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Adsorption processes with activated carbons can be used to remove heavy hydrocarbons from a natural gas flow. Using the Pressure Swing Adsorption (PSA) technology, one can introduce a flexible solution in pre-existing gas-processing units to deal with new marked demands, as for example a C3+ free gas composition to be used as adsorbed natural gas to vehicles fuel tanks. However, designing a PSA process is a laborious task because several cycle configurations and materials are available to perform the separation. To fulfill such task, a multiscale procedure is proposed. Molecular simulation, through Grand Canonical Monte Carlo (GCMC) method, was used to obtain adsorption isotherms for natural gas components in three different carbons: WV-1050, NORIT R1 and MAXSORB. Bed geometry was set based on the minimum fluidization velocity and on the working capacity of the adsorbents. Working capacities were calculated using Langmuir Isotherm applied to Ideal Adsorbed Solution Theory (IAST) to represent the mixture. Each PSA column was simulated in Aspen Adsorption® and operates according to a four steps cycle (Skarstrom cycle): pressurization, adsorption at 40 bar, blowdown, and purge at 1 bar. The operating conditions of the process (such as flowrates, bed geometry and step times) were optimized, seeking the maximization of the process performance parameters: purity, recovery and productivity. A preliminary design of the PSA unit indicates the carbon WV1050 as the best adsorbent to produce C3+ free gas fuel, ideal for storage by adsorption.

Objective To evaluate the effect of ab-interno goniotrabeculotomy (AIGT) on the intraocular pressure (IOP) in adult patients with primary open-angle glaucoma (POAG), compared with the effects of mitomycin C trabeculectomy (MT). Design Prospective, randomized, clinical trial. Participants Thirty-two eyes of 32 patients with medically uncontrolled POAG. Intervention Standard limbus-based trabeculectomy with adjunct mitomycin C (0.3 mg/mL for 3 minutes) in 16 eyes of 16 patients; AIGT was performed in 16 eyes of 16 patients. The groups were matched for age, preoperative IOP, duration of preoperative antiglaucoma treatment, use of preoperative beta-blockers and parasympathomimetics, and use of beta-blockers in the fellow eye. The IOP (average of the two highest values measured in the diurnal curve, from 8 am to 6 pm, every 2 hours) and complications were recorded 1, 3, 6, 12, 18, and 24 months after surgery. Main outcome measures Identification of complications and IOP. Results All patients were followed up for 24 months. More postoperative complications occurred in the MT group during the 2-year follow-up. One month after surgery, IOP was 10 ± 1.46 mmHg (range, 8–13) in the MT group and 12.12 ± 1.63 mmHg (range, 8–14) in the AIGT group (Student's t test, P = 0.001). Three months after surgery, IOP was 11.5 ± 1.59 mmHg (range, 8–14) and 12.75 ± 1.57 mmHg (range, 10–16) in the MT and AIGT groups, respectively (Student's t test, P = 0.033). From the 6th to the 24th postoperative month, no statistically significant difference in IOP was found between the two groups. At the end of follow-up, 14 of 16 eyes (87.5%) of the AIGT group and 13 of the 16 eyes (81.25%) of the MT group showed an IOP ≤14 mmHg. Conclusion Ab-interno goniotrabeculotomy appears to be a viable and safe surgical treatment for adult POAG. More extended follow-up, however, and a larger series of patients are needed to ascertain the actual effectiveness of this procedure in adult POAG.

Purpose: Color Doppler imaging (CDI) is a relatively new technique that allows quantification of blood flow velocity in orbital and ocular vasculature. Despite the numerous clinical studies that have used CDI, repeatability of this technique and agreement between observers have not been documented. Methods: The authors performed a prospective investigation of the repeatability and agreement between observers on ophthalmic artery blood flow velocity measurements in 35 patients (35 eyes). Results: Results on the estimated error of measurement (variability between repeated readings on the same subject) indicate good repeatability of the measurements; in fact, the measurement variances were only 5.6% for the peak systolic velocity, 11.4% for the end diastolic velocity, and 6.2% for the mean envelope velocity. The statistical analysis of repeatability showed a very narrow 95% confidence interval for both observers. The measurement of agreement between the two observers demonstrated the existence of a good concordance of the measurements taken by each observer on each subject. Conclusions: Results suggest that CDI is a reliable tool for quantitative assessment of ophthalmic artery blood flow velocity.

To evaluate the effect of ab-interno goniotrabeculotomy (AIGT) on the intraocular pressure (IOP) in adult patients with primary open-angle glaucoma (POAG), compared with the effects of mitomycin C trabeculectomy (MT).Prospective, randomized, clinical trial.Thirty-two eyes of 32 patients with medically uncontrolled POAG.Standard limbus-based trabeculectomy with adjunct mitomycin C (0.3 mg/mL for 3 minutes) in 16 eyes of 16 patients; AIGT was performed in 16 eyes of 16 patients. The groups were matched for age, preoperative IOP, duration of preoperative antiglaucoma treatment, use of preoperative beta-blockers and parasympathomimetics, and use of beta-blockers in the fellow eye. The IOP (average of the two highest values measured in the diurnal curve, from 8 AM to 6 PM, every 2 hours) and complications were recorded 1, 3, 6, 12, 18, and 24 months after surgery.Identification of complications and IOP.All patients were followed up for 24 months. More postoperative complications occurred in the MT group during the 2-year follow-up. One month after surgery, IOP was 10 +/- 1.46 mmHg (range, 8-13) in the MT group and 12.12 +/- 1.63 mmHg (range, 8-14) in the AIGT group (Student's t test, P = 0.001). Three months after surgery, IOP was 11.5 +/- 1.59 mmHg (range, 8-14) and 12.75 +/- 1.57 mmHg (range, 10-16) in the MT and AIGT groups, respectively (Student's t test, P = 0.033). From the 6th to the 24th postoperative month, no statistically significant difference in IOP was found between the two groups. At the end of follow-up, 14 of 16 eyes (87.5%) of the AIGT group and 13 of the 16 eyes (81.25%) of the MT group showed an IOPor = 14 mmHg.Ab-interno goniotrabeculotomy appears to be a viable and safe surgical treatment for adult POAG. More extended follow-up, however, and a larger series of patients are needed to ascertain the actual effectiveness of this procedure in adult POAG.

Purpose: A randomized clinical trial to assess ocular hypotensive effect of sublingual administration of timolol was performed. Patients and methods: Seventeen (9 male, 8 female; age range 45 to 68 years) with bilateral ocular hypertension were selected for the study. Each patient was evaluated with regard to IOP, arterial blood pressure and heart rate before and after each of the following experimental treatment: unilateral ocular administration of 20 μl of 0.5% timolol solution; sublingual administration of 20 μl of 0.5% timolol solution; unilateral ocular administration of 20 μl of saline solution (placebo); sublingual administration of 20 μl of saline solution (placebo). The sequence of the treatments and the eye topically treated were randomly chosen. At least four weeks wash-out elapsed between each experimental treatment. Results: Our results showed that sublingual administration of timolol was able to induce a bilateral significant reduction of the IOP. This reduction was not statistically different from that obtained in the eye treated with timolol. A significantly greater reduction of the IOP was obtained by sublingual timolol than in the contralateral eye after unilateral topical administration of timolol solution. No significant modification of arterial blood pressure and heart rate were evidenced after the treatment. Conclusions: Sublingual administration seems to be a new interesting way for reducing the IOP. Long term studies are required in order to test efficacy and safety of this new treatment.

Corneal damage of various origins initiates a series of processes which lead to repair but also tend to perpetuate the damage; healing thus depends on the prevalence of repair over progression processes. The plasminogen/plasmin system has an important impact on this process, particularly by degrading the extracellular matrix components with resulting interference of the repair processes. This paper presents the immunoblotting analysis of fibronectin, tissue and urokinase-type plasminogen activators and plasminogen/plasmin in the tear fluid of control subjects and patients affected by various ocular pathologies (corneal ulcers, thermal or chemical burns, herpetic keratitis). A significant modification was noted in the protein profiles of fibronectin, tissue and urokinase-type plasminogen activators and plasminogen/plasmin in the cases of corneal ulcers and thermal or chemical burns relative to the pattern observed in the control subjects, while in cases of herpetic keratitis, only plasminogen/plasmin showed slight variations. The altered protein patterns gradually normalized during therapeutic treatment and, at remission, coincided with those of the control subjects.

Purpose/Methods: Rubinstein-Taybi syndrome is a constellation of clinical findings characterized by mental and motor retardation, broad thumbs and broad first toes, marked growth retardation, microcrania, typical facies, higharched palate, and cryptorchidism in males. Ocular and adnexal abnormalities are quite common and include antimongoloid slant of the palpebral fissures, epicanthal folds, congenital obstruction of the lacrimal excretory system, ptosis, strabismus, and severe ametropia. Macrocornea, microophthalmos, colobomas of the iris and of the optic nerve head, congenital cataract, and optic nerve atrophy have also been described. Congenital glaucoma is a rare complication. We examined a patient with Rubinstein-Taybi syndrome with bilateral congenital glaucoma. Results/Conclusions: Examination of this patient revealed bilateral antimongoloid slants of the palpebral fissures, and bilateral congenital glaucoma. Gonioscopic examination revealed the iris to be inserted flatly into the trabecular meshwork. This case emphasizes the importance of detailed, complete ocular examinations in patients with Rubinstein-Taybi syndrome, and also highlights the occurrence of ocular abnormalities rarely associated with this disease.

Purpose/Methods A 35-year-old woman, who had undergone an uncomplicated Scopinarotype biliopancreatic bypass for obesity nine years previously, was examined because of severe bilateral corneoconjunctival xerosis and markedly decreased vision. One month earlier she had had a bout of nonspecific enteritis. She was treated with intramuscular vitamin A. Results/Discussion After one month of therapy, the ocular xerosis had cleared completely and her vision had returned to normal. This case suggests that this kind of operation can cause instability of vitamin A absorption.

As regards general and pre-operative ophthalmological problems in cataract surgery, all of those factors which together condition individual indications of operability must be analyzed. The different clinical peculiarities of each individual patient must be attentively considered in order to obtain the best surgical and functional results. Within the individual clinical context, general and local, precise critical pre-operative evaluation of the indications, contraindications and potential complications is essential for the best preparation for the operation and the exact choice of the most appropriate surgical techniques. A precise general anamnesis is the first step to be taken in examination of the patient.