Local Chiral Inversion of Thymine Dimers by Manipulating Single Water Molecules.

Water, as one of the most important and indispensable small molecules in vivo, plays a crucial role in driving biological self-assembly processes. Real-space detection and identification of water-induced organic structures and further capture of dynamic dehydration processes are important yet challenging, which would help to reveal the cooperation and competition mechanisms among water-involved noncovalent interactions. Herein, introduction of water molecules onto the self-assembled thymine (T) structures under ultrahigh vacuum (UHV) conditions results in the hydration of hydrogen-bonded T dimers forming a well-ordered water-involved T structure. Reversibly, a local dehydration process is achieved by in situ scanning tunneling microscopy (STM) manipulation on single water molecules, where the adjacent T dimers connected with water molecules undergo a local chiral inversion process with the hydrogen-bonding configuration preserved. Such a strategy enables real-space identification and detection of the interactions between water and organic molecules, which may also shed light on the understanding of biologically relevant self-assembly processes driven by water.

Assessment of an Artificial Intelligence Mandibular Osteotomy Design System: A Retrospective Study.

BACKGROUND: In this study, an AI osteotomy software was developed to design the presurgical plan of mandibular angle osteotomy, which is followed by the comparison between the software-designed presurgical plan and the traditional manual presurgical plan, thus assessing the practicability of applying the AI osteotomy software in clinical practices. METHODS: (1) Develop an AI osteotomy software: design an algorithm based on convolutional neural networks capable of learning feature point and processing clustering segmentation; then, select 2296 cases of successful 3D mandibular angle osteotomy presurgical plans, followed by using those 2296 cases to train the deep learning algorithm; (2) compare the osteotomy presurgical plan of AI osteotomy software and that of manual: first step: randomly selecting 80 cases of typical female head 3D CTs, and designing those 80 cases by means of AI osteotomy software designing (group A) and manually designing (group B), respectively; second step: comparing several indexes of group A and those of group B, including the efficiency index (time from input original CT data to osteotomy presurgical plan output), the safety index (the minimum distance from the osteotomy plane to the mandibular canal), the symmetry indexes (bilateral difference of mandibular angle, mandibular ramus height and mandibular valgus angle) and aesthetic indexes (width ratio between middle and lower faces (M/L), mandibular angle and mandibular valgus angle). RESULTS: The efficiency index: the design time of group A is 1.768 ± 0.768 min and that of group B is 26.108 ± 1.137 min, with P = 0.000; the safety index: The minimum distances from the osteotomy plane to the mandibular canal are 3.908 ± 0.361mm and 3.651 ± 0.437mm, p = 0.117 in groups A and B, respectively; The symmetry indexes: Bilateral differences of mandibular angle are 1.824 ± 1.834° and 1.567 ± 1.059° in groups A and B, respectively, with P = 0.278; bilateral differences of mandibular ramus height are 2.083 ± 1.263 and 2.965 ± 1.433, respectively, with P = 0.119 in groups A and B; Aesthetic indexes: M/L in groups A and B is 1.364 ± 0.074 and 1.371 ± 0.067, respectively, with P = 0.793; mandibular angles in groups A and B are 127.724 ± 5.800° and 127.242 ± 5.545°, respectively, with P = 0.681; Valgus angles in groups A and B are 11.474 ± 5.380 and 9.743 ± 4.620, respectively, with P = 0.273. CONCLUSIONS: With high efficiency, as well as safety, symmetry and aesthetics equivalent to those of a manual design, the AI osteotomy software designing can be used as an alternative method for manual osteotomy designing. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Using orthodontic elastic traction during the active period of distraction osteogenesis to increase the effective vertical extension of hemifacial microsomia patients: A multi-center randomized clinical trial.

In this study, the aim was to assess whether using elastic traction during the active period of distraction osteogenesis could effectively increase the vertical extension. Patients with Pruzansky-Kaban Type II mandibular deformity were recruited and randomly assigned into Elastic traction + Distraction Osteogenesis group or Distraction Osteogenesis group, respectively. During the active period, the experimental group received orthodontic elastic traction 3 days after distraction osteogenesis implantation, while the control group received no treatment. All the participants underwent computed tomography (CT) examination before surgery, at the end of the active period, 6 months and 2 years after distraction osteogenesis tractor implantation. The primary outcome was the effective vertical extension rate of the mandible from the baseline to the end of the active period after operations, and there were 7 secondary outcomes used. 70 patients were included. The effective vertical extension rates were 85.021% ± 7.432% (mean ± SD) and 68.811% ± 9.510% (mean ± SD) in the experimental and control groups, respectively (P = 0.001). The average distances between the lower middle incisor point to the sagittal plane at the end of the active period were 2.485 ± 1.411 mm and 3.938 ± 2.293 mm in the experimental and control groups, respectively (P = 0.026). At the end of the active period of distraction osteogenesis, the average values of the mandibular occlusal plane canting were -4.887 ± 3.126 mm and -0.177 ± 4.029 mm in the experimental and control groups, respectively (P = 0.026). Elastic traction-assisted distraction osteogenesis could improve traction efficiency and facial symmetry.

Reversible photoswitchable fluorescence in thin films of inorganic nanoparticle and polyoxometalate assemblies.

A novel type of inorganic hybridized ultrathin film consisting of Preyssler-type polyoxometalates K(14)[Na(H(2)O)P(5)W(30)O(110)] (Na-POMs) and CdSe@CdS nanoparticles (NPs) was prepared on the solid substrates by a layer-by-layer assembly technique. The film exhibits reversible fluorescence switching behavior under control of irradiation with either UV light or visible light, which is ascribed to the selective occurrence of fluorescence resonance energy transfer between luminescent NPs and different states of photochromic Na-POMs.

The effect of doxycycline-containing chitosan/carboxymethyl chitosan nanoparticles on NLRP3 inflammasome in periodontal disease.

A polyelectrolyte complex nanoparticle comprising chitosan (CS) and carboxymethyl chitosan (CMCS) was prepared (CS/CMCS-NPs) by ionic gelation, which was then used as a doxycycline carrier (Dox:CS/CMCS-NPs). The obtained CS/CMCS-NPs and Dox:CS/CMCS-NPs were characterized for various parameters and bacteriostatic ability against Porphyromonas gingivalis. The regulation of related genes and proteins of NLRP3 inflammasome and IL-1ß in human gingival fibroblasts (HGFs) was characterized by qRT-PCR, western blotting and ELISA. The results showed that Dox:CS/CMCS-NPs had an orderly morphology and an excellent cytocompatibility. P. gingivalis was strongly inhibited by Dox:CS/CMCS-NPs contrasted with control group. Dox:CS/CMCS-NPs effectively down-regulated both gene and protein levels of NLRP3 inflammasome and IL-1ß in HGFs. This study provides a new method for rational application of Dox in the clinical treatment of periodontal disease and a new direction for explaining the mechanism of action of Dox:CS/CMCS-NPs and more drug-carrying nanoparticles.

Biological effects on tooth root surface topographies induced by various mechanical treatments.

The cleaning and physicochemical properties on tooth root biointerfaces are pivotal for periodontal healing. Herein, this work investigated the impact of multi-treatment on the physicochemical features of tooth root surfaces and the responsive behavior of human gingival fibroblasts (hGFs). It was found that the combination of various mechanical treatments significantly affects the topographical pattern and size as well as wettability on tooth root surfaces. Furthermore, biological experiments revealed that hGF behaviors (i.e., cell adhesion, shape, spreading, arrangement, and viability) were regulated by the topography and wettability of tooth root surfaces. Also, there was no significant difference in the protein expression of NLRP3 inflammasome and IL-1ß in hGFs among tooth root surfaces under various treatments. This study provides new insights to efficiently remove the dental calculus and to understand the interaction between the tooth root interface and cell, which could guide the clinical operation and thereby is more conducive to periodontal recovery.

Doxycycline inhibits NAcht Leucine-rich repeat Protein 3 inflammasome activation and interleukin-1ß production induced by Porphyromonas gingivalis-lipopolysaccharide and adenosine triphosphate in human gingival fibroblasts.

OBJECTIVE: To investigate the effect of adenosine triphosphate (ATP) on inflammasome activation by Porphyromonas gingivalis-lipopolysaccharide (P. gingivalis-LPS) stimulation and the anti-inflammatory eff ;ect of doxycycline (Dox) in human gingival fibroblasts (HGFs). DESIGN: The optimal concentration of P. gingivalis-LPS (1.0 µg/mL) for cellular viability was determined by observing cell morphology and measuring the amount of formazan and the expression of pro-caspase-1. The expression of genes and proteins related to the NAcht Leucine-rich repeat Protein 3 (NLRP3) inflammasome, including NLRP3, apoptosis-associated speck-like protein containing CARD (ASC), caspase-1 and its activated forms, and the inflammatory factor interleukin-1ß (IL-1ß) and its activated forms were measured. RESULTS: The NLRP3 inflammasome (i.e., NLRP3, ASC, caspase-1) was not affected by stimulation with P. gingivalis-LPS or ATP. However, a combination of P. gingivalis-LPS and ATP significantly enhanced inflammasome activation and IL-1ß production at the gene and protein levels as measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. Furthermore, doxycycline addition markedly inhibited inflammasome activation and IL-1ß production induced by a combination of P. gingivalis-LPS and ATP. CONCLUSIONS: LPS, ATP, and doxycycline play critical roles in regulating host immune responses. This evidence provides guidance for the application of tetracycline drugs for the clinical treatment of periodontal disease.

Red-blue light irradiation in the prevention of surgical wound infection after mandibular distraction using internal distractors in hemifacial microsomia: A randomized trial.

BACKGROUND: Postoperative infection is a complication of mandibular distraction osteogenesis (DO) in patients with hemifacial microsomia (HFM). The risk of surgical wound infection in DO is reported to be high due to the long duration of the distraction process. Treatment during the perioperative period is critical in combating infection. AIM: This study aimed to evaluate the effectiveness of red-blue irradiation in the prevention of surgical wound infection after mandibular distraction. METHODS: In our single-centered, randomized clinical study, 118 patients diagnosed with HFM who had undergone DO between April 2016 and April 2018 were included. The patients were randomly divided into two groups: the experimental group received red-blue irradiation treatment and the control group received white-light irradiation. RESULTS: None of the infections occurring in this study resulted in serious complications. The postoperative infection rate during the 4 weeks after DO in the experimental group was 1.7%, whereas that in the control group was 13.6% (p = 0.016) (based on a modified NHSN wound infection criterion). The total social cost during the active period for the experimental group was 3386840 RMB, 5.12% higher than for the control group (3221882 RMB). CONCLUSIONS: Red-blue irradiation is recommended as adjunctive therapy after mandibular distraction osteogeneis in HFM.

MYC competes with MiT/TFE in regulating lysosomal biogenesis and autophagy through an epigenetic rheostat.

Coordinated regulation of the lysosomal and autophagic systems ensures basal catabolism and normal cell physiology, and failure of either system causes disease. Here we describe an epigenetic rheostat orchestrated by c-MYC and histone deacetylases that inhibits lysosomal and autophagic biogenesis by concomitantly repressing the expression of the transcription factors MiT/TFE and FOXH1, and that of lysosomal and autophagy genes. Inhibition of histone deacetylases abates c-MYC binding to the promoters of lysosomal and autophagy genes, granting promoter occupancy to the MiT/TFE members, TFEB and TFE3, and/or the autophagy regulator FOXH1. In pluripotent stem cells and cancer, suppression of lysosomal and autophagic function is directly downstream of c-MYC overexpression and may represent a hallmark of malignant transformation. We propose that, by determining the fate of these catabolic systems, this hierarchical switch regulates the adaptive response of cells to pathological and physiological cues that could be exploited therapeutically.

[Evaluation of the filling quality of different root canal obturation techniques using micro-CT].

PURPOSE: The aim of this study was to evaluate the quality of different root canal obturation techniques by micro-CT. METHODS: Forty single-canal upper incisors were collected and decoronated to obtain 12 mm root segments. The root canals were prepared by using ProTaper rotary files and allocated into 4 groups randomly（n=10）, then obturated with gutta-percha and(or) iRoot SP by cold lateral compaction (CLC), continuous wave condensation (CWC), single core (SC), sealer-only buckfill (SoB) techniques, respectively. Each tooth was then scanned with micro-CT, and the percentage of 3D volume and 2D slices of voids and gaps were calculated 1 week later. The data were analyzed using SPSS 22.0 software package. RESULTS: Percentage of cross-sections with voids and gaps in CWC group was significantly less than others (P<0.05) , and it had a significantly greater filling area in 3D volume in whole root canal, middle third and coronal third levels (P<0.05), while SOB group had the largest filling quality in apical third levels (P<0.05). CONCLUSIONS: No filling technology can avoid voids. CWC technology provides the best filling performance.

[Synthesis and molecule recognition capability of corilagin-molecularly imprinted polymer].

To study the molecule recognition capability of corilagin-molecularly imprinted polymer (MIP) by the high performance liquid chromatography (HPLC), the molecularly imprinted polymer was synthesized by using corilagin as the template. Chromatographic performance of corilagin was investigated in different mobile phases. The MIP was investigated for the recognition of corilagin and its derivatives and other compounds in the same mobile phase. The MIP exhibited very high affinity for corilagin in the mobile phase of acetonitrile. The K' value will be reduced when the content of polar solvent increased in the mobile phase. The MIP has good selectivity in the mobile phase of acetonitrile-methanol (95:5), but it has no affinity for corilagin's derivatives. The corilagin-MIP has good selectivity for corilagin and it can be used in extracting corilagin and its analogs from herbs.

Assessment of the Second Mesiobuccal Root Canal in Maxillary First Molars: A Cone-beam Computed Tomographic Study.

INTRODUCTION: The purpose of this study was to investigate the incidence and location of the second mesiobuccal (MB2) root canal of the maxillary first molar and the relationship between the presence of an MB2 canal and the distribution of canal orifices on the pulpal floor with the aid of cone-beam computed tomographic (CBCT) technology. METHODS: A total of 1008 maxillary first molars (548 patients) were randomly selected and analyzed through CBCT imaging. The association between the incidence of MB2 canals and potential impacting factors including sex, side, age, and the distribution of the main root canal orifices on the pulpal floor was explored. The interorifice distances (ie, the length of a line between the center point of any 2 orifices) at the pulpal floor level were measured using Mimics 10.01 software (ImageWorks, Materialise, Belgium). RESULTS: The majority of 3-rooted maxillary first molars showed 2 root canals (85.4%) in the mesiobuccal root. The incidence of MB2 canals had no statistically significant difference between the left and right sides (P > .05) but had a significant association with the patients' sex and age (P < .05). Receiver operating characteristic curve analysis showed a high diagnostic accuracy (the area under the receiver operating characteristic curve = 0.92) of using the distance ratio of the interorifice distance between the main mesiobuccal and the palatal root canal orifices to the interorifice distance between the distobuccal and the palatal root canal orifices to predict the presence of an MB2 canal. A larger distance ratio (>1.26) indicated a highly probable existence of an MB2 canal. In this study, no molar presented an MB2 canal with a distance ratio of less than 1.16, whereas all molars with a ratio greater than 1.37 presented an MB2 canal without exception. A Bland-Altman scatterplot showed great agreement between the distances of the main mesiobuccal and the distobuccal canal orifices and the second mesiobuccal and the distobuccal canal orifices. CONCLUSIONS: Understanding the incidence of MB2 canals and the distribution pattern of canal orifices on the pulpal floor may help clinicians to quickly identify and locate MB2 canals.

Topography, Wettability, and Electrostatic Charge Consist Major Surface Properties of Intraocular Lenses.

PURPOSE: To quantify potential relevant factors that affect the biocompatibility and functionality of intraocular lenses (IOLs) by analyzing the surface properties of various IOL materials. METHODS: Eleven IOL models with the same dioptric power made by different manufacturers were studied. The IOLs were made of poly-methyl methacrylate (PMMA), hydrophobic acrylate, hydrophilic acrylate, and silicone. The IOL surface topography was evaluated using atomic force microscopy (AFM). Surface potential was measured by electric force microscopy (EFM). Surface wettability was assessed with the water contact angle using the sessile drop method. RESULTS: The PMMA IOLs had statistically significant surface irregularities with the highest surface roughness values while the silicone and hydrophilic acrylic IOLs had the lowest values. Surface potentials on IOLs revealed that all IOL models made of PMMA had positive charge. The hydrophobic acrylic IOL had a significantly higher positive charge (6.2v ± 0.1v), while the hydrophobic acrylic with blue blocker exhibited negative charge. Negative charge was also observed on hydrophilic acrylic IOLs (-72mv ± 5mv) and silicone IOLs (-5.06v ± 0.02v). Contact angle values of PMMA IOLs ranged from 49° to 64°. Heparin modification resulted in significant reduction of the contact angle value. IOL models made of hydrophobic acrylate had contact angle values between 78° and 89°. The silicone IOL appeared to be significantly hydrophobic with the highest mean value of 107°. CONCLUSIONS: The variance of the parameters of surface roughness, contact angle, and electrostatic charge on the surfaces of PMMA, hydrophobic acrylic, hydrophilic acrylic, and silicone IOLs is useful to the interpretation of the differences in clinical behaviors of these materials. The negative surface charge of silicone and hydrophilic IOLs might account for the occurrence of IOL calcification.

Ultrathin reduced graphene oxide films as transparent top-contacts for light switchable solid-state molecular junctions.

A new type of solid-state molecular junction is introduced, which employs reduced graphene oxide as a transparent top contact that permits a self-assembled molecular monolayer to be photoswitched in situ, while simultaneously enabling charge-transport measurements across the molecules. The electrical switching behavior of a less-studied molecular switch, dihydroazulene/vinylheptafulvene, is described, which is used as a test case.