Cerebral revascularization with superficial temporal – middle cerebral artery anastomosis for complete carotid occlusion: An emerging modality for preventing recurrent stroke

Complete long segment carotid occlusion presents a treatment challenge. These patients cannot be managed adequately by endarterectomy or stenting. Despite best medical management, many continue to develop recurrent strokes. In this select group of patients, there may be role for flow augmentation techniques like superficial temporal-middle cerebral artery bypass. We report a patient who was thus successfully treated and remains asymptomatic. The relevant literature is reviewed.Key Words: Extra cranial-intracranial bypass, recurrent stroke, superficial temporal - middle cerebral artery bypass, total carotid occlusion     

Quantitative Comparison of Retrosigmoid Intradural Suprameatal Approach and Retrosigmoid Transtentorial Approach: Implications for Tumors in the Petroclival Region

Background Retrosigmoid transtentorial (RTT) and retrosigmoid intradural suprameatal (RISA) approaches have been used in the treatment of petroclival tumors.Objective To compare the area of exposure of brainstem and petroclival region obtained through RTT and RISA in cadaveric specimens.Methods Five cadaveric specimens with a total of 10 sides were analyzed. RTT and RISA were performed on five sides each. Brainstem and petroclival surface exposure were measured using both the approaches. These values were compared between the two approaches.Results Brainstem area exposure with RTT was 441 ± 63 mm² and that with RISA was 311 ± 61 mm². Student''s t-test revealed that the difference was significant (p = 0.01). The area of petroclival exposure medial to the Meckel cave through RTT was 696 ± 57 mm², and that through RISA was 716 ± 51 mm² (p = 0.69). The area of brainstem exposure between V and VII-VII complex through RTT and RISA was 387 ± 86 mm² and 378 ± 76 mm² (p = 0.87).Conclusion The RTT approach is an excellent approach to ventrolateral brainstem and petroclival region. It provides greater superoventral exposure of the ventrolateral brainstem than RISA and provides similar petroclival exposure.     

Graphene tailored by Fe3O4 nanoparticles: low-adhesive and durable superhydrophobic coatings

This study reports stable superhydrophobic Fe₃O₄/graphene hybrid coatings prepared by spin coating of the Fe₃O₄/graphene/PDMS mixed solution on titanium substrates. By tailoring graphene sheets with Fe₃O₄ nanoparticles, the superhydrophobicity of graphene platelets was largely enhanced with a water contact angle of 164° and sliding angle <2°. Fe₃O₄ nanoparticles interact with FLG sheets via Fe–O–C covalent link, to form a graphene micro-sheet pinned strongly by nano-sized Fe₃O₄. The newly-formed micro/nano-structured sheets interact with each other via strong dipole–dipole attractions among Fe₃O₄ nanoparticles, confirmed by the blue shifts of G band observed in Raman spectra. The strongly interactive micro/nano-structured sheets are responsible for the improvement of both the surface hydrophobicity and the durability towards water impacting. The obtained hybrid coatings possess excellent durability in various environments, such as acidic and basic aqueous solutions, simulating ocean water. And also the coatings can retain their stable superhydrophobicity in Cassie–Baxter state even after annealing at 250 °C or refrigerating at −39 °C for 10 h. We employed an AFM to probe nanoscale adhesion forces to examine further the ability of the as-prepared coatings to resist the initial formation of water layers which reflects the ability to prevent the water spreading. The most superhydrophobic and durable hybrid coating with 1.8 g Fe₃O₄, shows the smallest adhesion force, as expected, indicating this surface possesses the weakest initial water adhesive strength. The resulting low-adhesive superhydrophobic coating shows a good self-cleaning ability. This fabrication of low-adhesive and durable superhydrophobic Fe₃O₄/FLG hybrid coatings advances a better understanding of the physics of wetting and yield a prospective candidate for various practical applications, such as self-cleaning, microfluidic devices, etc.

Strongly interactive graphene micro-sheets tailored by Fe₃O₄ nanoparticles exhibit low-adhesive and durable superhydrophobicity.     

Semiautomated disinfection of ophthalmic contact lenses

The ophthalmic lenses that come in contact with the eyes pose a high risk for the transmission of bacterial and viral infections in eye clinics. Disinfecting these lenses does not happen stringently in a busy practice. We describe a novel method of disinfecting ophthalmic contact lenses using a semiautomated lens disinfector equipment, semiautomated lens disinfector. The equipment has motors to pump in and pump out water and disinfecting solution into a reservoir bath. The used ophthalmic lenses will be placed in a tray that partially dips into the bath for disinfection. Microbiology tests that were done to check the quality of the disinfection cycle showed good outcomes. Disinfection of ophthalmic contact lenses with the new equipment appeared to effectively eliminate contaminant microorganisms. This equipment can be used in busy ophthalmic clinics to alleviate the chances of cross-infection.     

An In Vitro Study to Compare the Effect of Two Etching Techniques on the Tensile Bond Strength of Resin Cement Bonded to Base Metal Alloy and Enamel

Resin-bonded retainers are being preferred for anterior restorations. To increase the retentive strength of the metal fixed to the tooth, the retainer surface has to be etched. Different etching techniques are described in the literature with different researchers expressing the superiority of one technique over the other. This study was conducted to compare electro chemical and chemical etching techniques and the mode of bond failure. Twenty human maxillary premolars with the crown portion separated from root were embedded in resin block such that mesial or distal portion of it was exposed on the top of the block. 4 × 5 mm area was marked on the tooth, and wax pattern was prepared to cover the exact area, with the opposite end having a hook like structure which was later attached to universal testing machine. Wiron99 Ni–Cr alloy was used for casting. Once the casting and etching procedures were finished, wax patterns were invested, casted and half the samples were etched chemically using Aqua-regia and the other half samples were etched electrochemically. The castings were cleaned and cemented to tooth structure using Rely-X ARC (3 M ESPE, USA) resin cement. Specimens were fixed to universal testing machine and de-bonded. The load required to de-bond and mode of de-bonding was noted. Results were subjected to five different statistical tests, each test specific to the variable being tested. The mean failure load was calculated as 5.95 kg for electrochemically etched samples and that of chemically etched samples was calculated as 11.15 kg. The standard deviation of the force required to debond the specimens (Kgf) was calculated and found to be 0.65 for electrochemically etched samples and 1.11 for chemically etched samples. The following conclusions have been drawn from the study. 1. Chemical etching of the samples created better retentive surfaces than electrochemical etching. 2. The results of mode of de-bonding show that in case of chemical etching maximum debonding occurred at resin-enamel interface and in electrochemical type it occurred at resin-metal interface.