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By combining surface-enhanced and discharge-assisted laser-induced breakdown spectroscopy, the study successfully realized the high-sensitivity quantitative analysis of trace heavy metals Cr, Cu, and Pb in aqueous solutions.

Reactivation of pre-existing structures and their influence on subsequent rift evolution have been extensively analysed in previous research on rifts that experienced multiple phases of rifting, where pre-existing structures were deemed to affect nucleation, density, strike orientation, and displacement of newly formed normal faults during later rifting stages. However, previous studies paid less attention to the extensional structures superimposing onto an earlier compressional background, leading to a lack of understanding of, e.g. the reactivation and growth pattern of pre-existing thrust faults as low-angle normal faults and the impact of pre-existing thrust faults on newly formed high-angle faults and subsequent rift structures. This study investigating the spatial relationship between intra-basement thrust and rift-related faults in the Enping sag, in the northern South China Sea, indicates that the rift system is built on the previously deformed basement with pervasive thrusting structures and that the low-angle major fault of the study area results from reactivation of intra-basement thrust faults. It also implies that the reactivation mode of basement thrust faults is dependent on the overall strain distribution across rifts, the scale of basement thrust faults, and the strain shadow zone. In addition, reactivated basement thrust faults influence the nucleation, dip, and displacement of nearby new faults, causing them to nucleate at or merge into downwards it, which is representative of the coupled and decoupled growth models of reactivated thrust faults and nearby new faults. This work not only provides insights into the growth pattern of rift-related faults interacting with reactivated low-angle faults but also has broader implications for how basement thrust faults influence rift structures, normal fault evolution, and syn-rift stratigraphy.

Inspired by real biological neural models, Spiking Neural Networks (SNNs) process information with discrete spikes and show great potential for building low-power neural network systems. This paper proposes a hardware implementation of SNN based on Field-Programmable Gate Arrays (FPGA). It features a hybrid updating algorithm, which combines the advantages of existing algorithms to simplify hardware design and improve performance. The proposed design supports up to 16 384 neurons and 16.8 million synapses but requires minimal hardware resources and archieves a very low power consumption of 0.477 W. A test platform is built based on the proposed design using a Xilinx FPGA evaluation board, upon which we deploy a classification task on the MNIST dataset. The evaluation results show an accuracy of 97.06% and a frame rate of 161 frames per second.

Prior sequence stratigraphic methods mainly employed two-dimensional (2-D) stacking patterns to reconstruct stratigraphic frameworks. The future of sequence stratigraphy will pay more attention to systems-tracts scale and three-dimensional (3-D) stratigraphic variability. Using 1.2 × 104 km2 (4.63 × 103 mi2) 3-D seismic data, tied to regional 2-D seismic lines and 21 boreholes, the present study examines systems-tract scale and 3-D stratigraphic variability of the 14.8–13.8 Ma Pearl River shelf-margin to deep-water sedimentary prisms. The studied prisms were divided into four main systems tracts, namely, highstand systems tract (HST), falling-stage systems tract (FSST), lowstand systems tract (LST), and transgressive systems tract (TST). Each systems tract is represented by a given clinoformal architecture and stacking pattern: (1) clinothem sets with aggradation to progradation are HST, (2) clinothem sets with progradation to degradation (PD) are FSST, (3) clinothem sets with progradation to aggradation (PA) are LST, and (4) clinothem sets with retrogradation are TST, LST, or HST. In addition, Pearl River FSST and LST display downdip stratigraphic variabilities which are regionally manifested in at least three ways: (1) shelf-edge deltas linked downdip to basin-floor fans, (2) shelf-edge deltas linked downdip without fans, and (3) basin-floor fans linked updip that lack deltas. In along-strike orientation, the Pearl River FSST could exhibit low-angle progradation, not just PD stacking. The LST could present retrogradational stacking, not just PA stacking. Therefore, the physical position of a systems tract is reemphasized in terms of assigning a given systems tract. The concepts of three systems tracts are then revised for chronostratigraphic significance. The LST is the lowermost systems tract of a sequence, presenting a normal regression of the shoreline as its diagnostic characteristic and including contemporaneous stratigraphic units laterally. The HST is the upper systems tract of a sequence, providing a normal regression of the shoreline as its diagnostic characteristic and including contemporaneous stratigraphic units laterally. The TST is the middle systems tract of a sequence, generating a backstep of the shoreline and excluding contemporaneous onlapping units of both the LST and HST laterally. The FSST has not been revised because FSST may be a supply-independent feature.

A series of new dyes (AL01–AL02t) were designed through introducing different conjugated bridges into the position of two hydroxyl groups on the natural dye 1,2-dihydroxyanthraquinone (alizarin), and their photoelectrical properties were systematically investigated as the dyes applied in the field of dye-sensitized solar cell (DSSC) via the density functional theory (DFT) and time-dependent DFT methods. Moreover, the key parameters related to the intramolecular charge transfer (ICT) properties of the dyes, such as the transferred charge and charge transferred distance were calculated. In addition, the light harvesting efficiency, free-energy change driving force, electron regeneration driving force and chemical reactivity parameters were obtained to evaluate the photoelectrical properties of the investigated dyes. The calculated results indicate that the designed dyes would show the better photoelectrical properties, owing to their lower energy gaps, red-shifted absorption spectra, the greater transferred charge and charge transferred distance. Therein, it is worth noting that the designed dye AL02t displays the lowest energy gap, widest absorption spectrum, smallest hole and electron reorganization energies, lowest electron regeneration driving force and chemical hardness, largest electroaccepting power and electrophilicity values, which mean that this designed dye would present the best photoelectrical properties among the investigated dyes. Significantly, the better optical and electrical characteristics of AL02-series dyes than that of AL01-series dyes indicate the modification for the hydroxyl group on R2 position of alizarin is more beneficial to improving its photoelectrical properties, which can provide a valuable reference for synthesizing the dyes with higher efficiency based on natural dyes in experiments.

Most sequence stratigraphy models have been derived from the observation of seismic profiles, which still retain the original form of the sedimentary stage. For folded and fractured formations, there is no way to establish a full view of the basin-wide continuous stratal configuration. This paper presents an approach to restore the sedimentary sequence original structural profile through a process of segmented line-drawing of seismic events, reassembly and modification. We use a case study from the Pearl River Mouth Basin, in the South China Sea, to demonstrate the principle and method of this technology. After restoration, we obtained a basin-wide, sedimentary stage form and continuous sequence stratigraphic structure profiles, and thus further investigated the sedimentary landforms, palaeo-water depth, sedimentary systems, stacking pattern, stratal configuration, parasequence sets and systems tract, which may be ambiguous in conventional seismic profiles. This approach may be applied to the study of basin and sequence stratigraphy and basin sedimentary process.

Reactivation of pre-existing structures and their influence on subsequent rift evolution have been extensively analysed in previous researches on rifts that experienced multiple phases of rifting, where pre-existing structures were deemed to affect nucleation, density, strike direction and displacement of newly-formed normal faults during later rifting stage. However, previous studies paid less attention to the extensional structures superimposing on an earlier compressional background, leading to a lack of understanding, e.g., reactivation and growth pattern of pre-existing thrust fault as low-angle normal fault, and impact of pre-existing thrust fault on newly-formed high-angle faults and subsequent rift structure. This study investigating the spatial relationship between intrabasement thrust and rift-related faults in the Enping sag, northern South China Sea, indicates that the rift system is built on the previously deformed basement with pervasive thrusting structures, and that the low-angle major fault of the study area results from reactivation of intrabasement thrust fault. In addition, reactivated basement thrust fault can affect the nucleation and dip of nearby new faults, cause new faults to nucleate at or merge into it in vertical, and finally generate typical fault interactions, i.e., merging, abutting and crosscutting faults. This work not only provides insights into understanding growth pattern of rift-related faults interacting with reactivated low-angle faults, but also has broader implications on how basement thrust faults influence rift structure, normal fault evolution and syn-rift stratigraphy.

Under-estimating the damage caused by trauma to the dental structures may delay treatment. Timely and accurate diagnosis remains challenging in clinical practice. Radiography is an important modality for the diagnosis of traumatic injuries. The aim of this study was to compare the efficacy of periapical radiography and cone beam computed tomography for the diagnosis of trauma to the anterior maxillary dentoalveolar region in children and adolescents.Images of patients who underwent both periapical radiography and cone beam computed tomography simultaneously because of trauma to the anterior maxillary region between January 2016 and January 2020 were analyzed retrospectively. Pairwise comparison between the receiver operating characteristic curves was performed to statistically compare the two methods for the diagnosis of crown fractures, root fractures, alveolar bone fractures and luxations, tooth resorption, and periapical radiolucencies.A total of 190 patients met the inclusion criteria. There were 120 (63.2%) males and 70 (36.8%) females, with a mean age of 11.1 years (range: 6-17 years). A crown fracture was observed in 144 teeth, while a root fracture was observed in 71 teeth. Alveolar fracture and luxation were observed in 44 incisors. During follow-up, tooth resorption and periapical radiolucencies were observed in 25 and 33 teeth, respectively. Pairwise receiver operating characteristic curve analysis revealed that cone beam computed tomography was significantly superior to periapical radiography for the diagnosis of root fractures, alveolar fractures and luxations, and tooth resorption (p .05). However, no significant differences were found for the diagnosis of crown fractures and periapical radiolucencies (p .05).Cone beam computed tomography in the low-dose mode was better for diagnosing root and bone fractures and resorption, but no different to periapical radiographs for crown fractures and periapical radiolucencies in pediatric patients.

The interfacial charge transfer still limits the photoactivity of artificial Z-scheme photocatalysts although they showed complementary light absorption and a strong photoredox ability. In this study, layered metallene is designed as an efficient electron mediator for constructing a C3N4/bismuthene/BiOCl 2D/2D/2D Z-scheme system. This bismuthene serves as a bridge processing superior charge conductibility, abundant metal-semiconductor contact sites, and the shortened charge diffusion distance, enhancing the photocatalytic CO2 reduction reaction activity and stability. Density functional theory calculations show that the bismuthene creates a built-in electric field and congregates interfacial electrons, which is confirmed by the stable and consistent emission of the ultrafast transient absorption spectra. This work gives new insight into the interface design of Z-scheme photocatalysts by selecting a novel metallene electron mediator.

Laser-induced breakdown spectroscopy (LIBS) is a good technique for detecting and analyzing material elements due to the plasma emission produced by the high-power laser pulse. Currently, a significant topic of LIBS research is improving the emission intensity of LIBS. This study investigated the effect of laser-polarization on femtosecond laser-ablated Cu plasma spectra at different sample temperatures. The measured lines under circularly polarized lasers were higher than those under linearly and elliptically polarized lasers. The enhancement effect was evident at higher Cu temperatures when comparing the plasma spectra that have circular and linear polarizations for different target temperatures. To understand the influence of laser-polarization and sample temperature on signal intensity, we calculated the plasma temperature (PT) and electron density (ED) . The change in PT and ED was consistent with the change in the atomic lines as the laser polarization was being adjusted. When raising the Cu temperature, the PT increased while the ED decreased. Raising the Cu temperature whilst adjusting the laser-polarization is effective for improving the signal of femtosecond LIBS compared to raising the initial sample temperature alone or only changing the laser polarization.

The twisted intramolecular charge transfer (TICT) state plays an important role in determining the performance of optoelectronic devices. However, for some nonfluorescent TICT molecules, the "invisible" TICT state could only be visualized by modifying the molecular structure. Here, we introduce a new facile pressure-induced approach to light up the TICT state through the use of a pressure-related liquid-solid phase transition of the surrounding solvent. Combining ultrafast spectroscopy and quantum chemical calculations, it reveals that the "invisible" TICT state can emit fluorescence when the rotation of a donor group is restricted by the frozen acetonitrile solution. Furthermore, the TICT process can even be effectively regulated by the external pressure. Our study offers a unique strategy to achieve dual fluorescence behavior in charge transfer molecules and is of significance for optoelectronic and biomedical applications.

Density functional theory and time-dependent density functional theory methods were carried out to investigate the excited-state intramolecular charge transfer process (ICT) of coumarin 340 (C340) in tetrahydrofuran (THF) solvent for the first time. The plotted electrostatic potential and optimized geometric structures vividly indicated that the intermolecular hydrogen bond can be formed between the N–H group of C340 monomer and the oxygen atom of THF solvent. The analysis of frontier molecular orbitals and the differences in electronegativity confirmed the occurrence of ICT process in hydrogen-bonded complex C340-THF upon photoexcitation. The results of calculated bond lengths and bond energies revealed that the intermolecular hydrogen bond in C340-THF is significantly strengthened in the first excited state. Furthermore, the calculated electronic spectra, non-covalent interactions and IR spectra provided strong evidence for the hydrogen bond reinforce. Based on the theoretical calculations, we demonstrated that the ICT process in C340-THF can be facilitated effectively by the excited-state intermolecular hydrogen bond strengthening.

The excited-state double proton transfer (ESDPT) process of dipyrido[2,3-a:3',2'-i]carbazole (DPC) in ethanol (EtOH) solvent is investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The computational results provide convincing evidence that proton transfer did not occur spontaneously for the DPC monomer due to the lack of hydrogen bonds. Interestingly, after adding EtOH to DPC, two intermolecular hydrogen bonds were formed in the ground-state, and the intermolecular hydrogen bonds were strengthened in the excited-state, as confirmed by comparing the changes in the primary bond parameters. In addition, the charge transfer was observed in the DPC-EtOH complex compared with the DPC monomer. In particular, a reliable ESDPT process occurs within the system upon photoexcitation, which was monitored by the formation and disappearance of characteristic peaks in the IR spectrum. All results adequately proved that the participation of EtOH exerts a remarkable effect on the ESDPT process. Overall, our work not only comprehensively elaborated the simultaneous mechanism of ESDPT but can also pave the way towards the design and synthesis of novel molecules.

Harnessing ingenious modification of molecular structure to regulate excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT) characteristics holds great promise in fluorescence sensing and imaging. Based on the 3-hydroxyflavone (3HF) molecule, 2-(2-benzo[b]furanyl)-3-hydroxychromone (3HB) and 2-(6-diethylamino-benzo[b]furan-2-yl)-3-hydroxychromone (3HBN) were designed by the extension of the furan heterocycle and the introduction of a diethylamino group. The analysis of important hydrogen bond length, frontier molecular orbitals, infrared spectra, and potential curves have cross-validated our results. The results indicate that proper site furan heterocycle extension and diethylamino donor group substitution not only shift the absorption and emission spectra to the red but also effectively modulate the excited-state dynamic behaviors. Strengthened ICT characteristics from 3HF to 3HB and to 3HBN make the occurrence of ESIPT increasingly difficult due to the higher energy barriers, which indicates that the ESIPT and ICT processes are competitive mechanisms. We envision that our work would open new windows for improving molecular properties and developing more fluorescent probes and organic radiation scintillators.

Existing seismic facies analysis schemes, including traditional seismic facies analysis, seismic slice analysis, and automatic classification of seismic facies, can reconstruct the sedimentary systems of basins; however, they are not ideal for basins with few boreholes and many rock types. Herein, we propose a new method for reconstructing sedimentary systems using seismic data, considering the Xisha Trough Basin in the Northern South China Sea as the research object to demonstrate the principles, methods, and technologies of this novel scheme. Based on the six commonly used seismic parameters, three additional seismic parameters (smoothness, neatness, and special waveform) and one geological marker (provenance) were added to improve the recognition of lithofacies. The scanned seismic interpretation technique was used to describe the distribution of sandstone and other skeleton lithofacies; sedimentary environments were determined according to the coastline, shelf break line, and slope toe line; flow path systems were determined according to the paleotopography, incised valleys, and sandstone distribution; and the sedimentary systems of the trough basin were reconstructed through the superposition of skeleton lithofacies, depositional environments, and flow paths. Results show that the sedimentary system reconstructed using the new method contains three elements, namely, lithofacies, the environment, and flow path, which fully reflect the concept of the sedimentary system defined by Fisher and McGowen (1967) ; this overcomes the inherent defects of previous schemes, such as poor lithofacies recognition and the uncertainty of types and boundaries of sedimentary bodies. This method enabled identifying subdivided seismic lithofacies directly from seismic profiles and enhanced the ability to obtain sedimentary information from seismic data. The proposed reconstruction method can be used in areas without boreholes or with many rock types and is significant for marine geology research and oil and gas exploration conducted in the deep sea.

Objective: To evaluate the effect of bite positions characterizing different splint treatments (anterior repositioning and stabilization splints) on the disc-condyle relation in patients with TMJ disc displacement with reduction (DDwR), using magnetic resonance imaging (MRI). Material and Methods: 37 patients, with a mean age of 18.8±4.3 years (7 male and 30 females) and diagnosed with DDwR based on the RDC/TMD, were recruited. MRI metrical analysis of the spatial changes of the disc/condyle, as well as their relationships, was done in three positions: maximum intercuspation (Position 1), anterior repositioning splint position (Position 2), and stabilization splint position (Position 3). Disc/condyle coordinate measurements and disc condyle angles were determined and compared. Results: In Position 1, the average disc-condyle angle was 53.4° in the 60 joints with DDwR, while it was −13.3° with Position 2 and 30.1° with Position 3. The frequency of successful "disc recapture" with Position 2 was significantly higher (58/60, 96.7%) than Position 3 (20/60, 33.3%). In Positions 2 and 3, the condyle moved forward and downward while the disc moved backward. The movements were, however, more remarkable with Position 2. Conclusions: Anterior repositioning of the mandible improves the spatial relationship between the disc and condyle in patients with DDwR. In addition to anterior and inferior movement of the condyle, transitory posterior movement of the disc also occurred.

The excited-state carrier dynamics of lead halide perovskites play a critical role in their photoelectric properties, and are greatly affected by lattice structural changes. In this work, the carrier dynamics of all-inorganic CsPbBr

Rift-related normal faults generally have various geometries, and cause the syn-rift stratigraphy in their hanging wall to be characterized by different infilling patterns. Our understanding of the tectonic control on the syn-rift stratigraphy mainly stems from the analysis of fault kinematics, stratigraphic styles and depositional facies. However, questions remain about how fault geometry, kinematics and slip rate influence the style of a rift-related half-graben and the syn-rift stratigraphy, and what enlightenment that relationship has for the hydrocarbon exploration in rifts. Using the 2D MOVE Software, this study attempts to simulate the development of a fault-bounded half-graben, with the aim of investigating the aforementioned questions. The modeling results show that, a planar, listric and ramp-flat-ramp border fault controls a tabular, wedged-shaped, and composite wedge-shaped growth package, respectively, but exceptionally, the planar fault bounds a wedge-shaped package if the fault rotates with movement. In addition, rollover structure forms when the border fault has a listric or ramp-flat-ramp shape, indicating that the fault geometry and kinematics dominate the syn-tectonic stratigraphic pattern. Besides, fault slip rate relative to sediment supply affects the scale, dip and infilling pattern of the syn-tectonic stratigraphy. In details, reduction of fault slip rate or increment of sediment supply results in: i) the extent of the syn-tectonic stratigraphy enlarging, ii) the dip angle of the syn-tectonic stratigraphy decreasing, and iii) the water depth in the related half-graben getting shallower. This study provides insights into understanding the origin of the variable styles of rift-related half-graben and syn-rift stratigraphy. Also, our modeling results have an important implication for evaluating source rock quality in rifts. Finally, we give a preliminary example of using the MOVE Software to investigate the geometry and evolution of fault-bounded basin, which is well worth being further explored.

This study evaluated the occurrence of degenerative temporomandibular joint (TMJ) changes in adolescents and young adults with recent on-set disc displacement without reduction (DDw/oR) using high-resolution cone beam computed tomography (CBCT). The associations between types of osteoarthrosis (OA) changes and clinical factors including disease duration were also examined. CBCT and clinical data of 300 patients (84.70% females, mean age 20.93 ± 4.77 years) diagnosed with unilateral DDw/oR (≤12 months) based on RDC/TMD were acquired. CBCT images of both symptomatic and contralateral asymptomatic TMJs were independently evaluated and scored by two radiologists. Associations between OA changes and gender, age, mouth opening and duration of DDw/oR were analyzed statistically. Condylar OA changes were present in 59.30% of the joints with DDw/oR. Early-stage OA changes (loss of continuity of articular cortex and/or surface destruction) constituted most (45.67%) of the alterations. Prevalence of early-stage OA increased from 24% to about 60% one month after TMJ closed-lock occurred. Logistic regression analysis showed the risk of developing early-stage OA changes was 5.33 times higher one month after onset of DDw/oR. A high prevalence of degenerative TMJ changes was observed with recent on-set DDw/oR in adolescents and young adults. Early diagnosis and intervention of DDw/oR is therefore prudent.

The migration history of shelf breaks in the stratigraphy of a basin contains significant information about sediment-budget partitioning into the deep water area, which is thus important in predicting the distribution and quality of deepwater reservoirs. Previous studies primarily focused on the sedimentary-dominated shelf breaks (e.g., progradational-type), which are controlled by sediment supply and relative sea-level changes. The location and migration pattern of structure-controlled shelf breaks are comparatively less well documented. The evolutionary history of shelf breaks in the Pearl River Mouth Basin from 30 Ma to present is examined here. Shelf breaks are picked from 280 2-D depositional dip-oriented seismic profiles in the forced regressive systems tracts of 20 3rd-order sequences (SQ 1-20) in four super sequences (SSQ 1-4). Planview distribution maps indicate these shelf breaks can be divided into two groups of different character. Shelf breaks in SSQ 1 (30–23.8 Ma) have migrated progressively and considerably basinward (∼50 km) along with the progradation of shelf-margin deltas, which were propelled by a very strong sediment supply even under the background of relative sea-level rise. They are consequently classified as sedimentary-dominated types. In contrast, shelf breaks in SSQ 2-4 have stayed fairly close (∼20 km) to the boundary between the Panyu Low Uplift and the Baiyun Sag, which is identified as a tectonic hinge zone across which subsidence rate increased abruptly basinward. Shelf breaks were close to the hinge zone even in SQ 11 and 12, in which the depositional shoreline breaks were located ∼80 km further landward. They are classified as structure-controlled types. Our study indicates that through the evolutionary history of the Pearl River Mouth Basin, the locations and migration pattern of the shelf breaks were mainly sediment-supply controlled during 30–23.8 Ma but changed to structure-controlled (i.e., tectonic hinge zone) during 23.8 Ma-Present.

Study of Subsidence and maturation evolution of a continental slope basin without a drilled well is an important problem in the early stage of deep-water exploration. Lack of some parameters, such as stratigraphic-age, porosity-depth relationship, exact paleo-water depth and heat flow value are common problems in the study of subsidence and maturity history. Using 46 long 2D seismic lines and paleo-water depth data from paleontological data of a well on the slope toe, the present study combines backstripping with thermal modeling to reconstruct the subsidence and maturation evolution of a lower-slope minibasin, Xingning Sag (XS), on the southeast Pearl River Mouth Basin (PRMB) of the South China Sea (SCS), now a new prospecting area. Stratigraphic-ages, porosity-depth relationship, lithology of XS were estimated using data from an adjacent basin. Paleo-water depths were obtained by clinoform geometry using seismic facies and paleontological method. With these parameters, the subsidence curves were created by backstripping. Crustal stretching factors (β) were obtained by best fit of tectonic subsidence curve and thermal modeling. With these stretching factors, the theoretical subsidence and heat flow values were obtained at the same time. Based on the heat flow value and the backstripping parameters, the maturation history of this basin was simulated. The result shows XS evolved through three cycles of subsidence during 46–23.03 Ma, 23.03–13.82 Ma and 13.82–0 Ma, respectively. Each cycle shows a rifting phase of relatively rapid tectonic subsidence followed a cooling phase of slow subsidence. Potential Eocene lacustrine source rocks are distributed primarily in the central depression area (Xingning main sub-sag), and would have entered the main oil-generation window and main gas generation during early- and mid-Miocene respectively.

The spectroscopic properties of 3-Aminophthalimide (3AP) molecule were investigated [Chem. Phys. 2002, 283, 249, New J. Chem. 2018, 42, 1181]. The result was that the 3AP molecule was exhibiting excited-state intramolecular proton transfer (ESIPT). In the research, we revised previous result using time-dependent density functional theory (TDDFT) method. The fluorescence spectrum shows that the only fluorescence peak is from initial enol form, which is different from the traditional case of ESIPT. The red shift of characteristic peaks in infrared vibration spectra is not induced by ESIPT process. The change in the vibration mode of the amino group causes the red shift of characteristic peak in the infrared spectrum. Energy curves indicate that the barrier (19.71 kcal/mol) is anomalously high in the first excited state. In addition, there are not stable points to lead the ESIPT to form a keto isomer. Together, these results demonstrate that there is not an ESIPT process happening of 3AP molecule.

Maxillary sinus disease is frequently observed in patients with unilateral cleft lip and palate (UCLP). The anatomical variations of maxillary sinus and maxilla may play a role in the high incidence of sinusitis. The aims of this study were to evaluate and compare the three-dimensional (3D) structural features of maxillary sinus and maxilla in UCLP adolescent patients between the defect and non-defect sides, and investigate the morphological relationship between the maxillary sinus and maxilla on the defect side by using cone-beam computed tomography (CBCT).CBCT images were acquired from 42 UCLP adolescent patients. Maxillary sinus and maxilla on the defect and non-defect sides were segmented respectively and assessed three dimensionally, and the comparison was performed by paired t-test. A multiple linear regression was conducted to investigate the morphological relationship between the maxillary sinus and maxilla on the defect side.No statistically significant difference was observed in any parameter of the maxillary sinus between the defect and non-defect sides (P 0.05). Significant differences were observed in the length, anterior width, anterior height, and volume of the maxilla between the defect side and non-defect sides (P 0.05). The parameters of maxillary sinus were significant related to the posterior width and height of maxilla on the defect side.Adolescent patients with UCLP present similar 3D structural features of the maxillary sinus on both sides. Significant differences of the maxilla between the defect and non-defect sides were displayed in the area adjacent to the defect but not showed in the posterior portion of maxilla. Certain structures of the posterior portion of maxilla contribute to the variability of maxillary sinus.

Excited-state deactivation dynamics of Thioflavin-T (ThT) in gradual viscosity solvents were investigated. Femtosecond transient absorption spectra and dynamic decay curves both present significant distinction of ThT in different volume ratios binary mixtures solvents. Dynamics fitting lifetime of twisted intramolecular charge transfer (TICT) state is strongly dependent on solvents viscosity. Compared to rotation corresponding time of ThT in low viscosity solvent (0.6 cp) experimentally coincident well with Stokes-Einstein-Debye (SED) equation, the relation between rotation corresponding time and relatively high viscosity (5.9 cp to 1091.2 cp) is more consistent with fractional SED equation. Combined with optimized geometric structures of ThT by density functional theory and time-dependent density functional theory, further understand TICT state lifetime increases with increasing solvents viscosity. Our work provides a comprehensive understanding of fluorescence molecular rotor (FMR) deactivation process in different viscosity solvents and is helpful to design new FMR.

Studies of excited state multiple proton transfer (ESMPT) are paramount importance for both biological systems and chemical reactions while its mechanism in a controllable manner has been long sought. For this purpose, we conducted a theoretical study on the ESMPT mechanisms of 1-H-pyrrolo[3,2-h]quinoline (PQ) connecting different number methanol (MeOH) molecules (PQ-(MeOH)n=1,2). The results show that the ESMPT process can occur for PQ-(MeOH)n=1,2 complexes and MeOH molecules can effectively regulate the proton transfer barriers. The non-fluorescence of PQ-MeOH was explained by the combination of rapid ESMPT and following intersystem crossing (ISC) processes. The observed fluorescence of PQ-(MeOH)2 was owing to the contribution of increased excited-state barriers to emission is greater than the consumption of ISC process. These exciting findings revealed the cooperation mechanism between ESMPT and ISC processes for PQ-(MeOH), whereas the competitive mechanism for PQ-(MeOH)2. Our work firstly implemented the bidirectional regulation of the ESMPT mechanism, which will open new avenues for improving the luminescence properties and characterizing the cluster structure.

In this work, density functional theory and time-dependent density functional theory were performed to investigate intermolecular hydrogen bond (H-bond) effect on Coumarin-1 (C1). The optimized geometric structures of C1 in acetonitrile and methanol (MeOH) revealed that C1 exhibits planar configuration in ground state and locally excited (LE) state. Due to intermolecular H-bond interaction between C1 and MeOH, twisted intramolecular charge transfer (TICT) state with twist configuration exists in excited state for C1–MeOH. The apparent variation of characteristic group frequencies and intensities for IR spectra is ascribed to dramatic charge density changes. Compared with molecular orbitals of LE state, the low charge coupling degree of C1–MeOH in TICT state is induced by twist configuration in TICT state. Indeed, such low charge coupling degree induced TICT state is nonluminous that responsible for low fluorescence quantum yield of C1–MeOH. We not only provide a comprehensive understanding of TICT state deactivation process but also benefits to design new environment-sensitive probe.

Excited-state intramolecular proton transfer (ESIPT) and twist intramolecular charge transfer (TICT) are the two most fundamental dynamic processes, ubiquitous in biological and chemical reactions. The excited-state properties of (E-8-((4-dimethylamino-phenylimino)-methyl)-7-hydroxy-4-methyl-2H-chromen-2-one (CDPA) in various solvents with different polarities were investigated by using steady-state and femtosecond transient absorption spectroscopy combined with DFT/TDDFT calculations. The results demonstrated that CDPA exhibited low fluorescence in polar acetonitrile (ACN) due to ESIPT but high fluorescence in nonpolar n-Hexane was attributed to intramolecular rotation blocking ESIPT. TDDFT calculations confirmed that the dramatic phenyl group torsional of CDPA in Hexane, whereas a near planar conformation in ACN solvent. The ESIPT barrier decreases regularly with the increase of solvent polarity from n-Hexane, tetrahydrofuran to ACN solvent. These results demonstrated that the ESIPT and TICT processes of CDPA are competitive mechanisms. Our work revealed the effect solvent polarity on the emission behavior and excited-state deactivation mechanism of CDPA, which could help to design and develop new polarity probe in the microenvironments.

Judiciously tuning the forward-backward excited state intramolecular proton transfer (ESIPT) barriers can effectively influence the generation of white light. Harnessing the 1-hydroxy-9H-fluoren-9-one (HHF) ESIPT characteristics as the prototype, two electron-withdrawing substituents (nitro group and formyl group) were introduced. The influence of electron-withdrawing group on the energy barrier of the forward-backward ESIPT processes has been studied by density functional theory (DFT) and time-dependent DFT (TDDFT) methods. The frontier molecular orbitals, infrared spectra, non-covalent interactions, electrostatic potential, electronic spectra, molecular structure have cross-validated our results. These results indicate that the electron-withdrawing groups dramatically promote the occurrence of the forward ESIPT process and hinder the backward ESIPT. The potential curves revealed that the forward ESIPT energy barrier was obviously reduced to 5.73 kcal/mol (HHF-CHO) and 4.55 kcal/mol (HHF-NO2) compared with HHF (7.64 kcal/mol). Meanwhile, the backward ESIPT energy barrier is availably improved to 3.57 kcal/mol (HHF-CHO) and 3.84 kcal/mol (HHF-NO2) compared with HHF (2.51 kcal/mol). Through the introduction of the electron-withdrawing groups, the energy barrier of the forward-backward ESIPT is efficaciously modulated. Furthermore, the more stable and better white fluorescence has been achieved. Our work will be conducive to improve molecular ESIPT properties and exploit white luminescent molecules.