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Magnesium (Mg) and its alloys possess many outstanding properties, showing great potential to be extensively applied in different fields. Unfortunately, they are highly susceptible to corrosion, especially to corrosive chloride ions. This causes huge economic loss and has restricted their applications in industry. Among different strategies, protective coatings/surface modifications attract considerable attention because they can reduce or even restrain corrosion by preventing contact with the external environment. This review focuses on the recent advances in various protective coating/surface modification technologies pertinent to Mg alloys to offer a clear picture for researchers and engineers in the relevant research area. The topics covered include anodic oxidation, plasma electrolytic oxidation, chemical conversion coating, sol-gel coating, laser cladding, cold spray, electrophoretic deposited coating, layered double hydroxide coating and superhydrophobic coating. In addition, the industrial applications of electrochemical (anodic oxidation and plasma electrolytic oxidation) and chemical conversion coatings are briefly presented. The existing issues and future perspectives are discussed to accelerate the broad applications of Mg alloys.

The layered 2D hexagonal boron nitride (h-BN) nanosheets (BNNSs) have received significant attention as effective fillers for composite protective coatings in anti-corrosion, anti-oxidation and anti-wear applications. Vapour deposited h-BN mono/multilayers are related classes well-recognized as protective thin films and coatings. This review comprehensively accounts for the research and development of BNNSs in protective coatings. Chemical vapour deposited (CVD) BN thin films and exfoliated BNNSs-incorporated composite polymer coatings are primarily discussed. Inorganic and nanocarbon-based composite coatings are also covered. Future research potentials are presented.

The easy and scalable synthesis, biocompatibility, one-dimensionality, high aspect ratio, viability for surface modifications, and the ability for cargo-loading and release make organic nanotubes ideal candidates for smart coatings with slow and controlled release corrosion inhibitors and anti-biofouling agents. The wide-ranging applicability of organic nanotubes as controlled release nanocarriers for smart anti-corrosion and anti-biofouling coatings is foreseen.

Organic nanotubes (ONTs) have entranced considerable research attention for their potential applications in drug delivery, sensors, catalysts, optical devices, ferro/piezoelectrics, template/scaffolds, hydro/organogels, enzymatic reactors, biomarkers, and various biomedical applications. Substantial information is available on ONTs as nanocarriers for drug delivery. We comprehensively review various supramolecular ONTs reported in drug delivery applications. The major supramolecular ONTs discussed are lipids-based, peptides, and DNA nanotubes. Drug delivery by polymer-ONTs conjugates and ONTs-based hydrogels are also discussed. The collective information provided is helpful to further advance research and development in ONTs-based drug delivery systems.

Superhydrophobic coatings are projected as a practical approach to tackle the weak aqueous corrosion resistance of Mg/Mg alloys. The present review provides the most recent updates in this area. The various low surface energy treatments reported are presented first, followed by the methods employed for developing hierarchical surface micro/nanostructuring. Reported works in different application areas, including anti-corrosion, biomedical and anti-icing are systematically discussed. Concise descriptions of self-healing characteristics and long-term durability of the superhydrophobic surfaces provided. Reports on superamphiphobic surfaces also deliberated.

Saravanakumari Vijayakumar,1 Stalin Viswanathan,2 Rajeswari Aghoram3 1Pathology, Sri Lakshmi Narayana Institute of Medical Sciences, Pondicherry 605502, India; 2General Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry 605006, India; 3Department of Neurology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry 605006, IndiaCorrespondence: Rajeswari AghoramDepartment of Neurology, Jawaharlal Institute of Postgraduate Medical Education and Research, D. Nagar, Pondicherry 605006, IndiaTel +91 413 229 7285Email rajeswari.a@gmail.comAbstract: Idiopathic CD4 lymphocytopenia is a condition characterized by low CD4 counts. It is rare and most of the information about this illness comes from case reports. Presentation is usually in the 4th decade of life with opportunistic infections, autoimmune disease or neoplasia. The pathophysiology of this condition is not well understood. Management revolves around treatment of the presenting condition and close follow-up of these patients. This review presents a narrative summary of the current literature on idiopathic CD4 lymphocytopenia.Keywords: CD4 T cell lymphocytopenia, opportunistic infections, neoplasia, autoimmune disease

Rare-earth elements-based conversion coatings are actively researched as an environmentally benign alternative to conventionally used chromate-based conversion coatings for magnesium and its alloys. Here, we reviewed the topic comprehensively. The review starts with a short introduction on corrosion of magnesium alloys and chemical conversion treatments, and that is followed by a detailed description of cerium-based conversion coatings. Morphology, structure and composition of the cerium conversion coatings, their mechanism of formation and competence for corrosion control explained. Influence of various inorganic (hydrogen peroxide, phosphates, permanganates, vanadates, molybdates, etc.) and organic (silane, gelatin, phytic acid, etc.) co-additives discussed. Effect of various pre- and post-treatments described. Reported works on rare-earths other than cerium, viz. lanthanum, yttrium, samarium, neodymium, gadolinium and praseodymium are also reviewed. Future potentials of R & D presented. Keywords: Magnesium and its alloys, Corrosion, Chemical conversion coatings, Rare-earths

Background and Objectives: The advent of new fluoroquinolones has drawn the attention for reliable methods on the in-vitro susceptibility testing of Streptococccus pneumoniae. This study attempts to determine the minimum inhibitory concentration (MIC) of second-generation (ciprofloxacin and ofloxacin), third-generation (levofloxacin) and the fourth-generation (moxifloxacin and gatifloxacin) fluoroquinolones against S. pneumoniae recovered from bacterial keratitis. Materials and Methods: In retrospect, the MICs of 50 strains of S. pneumoniae isolated from the corneal scrapes of patients with bacterial keratitis were determined against ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin and moxifloxacin using E-tests. The National Committee of Clinical Laboratory Standards (NCCLS) susceptibility patterns and the potencies of the MICs were statistically compared. Results: The median MIC of ciprofloxacin (0.25μg/ml) was found to be lower than the median MICs of ofloxacin (0.5μg/ml) (P < 0.449) and levofloxacin (1.0μg/ml) (P < 0.001). The median MICs of gatifloxacin (0.1μg/ml) was lower than the median MICs of ciprofloxacin (0.25μg/ml) (P < 0.001), ofloxacin (0.5μg/ml) (P < 0.001) and levofloxacin (1.0μg/ml) (P < 0.001). Moxifloxacin (0.06μg/ml) had showed lower median MICs than gatifloxacin (0.1μg/ml) (P < 0.001) levofloxacin (1.0μg/ml) (P < 0.001), ofloxacin (0.5μg/ml) (P < 0.001) and ciprofloxacin (0.25μg/ml) (P < 0.001). Moxifloxacin (0.06μg/ml) had a lower MIC50 (μg/ml) than gatifloxacin (0.1μg/ml), levofloxacin (1.0μg/ml), ciprofloxacin (0.25μg/ml) and ofloxacin (0.5μg/ml). MIC90 (μg/ml) of moxifloxacin (0.06μg/ml) was found to be lower than the MIC90 (μg/ml) of gatifloxacin (0.5μg/ml), levofloxacin (1.0μg/ml), ofloxacin (0.5μg/ml) and ciprofloxacin (0.5μg/ml). Conclusion: Based on in-vitro testing, the five portrayed fluoroquinolones 100% sensitivity to S. pneumoniae. However, the fourth-generation fluoroquinolone, moxifloxacin appeared to be more effective against S. pneumoniae than gatifloxacin, levofloxacin, ofloxacin and ciprofloxacin.

Background / Aims: The eye may be infected from external sources or through intra-ocular invasion of micro-organisms carried by the blood stream. This study was undertaken to isolate and identify the specific bacterial pathogens causing ocular infections and to determine their in-vitro antibacterial susceptibilities to commonly used antibacterial agents. Materials and Methods: A retrospective analysis of all patients with clinically diagnosed bacterial ocular infections such as blepharitis, conjunctivitis, internal and external hordeolum, suppurative scleritis, canaliculitis, keratitis, dacryocystitis, preseptal cellulitis, endophthalmitis and panophthalmitis presenting between January 2005 and December 2005 was performed. Extra-ocular and intra-ocular specimens were collected and were subjected to direct microscopy and culture. Results: A total of 756 patients with bacterial ocular infections were analyzed, of which 462(61%) eyes had adnexal bacterial infection, 217(28.7%) had corneal infection, 6 (0.8%) had scleral involvement and the remaining 71(9.39%) eyes had infection of the intra-ocular tissues. The predominant bacterial species isolated was S. aureus (195 of 776; 25%) followed by S. pneumoniae (169 of 776; 21.78%) and coagulase negative staphylococci (142 of 776; 18.3%). The largest number of gram-positive isolates were susceptible to cefazolin (545 of 624; 87.34%), chloramphenicol (522 of 624; 83.65%) and gatifloxacin (511 of 624; 81.89%) and gram-negative isolates were to amikacin (127 of 136; 93.38%), gatifloxacin (125 of 136; 91.91%) and ofloxacin (119 of 136; 87.5%), while aerobic actinomycetes were to amikacin (100%), gatifloxacin (14 of 16; 87.5%), chloramphenicol (14 of 16; 87.5%) and ofloxacin (13 of 16; 81.25%). Conclusions: S. aureus frequently causes infections of eyelids and conjunctiva, S. pneumoniae of lacrimal apparatus and cornea and coagulase negative staphylococci causes intra-ocular infections. Of all routinely used antibacterials tested, flouroquinolones, especially gatifloxacin and ofloxacin represented a good choice for treating bacterial ocular infections.