, design, acquisition of data, or analysis and interpretation of data, or who was involved in drafting the manuscript or revising it critically for important intellectual content, but who does not meet the criteria for authorship. Please also include the source(s) of funding for the study. Please also acknowledge anyone who contributed materials essential for the study. If a language editor has made significant revision of the manuscript, we recommend that you acknowledge the editor by name, where possible.

Authors should obtain permission to acknowledge from all those mentioned in the Acknowledgements section

All references, including URLs, must be numbered consecutively, in square brackets, in the order in which they are cited in the text, followed by any in tables or legends. Each reference must have an individual reference number. If automatic numbering systems are used, the reference numbers must be finalized and the bibliography must be fully formatted before submission.

Only articles, clinical trial registration records and abstracts that have been published or are in press, or are available through public e-print/preprint servers, may be cited; unpublished abstracts, unpublished data and personal communications should not be included in the reference list, but may be included in the text and referred to as "unpublished observations" or "personal communications" giving the names of the involved researchers. Obtaining permission to quote personal communications and unpublished data from the cited colleagues is the responsibility of the author. Journal abbreviations must follow Index Medicus/MEDLINE. Citations in the reference list should include all named authors.

Any in press articles cited within the references and necessary for the reviewers' assessment of the manuscript should be made available if requested by the editorial office.

Examples of the JHCS reference style are shown below. Please ensure that the reference style is followed precisely; if the references are not in the correct style they may have to be retyped and carefully proofread.

Article within a journal
Agarwal R and Agarwal P. Glaucomatous neurodegeneration: TNF-alpha. Ind J Ophthalmol. 2012;60(4):255-61.

Article within a journal by DOI(ahead of print)
Khan MS, Gan C, Ahmed K et al. A single-centre early phase randomised controlled three-arm trial of open, robotic, and laparoscopic radical cystectomy (CORAL). Euro Uro. 2015;doi: 10.1016/j.eururo.2015.07.038

Article within a journal supplement
Rajikin MH, Kamsani YS, Chatterjee A et al. Gamma-tocotrienol supplementation improves embryo development and fetal survival rate in nicotine-treated pregnant mice. Hum Repro 2013; 28 Suppl 1: 232-33.

Book chapter, or an article within a book
Harbindar JS. Close relationship between bone strength and mass in jumping exercised rats. Physical activity and exercise: health promotion and disease prevention. Aitner: 2012. p. 201-227.

Online First chapter in a series (without a volume designation but with a DOI)
Mokhtar SS, Marshall CR, Phipps ME et. al. Novel population specific autosomal copy number variation and its functional analysis amongst negritos from peninsular Malaysia patient. PLoS One. 2014. doi: 10.1371/journal.pone.0100371.

Complete book, authored
Yusoff K. Panduan elektrokardiografi. Universiti Kebangsaan Malaysia; 1993.

Online document
Rani MFA. COPD: what is it and do you suffer from it. Expat Go Malaysia. 2013. http://www.expatgo.com/my/2013/06/12/copd-what-is-it-and-do-you-suffer-from-it/. Accessed 23 Aug 2013.

Online database
Ribavirin. American Society of Health System Pharmacists. DynaMed, EBSCO Information Services. 1995. http://search.ebscohost.com. Accessed 15 May 1996.

Supplementary material/private homepage
Zudrop J. High performance computing. 2014. http://www.jenszudrop.de/research/. Accessed 19 Sep 2015.

University site
Ismail, K: Center for coal and biomass energy. http://fsg.uitm.edu.my/v1/research/research-news/202-center-for-coal-and-biomass-energy.html (2016). Accessed 24 Jan 2016.

FTP site
Schrier, RW: Atlas of diseases of the kidney. ftp://ftp.cap.org/superlinks/ref.html (1999). Accessed 9 Feb 2001.

Organization site
IFLA Metadata Newsletter. http://www.issn.org/ifla-metadata-newsletter (2016). Accessed 20 Jan 2016.

Dataset with persistent identifier
Kluver N, Konig M, Ortmann J et al. Fish embryo toxicity test: identification of compounds with weak toxicity and analysis of behavioral effects to improve prediction of acute toxicity for neurotoxic compounds. Env Sci & Tech. 2015. http://pubs.acs.org/doi/abs/10.1021/acs.est.5b01910.

Illustrations should be provided as separate files, not embedded in the text file. Each figure should include a single illustration and should fit on a single page in portrait format. If a figure consists of separate parts, it is important that a single composite illustration file be submitted which contains all parts of the figure.

Please read our figure preparation guidelines for detailed instructions on maximising the quality of your figures.

Formats
All figures should be submitted in TIFF or JPEG formats.

Figure legends
The legends should be included in the main manuscript text file at the end of the document, rather than being a part of the figure file. For each figure, the following information should be provided: Figure number (in sequence, using Arabic numerals - i.e. Figure 1, 2, 3 etc); short title of figure (maximum 15 words); detailed legend, up to 300 words.

Please note that it is the responsibility of the author(s) to obtain permission from the copyright holder to reproduce figures or tables that have previously been published elsewhere.

Preparing a personal cover page
If you wish to do so, you may submit an image which, in the event of publication, will be used to create a cover page for the PDF version of your article. The cover page will also display the journal logo, article title and citation details. The image may either be a figure from your manuscript or another relevant image. You must have permission from the copyright to reproduce the image. Images that do not meet our requirements will not be used.

Images must be 300dpi and 155mm square (1831 x 1831 pixels for a raster image).

Allowable formats -, TIFF & JPEG.

Each table should be numbered and cited in sequence using Arabic numerals (i.e. Table 1, 2, 3 etc.). Tables should also have a title (above the table) that summarizes the whole table; it should be no longer than 15 words. Detailed legends may then follow, but they should be concise. Tables should always be cited in text in consecutive numerical order.

Smaller tables considered to be integral to the manuscript can be pasted into the end of the document text file, in A4 portrait or landscape format. These will be typeset and displayed in the final published form of the article. Such tables should be formatted using the 'Table object' in a word processing program to ensure that columns of data are kept aligned when the file is sent electronically for review; this will not always be the case if columns are generated by simply using tabs to separate text. Columns and rows of data should be made visibly distinct by ensuring that the borders of each cell display as black lines. Commas should not be used to indicate numerical values. Color and shading may not be used; parts of the table can be highlighted using symbols or bold text, the meaning of which should be explained in a table legend. Tables should not be embedded as figures or spreadsheet files.

Although JCHS does not restrict the length and quantity of data included in an article, we encourage authors to provide datasets, tables, movies, or other information as additional files.

Please note: All Additional files will be published along with the article. Do not include files such as patient consent forms, certificates of language editing, or revised versions of the main manuscript document with tracked changes.

Results that would otherwise be indicated as "data not shown" can and should be included as additional files.

Certain supported files formats are recognized and can be displayed to the user in the browser. These include most movie formats (for users with the Quicktime plugin), mini-websites prepared according to our guidelines, chemical structure files (MOL, PDB), geographic data files (KML).

If additional material is provided, please list the following information in a separate section of the manuscript text:

- File name (e.g. Additional file 1)
- File format including the correct file extension for example .pdf, .xls, .txt, .pptx (including name and a URL of an appropriate viewer if format is unusual)
- Title of data
- Description of data

Additional files should be named "Additional file 1" and so on and should be referenced explicitly by file name within the body of the article, e.g. 'An additional movie file shows this in more detail [see Additional file 1]'.

Style and language

General
Currently, JCHS only accepts manuscripts written in English. Spelling should be US English or British English, but not a mixture.

The total number of figures, and tables must not exceed eight (8). Figures and tables should be numbered in the order in which they are referred to in the text.

Help and advice on scientific writing
American Scientist provides a list of resources for science writing.

Abbreviations
Abbreviations should be used as sparingly as possible. They should be defined when first used.

 Typography

• Please use double line spacing.
• Type the text unjustified, without hyphenating words at line breaks.
• Use hard returns only to end headings and paragraphs, not to rearrange lines.
• Capitalize only the first word, and proper nouns, in the title.
• All pages should be numbered. The lines should be numbered separately on each page.
• Use the JCHS reference format.
• Please do not format the text in multiple columns.
• Greek and other special characters may be included. If you are unable to reproduce a particular special character, please type out the name of the symbol in full. Please ensure that all special characters used are embedded in the text, otherwise they will be lost during conversion to PDF.

Units
SI units should be used throughout (liter and molar are permitted, however).