Gel Injection Research Articles

Experimental Investigation of Low-Concentrated Nanocomposite Polymer Gels for Water Shutoff Treatment Under Reservoir Conditions

Summary Excessive water production is one of the main challenges in mature oil fields. Applying polymer gels has proven to be an effective chemical treatment to this problem. Because of some limitations in application of polymer gels in oil reservoirs with harsh conditions, using nanoparticles (NPs) in gel structure has been proposed recently to improve the performance of such systems. However, while main body of the previous studies has only focused on improvement of bulk properties of polymer gels in presence of NPs, there is a serious lack of data on their performance in porous media. In this study, we have conducted a comprehensive investigation on application of two new nanocomposite polymer gels through bulk-gel static tests and dynamic core displacement tests. Fe2O3 and NiO NPs at low concentrations (<100 mg·L−1) in AN125VLM/chromium acetate polymer gel system were used. The results of bulk bottle tests at 82℃ demonstrated that the nanocomposite gel systems have the same gelation time and gel strength as the NPs-free gel. Swelling ratio measurements were also performed in a high-salinity formation water (268 949 mg·L−1), and accordingly, while NiO NPs deteriorated the swelling behavior of the gel system, Fe2O3 NPs showed a positive impact. The results of the strain-sweep test demonstrated relatively similar linear viscoelastic region and thus the same gel strength for all gel samples. In addition, the results of the thermogravimetric analysis (TGA) revealed that Fe2O3 NPs had a minor positive impact on thermal resistance of the polymer gel system. Finally, high pressure-high temperature coreflooding experiments were carried out on three sandstone reservoir core samples. Although the NPs-free gel showed a desirable level of disproportionate permeability reduction, the injection of Fe2O3 nanocomposite gel showed unsatisfactory results and caused rock permeability degradation. The pressure drop trend and deposition of polymer gel particles at the upstream injection side confirmed the aggregation and plugging effect of NPs during injection. Our findings demonstrate the critical aspect of dynamic core displacement testing of nanocomposite gels before their use for field applications.

Effects of Subcutaneous Repository Corticotropin Gel Injection on Regulatory T Cell Population in Noninfectious Retinal Vasculitis

ABSTRACT Aim To evaluate the effect of repository corticotropin injection (RCI) on regulatory T cell population in patients with noninfectious retinal vasculitis. Patients and Methods Patients with active noninfectious retinal vasculitis were included in a prospective nonrandomized open-label study. Results Eighteen patients (33 eyes) were included in the study. Eleven (61.1%) patients [20 (60.6%) eyes] and 7 (38.9%) patients [13 (33.3%) eyes] were in the responsive and non-responsive groups, respectively. We did not find any statistically significant difference within the PPP-R group, within the PPP-NR group, or between these two groups in regard to regulatory T cell population. No significant systemic or ocular complications were found. Conclusion RCI may be a complementary treatment in patients with non-infectious retinal vasculitis with or without uveitis. This study did not demonstrate an increase in regulatory T cell population in patients with noninfectious retinal vasculitis.

Efficacy of Cross-Linked Hyaluronic Acid Gel for the Reduction of Post-operative Obstructive Symptoms Due to Adhesions.

BackgroundAdhesions occur frequently after surgery. A number of methods are being employed for reducing post-operative adhesions. The purpose of this study was to determine the efficacy of hyaluronic acid gel in the reduction of post-operative bowel obstruction symptoms in patients undergoing emergency laparotomy due to small bowel perforation and presenting with peritonitis.MethodsIn this experimental study, 78 patients were evaluated. All had presented to the emergency department with peritonitis secondary to small bowel perforation. Exploratory laparotomy was performed and after thorough lavage, a loop stoma was formed on the right side of the abdomen with an injection of hyaluronic acid gel injected into the abdominal cavity before the closure of the abdomen. Postoperative obstructive symptoms at one, three, and six months were evaluated. All patients underwent stoma reversal at three months.ResultsObstructive bowel symptoms were seen in 18 patients (23.07%) patients. The cumulative incidence of obstructive symptoms at three months was only 8.97% but after the second intervention without protective gel, it increased to 23.07% at six months.ConclusionsCross-linked hyaluronic acid gel was effective in the reduction of post-operative bowel obstructive symptoms due to adhesions in patients who had presented with peritonitis due to small bowel perforation and had undergone exploratory laparotomy with stoma formation.

Effect of Hyaluronate Acid Injection on Dose-Volume Parameters in Brachytherapy for Cervical Cancer

PurposeHyaluronate gel has been injected as a spacer into the rectovaginal fossa and vesicouterine fossa during brachytherapy for patients with cervical cancer at our institution. The effect of hyaluronate gel injection (HGI) on dose-volume parameters was investigated in this study. Methods and MaterialsBetween July 2008 to January 2020, a total of 104 patients (non-HGI group: 52 patients; HGI group: 52 patients) who underwent curative radiation therapy for cervical cancer were selected. The total doses of external beam radiation therapy and brachytherapy for high-risk clinical target volume (CTVHR) D90, bladder D2cc, and rectal D2cc were converted to the equivalent dose in 2 Gy fractions (EQD2) and were analyzed for association with HGI. ResultsMedian CTVHR D90 (EQD2) in the non-HGI group was 76.0 Gy (63.7-99.5 Gy), and in the HGI group it was 79.4 Gy (52.6-97.5 Gy) (P = .017). The median bladder D2cc and rectal D2cc (EQD2) were 62.9 Gy and 56.0 Gy in the non-HGI group and 63.7 Gy and 54.8 Gy in the HGI group, which had no significant difference. ConclusionsIn cases with HGI, a significant CTVHR D90 dose increase was obtained with sufficient bladder and rectal doses suppression.

Mechanism study of water control and oil recovery improvement by polymer gels based on nuclear magnetic resonance

Polymer gels have been widely used to control excessive water production and improve oil recovery. NMR techniques have been gradually applied to analyze the remaining oil distributions in the core during gel treatment in recent years. However, studies about the NMR technique applied to analyze the gelation performance and microscopic water control mechanisms are still immature. In this paper, we first compared the gelation performance of polymer gels using both the Bottle Test method and core displacement method by monitoring the changes in the real-time tested relaxation time (T2) values. Then, the T2 changes of both oil- and water-phase permeabilities after gel treatment in cores were investigated separately. Finally, the disproportionate permeability reduction (DPR) mechanism of polymer gels was investigated by combining the NMR technique in the displacement experiment. Results show that the gelation time of polymer gel in both the tube and the cores can be measured- by the relationship curve between 1/T2 and reaction time. The reduction of single-phase permeability of oil after polymer gel treatment is much smaller than that tested by the water phase. T2 data also proves that the polymer gel has certain selective water plugging performance. In addition, when the oil and water coexist, polymer gel's disproportionate permeability reduction (DPR) mechanism is mainly reflected in the gradual increase of oil saturation after gel treatment. However, the flow resistance of water in the pore space gradually increases due to the continuous water absorption and swelling of gels. It can squeeze the crude oil channel during the chase water flooding period. Finally, gel injection in heterogeneous cores can plug the high-permeability layer. MRI results demonstrated that the chase water could divert and flood the low-permeability layer usually with high residual oils, thus improving oil recovery. In summary, this study's results will help further enhance the understanding of polymer gel cross-linking mechanisms in porous media and provide an experimental basis in the analysis of the DPR mechanism of polymer gels. It can also lay a theoretical foundation for the field application of polymer gels.

Autologous Dedifferentiated Osteogenic Bone Marrow Mesenchymal Stem Cells Promote Bone Formation in a Rabbit Model of Anterior Cruciate Ligament Reconstruction versus Bone Marrow Mesenchymal Stem Cells

This study aimed to verify whether transplantation of dedifferentiated osteogenic bone marrow mesenchymal stem cells (De-BMSCs) at the tendon-bone interface could result in more bone formation than BMSC transplantation in anterior cruciate ligament (ACL) reconstruction. BMSCs from femur and tibia of New Zealand White rabbit were subjected to osteogenic induction and then cultured in osteogenic factor-free medium; the obtained cell population was termed De-BMSCs. Bilateral ACL reconstruction was performed in 48 adult rabbits. Three groups were established: control group with alginate gel injection, BMSCs group with the BMSCs injection, and De-BMSCs group with the De-BMSCs injection. At week 4 and 12 postoperatively, tendon-bone healing by histologic staining, micro-computed tomography examination, and biomechanical test were evaluated. The expression of α1 chain of type I collagen, osteocalcin, and osteopontin at the tendon-bone interface in the De-BMSCs group was greater than in the control or BMSCs group. The bone volume/total volume by micro-computed tomography scan was significantly greater in the De-BMSCs group than that in the control group (P= .013) or BMSCs group (P= .045) at 4 weeks, and greater than that in the control group (P= .014) or BMSCs group (P= .017) at 12 weeks. The tunnel area was significantly smaller in the De-BMSCs group than in the control group (P= .013) or BMSCs group (P= .044) at 12 weeks. The failure load and stiffness in De-BMSCs group were both significantly enhanced at 4 and 12 weeks than control group or De-BMSCs group. De-BMSCs transplantation can promote bone formation at the tendon-bone interface better than BMSCs transplantation in ACL reconstruction and increase the early biomechanical strength of the reconstructed ACL CLINICAL RELEVANCE: De-BMSCs transplantation is a potential choice for enhancing early bone formation in the tunnel in ACL reconstruction.

Beneficial effects of transdermal administration of tamoxifen on capsular contracture after breast implantation in murine models.

Capsular contracture is the most common complication with smooth-type silicone implants. We investigated the preventive effect of an active metabolite of tamoxifen, 4-hydroxytamoxifen (4-OH TAM), on capsular contracture. A silicone sheet was implanted into the back of 28 female ICR mice. Mixtures of gel with 0.2% 4-OH TAM and 0.1% 4-OH TAM were administered transdermally once a day for 4weeks. Saline was administered to the control. After killing the mice, capsular thickness was measured in H&E-stained specimens. Estrogen receptor (ER), α-smooth muscle actin (α-SMA), and transforming growth factor-β (TGF-β) expressions were immunohistochemically investigated in the capsules. The capsule was thinner in the 0.2% 4-OH TAM gel group than in the control group (control, 0.1% 4-OH TAM gel, 0.2% 4-OH TAM gel: 52.8 ± 3.4µm, 54.2 ± 6.8µm, 46.4 ± 3.3µm, respectively). ER was found in most fibroblasts of all samples. α-SMA expression in the capsule was significantly lower in the 4-OH TAM gel groups than in the control group (control = 70.0 ± 3.4%, 0.1% 4-OH TAM = 57.0 ± 3.4%, 0.2% 4-OH TAM = 49.4 ± 4.9%). TGF-β expression was significantly reduced by the 4-OH TAM gel injections dose-dependently (control = 67.3 ± 2.2%, 0.1% 4-OH TAM = 52.4 ± 3.1%, 0.2% 4-OH TAM = 45.1 ± 2.4%). The transdermal administration of 0.1% and 0.2% 4-OH TAM gels inhibited capsule development. The inhibition of TGF-β expression is a mechanism by which 4-OH TAM suppresses fibroblast growth, preventing capsular formation.

Intention to use novel methods of male directed contraception among college students

Purpose: Currently, men have two choices for contraception: the male condom and vasectomy. Male condoms have limited user efficacy, and vasectomies are not easily reversible. To supplement vasectomy and condom use, the World Health Organization has backed the urgent development of male-directed contraception (MDC). Using the Theory of Planned Behavior (TPB), this study was guided by the following aims: (1) describe college men’s attitudes, subjective norms, and perceived behavioral control towards male birth control methods and (2) determine if the following factors are associated with intention to use MDC methods: masculinity, attitudes, subjective norms, and perceived behavior control.Methods: This study used a cross-sectional design. Data were collected online, via email, from male college students at one Midwestern University.Results: Attitudes, subjective norms, and perceived behavioral control were statistically significant predictors of intention to use a male hormonal pill, transdermal gel, and hormonal injection. Attitudes and subjective norms were also found to be associated with intention to use a male birth control implant.Conclusions: These results suggest the TPB may be a suitable theory for further investigation into the intended use of MDC. Attitudes and subjective norms accounted for the most variability in intention to use MDC. Future research should therefore investigate specific attitudes and subjective norms that influence the intention to use developmental methods of MDC. Future research should also consider additional theoretical models, such as the Health Belief Model, to continue investigating intention to use developmental methods of MDC.

Auto-Cross Linked Hyaluronan Gel Enhances Effects of Hysteroscopic Adhesiolysis Treatment in Patients with Moderate to Severe Intrauterine Adhesions

Background: Moderate to severe intrauterine adhesions affect women’s reproductive and mental health. Hysteroscopic surgery alone cannot improve the prognosis of IUA patients. The present study was to analyse whether auto-cross linked hyaluronan gel facilitates the hysteroscopic adhesiolysis treatment effect and reproductive performance of patients with moderate to severe IUA. Methods: Patients with moderate to severe IUA and fertility desire were included in this retrospective study. A total of 47 patients received standard hysteroscopic adhesiolysis alone served as control group. A total of 38 patients received cHA gel injection at the end of hysteroscopic adhesiolysis were were included in the treatment group. The IUA recurrence rate, endometrial thickness, AFS score, clinical pregnancy rate, and live birth rate were analysed. Results: The endometrial thickness (6.33±1.160 vs. 5.72±1.16 mm, P=0.029), clinical pregnancy rate [51.7 (26/42) vs. 14.29% (5/35); P=0.000) and live birth rate (36.2 vs.13.2%; P=0.000) were significantly higher in the treatment group compared with the control group, and the American Fertility Society score (P=0.018) was lower in the treatment group compared with the control group. Conclusion: The combination therapy of cHA gel plus hysteroscopic adhesiolysis in patients with moderate to severe IUA resulted in a better outcome in decreasing the severity of IUAs, and improving the quality of endometrium and enhancing the live birth rate compared with hysteroscopic adhesiolysis alone. Trial Registration: Clinical trial register number ChiCTR2100051670. Date of Retrospectively registered on September 30, 2021.

Monotherapy of Biofiller for Atrophic Acne Scars: A Prospective Nonrandomized Study.

Atrophic acne scarring is an unpleasant and often permanent complication and a therapeutic challenge for dermatologists. Platelet-poor plasma (PPP) gel injections are derived from the patient's own blood and used as a "biofiller" for skin rejuvenation. The objective was to study the efficacy and safety profile of PPP gel in atrophic acne scars. Thirty patients with atrophic acne scars were included in the study. Topical anesthesia was applied on the area of interest 45 min prior to the procedure. 20 mL of blood was collected in eight sodium citrate bulbs and centrifuged to get PPP that is coagulated with heat to form gel. This gel (biofiller) was injected in the scarred areas monthly for 6 months. Patients were evaluated using Goodman and Baron Scar (GBS) scale (quantitative and qualitative), Physician Global Assessment, and Visual Analogue Scale (VAS) at each visit. The final visit was after 3 months of the last procedure. The mean value of GBS at the first visit was 28, which reduced to 8.2 at the final visit. The analysis of variance test was applied to the quantitative scale from the baseline visit to the final visit. The F value was 462.55 with a P value < 0.0001. The paired t-test was applied for the GBS quantitative scale, which showed a value of 22.86 with a P value of <0.001. Transient local side effects were noted. Biofiller is efficacious in improving atrophic acne scars. It is a simple, minimally invasive, cost-effective procedure with no risk of immunogenic reaction.

Intrauterine Injection of Umbilical Cord Mesenchymal Stem Cell Exosome Gel Significantly Improves the Pregnancy Rate in Thin Endometrium Rats

Human umbilical cord mesenchymal stem cell (HUMSC)-exosome gel played a significant role in promoting thin endometrial receptivity and improving the pregnancy rate by inhibiting endometrial fibrosis and accelerating subendometrial microangiogenesis. High-quality HUMSC-exosome were obtained by pretreating HUMSC with transforming growth factor-β1 (TGF-β1). Exosome gel mixture has good biocompatibility and physical rheological properties, stabilizing the structure of exosomes and prolonging the action of exosomes in the uterine cavity. HUMSC or HUMSC-derived exosomes were used to treat rat model of thin endometrium. In animal experiments, four groups, including the HUMSC, HUMSC-exosome, model (negative control), and sham operation groups, were designed. The therapeutic effects were evaluated by the thickness of the endometrium, the number of glands, the subendometrial vessel density, the markers of endometrial receptivity, and the pregnancy rate. In an in vivo study, three groups, involving HUMSC-coculture, HUMSC-exosome, and the control, were explored. The proliferation and migration of the human endometrial stromal cells (HESCs) were further determined by cell scratch and 5-ethynyl-2′-deoxyuridine (EdU) assays. The protein expression of the TGF-β1/smad2/3 signaling pathway was determined by Western blot. After treatment, the thickness of the endometrium, the number of glands, and the subendometrial microangiogenesis were obviously increased, and the level of inhibition of endometrial fibrosis, molecular markers of endometrial receptivity, and the pregnancy rate were also significantly improved. HUMSC-exosome and HUMSC significantly promoted the migration and proliferation of HESCs. And it was confirmed that HUMSC-exosome were superior to HUMSC in inhibiting HESCs fibrosis through TGF-β1/smad2/3 signaling pathway at the protein expression level.

A Review of Gender-Affirming Hormone Therapy for Transgender and Gender Diverse Adults in South Korea.

Recently, gender-affirming hormone therapy for gender incongruence has become an issue in various countries and organizations with various guidelines. In South Korea, several clinical treatments are also used with many possible options. These treatments include masculinizing (female-to-male [FTM]) or feminizing (male-to-female [MTF]) hormone therapies, with regimens usually driven by standards of hormonal replacement therapy for hypogonadism (i.e., hypogonadal natal men and postmenopausal women). This cross-sex hormone therapy can change patients' physical appearance to better match their gender identity and expression. Regarding masculinizing therapy, injection and transdermal gel types of testosterone are used according to international guidelines. Progesterone is utilized in the form of oral pills, injections, or intrauterine devices to suppress menstruation and avoid pregnancy. Essentially, feminizing therapy uses androgen blockers along with estrogen. This is because estrogen alone cannot exert sufficient androgen-suppressing effects. In South Korea, the most commonly used androgen blockers are spironolactone and cyproterone acetate. Gonadotropin-releasing hormone (GnRH) agonist is also available. Regarding estrogen, oral pills, injections, and transdermal gels are utilized. This review introduces these gender-affirming hormone therapies in South Korea and discusses the side effects of each regimen.

A Pre-Gelled EEG Electrode and Its Application in SSVEP-Based BCI.

Electroencephalogram (EEG) electrodes are critical devices for brain-computer interface and neurofeedback. A pre-gelled (PreG) electrode was developed in this paper for EEG signal acquisition with a short installation time and good comfort. A hydrogel probe was placed in advance on the Ag/AgCl electrode before wearing the EEG headband instead of a time-consuming gel injection after wearing the headband. The impedance characteristics were compared between the PreG electrode and the wet electrode. The PreG electrode and the wet electrode performed the Brain-Computer Interface (BCI) application experiment to evaluate their performance. The average impedance of the PreG electrode can be decreased to 43 [Formula: see text] or even lower, which is higher than the wet electrode with an impedance of 8 [Formula: see text]. However, there is no significant difference in classification accuracy and information transmission rate (ITR) between the PreG electrode and the wet electrode in a 40 target BCI system based on Steady State Visually Evoked Potential (SSVEP). This study validated the efficiency of the proposed PreG electrode in the SSVEP-based BCI. The proposed PreG electrode will be an excellent substitute for wet electrodes in an actual application with convenience and good comfort.

Plasma Radiofrequency Ablation for Scar Treatment.

Scars are a common disfiguring sequela of various events such as acne, hidradenitis suppurativa, surgery, trauma, and burns, which can lead to serious psychosocial problems with a negative effect on the quality of life. Many conventional approaches have been proposed for the treatment of scars, including surgical techniques, dermabrasion, chemical peels, topical silicone gel, 5-fluorouracile and dermal fillers injection or autologous fat transfer for atrophic scars, and corticosteroids injection for hypertrophic and keloid scars; however, they have sporadic effects. Ablative lasers, such as carbon dioxide laser or Erbium Yag laser, are associated with many collateral effects limiting their application. Non-ablative laser treatments have been shown to be safer and to have fewer side effects, but they have a reduction of clinical efficacy compared to ablative lasers and a minimal improvement of scars. The demand for minimal invasive and safe technology for the treatment of a scars has stimulated the search for more effective novel therapy with fewer collateral effects. Plasma radiofrequency ablation is a new technique consisting of the generation of plasma energy through the production of ionized energy, which thermally heats tissue in a uniform and controlled manner, through a plasma radiofrequency device, inducing a sublimation of the tissue. The aim of this study is to evaluate the effectiveness of P-RF ablation in the treatment of scars performed with D.A.S. Medical device (Technolux, Italia), which is a tool working with the long-wave plasma radiofrequency principle.

Numerical analysis and experimental research on cathode pore-forming characteristics and mass transfer performance of direct ethanol fuel cell

Design of direct ethanol fuel cell (DEFC) plays a key role in its viability. A novel tubular DEFC is proposed to reconstruct the conventional structure, and tubular cathode is prepared by gel injection molding with Mesocarbon microbeads (MCMB), graphite and NH4Cl with different contents as raw materials. Moreover, simulation on the mass transfer and electrochemical performance of DEFC with a wider range of cathode porosity is carried out. Experiment results indicates that the support has higher porosity and strength when the graphite doping and NH4Cl is 40% and 2%–10%, respectively. Furthermore, superior performance of cathode and DEFC electrical performance are perceived due to larger porosity, especially when the porosity is 0.5. Moreover, in the simulation the results also show that porosity of cathode diffusion layer (CCL) has a significant effect on the oxygen mass transfer and removal of liquid water. Larger porosity means better electrical performance and delivers more power, which is more obvious at 0.2–0.6. It is proved that when the porosity is about 0.5, comprehensive performance of tubular DEFC is better than other models.

The optimization and economic evaluation of oil production using low salinity polymer flood: a case study for EOR 26

Trinidad and Tobago (TT) have been producing crude oil commercially since 1908. For the past few decades, TT’s crude oil production has been in steady decline because most of the oil reservoirs are beyond the primary phase of their production. This situation coupled with lower energy prices have resulted in a shortfall in TT’s energy revenues and presents TT with major economic challenges. The objective of this study was to optimize a field simulation model of a combined Low Salinity Polymer Gel flood to highlight the possibility that Enhanced Oil Recovery (EOR) can boost crude oil production especially from heavy oil reserves and mature fields. A field simulation model of the EOR 26 Upper Forest Sands was built using the CMG Builder software. The EOR 26 Upper Forest Sand reservoirs of the Forest Reserve field are delineated by shale-outs, faults and water–oil contacts. The entire Forest Reserve is bordered by the Fyzabad anticline to its north-west and the Los Bajos fault to its south-west. A dynamic field simulation model of the combined Low Salinity Polymer Gel flooding of EOR 26 Upper Forest Sands was created using CMG STARS software and the optimum parameters of polymer gel concentration, salinity concentration and injection rates and pressure for the highest oil recovery were investigated. The highest oil recovery was obtained using a polymer gel concentration of 500 ppm with a salinity of 1000 ppm and an injection rate of 900 bbls/day during continuous polymer gel injection for a period of 545 days. The polymer gel injection was preceded by pre flush water injection for 180 days and followed by water injection for the duration of the ten (10) year period. The predicted oil recovery for the project is an additional 14.52% of OOIP and is considered economically feasible at a crude oil price of US$50 per barrel with a payback period of two years and an IRR of 63.53%.

Identification of Water Production Mechanism in One of Iran’s Oil Fields and Treat it With Gel Injection

In this study, the problem of water production in one of Iran's oil reservoirs will be examined. First, using the flow rate diagram of oil and water production, the problem of water production will be examined according to time. Then, after confirming the occurrence of water production problem, the mechanism of water production will be investigated using Chan diagnostic diagrams and the created sector model. The results of this study indicate that firstly, the problem of water production in the well under study is observed, and secondly, according to the Decline-curve analysis diagrams, Recovery plot, Chan derivative diagram and schematic shape of the fluid flow movement, it shows the mechanism. Water production is a channel flow process under water injection. A gel treatment at early time with 25% of water cut was studied, for that it was modelled a gel treatment after 500 days of production.The main observation is that by increasing the concentration of injected gel, the rate of oil production increases and the rate of water production decreases. The concentration evaluated concentration was from 0 to 100 (lb/bbl) of solution, a stabilization concentration was not observed. Finally, first by identifying the type of water production mechanism for this reservoir in Iran, it has been determined that it has water production through the canal and then by using a simulation of gel injection, the water production rate has decreased and the oil production rate has increased.

Preferences regarding emerging HIV prevention technologies among Toronto men who have sex with men: a discrete choice experiment

New forms of HIV pre-exposure prophylaxis (PrEP) include long-acting injectables and topical microbicides, each with unique attributes that may appeal to distinct users. We used a discrete choice experiment to characterize preferences for new PrEP formulations among Toronto men who have sex with men. MSM undergoing anonymous HIV testing completed a discrete choice experiment with 12 choice sets by selecting their preferred option within each set. Each set included “usual methods to prevent HIV” (excluding PrEP) as one alternative and two hypothetical PrEP alternatives, which differed according formulation/dosing, side effects (none/mild), risk of drug resistance (none/low/moderate), and HIV prevention efficacy (50%, 65%, 80% or 99% risk reduction). We used mixed logistic regression to infer preferences for PrEP attributes and calculate the marginal rate of substitution between efficacy and other PrEP attributes. 306 men with median (interquartile range) age = 29 (25, 36) years participated, and reported 6 (3, 10) partners and 0 (0, 2) condomless receptive anal sex acts in the preceding six months. An on-demand pill was the most preferred formulation, followed by a monthly injection, daily pill, and on-demand rectal gel. Drug resistance was an important determinant of preferences if the risk was moderate, but not if it was low. The minimum efficacy required for an on-demand pill to be preferred over no PrEP was 32.6% (95%CI = 21.2–43.9%); for a daily pill, injections, and rectal gel, minimum efficacy was 57.9% (95%CI = 44.1–71.7%), 40.1% (27.0–53.2%), and 71.3% (60.5–82.1%), respectively. Attitudes towards PrEP formulations vary among men who have sex with men, with on-demand pills and monthly injections having the highest average preference scores. Understanding these preferences may help to predict uptake.

Experimental Study of Transport Behavior of Swellable Microgel Particles in Superpermeable Channels for Conformance Control

SummaryGel treatment is an effective way to attack excessive water production during oil development. The transport behavior of gel materials in reservoirs is of crucial importance to the effectiveness of gel treatments. The aim of this paper is investigating the transport behavior of swellable micrometer-sized preformed particle gels (PPGs, or microgels) through superpermeable (super-K) channels. Sandpacks with permeabilities ranging from 27 to 221 darcies were used to mimic the super-K channels. Multiple pressure sensors were applied along the sandpack models to monitor the propagation behavior of the microgels. The tested microgel particles could transport through the super-K channels, and a higher driving pressure gradient was required when the particle/pore size ratio was larger. The pressure gradient distribution along the super-K channels was relatively uniform when the particle/pore ratio was low (less than 1.3). However, the inlet section would show increasingly higher pressure gradients as the particle/pore ratio was increased, indicating increased difficulty in propagation. The propagation of the gel particles was significantly slower compared with the carrying fluid. The delayed propagation behavior was more pronounced when the particle/pore ratio was higher. The injection pressure was much less sensitive to the injection flow rate compared with a Newtonian fluid. The gel dispersion exhibited an apparent shear thinning (pseudoplastic) behavior when transporting through the porous channels. Breakage of the gel particles was observed especially at high superficial velocities. The particle breakage was partially responsible for the apparent shear thinning behavior. The breakage phenomenon was in favor of deep placement of the gel particles. The channel permeabilities were significantly reduced by the microgels, bringing sufficient resistance to subsequent waterflooding (more than 99.5%). At given matching size conditions, softer gels were more likely to establish in-depth placement and uniform water blocking capacity in the channels. The microgel particles exhibited salinity-responsive behavior to the post-brine flush. The gel particles could shrink and reswell according to the salinity of the injected water. Possibilities were discussed to use this salinity-responsive behavior. Also, the microgels exhibited a particular disproportionate permeability reduction (DPR) effect. After gel injection, the channel permeability to water flow was reduced by more than 20 to 92 times of the permeability to oil flow. This work provides important support to understand the transport behavior of gel particles in super-K channels. The achievements are helpful for gel product selection and gel treatment design.

A randomized, double-blind, comparative study for efficacy assessment of two hyaluronic acid nasolabial fillers

&lt;p class="Default"&gt;Hyaluronic acid fillers are considered safe for use in cosmetics as described in the safety assessment. This study was aimed to assess and compare the efficacy and safety of two hyaluronic acid (HA) fillers on mild nasolabial folds. Ten women aged 30-50 years with mild nasolabial folds participated for injection of A and B gels into right or left nasolabial folds. The volume and surface of nasolabial folds were measured by CSI software and the density and thickness of dermis assessed by skin ultrasonography before and 2, 12, and 24 weeks after injection. The data were analyzed using SPSS software version 20, and p-value &amp;lt;0.05 were considered as significant. Global assessment showed over 50% improvement in patients injected with both gel A and B. At 2 weeks after injecting gel A the volume and surface of wrinkles decreased significantly. In the side injected with gel B, this reduction was significant at 2 and 12 weeks after injection. In addition, 24 weeks after injection of both gels the dermis echo-density increased and the dermis thickness decreased. This study indicated the significant positive filling effect of both HA fillers in decreasing the clinical signs of wrinkles at nasolabial folds. Comparing both fillers, there were not any statistically significant differences in any of measurements, but the persistence of gel B to improve the wrinkle appearance was slightly better than gel A. &lt;/p&gt;