Novel Suturing Methods for the Management of Traumatic Choroidal Avulsion in Globe Injuries

PurposeTo explore the long-term efficacy of novel choroidal suturing methods including trans-scleral mattress suturing (TSS) and intraocular suturing (IOS) in the treatment of choroidal avulsion.DesignProspective cohort, hospital-based study.MethodsA total of 24 patients who were diagnosed with choroidal avulsion were enrolled in this study. The demographic characteristics, baseline information of trauma, best-corrected visual acuity (BCVA), and intraocular pressure (IOP) were collected before surgery, and the anatomic abnormities of the globe were recorded before or during surgery. All patients were diagnosed with choroidal avulsion and underwent choroid suturing treatment during vitrectomy, postoperative functional variables including BCVA and IOP, anatomic variables including retinal and choroidal reattachment rate, and silicone oil migration rate, which were recorded at the regular follow-ups at least 1 year after surgery.ResultsAll patients with open globe injury involved zone III, 70.8% of the patients presented with two quadrants of the avulsed choroid, and 29.2% with one quadrant involved; moreover, all patients had complications with retinal detachment (RD), of which 58.3% of patients had closed funnel retinal detachment. TSS was applied in nineteen patients and IOS in five patients. Postoperatively, a significant improvement on LogMAR BCVA was observed at each follow-up from 3.57 ± 0.69 before surgery to 2.82 ± 0.98 at the last follow-up (p < 0.05), and the proportion of no light perception (NLP) was also reduced from 69.6 to 37.5%. IOP was markedly elevated from 6.4 ± 4.1 mmHg preoperatively to 11.3 ± 4.3 mmHg at the last follow-up (p < 0.05). Choroidal reattachment was achieved in 91.7% of patients; two patients were observed with silicone oil migration at 3 months after surgery and underwent drainage of suprachoroidal silicone oil and sclera buckling. Meanwhile, retinal attachment was observed in 95.8% of patients, only one patient developed partial RD due to postoperative proliferative vitreoretinopathy, and secondary vitrectomy was performed; all patients were observed with complete retinal and choroidal attachment at the last follow-up. Eventually, four patients were silicone oil-free, and 20 patients were silicone oil-dependent.ConclusionsChoroidal suturing proved to be an effective method to fix the avulsed choroid, which greatly improved the BCVA and maintained the IOP, and efficiently increased the choroidal and retinal reattachment rate and preservation of the eyeball.

LA-ICP-MS U-Pb dating and geochemical characterization of oil inclusion-bearing calcite cements: Constraints on primary oil migration in lacustrine mudstone source rocks

To date, few isotope age constraints on primary oil migration have been reported. Here we present U-Pb dating and characterization of two fracture-filling, oil inclusion-bearing calcite veins hosted in the Paleocene siliciclastic mudstone source rocks in Subei Basin, China. Deposition age of the mudstone formation was estimated to be ca. 60.2−58.0 Ma. The first vein consists of two major phases: a microcrystalline-granular (MG) calcite phase, and a blocky calcite phase, each showing distinctive petrographic features, rare earth element patterns, and carbon and oxygen isotope compositions. The early MG phase resulted from local mobilization of host carbonates, likely associated with disequilibrium compaction over-pressuring or tectonic extension, whereas the late-filling blocky calcite phase was derived from overpressured oil-bearing fluids with enhanced fluid-rock interactions. Vein texture and fluorescence characteristics reveal at least two oil expulsion events, the former represented by multiple bitumen veinlets postdating the MG calcite generation, and the latter marked by blue-fluorescing primary oil inclusions synchronous with the blocky calcite cementation. The MG calcite yields a laser ablation−inductively coupled plasma−mass spectrometry U-Pb age of 55.6 ± 1.4 Ma, constraining the earliest timing of the early oil migration event. The blocky calcite gives a younger U-Pb age of 47.8 ± 2.3 Ma, analytically indistinguishable from the U-Pb age of 46.5 ± 1.7 Ma yielded by the second calcite vein. These two ages define the time of the late oil migration event, agreeing well with the age estimate of 49.7−45.2 Ma inferred from fluid-inclusion homogenization temperature and published burial models. Thermodynamic modeling shows that the oil inclusions were trapped at ∼27.0−40.9 MPa, exceeding corresponding hydrostatic pressures (23.1−26.7 MPa), confirming mild-moderate overpressure created by oil generation-expulsion. This integrated study combining carbonate U-Pb dating and fluid-inclusion characterization provides a new approach for reconstructing pressure-temperature-composition-time points in petroleum systems.

Supplemental Material: LA-ICP-MS U-Pb dating and geochemical characterization of oil inclusion-bearing calcite cements: Constraints on primary oil migration in lacustrine mudstone source rocks

Table S1: LA-ICP-MS U-Pb contents (ppm), and 238U/206Pb-207Pb/206Pb ratios of the microcrystalline-granular calcite (MGC) and blocky calcite (BC) in vein samples FSX1-1 and FSX1-2; Table S2: LA-ICP-MS rare earth element (REE) data (ppm) for calcite cements in vein samples FSX1-1 and FSX1-2.

Supplemental Material: LA-ICP-MS U-Pb dating and geochemical characterization of oil inclusion-bearing calcite cements: Constraints on primary oil migration in lacustrine mudstone source rocks

Table S1: LA-ICP-MS U-Pb contents (ppm), and 238U/206Pb-207Pb/206Pb ratios of the microcrystalline-granular calcite (MGC) and blocky calcite (BC) in vein samples FSX1-1 and FSX1-2; Table S2: LA-ICP-MS rare earth element (REE) data (ppm) for calcite cements in vein samples FSX1-1 and FSX1-2.

Prediction of favorable areas for oil accumulation in outer-source tight reservoirs under the control of lateral migration distance: a case study of Baikouquan Formation, Mahu Sag, Junggar Basin, China

There is a starting pressure gradient (SPG) for oil migration in tight reservoirs (TRs), and the SPG and the migration force jointly control the migration distance of oil. The key factor of oil accumulation in the tight glutenite reservoir (TGR) of the Lower Triassic Baikouquan Formation (T1 b) in the Mahu Sag is whether the oil can be laterally charged into the TRs. To analyze the lateral migration distances of oil in TRs and predict the favorable accumulation areas for oil, we have carried out a physical simulation experiment of oil charging on glutenite reservoirs of T1 b for obtaining the SPG of oil migration and knowing the relationship between SPGs and the reservoirs’ physical property. According to the basin simulation, we have obtained the pressure evolution of the source rock formation as well as reservoir formation and the physical property evolution of the reservoir. Finally, we have predicated the favorable oil accumulation areas through calculating the distribution characteristics of SPGs as well as the theoretical distances of lateral migration of oil during the key oil accumulation period and considering the theoretical distance of the lateral migration of oil as the main controlling factor. Our results suggest that there is a SPG in the TGR of the T1 b and that there is a power function relationship between the SPG and the permeability. The theoretical lateral migration distance of oil in T1 b during the key oil accumulation period was the farthest in the northern sag, which was gradually shortened to the east, west, and south. In class I favorable areas, the reservoirs have good physical properties where overpressure has developed; in addition, the lateral migration distance of oil is far. Therefore, these are the most favorable areas for oil accumulation.

Effect of the Epoxide Contents of Liquid Isoprene Rubber as a Processing Aid on the Properties of Silica-filled Natural Rubber Compounds

In this study, we examined the feasibility of using epoxidized liquid isoprene rubber (E-LqIR) as a processing aid for truck and bus radial (TBR) tire treads and investigated the effects of the epoxide content on the wear resistance, fuel efficiency, and resistance to extraction of the E-LqIRs. The results confirmed that, compared to the treated distillate aromatic extract (TDAE) oil, the E-LqIRs could enhance the filler–rubber interactions and reduce the oil migration. However, the consumption of sulfur by the E-LqIRs resulted in a lower crosslink density compared to that of the TDAE oil, and the higher epoxide content decreased the wear resistance and fuel efficiency because of the increased glass-transition temperature (Tg). In contrast, the E-LqIR with a low epoxide content of 6 mol% had no significant effect on the Tg of the final compound and resulted in superior wear resistance and fuel efficiency, compared to those shown by TDAE oil, because of the higher filler–rubber interactions.

A Method to Simulate the Migration and Accumulation of Hydrocarbon with Analogue Modeling

Subsurface migration and accumulation of oil and gas have interested researchers for a long time, but these processes may occur over very long geological periods and are difficult to observe directly, so experimental simulations are warranted. In this study, an experimental method was developed to model hydrocarbon migration in the subsurface structure. Oil migration was simulated in a sandbox model, and industrial CT scanning was used to observe both the internal geometry of the model and the oil migration pathways. In the sandbox model, a NaI solution was used to simulate water, white oil was used to simulate hydrocarbon, and fine quartz sand, glass bead, silica powder, and brown corundum were chosen to represent brittle crust, based on suitable material parameters. A NaI-saturated layered sandbox model was constructed with an along-strike basal discontinuity, which during compression allowed a simple anticline with doubly verging reverse faults to form. Oil was then released continuously at a low rate from an orifice under one limb of the anticline. Initially, the oil migrated vertically through the fault zone until it reached the top of the fault zone; it then migrated laterally along the core of the anticline, saturating a model reservoir by buoyancy and capillary force. This experimental analog helps to explain hydrocarbon migration and accumulation within the Anjihai and Santai anticlines in northwest China.