Influence of the length of the spacer group on the performance of the sulfate-based Gemini surfactants

PurposeA series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions.Design/methodology/approachA series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions. The structures of the intermediate and final products were characterized by FT-IR (Fourier transform infrared spectroscopy analysis), 1H-NMR (proton nuclear magnetic resonance spectroscopy) methods. The thermal performance of surfactants was analyzed using thermogravimetric analysis (TGA). The thermogravimetric results showed that the sulfate-based Gemini surfactants had good heat resistance (the thermal decomposition temperature of which was in the range of 140∼170?). The Krafft point, surface tension, foaming, Hydrophile–Lipophile Balance Number (HLB), emulsifying, wetting, and lime-soap dispersing performance were measured by visual observation, hanging drop method, aqueous surfactant solution method and Borghetti–Bergman method, respectively. The results have shown that all the sulfate-based Gemini surfactants had good water solubility and lime-soap dispersing ability. When spacer group was -(CH2)2-, with the increase of the carbon chain length from C12 to C14, the micellar concentration critical micelle concentration and surface tension (CMC) gradually increased from 8.25 × 10–4 mol/L to 8.75 × 10–4 mol/L and 27.5 mN/m to 30.9 mN/m, respectively. Also, the sulfate-based Gemini surfactants with the different length of the spacer group had a different effect on their performance on foaming properties and foam properties, HLB and emulsifying ability and wetting ability. FindingsIn view of the important role of the spacer group and the general use of anionic surfactants in oil fields, this article considers the preparation of a series of sulfate-based Gemini surfactants by changing the spacer group and the chain length of the hydrophobic group and evaluating their surface activity, and finally its Kraffi, on the foam properties, HLB value, emulsifying performance, lime soap dispersing ability etc.Originality/valueSulfate-based Gemini surfactants have broad application prospects in the fields of oil and gas exploitation, environmental protection, chemistry and daily chemical industry and so on.

Dosimetric Feasibility of Moderately Hypofractionated/dose Escalated Radiation Therapy for Localised Prostate Cancer With Intensity-modulated Proton Beam Therapy Using Simultaneous Integrated Boost (SIB-IMPT) and Impact of Hydrogel Prostate-rectum Spacer

Purpose: To examine the dosimetric feasibility of hypofractionated/dose escalated radiation therapy in patients with localized prostate carcinoma using simultaneous integrated boost intensity-modulated proton beam therapy (SIB-IMPT) in absence or presence of prostate-rectum spacer. Methods: IMPT technique was implemented in 23 patients with intermediate- and high-risk prostate cancer treated at West German Proton Therapy Centre from March 2016 till June 2018, using SIB technique prescribing 60 GyRBE and 72 GyRBE in 30 fractions to PTV1 (prostate and seminal vesicle) and PTV2 boost (prostate and proximal seminal vesicle), respectively. In 15 patients, a transperineal injection of hydrogel was applied prior to radiotherapy to increase the distance between prostate and rectum. Planning and all treatments were performed with a 120 ml fluid-filled endorectal balloon customised daily for each patient. For each patient, 2 lateral IMPT beams were implemented taking a field-specific range uncertainty (RU) into account. Dose volume histograms (DVH) were analyzed for PTV2, PTV2 with range uncertainty margin (PTV2RU), rectum, bladder, right/left femoral heads, and penile bulb. For late rectal toxicities, the normal tissue complication probabilities (NTCP) were calculated using different biological models. A DVH- and NTCP-based dosimetric comparison was carried out between non-spacer and spacer groups. Results: For the 23 patients, high-quality plans could be achieved for target volume and for other organs at risk (OARs). For PTV2, the V107% was 0% and the Dmax did not exceed 106.2% of the prescribed dose. The volume PTV2RU covered by 95% of the dose ranged from 96.16- 99.95%. The conformality index (CI) for PTV2RU was 1.12±0.057 and the homogeneity index (HI) was 1.04±0.014. Rectum Dmax and rectal volume receiving 73 to 50 Gy could be further reduced for the spacer-group. Significant reductions in mean and median rectal NTCPs (stenosis/necrosis, late rectal bleeding ≥ 2, and late rectal toxicities ≥ 3) were predicted for the spacer group in comparison to the non-spacer group. Conclusion: Hypofractionated/dose escalated radiotherapy with SIB-IMPT is dosimetrically feasible. Further reduction of the rectal volumes receiving high and medium dose levels (73 -50 Gy) and rectal NTCP could be achieved through injection of spacers between rectum and prostate.

Feasibility And Safety of A CaO-SiO2-P2O5-B2O3 Bioactive Glass Ceramic Spacer In Posterior Lumbar Interbody Fusion: A Prospective Randomized Controlled Trial

Study design: Prospective randomized controlled trial.Background: The CaO-SiO2-P2O5-B2O3 glass-ceramic (BGS-7) spacer is a recently developed spacer that shows chemical bonding to bone with high mechanical stability. Further, this spacer achieves similar results to those of titanium cages. However, evidence regarding the advantages of the BGS-7 spacer is weak compared to polyetheretherketone (PEEK) cage. A randomized controlled trial is therefore warranted. The purpose of this study was to compare the radiographic and clinical efficacies and safety of the BGS-7 spacer compared to those of the PEEK cage in patients who underwent posterior lumbar interbody fusion (PLIF). Methods: The 54 participants who required one- or two-level PLIF due to lumbar degenerative disorders were randomly assigned to receive a BGS-7 spacer or PEEK cage. Visual analog scale (VAS), Oswestry Disability Index (ODI), European Quality of Life-5 Dimensions (EQ-5D), painDETECT score were evaluated before surgery and at 3, 6, and 12 months after surgery. The fusion rate, degree of osteolysis, cage migration and subsidence around the cage (spacer) were evaluated on computer tomography (CT) images at 12 months after surgery. Results: The 12-month fusion rates were 75% in the BGS-7 spacer group and 79.3% in the PEEK cage group, with no significant difference (p=0.676). The result regarding the non-inferiority of BGS-7 spacer was inconclusive. The linear mixed model showed no significant intervention effect in VAS, ODI, EQ-5D, and painDETECT score at the 3-, 6-, or 12-month follow-up. In addition, we found no significant between-group differences in the extent of osteolysis, spacer migration. However, the subsidence around the cage was significantly lower in the BGS-7 spacer group. Conclusions: This trial found similar fusion rates, clinicoradiographic outcomes, and adverse events between the BGS-7 spacer and PEEK cage for PLIF. However, the non-inferiority was inconclusive, and thus, the BGS-7 spacer can be a feasible and safe alternative to PEEK cage in PLIF surgery after further studies.

Subacromial Balloon Spacer versus Partial Repair for Massive Rotator Cuff Tears: A Prospective, Randomized, Multi-center Trial

Objectives: Despite various treatment options, the successful management of irreparable, massive rotator cuff tears (MRCTs) remains challenging. Implantation of a biodegradable subacromial balloon spacer (InSpaceTM system; OrthoSpace, Caesarea, Isreal) has gained considerable interest for the treatment of MCRTs due to its ability to effectively recenter the humeral head within the glenoid. Despite promising results, investigations examining outcomes following balloon spacer implantation are limited to small case series and short-term prospective trials without comparison to other surgical modalities. The purpose of the present investigation was to prospectively evaluate the safety and efficacy of the arthroscopically deployed, subacromial spacer balloon compared to partial rotator cuff repair in patients with MRCTs at 24 month follow up. Methods: A non-inferiority, prospective, single-blinded, multicenter, randomized, controlled, pivotal study was conducted to compare the outcomes of arthroscopic subacromial balloon spacer implantation to partial repair in the treatment of MRCTs. Patients ≥ 40 years of age with symptomatic full thickness MRCTs (tears ≥ 5 cm or ≥ 2 tendons) that had failed non-operative management were included. Clinical outcome data, derived from subjective questionnaires and physical examination, were collected at baseline and follow-up intervals at Day 10, Week 6, Month 3, 6, 12 and 24. Postoperative magnetic resonance imaging (MRI) scans were obtained at 6 weeks and 12 months. The primary composite effectiveness endpoint was defined as achievement of the minimal clinically important difference (MCID) for the Western Ontario Rotator Cuff (WORC) score (275 points) and American Shoulder and Elbow Society (ASES) score (6.4 points) by week 6 and maintenance at month 12 without subsequent secondary surgical intervention (SSSI) or serious adverse device effects (SADEs). Secondary effectiveness endpoints included changes in individual and composite clinical outcome scores relative to baseline in addition to MRI findings. Intention-to-treat (ITT), per-protocol (PP), and safety analyses were performed separately. Results: A total of 20 sites were enrolled in the investigation. One hundred, eighty-four patients were randomized into the clinical study (n= 93 balloon spacer; n= 91 partial repair) and included in the safety population, of which 183 patients were included in the ITT analysis (n=93 balloon spacer; n= 90 partial repair) and 176 in the PP analysis (n= 88 balloon spacer; n= 88 partial repair). No significant difference in demographic characteristics based on mean age, sex, race or body mass index were appreciated between groups. Mean procedure duration was 44.6 ± 16.9 minutes for the balloon spacer group and 71.2 ± 30.1 minutes for the partial repair group. Significant improvement over time relative to baseline was observed in all WORC (Fig. 1) and ASES (Fig. 2) scores in both groups. The magnitude of improvement for subjects in the balloon spacer group was the same or better than for subjects in the partial repair group at 12 and 24 month follow up. At 12 months, 51% (n=45 of 88) of patients in the balloon spacer group and 35 patients 40% (n= 35 of 88) in the partial repair group had reached and maintained the primary composite endpoint, meeting the noninferiority criteria (non-inferiority margin 10%; p = 0.0049) and corresponding to an 11.4% mean advantage for the spacer implant group. Non-inferiority was similarly confirmed in the ITT population (p=0.0089). SSSI occurred in 6 subjects (n=3 balloon spacer; n=3 partial repair), with two subjects in each group requiring reverse shoulder arthroplasty and one subject in each group undergoing shoulder arthroscopy. Conclusions: Use of the balloon spacer was found to produce non-inferior outcomes when compared to partial rotator cuff repair for patients with MRCTs at 24 month follow up. Outcomes following balloon spacer device placement met non-inferiority criteria when compared to the partial repair group based on primary composite endpoints.

Injection of hydrogel spacer increased intrafractional prostate motion during volumetric modulated arc therapy-stereotactic body radiation therapy for prostate cancer

BackgroundThe aim of this study was to clarify the association between intrafractional prostate shift and hydrogel spacer.MethodsThirty-eight patients who received definitive volumetric modulated arc therapy (VMAT)-stereotactic body radiation therapy (SBRT) for prostate cancer with prostate motion monitoring in our institution in 2018–2019 were retrospectively evaluated. In order to move the rectum away from the prostate, hydrogel spacer (SpaceOAR system, Boston Scientific, Marlborough, the United States) injection was proposed to the patients as an option in case of meeting the indication of use. We monitored intrafractional prostate motion by using a 4-dimensional (4D) transperineal ultrasound (US) device: the Clarity 4D ultrasound system (Elekta AB). The deviation of the prostate was monitored in each direction: superior-inferior (SI), left-right (LR), and anterior-posterior (AP). We also calculated the vector length (VL). The maximum intrafractional displacement (MID) per fraction for each direction was detected and mean of MIDs was calculated per patient. The MIDs in the non-spacer group and the spacer group were compared using the unpaired t-test.ResultsWe reviewed 33 fractions in eight patients as the spacer group and 148 fractions in 30 patients as the non-spacer group. The superior MID was 0.47 ± 0.07 (mean ± SE) mm vs. 0.97 ± 0.24 mm (P = 0.014), the inferior MID was 1.07 ± 0.11 mm vs. 1.03 ± 0.25 mm (P = 0.88), the left MID was 0.74 ± 0.08 mm vs. 0.87 ± 0.27 mm (P = 0.55), the right MID was 0.67 ± 0.08 mm vs. 0.92 ± 0.21 mm (P = 0.17), the anterior MID was 0.45 ± 0.06 mm vs. 1.16 ± 0.35 mm (P = 0.0023), and the posterior MID was 1.57 ± 0.17 mm vs. 1.37 ± 0.22 mm (P = 0.56) in the non-spacer group and the spacer group, respectively. The max of VL was 2.24 ± 0.19 mm vs. 2.89 ± 0.62 mm (P = 0.19), respectively.ConclusionsOur findings suggest that intrafractional prostate motion during VMAT-SBRT was larger in patients with hydrogel spacer injection in the superior and anterior directions.

Controlling Light Emitting Properties in Bis(pyrenyl)-di-imines by Tuning Chemical Functionality of Spacer Group

Aggregation caused quenching (ACQ) and aggregation induced emission (AIE) are dictated by the molecular aggregation which in turn is decided by the chemical features present in a molecule. The photophysical...

Rectal spacer hydrogel in 1.5T MR-guided and daily adapted SBRT for prostate cancer: dosimetric analysis and preliminary patient-reported outcomes

Objective: The main aim of the current analysis was to explore the hypothetical advantages using rectal spacer during 1.5T MR-guided and daily adapted prostate cancer stereotactic body radiotherapy (SBRT) compared to a no-rectal spacer hydrogel cohort of patients. Methods: The SBRT-protocol consisted of a 35 Gy schedule delivered in 5 fractions. Herein, we present a dosimetric analysis between spacer and no-spacer patients. Furthermore, treatment tolerability and feasibility were preliminarily assessed according to clinicians-reported outcomes at the end of treatment and patient-reported outcomes measures (PROMs) in both arms. Toxicity and quality of life were assessed at baseline and after treatment using the Common Terminology Criteria for Adverse Events v. 5.0, International Prostatic Symptoms Score, ICIQ-SF, IIEF-5, and EORTC-QLQ-C30 and PR-25 questionnaires. Results: 120 plans (pre- and daily adaptive SBRT planning) were analyzed in 20 patients (10 patients in spacer group and 10 patients in no-spacer group) treated using 1.5T MR-guided adaptive SBRT. Statistically significant dosimetric advantages were observed in favor of the spacer insertion, improving the planning target volume coverage in terms of V33.2Gy >95% and planning target volume 37.5 Gy <2% mainly during daily-adapted SBRT. Also, rectum V32, V28 and V18Gy and bladder V35Gy <1 cc were significantly reduced in the spacer cohort. Concerning the PROMS, all questionnaires showed no difference between the pre- and post-SBRT evaluation in both arms, excepting the physical functioning item of EORTC QLQ-C30 questionnaire that was declined in the no-spacer group. Conclusion: These preliminary results strongly suggest the adoption of perirectal spacer due to dosimetric advantages not only for rectal sparing but also for target coverage. Longer follow-up is required to validate the clinical impact in terms of clinicians-reported toxicity and PROMs. Advances in knowledge: This the first experience reporting preliminary data concerning the potential dosimetric impact of rectal hydrogel spacer on MR-guided SBRT for prostate cancer.

Spacer group-controlled luminescence and response of C3-symmetric triphenylamine derivatives towards force stimuli

Spacer groups have the ability to regulate the responses of two C3-symmetric triphenylamine derivatives. Double bonds induced larger spectral shifts compared to that of single bonds.