Non-modified Group Research Articles

Effect of stabilization of patients on the accuracy and scanning time of maxillary dentate quadrants: A clinical study

As intraoral scanning has gained widespread acceptance as an alternative to conventional impression-making, numerous studies have evaluated the influence of operator-related factors and patient-related factors on scanning accuracy. While several authors have noted patient movements as a clinical limitation of scanning technologies, research providing empirical data or testing this hypothesis is lacking. The purpose of this clinical study was to assess the effect of using the Zero Motion Scanning Band, a silicone occlusal mouth prop, and an OptraGate lip retractor for stabilizing the head and jaw on the accuracy (trueness and precision) and scanning time of digital quadrant scans. A conventional impression was made of the maxillary right quadrant with polyvinyl siloxane material and then digitized using a calibrated extraoral scanner to create the reference file. Two different groups were created: no scanning aids (NSA) and with scanning aids (WSA). For the NSA group, scans were made without considering the participant's movements. For the WSA group, scans included the Zero Motion Scanning Band, a silicone occlusal mouth prop, and an OptraGate lip retractor. Sixty-four scans were captured with an intraoral scanner (TRIOS 3) for each group, and the scanning time was recorded. Using an inspection and metrology software program, scans of each group were superimposed on the reference file to determine 3-dimensional (3D) deviations. The Kolmogorov-Smirnov test evaluated the normality of the distribution of variables, and the Mann-Whitney U test was selected for data analysis of non-normally distributed variables, including 3D deviations and scanning time (α=.05). Significant differences for trueness and scanning time mean values were observed under different scanning conditions: with and without head and jaw positioning (P<.05). The modified scan protocol exhibited higher trueness, with smaller mean root mean square values of 38.4 ±2.7µm compared with 40.8 ±3.1µm in the nonmodified group. However, precision did not display a statistically significant difference with varying scanning conditions (P>.05). The use of the Zero Motion Scanning Band, a lip retractor, and a silicone occlusal mouth prop on the contralateral side of the scanned quadrant significantly improved the trueness and scanning time of the quadrant digital scan. Further evaluation of head and jaw stabilizing tools is recommended in more complex clinical scenarios, such as complete arch digital scans and scanning implant-supported restorations.

Organ preservation strategies after neoadjuvant chemoimmunotherapy in resectable non-small cell lung cancer: A multi-center retrospective cohort study.

Neoadjuvant chemoimmunotherapy has shown a good therapeutic effect on non-small cell lung cancer, which also opens up the possibility of applying organ preservation strategies. This study investigated the feasibility of modified surgery after potent neoadjuvant chemoimmunotherapy in central type non-small cell lung cancer. In this multi-center retrospective cohort study, patients with central type non-small cell lung cancer who received 2-4 cycles of neoadjuvant chemoimmunotherapy between January 2019 and June 2022 at XXX Hospital and XXX Hospital were eligible. Patients were divided into modified and non-modified groups according to the extent of surgery, after which, safety and long-term prognosis of surgery were investigated. A total of 84 patients were enrolled. Of 36 (42.9%) patients who underwent modified surgery, 21 patients underwent lobectomy, 12 patients underwent lobectomy with bronchoplasty, 2 patients underwent sleeve lobectomy, and 1 patient underwent bilobectomy. The modification rate for the initially estimated pneumonectomy, sleeve lobectomy, and bilobectomy was 48.6%, 44.8%, and 30%, respectively. Grade II-V postoperative complications were found in 5 (13.9%) patients in the modified group and 17 (35.4%) patients in the non-modified group (relative risk, 0.393; 95% CI, 0.016 to 0.963; P=0.026). No significant difference was observed regarding the surgical approach, operative duration, blood loss, or R0 resection rate. The 2-year local recurrence rate was 3.7% (95% CI, 0.004-0.175) and 5.2% (95% CI, 0.012-0.168) in the modified group and non-modified group, respectively. The one-year PFS rate of modified and non-modified groups was 97.1% (95% CI, 83.7-99.8) and 86.9% (95% CI, 73.4-94.4), respectively, while two-year PFS were 89.8% (95% CI, 74.1-96.9) and 71.8% (95% CI, 56.7-83.4), respectively. Applying organ preservation strategies, i.e., undergoing modified surgery after neoadjuvant chemoimmunotherapy, is feasible for selected central-type NSCLC patients with favorable safety and long-term survival.

Preparation and in vitro evaluation of arsenic trioxide glioma targeting drug delivery system loaded by PAMAM dendrimers co-modified with RGDyC and PEG

Arsenic trioxide (ATO) is an effective component of traditional Chinese medicine arsenic. The existing studies have shown its good inhibition and apoptosis ability on a variety of tumours. However, its toxicity and difficulties in the permeability into the blood brain barrier (BBB) has the limitation in the application of glioma treatment. Polyamide-amine dendrimer (PAMAM) is a synthetic polymer with many advantages, such as a good permeability, stability and biocompatibility. Additionally, the 5th generation of PAMAM is an ideal drug carrier due to its three-dimensional structure. In this study, the 5th generation of PAMAM co-modified with RGDyC and PEG, then confirmed by ¹H-NMR. The average particle size of nanoparticles was about 20 nm according to the nanoparticle size-potential analyser and transmission electron microscopy. in vitro release showed that the nanocarrier not only has the sustained release effect, but also some pH-sensitive properties. The cell results showed that PAMAM co-modified with RGDyC and PEGAM has a lower cytotoxicity than the non-modified group in vitro. Accordingly, the drug delivery system has a better anti-tumour effect across the blood brain barrier (BBB) in vitro, which further proves the tumour targeting of RGDyC.

Chitosan surface modified electrospun poly(ε-caprolactone)/carbon nanotube composite fibers with enhanced mechanical, cell proliferation and antibacterial properties

The surface modification is one of the most effective methods to improve the bioactivity and cell affinity effect of electrospun poly(ε-caprolactone) (PCL) fibers. In the present study, chitosan (CS), a cationic polysaccharide, was used to modify the surface of electrospun PCL fibers. To obtain strong interaction between CS and PCL fibers, negatively charged PCL fibers were prepared by the incorporation of acid-treated carbon nanotubes (CNTs) into the fibers. In this way, the positively charged chitosan could be immobilized onto the surface of PCL fibers tightly by the electrostatic attraction. Besides, the incorporation of CNTs could significantly improve the mechanical strength of electrospun PCL fibers even after the CS modification, which guaranteed their usability in practical applications. The CS modification could effectively improve the wettability and bioactivity of electrospun PCL fibers. Cultivation of L929 fibroblast cells on the obtained fibers and the antibacterial activity were both evaluated to discuss the influence of chitosan modification. The results indicated that this modification could enhance the cell proliferation and antibacterial ability in comparison to the non-modified groups.

Peptide REDV-modified polysaccharide hydrogel with endothelial cell selectivity for the promotion of angiogenesis.

Rapid and controlled vascularization of engineered tissues remains one of the key limitations in thick tissue engineering. Although many studies have focused on improving the rapid vascularization through the immobilization of bioactive molecules, the competition in growth between endothelial cells (ECs) and other cell types is to some extent neglected. In this study, we developed a peptide GREDV-modified scaffold for selective adhesion of human umbilical vein endothelial cells (HUVECs) through the specific recognition of the REDV peptide and integrin α4 β1 . In vitro studies showed that GREDV-conjugated alginate (ALG-GREDV) improved HUVEC adhesion, migration and proliferation when compared with a non-modified group. Furthermore, ALG-GREDV exhibited a superior capability for promoting the proliferation and selective adhesion of HUVEC over that of other peptide (RGD and YIGSR) modified groups (ALG-Pep). In vivo angiogenic assays demonstrated that the ALG-GREDV scaffold induced an angiogenic potential by stimulating new vessel formation and showed the highest blood vessel density among all samples after 21 days of implanting (83.7 vessels/mm(2) ). More importantly, the blood vessel density in cambium fibrous tissue of ALG-GREDV was about 1.5 times greater than other ALG-Pep groups, indicating facilitation of ALG-GREDV on selective angiogenesis in vivo. These results demonstrated that REDV-conjugated alginate could be a useful scaffold for stimulating and inducing angiogenesis in tissue-engineered applications.

Surface-modified bacterial nanofibrillar PHB scaffolds for bladder tissue repair

The aim of the study is in vitro investigation of the feasibility of surface-modified bacterial nanofibrous poly [(R)-3-hydroxybutyrate] (PHB) graft for bladder reconstruction. In this study, the surface of electrospun bacterial PHB was modified with PEG- or EDA via radio frequency glow discharge method. After plasma modification, contact angle of EDA-modified PHB scaffolds decreased from 110 ± 1.50 to 23 ± 0.5 degree. Interestingly, less calcium oxalate stone deposition was observed on modified PHB scaffolds compared to that of non-modified group. Results of this study show that surface-modified scaffolds not only inhibited calcium oxalate growth but also enhanced the uroepithelial cell viability and proliferation.

Effect of Surface Modification of Steel Fiber on Concrete Comprehensive Performance

In order to investigate the influence of surface modification on concrete comprehensive properties, special electrodeposition process is applied to modify the surface of steel fiber. Then the modified fiber and the non-modified fiber are added into concrete for comparisive test and analysis. The results illustrate that the bond strength between the modified fiber and concrete increases about 50% when competing with the non-modified group. Besides, the crack area of non-modified fiber group declines 46% and the toughening effect rises approximately 30%.

Human bone marrow stromal cell and ligament fibroblast responses on RGD-modified silk fibers.

Adhesion, spreading, proliferation, and collagen matrix production of human bone marrow stromal cells (BMSCs) on an RGD-modified silk matrix was studied. Anterior cruciate ligament fibroblasts (ACLFs) were used as a control cell source. Scanning electron microscopy (SEM) and MTT analyses demonstrated that the modified silk matrices support improved BMSC and ACLF attachment and show higher cell density over 14 days in culture when compared with the non-RGD-modified matrices. Collagen type I transcript levels (at day 7) and content (at day 14) was significantly higher on the RGD-modified substrate than on the nonmodified group. The ability of RGD-coupled silk matrices to support BMSC attachment, which leads to higher cell density and collagen matrix production in vitro, combined with mechanical, fatigue, and biocompatibility properties of the silk protein matrix, suggest potential for use of this biomaterial for tissue engineering.