Bubble Technique Research Articles

Dalk – when and how

Deep anterior lamellar keratoplasty (DALK) is a surgical procedure that involves replacing the anterior portion of the cornea with donor tissue while preserving the patient's endothelium. This technique has gained popularity in recent years as an alternative to traditional penetrating keratoplasty (PK) due to its potential advantages in terms of visual outcomes, graft survival and reduced risk of endothelial rejection.The decision to perform DALK in keratoconus is based on various factors, including the keratometric readings, corneal thickness, corneal clarity and RGP tolerability.Surgical technique plays a critical role in the success of DALK. Several approaches have been described to perform the DALKs; the big bubble technique is considered the most convenient for all surgeons. Other techniques were used according to the associated pathology.This presentation is a quick journey into DALK indications and various techniques used in eyes with keratoconus.

Descemet Membrane Endothelial Keratoplasty Graft Preparation Using the Liquid Bubble Technique with Subtrabecular Hydrodissection: A Retrospective Real-Life Study

Background: Techniques for the preparation of grafts for Descemet membrane endothelial keratoplasty (DMEK) can be classified into those that involve the manual dissection of the Descemet membrane (DM) and those that use an injection of a liquid or a gas to achieve a separation of the DM from the posterior corneal stroma. The purpose of this study was to evaluate the efficiency of the liquid bubble technique. Methods: The success rate of the technique was calculated retrospectively using the operating reports. Video files for each graft preparation were retrieved and the time, number of injections, and number of injections sites required for the hydrodissection were measured. The number of cases in which a manual dissection of the Descemet membrane was necessary was recorded. Information on donor age and graft preservation time were retrieved from the eye bank file. Results: In 58 cases, the success rate was 98.3%. In the 28 procedures where a video was available, the median time for hydrodissection was 4.4 min. The median number of injection sites was 2, with a median number of injections of 3.5. Manual dissection as a rescue technique was performed in 25% of cases, with one case resulting in graft tears. The mean graft diameter was 7.6 mm. The mean donor age was 66 years, and the mean graft storage time was 22 days. Conclusions: The liquid bubble technique can be a fast and valuable choice for DMEK graft preparation, especially in centers where the tissue is prepared in the operating theater.

Prevention of Argentinian flag sign in intumescent cataracts using anterior chamber air bubble and cortical fluid release techniques

BackgroundTo investigate the efficiency of a new method for the prevention of argentinian flag sign during the process of continuous, circular, and centered anterior capsulotomy (CCC) on the anterior capsule in cortically liquefied intumescent cataracts. This study was registered in an appropriate registry and the registration number of registration was xyy11[2022]-XJSFX-087; The date of of registration was 2022-04-29.MethodsPreoperative examinations including slit-lamp examination, ocular A-scan ultrasonography, and Ultrasound Biomicroscopy (UBM) UBM were conducted on 61 patients with intumescent cataracts. Cases with cortically liquefied intumescent cataracts were selected and after staining with indocyanine green, the anterior chamber air bubble technique was used to compress the anterior capsule, and liquefied cortex was aspirated using a puncture needle. Corrected Distance Visual Acuity (CDVA) and intraocular pressure were recorded on postoperative days 1, 1 week, 1 month, and 6 months. Intraoperative and postoperative complications were documented and analyzed.ResultsFifty eyes were identified as having cortically liquefied intumescent cataracts. No cases of the Argentinian flag sign occurred, and standard capsulorrhexis was achieved, facilitating smooth phacoemulsification. All patients achieved satisfactory outcomes at follow-ups of 1 day, 1 week, 1 month, and 6 months postoperatively. Mild corneal edema was observed in three cases on the first postoperative day, with no other complications noted.ConclusionsThe anterior chamber air bubble technique combined with cortical fluid release technique can prevent the occurrence of the Argentinian flag sign in cortically liquefied intumescent cataracts, this method is simple, convenient and economic for the clinical promotion.

The Role of Hysteroscopy in the Assessment of Fallopian Tubal Patency: A Comprehensive Review and Meta-analysis.

Hysteroscopy has been recognized as a reliable method for the evaluation of female infertility for several years. The outpatient setting is particularly convenient, as patients do not require general anesthesia and do not have to stay overnight. In recent years, more and more articles have dealt with the role of diagnostic hysteroscopy in tubal evaluation. Twenty-four articles were included in this comprehensive review and 14 of them were also included in a meta-analysis. This review provides an overview of the different techniques of hysteroscopic tubal evaluation, with a focus on perioperative changes in cul-de-sac volume, the air bubble technique ("Parryscope" technique), the Flow technique and selective hysteroscopic pertubation with methylene blue dye (SHPMBD). In pooled analyses, SHPMBD achieved the highest sensitivity for tubal patency (91.7%, 95% confidence interval, CI: 88.8-94.0), whereas the air bubble technique revealed the highest specificity of all methods (98.4, 95% CI: 95.3-99.6). Furthermore, in a meta-analysis of all methods on the assessment of single tubes, an overall sensitivity of 87.1% and an overall specificity of 79.8% (95% CI: 76.4-82.9) could be shown. In conclusion, the techniques of hysteroscopic tubal evaluation are well-tolerated, clinically relevant, and reliable.

Quantifying Contributions of Different Repulsion to Film Drainage Time during the Bubble-Solid Surface Attachment and Implications for the Flotation of Fine Particles.

The flotation recovery of fine particles faces serious challenges due to the lack of kinetic energy required for supporting their radial displacement and attachment with bubbles. Generally, the hydrodynamic resistance and repulsive disjoining pressure successively inhibit the liquid outflow intervening between the bubble and solid surfaces. To quantitatively characterize the influence of the main repulsion on film thinning time, experiments have been designed in three different aqueous systems. Bubble surface mobility closely associated with hydrodynamic resistance was determined by the rising bubble technique, and the DLVO theory was employed to confirm the evolution of electrostatic repulsion. The film drainage process was then measured based on the high-speed microscopic interferometry. Furthermore, the influence of the main repulsion on bubble-solid surface interactions was examined by flotation recovery. Results show that the earlier buildup of hydrodynamic force ran through the whole film thinning process, and under immobile conditions, the central region gradually became dominant in film thinning due to the very limited fluid flow at the thinnest rim position. Therefore, to achieve the identical film thickness (∼100 nm), the large hydrodynamic resistance could prolong the film thinning time by about 1 order of magnitude, compared with that induced by electrostatic repulsion, which accounts for the increased flotation recovery by 10% using mobile bubbles. This study not only enhances the understanding of how typical repulsive forces work in film drainage dynamics but also opens up an avenue for enhancing flotation and avoiding wasting resources by modulating bubble surface mobility and thus micro/nanoscale fluid flow.

Long-term Outcomes of Deep Anterior Lamellar Keratoplasty in Macular Corneal Dystrophy—A Retrospective Analysis

Abstract Purpose: To study the long-term outcomes and complications in patients who underwent deep anterior lamellar keratoplasty (DALK) for macular corneal dystrophy (MCD). Methods: This is a retrospective analysis of all patients who underwent DALK in a tertiary eye care hospital in South India from 2011 to 2020. A total of 51 eyes of 33 patients were evaluated. All eyes underwent successful DALK by big bubble technique (32 eyes) or layer-by-layer dissection (19 eyes). Patients were followed up for 18 months to 9 years. Results: There was a significant improvement in vision (uncorrected and best-corrected visual acuity) post-DALK. The best corrected visual acuity after surgery was 0.3 logMAR (20/40) or better in 66.7% of operated eyes. Complications noted during surgery were intra-operative perforation. Post-operative complications include double AC, cataract, raised intraocular pressure, interface vessels and recurrence of the dystrophy. Conclusion: DALK is a safe and viable procedure for MCD management and gives good visual outcomes.

The role of AS-OCT in the diagnoses and treatment of retained Descemet’s membrane–endothelial layer complex after penetrating re-keratoplasty. A case report and review of the literature

To report the successful management of a retained Descemet’s membrane–endothelial layer complex (DM-ELC) after penetrating re-keratoplasty in a patient with history of keratoconus and trabeculectomy. Femto-laser was used to cut both the host and the donor tissues. On postoperative day 1, a weak corneal suture and an endothelial detachment were detected. Rebubbling and substitution of the weak suture were performed. The persistence of the membrane the day after with a clear lenticule led to the diagnosis of retained DM-ELC. Intraoperative OCT, trypan blue staining, and shifting bubble technique were used for the surgical removal of the supernumerary membrane.

Experiment and Simulation Study of the Laser-Induced Cavitation Bubble Technique for Forming a Microgroove in Aluminum Foil.

The present work introduces a laser-induced cavitation bubble technique for forming an axisymmetric structure (i.e., microgroove) and the dynamics of a cavitation bubble from initial expansion to the collapse stages that were also simulated. Furthermore, the shock wave signals and dynamic properties of the cavitation bubble were recorded using a hydrophone and a high-speed camera. The experiments on microgrooves formed by laser-induced cavitation bubble stamping were carried out, and the effects of laser energy, the initial position of the bubble, and the number of impacts on the microformability of aluminum sheets are discussed. The depth of the microgroove was investigated using experiments, and it was found that the process can serve as a rapid technique for impressing microfeatures on thin-sheet metals. The experimental results showed that as the initial position of the bubble increased, the deformation depth decreased. As the laser energy and number of impacts increased, the deformation depth increased. The results of the response surface experiments showed that a laser energy of 27 mJ, 3 impacts, and a bubble position of 3 mm were optimal for the process. By using the optimal parameters, flat and smooth microgrooves with a forming depth of 102.54 µm were successfully fabricated. Furthermore, the maximum thickness thinning of the microgroove section occurred at the entrance areas, and this area had the greatest hardness. This also indicated that the greatest amount of plastic deformation of the material and grain refinement occurred in this area. On the other hand, the aluminum foil did not undergo oxidation during the plastic deformation process. These results demonstrated that laser-induced bubble stamping is an advanced micromachining method with promising applications.

Investigation into drag coefficient for sub-millimeter bubbles in gas–liquid bubbly flow: Experiments and CFD simulations

The sub-millimeter bubble technique can enhance the gas–liquid inter-phase mass transfer and show immense potential to increase production efficiency. The two-fluid model (TFM), suitable for the CFD simulations on the scale of actual reactors, is a powerful tool for exploring the application of the sub-millimeter bubble technique. Although the accuracy of TFM is largely affected by the drag models, the applicability of the drag models for gas–liquid two-phase flow of sub-millimeter bubbles is scarcely investigated. In the present work, the applicability of the single-bubble drag models was apprised with experimental data of single sub-millimeter bubbles. Then, the bubble swarm effect and its influence on the calculation of drag coefficients were investigated for the gas–liquid two-phase flow of sub-millimeter bubbles under a wide range of gas holdups (0.02–0.21). The accelerating effect was observed in the experiments of gas–liquid two-phase flows. A reasonable explanation for the accelerating effect was discussed based on the bubble size distribution obtained by applying our original image processing method. Based on the experiments, an equation for the drag modification factors was proposed to include the bubble swarm effect. The accuracy and applicability of the proposed equation were validated by applying it together with the accurate single-bubble drag model in the CFD simulation by TFM. The present work investigated the hydrodynamic characteristics of sub-millimeter bubbly flows experimentally and provided an accurate CFD method for further investigation.

Ex vivo demonstration of canine corneal pre-Descemet’s anatomy using pneumodissection as for the big bubble technique for deep anterior lamellar keratoplasty

The recent discovery and characterization of pre-Descemet’s layer (PDL; also termed the Dua’s layer or the Dua-Fine layer) has advanced the understanding of various posterior corneal pathologies and surgeries in human. This study aimed to characterize the ultrastructure of the posterior stroma and interfacial zone of Descemet’s membrane (DM) in canine eyes. Eighteen canine corneo-scleral discs were included. Intrastromal air injection resulted in the formation of type 1 big bubble (BB) in 73% (n = 11/15) of corneas, with a mean diameter of 11.0 ± 1.3 mm. No type 2 BB was created. Anterior segment optical coherence tomography, histology and transmission electron microscopy confirmed that the wall of BB was composed of DM, in contact with remaining stroma (canine PDL; cPDL). The cPDL was populated with keratocytes, of varying thickness of 16.2 ± 4.2 µm in close apposition to the DM, and composed of collagen bundles arranged in transverse, longitudinal and oblique directions. The interfacial zone, between DM and cPDL, showed fibril extension in all three directions, predominantly longitudinal. Irregular extensions of DM material into cPDL stroma were observed. No long-spaced collagen was detected. In conclusion, there exists a well-defined cleavage plane between the posterior stroma and cPDL, with similar but not identical characteristics as in humans, that is revealed by pneumodissection. This adds to our understanding of the anatomy of the posterior most canine cornea, which will have significant clinical impact on posterior corneal surgery and understanding of corneal pathology in dogs.

Elliptical deep anterior lamellar keratoplasty in severe Acanthamoeba keratitis.

Acanthamoeba keratitis (AK) is an intractable infection of the cornea. Penetrating keratoplasty is widely used for the management of severe AK but suffers from complications like graft rejection, endophthalmitis, and glaucoma. Herein, we aimed to describe the surgical technique and the results of elliptical deep anterior lamellar keratoplasty (eDALK) for the management of severe AK. In this retrospective case series, records of consecutive patients with AK poorly responsive to medical treatment who underwent eDALK from January 2012 to May 2020 were reviewed. The largest diameter of infiltration was ≥8 mm and did not involve the endothelium. The recipient bed was made by an elliptical trephine, and big bubble or wet-peeling technique was performed. Postoperative best spectacle-corrected visual acuity, endothelial cell density, corneal topographic data, and complications were evaluated. Thirteen eyes of thirteen patients (eight men and five women, 45.54 ± 11.78 years old) were included in this study. The mean follow-up interval was 21.31 ± 19.59 months (range, 12-82 months). At the last follow-up, the mean best spectacle-corrected visual acuity was 0.35 ± 0.27 logarithm of the minimum angle of resolution. The mean refractive and topographic astigmatism were - 3.21 ± 1.77 and 3.08 ± 1.14 D, respectively. Intraoperative perforation was encountered in one case and double anterior chambers occurred in two cases. One graft developed stromal rejection and one eye developed amoebic recurrence. eDALK can serve as the first-line surgical management of severe AK poorly responsive to medical treatment.

Comparison of visual outcomes, keratometric parameters and biomechanical profiles between deep anterior lamellar keratoplasty with big-bubble technique vs. Melles technique for keratoconus: a retrospective study

ObjectiveComparing results of two different DALK surgery techniques (big bubble vs. Melles) in patients with advanced keratoconus.Designa retrospective comparative clinical study.ParticipantsThis study conducted on 72 eyes of 72 participants.IntroductionThis study designed to compare the results of two different DALK surgery techniques (big bubble vs. Melles) in patients with advanced keratoconus.MethodThirty-seven eyes were treated using the big bubble DALK method, while 35 eyes were treated using the Melles approach. Uncorrected visual acuity (UCVA), best corrected spectacle visual acuity (BCSVA), manifest refraction, keratometric characteristics, contrast sensitivity, corneal aberrations, corneal biomechanical characteristics, and endothelial cell profile are the outcome measurements.ResultsMean UCVA in big bubble group was 0.61 ± 25 LogMAR and in Melles group was 0.89 ± 0.41 LogMAR (p-value 0.043). Mean BCSVA in big bubble group (0.18 ± 0.12 Log MAR) was significantly better than Melles group (0.35 ± 0.16 Log MAR). Mean of sphere and cylinder refraction showed no significant difference between two groups. Comparing the endothelial cell profile, corneal aberrations, corneal biomechanical properties and keratometry had no significantdifferences. Contrast sensitivity reported as modulation transfer function (MTF) showed higher values in big bubble group and differences with Melles group weresignificant. Results of point spread function (PSF) in big bubble group had superiority to Melles group with considerable statistical P value of 0.023.ConclusionWhen opposed to the Melles approach, the big bubble technique generates a smooth interface with less stromal residue, which results in higher visual quality and contrast sensitivity.

Spherical equivalent (SE) outcomes after suture manipulation in post operative deep anterior lamellar keratoplasty (DALK) patients

Introduction: Deep anterior lamellar keratoplasty (DALK) is a successful intervention among other surgical options for treating keratoconus. However after DALK surgery there are other post operative refractive morbidities which affects patient satisfaction. This study analyzes how suture manipulation in post-DALK patients affects the Spherical Equivalent (SE) outcome and whether it’s adhering to the corneal coupling concept.Objective: To determine the pre and post suture manipulations adhered to the concept of corneal coupling and the effect of timing of suture removal on the Spherical Equivalent (SE) outcome.Methodology: This retrospective study involved 40 manipulations in 18 patients who underwent DALK from 2020 to 2021 for keratoconus. All the Surgeries performed by single Consultant Eye Surgeon using big bubble (BB) technique. All grafts anchored using 16 interrupted 10/0 nylon sutures. Data was obtained from hospital and patient records. Objective and Subjective SE, Mean K readings were monitored.Conclusion: Pre and Post suture manipulations adhered to the corneal coupling and there was no statistically significant SE change. Furthermore, it was observed that delaying the removal of sutures resulted in minimal changes in the SE.

Inadvertent Viscoelastic Separation of the Pre-Descemet (Dua) Layer in Deep Anterior Lamellar Keratoplasty With Structural Features Revealed by Polarization Microscopy.

Deep anterior lamellar keratoplasty (DALK) is a corneal transplant technique that removes the host stroma down to either the pre-Descemet (Dua) layer or Descemet membrane. It is most common for the big bubble technique to create a cleavage plane between the posterior stroma and the pre-Descemet layer. This is advantageous because the pre-Descemet layer has been found to be much stronger than Descemet membrane, and makes the procedure easier to perform. In this report, we present an uncommon viscoelastic-related complication of DALK that resulted in excising the pre-Descemet layer and allowing it to be studied using polarization microscopy. DALK was performed using a standard big bubble technique. Postoperatively, a double anterior chamber was found to have been created by the inadvertent passage of an ophthalmic viscoelastic device (OVD) through the pre-Descemet layer. This resulted in the OVD being trapped between the pre-Descemet layer and Descemet membrane. The pre-Descemet layer was then resected in a subsequent operation. The pre-Descemet layer and posterior stroma were studied by polarization microscopy using Sirius Red histochemical staining to elucidate the orientation of the collagen fibers. The pre-Descemet layer is composed of lamellar arrays of collagen that have consistent polarization properties within each layer but show variable polarization of the strands, indicative of anisotropic strand orientation. The degree of variable polarization of the pre-Descemet layer is distinct from the overlying posterior stroma. Injecting an OVD into a big bubble in DALK may result in it being trapped between the pre-Descemet layer and Descemet membrane. The pre-Descemet layer shows alternating layers of varying polarization of collagen. This anisotropic structure helps explain the basis for the additional strength that the pre-Descemet layer is known to have.

DescePrep Significantly Increases Descemet Membrane Endothelial Keratoplasty Processing Efficiency and Success Rate in Diabetic Human Donor Corneas in Comparison With Manual Dissection.

The purpose of this study was to compare the safety, efficacy, and efficiency of a Descemet membrane endothelial keratoplasty (DMEK) graft processing device, DescePrep, with a manual dissection technique through the measurement of tissue yield, processing time, and graft viability in nondiabetic and diabetic donor corneas. Nondiabetic (n = 20) and diabetic (n = 20) donor corneas were processed using DescePrep, which standardizes the liquid bubble technique. Nondiabetic (n = 20) and diabetic (n = 24) donor corneas were also processed through manual dissection. Corneas were stained, processed, and then evaluated for processing success rate and time. Randomly selected corneas (n = 5, each) were evaluated for cell viability using live/dead staining. One hundred percent of nondiabetic and 95% of diabetic corneas were processed successfully with DescePrep in an average of 3.37 minutes. Ninety percent of nondiabetic and 50% of diabetic corneas were processed successfully with manual dissection in an average of 9.87 minutes. DescePrep had a significantly lower processing time ( P < 0.0001) and significantly higher success rate in comparison with manual dissection. DescePrep grafts had an average cell viability of 91.1% ± 3.3% in nondiabetic and 91.5% ± 2.4% in diabetic corneas. Grafts prepared with manual dissection had an average cell viability of 89.5% ± 5.8% in nondiabetic and 88.1% ± 4.3% in diabetic corneas. DescePrep provides a more effective and efficient method of cornea preparation in comparison with the current standard, particularly in diabetic corneas, while providing comparable cell viability. Thus, DescePrep offers standardized DMEK processing that produces high-quality grafts at high yields, with the potential to expand access and improve the quality of DMEK graft preparation in a larger pool of donors.

A deep learning-based image processing method for bubble detection, segmentation, and shape reconstruction in high gas holdup sub-millimeter bubbly flows

The sub-millimeter bubble technique can enhance the gas–liquid inter-phase mass transfer by significantly reducing the bubble size and increasing the gas–liquid interfacial area. To accurately describe the flow and mass transfer characteristics, it is necessary to characterize bubble parameters. High-speed photography followed by image processing is an effective way to characterize the gas bubbles in the multiphase flows. However, the efficient image processing method for the sub-millimeter bubbly flows with high gas holdup and high bubble overlap has not been reported yet. The present work developed a novel deep learning-based image processing method for bubble detection, segmentation, and shape reconstruction in high gas holdup sub-millimeter bubbly flows. In order to segment the highly overlapping sub-millimeter bubbles, our method was built based on Mask R-CNN, with which the pixel-level segmentation masks can be obtained, and the shape of the overlapping bubbles can be accurately described. The feature pyramid architecture was coupled with ResNet101 and Feature Pyramid Network to detect sub-millimeter bubbles with significant size differences. A shape reconstruction module was proposed to restore the real shape of overlapping bubbles and improve prediction accuracy. In order to sufficiently validate the proposed method, adequate images of sub-millimeter bubbly flows were obtained by changing the experimental media (air-tap water, air-sodium dodecyl sulphate aqueous solution, air-diesel, and air-diesel-fine catalyst particles), reactor configurations (3D beds and 2D beds), lenses, and photography (shadowgraphy and front illumination). Our method shows high accuracy under the experimental conditions and can process sub-millimeter bubble images under gas holdup up to 20%.

Biotechnology Approach to Mineral Separation via Phage Flotation Collectors.

A long-standing challenge in the mining industry is the separation of mineral particles that have similar surface characteristics for which surfactant-based flotation collectors cannot discriminate. In Florida phosphate mining, this problem occurs in the separation of dolomite [CaMg(CO3)2] contaminants from the desired francolite mineral {a fluorapatite [Ca5(PO4)3(F,OH)]}. In this study, phage display techniques were used to select phage clones with specific binding affinity to francolite, which were then tested in a benchtop bubbler flotation apparatus for their ability to selectively float francolite particles from mixtures containing dolomite. Contact angles measured with the captive bubble technique were used to examine changes in the surface character of the mineral particles upon adsorption of the phage, which showed that the most selective phage led to an increase in the contact angle from 16 to 50°. Although this is below the level considered hydrophobic, the correlation between contact angles and increased flotation recovery suggests that the phage coat proteins are behaving as efficient bioamphiphiles for the attachment of the particles to air bubbles, demonstrating a new and environmentally friendly type of biocollector system. The chemical and physical characteristics of the phage "tail" peptides were evaluated to offer an explanation for the specificity of phage binding. We conclude with a discussion of the potential benefits of this biotechnology approach, even for commodity industries such as mining or other particle separation systems, when costs and sustainability are considered.

A novel method of tunnel creation using intraoperative optical coherence tomography-guided deep anterior lamellar keratoplasty.

The big bubble technique has become the technique of choice for performing deep anterior lamellar keratoplasty (DALK) since its inception in 2002. The main challenge with this technique is in achieving a big bubble while preventing inadvertent perforation of the Descemet’s membrane. Although femtosecond lasers have increased the safety, accuracy, and predictability of corneal dissection in DALK, the challenge of achieving a big bubble still exists. To overcome this challenge, Zeimer Z8 Femto LDV has launched a new software module for DALK, which has an added advantage of real-time optical coherence tomography–assisted femtosecond tunnel creation for achieving a big bubble.

Evaluation of Efficacy, Efficiency, and Cell Viability of a Novel Descemet Membrane Endothelial Keratoplasty Graft Preparation Device, DescePrep, in Nondiabetic and Diabetic Human Donor Corneas.

The purpose of this study was to evaluate the safety, efficacy, and efficiency of a Descemet membrane endothelial keratoplasty (DMEK) graft preparation device, DescePrep, through measurement of graft viability, yield, and preparation time in both healthy and diabetic (high-risk) donor eyes. Twenty nondiabetic and 10 diabetic donor corneas were processed using DescePrep, which standardizes the liquid bubble technique. Corneas were stained with trypan blue and then processed. Cell counts through specular microscopy, optical coherence tomography imaging, and slit-lamp analysis were used for the evaluation of graft separation and viability in 5 nondiabetic corneas. The remaining 25 corneas (15 nondiabetic and 10 diabetic) were evaluated for preparation success rate and processing time. Ten corneas (5 nondiabetic and 5 diabetic) were randomly selected for further evaluation of global cell loss through staining. Ninety-seven percent of corneas (29 of 30) were prepared successfully with DescePrep. The average preparation time was 2.83 ± 1.8 minutes. There was no significant difference in the time of preparation between the nondiabetic and diabetic groups (P = 0.077). The overall average cell death after processing was 7.9% ± 3.7% for all corneas. There was no significant difference in cell viability between diabetic and nondiabetic tissues after DescePrep processing (P = 0.769). DescePrep is a new DMEK preparation technique that can process both nondiabetic and diabetic donor corneas at high yields in minutes. High-yield preparation of diabetic corneas may offer eye banks access to a larger donor pool, which is important because the demand for DMEK grafts continues to rise worldwide.

Rhamnolipids as Effective Green Agents in the Destabilisation of Dolomite Suspension.

In this paper, we describe an application of mono- and dirhamnolipid homologue mixtures of a biosurfactant as a green agent for destabilisation of a dolomite suspension. Properties of the biosurfactant solution were characterised using surface tension and aggregate measurements to prove aggregation of rhamnolipids at concentrations much lower than the critical micelle concentration. Based on this information, the adsorption process of biosurfactant molecules on the surface of the carbonate mineral dolomite was investigated, and the adsorption mechanism was proposed. The stability of the dolomite suspension after rhamnolipid adsorption was investigated by turbidimetry. The critical concentration of rhamnolipid at which destabilisation of the suspension occurred most effectively was found to be 50 mg·dm−3. By analysing backscattering profiles, solid-phase migration velocities were calculated. With different amounts of biomolecules, this parameter can be modified from 6.66 to 20.29 mm·h−1. Our study indicates that the dolomite suspension is destabilised by hydrophobic coagulation, which was proved by examining the wetting angle of the mineral surface using the captive bubble technique. The relatively low amount of biosurfactant used to destabilise the system indicates the potential application of this technology for water treatment or modification of the hydrophobicity of mineral surfaces in mineral engineering.