Influence of Parylene F Coatings on the Wetting Properties of Soft Polydimethylsiloxane (PDMS).

Understanding the wettability of soft surfaces is of key importance for the development of protective and repellent coatings and controlling droplet dynamics when required. There are many factors that affect the wetting and dynamic dewetting behavior of soft surfaces, such as the formation of wetting ridges, the adaptive behavior of the surface caused by the interaction of the fluid with the surface, or the presence of free oligomers that are washed out of the soft surface. In this work, we report the fabrication and characterization of three soft polydimethylsiloxane (PDMS) surfaces with elastic moduli ranging from 7 kPa to 56 kPa. The dynamic dewetting behavior of liquids with different surface tensions was studied on these surfaces, and the data show soft and adaptive wetting behavior of the soft PDMS, as well as the presence of free oligomers. Thin layers of Parylene F (PF) were introduced to the surfaces and their influence on the wetting properties was studied. We show that the thin layers of PF prevent adaptive wetting by preventing the diffusion of liquids into the soft PDMS surfaces and by causing the loss of the soft wetting state. The dewetting properties of the soft PDMS are enhanced, leading to low sliding angles of ≤10° for water, ethylene glycol, and diiodomethane. Therefore, the introduction of a thin PF layer can be used to control wetting states and to increase the dewetting behavior of soft PDMS surfaces.

Superrepellent Porous Polymer Surfaces by Replication from Wrinkled Polydimethylsiloxane/Parylene F.

Superrepellent surfaces, such as micro/nanostructured surfaces, are of key importance in both academia and industry for emerging applications in areas such as self-cleaning, drag reduction, and oil repellence. Engineering these surfaces is achieved through the combination of the required surface topography, such as porosity, with low-surface-energy materials. The surface topography is crucial for achieving high liquid repellence and low roll-off angles. In general, the combination of micro- and nanostructures is most promising in achieving high repellence. In this work, we report the enhancement of wetting properties of porous polymers by replication from wrinkled Parylene F (PF)-coated polydimethylsiloxane (PDMS). Fluorinated polymer foam "Fluoropor" serves as the low-surface-energy polymer. The wrinkled molds are achieved via the deposition of a thin PF layer onto the soft PDMS substrates. Through consecutive supercritical drying, superrepellent surfaces with a high surface porosity and a high water contact angle (CA) of >165° are achieved. The replicated surfaces show low roll-off angles (ROA) <10° for water and <21° for ethylene glycol. Moreover, the introduction of the micro-wrinkles to Fluoropor not only enhances its liquid repellence for water and ethylene glycol but also for liquids with low surface tension, such as n-hexadecane.

Comparison of the Efficacy and Safety of Apixaban and Warfarin in the Prevention of Stroke in Patients With Non-valvular Atrial Fibrillation: A Meta-Analysis.

Atrial fibrillation is an irregular heart rhythm, and it is one of the most common cardiac arrhythmias. It is associated with a five times increase in the risk of stroke. Anti-coagulants are prescribed routinely to prevent strokes, especially in patients with atrial fibrillation for many years decreasing the risk of stroke among patients with atrial fibrillation. Non-vitamin K oral anticoagulants especially apixaban and rivaroxaban are frequently used and they are considered to be safe and more effective than warfarin. The aim of this meta-analysis is to compare the efficacy and safety of apixaban and warfarin in preventing stroke among patients with non-valvular arterial fibrillation. The current meta-analysis was conducted using the guidelines established by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A systematic search was done using databases, including PubMed, EMBASE, and Cochrane Library, with no restrictions on language and year of publication. The current meta-analysis included randomized control trials and non-randomized control trials (prospective and retrospective cohort studies) comparing the efficacy and safety of apixaban and warfarin in preventing stroke in patients with non-valvular atrial fibrillation. The primary efficacy outcome was stroke or systemic embolism while the primary safety outcome was major bleeding events. Overall, nine articles were included in the current meta-analysis with a pooled sample size of 267998 patients with non-valvular atrial fibrillation. The administration of apixaban was associated with a significant decrease in stroke or systemic embolism (RR: 0.77, 95% CI: 0.67-0.90) and major bleeding events (RR=0.63, 95% CI: 0.58-0.68) as compared to warfarin. However, no significant difference was reported in all-cause mortality (RR=0.80, 95% CI: 0.30-2.14) between the two groups. The current meta-analysis concluded that apixaban, compared to warfarin in patients with non-valvular atrial fibrillation showed a reduction in stroke and systemic embolism. Apixaban has also a better safety profile in terms of reduction in overall major bleeding events.

Preoperative subconjunctival combined injection of bevacizumab and mitomycin C before the surgical excision of primary pterygium: clinical and histological results.

PURPOSE: The aim of this study was to detect the clinical and histological effects of preoperative subconjunctival injection of both bevacizumab and mitomycin C (MMC) 1 month before the surgical excision of primary pterygium using a bare sclera technique. PATIENTS AND METHODS: A total of 20 patients with primary pterygium underwent subconjunctival combined injection of 0.1 mL of MMC (0.1 mg/mL) and 0.1 mL of bevacizumab (1.25 mg/0.1 mL) 1 month before bare sclera excision of the pterygium. The excised pterygium tissues were examined histologically and immunohistologically by CD31 staining, and the patients were followed up clinically for at least 2 years. The excised pterygia of two patients without preoperative injection were used for histological comparison. RESULTS: Clinically, there were no intraoperative or postoperative complications. No recurrence was noted during the follow-up period. Histologically, the previously injected pterygia showed a decreased number of epithelial cells and stromal fibroblasts. The latter were rounded or oval and swollen rather than spindle shaped, and some were degenerating or apoptotic. Collagen and elastic fibers were degenerated, distorted, and decreased in density, while blood capillaries were obliterated. There was a significant decrease in CD31-positive cells in previously injected pterygia. CONCLUSION: Preoperative subpterygium combined injection of bevacizumab and MMC is safe and effective in reducing the postoperative recurrence of primary pterygium. Histological and immunohistological changes in the form of decreased fibrovascular activity and degeneration of the extracellular matrix and nerve axons were noted.

The efficacy of Alahmady ring implantation in the management of neovascular glaucoma.

PURPOSE: To evaluate the efficacy and safety of Alahmady ring implantation in the management of neovascular glaucoma. METHODS: A total of 15 eyes of 15 patients with intractable neovascular glaucoma with intraocular pressure (IOP) ≥28 mmHg not responding to medical treatment were retrospectively analyzed. All patients had poor visual acuity and underwent Alahmady ring implantation. The ring was designed from fenestrated silicon tube used in lacrimal surgeries and was implanted subsclerally after passing it through the anterior chamber. Patients were followed up for at least 24 months. Success in this study was defined based on IOP ≥8 mmHg and <21 mmHg, with not more than 1 glaucoma drug, and improvement of patient symptoms and signs with maximum use of beta blocker as antiglaucoma drug. RESULTS: A total of 15 eyes of 15 patients (9 males [60%] and 6 females [40%]) were analyzed in this study. The mean IOP before surgery was 38.6 mmHg (standard deviation [SD]: 6.98) and it was 14.05 mmHg (SD =7.57) after surgery. The follow-up range was 24-36 months. Success of silicon drainage device was defined as an IOP <21 mmHg on the last follow-up visit. Medications included only beta-blockers and topical steroids for those who were without severe complications or for those who were not in a condition to undergo a further glaucoma surgery. CONCLUSION: Alahmady ring implantation proves to be a good surgical option for neovascular glaucoma; however, a longer follow-up period is recommended.

High osmolarity effect of intravitreal plasmin enzyme on rabbit retina.

We conducted a study of the effect of intravitreal plasmin on retinal thickness in rabbits. Forty rabbit eyes were injected with 0.4, 1, 2, and 5 IU of plasmin (8 eyes/group). The same volume of BSS-plus(®) was injected in control eyes. Four eyes in each group underwent vitrectomy 60 minutes after the injections. The retinal thickness was measured in optical coherence tomographic (OCT) images before, 30 minutes, and 1 week after the injection. To study the effect of hyperosmolarity, 4 eyes received an injection of mannitol solution whose osmolarity was the same as the plasmin solutions. Thirty minutes after the plasmin injection, 4 eyes developed a serous retinal detachment (SRD). The mean retinal thickness including SRD was increased at 30 minutes in a dose-dependent way. The increase in eyes with 5 IU of plasmin was significantly greater than that in eyes with BSS-Plus(®) or 0.4 IU of plasmin (P = 0.0266, P = 0.0371, respectively). One week after the injection, SRD disappeared, and the mean retinal thickness decreased. The eyes injected with mannitol, the same osmolarity of 1, 2, 5 IU of plasmin, developed SRD at 30 minutes, and it disappeared after 1 week in all eyes. The results of this study demonstrated that an intravitreal injection of plasmin increases the retinal thickness in a dose-dependent way in rabbit eyes. The results with mannitol suggest that the increase in retinal thickness following plasmin is most likely caused by the hyperosmolarity of plasmin solution.

Twenty five-gauge sutureless vitrectomy versus 20-gauge vitrectomy in epiretinal membrane surgery.

PURPOSE: To compare visual outcomes, intraoperative and postoperative complications of 25-gauge transconjunctival sutureless vitrectomy (25-G TSV) versus conventional 20-gauge vitrectomy in epiretinal membrane (ERM) surgery. METHODS: A retrospective comparative study was conducted on 200 eyes with idiopathic ERM who underwent either primary 20-gauge vitrectomy (n=95) or 25-G TSV (n=105) with 6 months follow up. The following parameters were collected and compared: age, gender, best corrected visual acuity (BCVA), intraocular pressure (IOP), postoperative anterior chamber inflammation, intraoperative and postoperative complications. RESULTS: Twenty-five gauge group achieved a significantly better vision at the 1(st) postoperative month (p=0.008) and a significantly higher incidence of visual improvement 6 months postoperatively (p=0.04) than 20-gauge group. Intraocular pressure was significantly higher at the 1(st), 3(rd) and 6(th) postoperative months compared with baseline in the 20-G group. However, in the 25-gauge group IOP remained near to the baseline at the same period. Twenty five-gauge group achieved a significantly lower anterior chamber inflammation and a lower incidence of postoperative cystoid macular edema (CME) (p=0.01), hyphema (p=0.000) and after cataract (p=0.000) than 20-gauge group. CONCLUSIONS: The 25-gauge sutureless vitrectomy achieves rapid and higher visual improvement, less postoperative inflammation and complications than the 20-gauge vitrectomy in ERM surgery.

Inhaled foreign bodies: management according to early or late presentation.

OBJECTIVE: This retrospective study aims to compare the early and late clinical and management aspects of tracheobronchial aspirated foreign body (AFB), to evaluate the factors associated with delayed diagnosis of foreign body aspiration (FBA) in children and to compare clinical, radiological and bronchoscopic findings in the patients with suspected FBA. A retrospective review of a 10-year experience (from 1995 to 2005). A 1512-bed Mansoura University Hospital and 184-bed Mansoura University Emergency Hospital. METHODS: The medical records of 3300 patients who underwent bronchoscopy for suspected FBA were reviewed. The data were analysed in three groups: the patients with negative bronchoscopy for FBA (group I), early (group II) and delayed diagnosis (group III). Foreign body was removed using the rigid bronchoscope with or without using the extracting forceps (Egyptian novel technique described in the hand made illustration). RESULTS: The majority of the patients with FBA were between 3 and 10 years of age. The penetration syndrome and decreased breath sounds were determined in a significantly higher number of the patients with FBA. The plain chest radiography revealed radio-opaque foreign bodies (FBs) in 23.56% of all patients with FBA. Pneumonia and atelectasis were significantly more common in the groups with negative bronchoscopy and with delayed diagnosis (P<0.01). The FBs were most frequently of vegetable origin, such as seeds and peanuts. A significant tissue reaction with inflammation and postbronchoscopic complications were more common in the delayed cases. The novel technique was used since then in 100 cases (4.62%) with a history of FBI (Pins and or small rounded materials). It was successful in 73 (73%) cases of non-impacted inhaled pins. Use of forceps was needed in 21 (21%) cases. Rebronchoscopy despite using both techniques was needed in six (6%) cases within 72h. Failed extraction of the inhaled FB occurred in three cases (3%) for whom bronchotomy was needed. CONCLUSIONS: Bronchoscopy is indicated on appropriate history and on suspicion. To prevent delayed diagnosis, characteristic symptoms, signs and radiological findings of FBA should be checked in all suspected cases. As clinical and radiological findings of FBA in delayed cases may mimic other disorders, the clinician must be aware of the likelihood of FBA.

Epidermoid cyst radiologically mistaken as a left sided subpulmonic effusion.

A 33-year-old female had a left sided chest pain for the last 3 months. Chest X-ray showed a left basal opacity. Computed tomography chest suggested a left sided subpulmonic effusion (17.5x12.2x13 cm) with thick enhanced walls with marked collapse of the left lower lobe and displacement of the heart and mediastinum to the right side. Trial of thoracocentesis was done and it was positive. Trial of intercostal tube insertion was done with a sense of very thick pleura and the patient developed a vasovagal attack. Accordingly, exploratory thoracotomy was decided. Intraoperative assessment showed a huge anterosuperior mediastinal cyst attached to the pericardium and was successfully resected. The pathological findings were compatible with epidermoid cyst.