Regulating Planarized Intramolecular Charge Transfer for Efficient Single-Phase White-Light Emission in Undoped Metal-Organic Framework Nanocrystals.

The technology of combining multiple emission centers to exploit white-light-emitting (WLE) materials by taking advantage of porous metal-organic frameworks (MOFs) is mature, but preparing undoped WLE MOFs remains a challenge. Herein, a pressure-treated strategy is reported to achieve efficient white photoluminescence (PL) in undoped [Zn(Tdc)(py)]n nanocrystals (NCs) at ambient conditions, where the Commission International del'Eclairage coordinates and color temperature reach (0.31, 0.37) and 6560 K, respectively. The initial [Zn(Tdc)(py)]n NCs exhibit weak-blue PL consisting of localized excited (LE) and planarized intramolecular charge transfer (PLICT) states. After pressure treatment, the emission contributions of LE and PLICT states are balanced by increasing the planarization of subunits, thereby producing white PL. Meanwhile, the reduction of nonradiative decay triggered by the planarized structure results in 5-fold PL enhancement. Phosphor-converted light-emitting diodes based on pressure-treated samples show favorable white-light characteristics. The finding provides a new platform for the development of undoped WLE MOFs.

Rapid Sample Pretreatment Facilitating SERS Detection of Trace Weak Organic Acids/Bases in Complex Matrices.

Fast and efficient sample pretreatment is the prerequisite for realizing surface-enhanced Raman spectroscopy (SERS) detection of trace targets in complex matrices, which is still a big issue for the practical application of SERS. Recently, we have proposed a highly performed liquid-liquid extraction (LLE)-back extraction (BE) for weak acids/bases extraction in drinking water and beverage samples. However, the performance efficiency decreased drastically on facing matrices like food and biological blood. Based on the total interaction energies among target, interferent, and extractant molecules, solid-phase extraction (SPE) with a higher selectivity was introduced in advance of LLE-BE, which enabled the sensitive (µg L-1 level) and rapid (within 10 min) SERS detection of both koumine (a weak base) and celastrol (a weak acid) in different food and biological samples. Further, the high SERS sensitivity was determined unmanned by Vis-CAD (a machine learning algorithm), instead of the highly demanded expert recognition. The generality of SPE-LLE-BE for various weak acids/bases (2 < pKa < 12), accompanied by the high efficiency, easy operation, and low cost, offers SERS as a powerful on-site and efficient inspection tool in food safety and forensics.

Ba3Lu(BO3)3:Ce3+,Tb3+/Mn2+: Dual-Functional Material for WLEDs and Optical Pressure Sensing.

Ba3Lu(BO3)3(BLB):Ce3+,Tb3+/Mn2+ phosphors were designed to explore effective and multifunctional applications. Under the excitation of near-ultraviolet (n-UV) light, the BLB:Ce3+ phosphor showed broad-band blue emission. After codoping with Mn2+ ions, the single-phase white light phosphor is achieved through the energy transfer (ET) between Ce3+ and Mn2+. In addition, thermal stability is significantly enhanced by the addition of Tb3+ (BLB:0.02Ce3+,0.20Tb3+) compared to that codoped with Mn2+ (BLB:0.02Ce3+,0.10Mn2+). The light-emitting diode (LED) device with warm white light emission is fabricated with UV-chip-coated BLB:0.02Ce3+,0.05Tb3+ and Sr2Si5N8:Eu2+ phosphors, showing a good potential application value for LEDs. Additionally, the spectral properties of borate-based phosphors (BLB:0.02Ce3+) under high pressure were studied for the first time. Surprisingly, the change of pressure enabled the emission peak of BLB:0.02Ce3+ to be tuned from 485 to 552 nm, and dλ/dP is 3.51 nm GPa-1. The color changes from blue to yellow with an increase of pressure. Compared with the reported data, the pressure-sensing sensitivity based on the central peak shift in this work is the highest in all Ce3+ single-doped samples. In addition, the emitting color and intensity were gradually regained after decompression. The intensity can reach 80% of the initial intensity. All data demonstrate that the BLB:0.02Ce3+ phosphor has the potential to be utilized as an optical pressure sensor due to the high-pressure sensitivity and visible color tuning.

Synthesis Design and Properties of Ca5(BO3)3F: Bi3+/Eu3+: Insight into Luminescence, Temperature, and Pressure Sensing.

Nowadays, the utilization of noncontact temperature and pressure sensing is experiencing growing popularity. In this work, Bi3+, Eu3+-doped Ca5(BO3)3F (CBOF) phosphors were synthesized via an ionic liquid-assisted electrospinning approach. The effect of molecular weight of polyvinylpyrrolidone on the morphology of CBOF was investigated, and a comprehensive analysis of its formation mechanism was presented. The luminescence properties of CBOF: Bi3+, Eu3+ were studied systematically. The temperature-dependent emission of CBOF: Bi3+, Eu3+ phosphor was discussed, and it displayed thermal sensitivity, which can be attributed to the distinct thermal response emission behaviors of Bi3+ and Eu3+. The investigation of the pressure-dependent emission behavior of the CBOF: Bi3+ phosphor revealed an anomalous phenomenon: with the increase of pressure, the emission peak showed a trend of first a blue shift and then a red shift. This anomaly was discussed in detail. The phosphor exhibits visual color change (blue to cyan), remarkable pressure sensitivity (4.76 nm/GPa), and a high upper pressure limit (24.2 GPa), indicating its potential use as an optical pressure sensor. Consequently, this study presents an innovative synthetic approach for fabricating CBOF, presenting a bifunctional material with promising prospects in the fields of temperature and pressure sensing.

Band-Gap Narrowing and Electric Transport Regulation of Hybrid Perovskites via Pressure Engineering.

Lead-free organic-inorganic hybrid perovskites are one class of promising optoelectronic materials that have attracted much attention due to their outstanding stability and environmentally friendly nature. However, the intrinsic band gap far from the Shockley-Queisser limit and the inferior electrical properties largely limit their applicability. Here, a considerable band-gap narrowing from 2.43 to 1.64 eV with the compression rate up to 32.5% is achieved via high-pressure engineering in the lead-free hybrid perovskite MA3Sb2I9. Meanwhile, the electric transport process changes from the initial interaction of both ions and electrons to only the contribution of electrons upon compression. The alteration in electrical characteristics is ascribed to the vibration limitation of organic ions and the enhanced orbital overlap, resulting from the reduction of the Sb-I bond length through pressure-induced phase transitions. This work not only systematically investigates the correlation between the structural and optoelectronic properties of MA3Sb2I9 but also provides a potential pathway for optimizing electrical properties in lead-free hybrid perovskites.

Considerable Piezochromism in All-Inorganic Zero-Dimensional Perovskite Nanocrystals via Pressure-Modulated Self-Trapped Exciton Emission.

Piezochromic materials refer to a class of matters that alter their photoluminescence (PL) colors in response to the external stimuli, which exhibit promising smart applications in anti-counterfeiting, optoelectronic memory and pressure-sensing. However, so far, most reported piezochromic materials have been confined to organic materials or hybrid materials containing organic moieties with limited piezochromic range of less than 100 nm in visible region. Here, we achieved an intriguing piezochromism in all-inorganic zero-dimensional (0D) Cs3Cu2Cl5 nanocrystals (NCs) with a considerable piezochromic range of 232 nm because of their unique inorganic rigid structure. The PL energy shifted from the lowest-energy red fluorescence (1.85 eV) to the highest-energy blue fluorescence (2.83 eV), covering almost the entire visible wavelength range. Pressure-modulated self-trapped exciton emission between different energy levels of self-trapped states within Cs3Cu2Cl5 NCs was the main reason for this piezochromism property. Note that the quenched emission, which is over five times more intense than that in the initial state, is retained under ambient conditions upon decompression. This work provides a promising pressure indicating material, particularly used in pressure stability monitoring for equipment working at extreme environments.

Pressure-Tuning Localized Excitons Toward Enhanced Emission, Photocurrent Enhancement and Piezochromism in Unconventional ACI-Type 2D Hybrid Perovskites.

Simultaneous enhancement of free excitons (FEs) emission and self-trapped excitons (STEs) emission remains greatly challenging because of the radiative pathway competition. Here, a significant fluorescence improvement, associated with the radiative recombination of both FEs and STEs is firstly achieved in an unconventional ACI-type hybrid perovskite, (ACA)(MA)PbI4 (ACA=acetamidinium) crystals with {PbI6} octahedron units, through hydrostatic pressure processing. Note that (ACA)(MA)PbI4 exhibits a 91.5-fold emission enhancement and considerable piezochromism from green to red in a mild pressure interval of 1 atm to 2.5 GPa. The substantial distortion of both individual halide octahedron and the Pb-I-Pb angles between two halide octahedra under high pressure indeed determines the pressure-tuning localized excitons behavior. Upon higher pressure, photocurrent enhancement is also observed, which is attributed to the promoted electronic connectivity in (ACA)(MA)PbI4. The anisotropic compaction reduces the distance between neighboring organic molecules and {PbI6} octahedra, leading to the enhancement of hydrogen bonding interactions. This work not only offers a deep understanding of the structure-optical relationships of ACI-type perovskites, but also presents insights into breaking the limits of luminescent efficiency by pressure-suppressed nonradiative recombination.

Piezofluorochromism in Covalent Organic Frameworks: Pressure-Induced Emission Enhancement and Blue-Shifted Emission.

Achieving enhanced or blue-shifted emission from piezochromic materials remains a major challenge. Covalent organic frameworks (COFs) are promising candidates for the development of piezochromic materials owing to their dynamic structures and adjustable optical properties, where the emission behaviors are not solely determined by the functional groups, but are also greatly influenced by the specific geometric arrangement. Nevertheless, this area remains relatively understudied. In this study, a successful synthesis of a series of bicarbazole-based COFs with varying topologies, dimensions, and linkages was conducted, followed by an investigation of their structural and emission properties under hydrostatic pressure generated by a diamond anvil cell. Consequently, these COFs exhibited distinct piezochromic behaviors, particularly a remarkable pressure-induced emission enhancement (PIEE) phenomenon with a 16-fold increase in fluorescence intensity from three-dimensional COFs, surpassing the performance of CPMs and most organic small molecules with PIEE behavior. On the contrary, three two-dimensional COFs with flexible structures exhibited rare blue-shifted emission, whereas the variants with rigid and conjugated structures showed common red-shifted and reduced emission. Mechanism research further revealed that these different piezochromic behaviors were primarily determined by interlayer distance and interaction. This study represents the first systematic exploration of the structures and emission properties of COFs through pressure-treated engineering and provides a new perspective on the design of piezochromic materials.

Piezofluorochromism in Hierarchical Porous π-stacked Supermolecular Spring Frameworks from Aromatic Chiral Cages.

Piezochromic materials that exhibit pressure-dependent luminescence variations are attracting interest with wide potential applications in mechanical sensors, anticounterfeiting and storage devices. Crystalline porous materials (CPMs) have been widely studied in piezochromism for highly tunable luminescence. Nevertheless, reversible and high-contrast emission response with a wide pressure range is still challenging. Herein, the first example of hierarchical porous cage-based πOF (Cage-πOF-1) with spring structure was synthesized by using aromatic chiral cages as building blocks. Its elastic properties evaluated based on the bulk modulus (9.5 GPa) is softer than most reported CPMs and the collapse point (20.0 GPa) significantly exceeds ever reported CPMs. As smart materials, Cage-πOF-1 displays linear pressure-dependent emission and achieves a high-contrast emission difference up to 154 nm. Pressure-responsive limit is up to 16 GPa, outperforming the CPMs reported so far. Dedicated experiments and density functional theory (DFT) calculations illustrate that π-π interactions-dominated controllable structural shrinkage and porous-spring-structure-mediated elasticity is responsible for the outstanding piezofluorochromism.

Reticular Modulation of Piezofluorochromic Behaviors in Organic Molecular Cages by Replacing Non-Luminous Components.

Organic piezochromic materials that manifest pressure-stimuli-responses are important in various fields such as data storage and anticounterfeiting. The manipulation of piezofluorochromic behaviors for these materials is promising but remains a great challenge. Herein, a non-luminous components regulated strategy is developed and organic molecular cages (OMCs), a burgeoning class of crystalline organic materials with structural dynamics, are first explored for the design of piezofluorochromic materials with tunable luminescence. A series of OMCs based on aggregation-induced emission (AIE) chromophores, termed Cage 1-3, are synthesized and their piezofluorochromic behaviors are investigated by diamond anvil cell technique. Due to the sufficient voids between its flexible chromophores offered by the OMC structure, Cage 1 exhibits thermofluorochromic and piezofluorochromic properties. Moreover, the piezofluorochromic performance of this OMC could be further promoted by replacing its non-luminous components with improved flexibilities, and a remarkable luminescence peak shift by 150 nm together with a response sensitivity of 13.8 nm GPa-1 was achieved upon hydrostatic compression. The cage structure plays a vital role in facilitating efficient and reversible piezofluorochromic behaviors. This study has shed light on the rational design and exploitation of OMCs as an exceptional platform to accomplish customizable piezofluorochromic behaviors and enlarge their potential applications in pressure-based luminescence.

Pedicle ossification after fibular flap reconstruction of maxillary defects: A case report and literature review.

Key Clinical Message: The phenomenon of vessel pedicle ossification is a noteworthy aspect of the repair and reconstruction of maxillofacial defects. Imaging findings typically reveal high-density shadows within the vascular pedicle pathway, which may be managed through conservative observation or surgical intervention as deemed appropriate. Abstract: Vessel pedicle ossification is a relatively uncommon complication associated with the reconstruction of oral and maxillofacial tissue defects using free tissue flap repair. In this paper, we report a case of pedicle ossification and conduct a comprehensive review of previous literature. A 39-year-old man presented with a limited ability to open his mouth 6 months after fibular flap reconstruction of the mandible. Plain film X-ray and computed tomography (CT) indicated pedicle ossification. Two years after the initial operation, the restriction in the patient's ability to open his mouth had not worsened, although there were more pronounced radiographic abnormalities.

Investigation on the Effectiveness of Digital Scanning Combined with Reverse Engineering Technology in Demonstrating Full Crown Tooth Preparation.

OBJECTIVE: To investigate the effect of digital scanning combined with reverse engineering technology in the demonstration of full crown tooth preparation. METHODS: Thirty-one students were randomly divided into the two groups. The students in the control group carried out traditional demonstration by the use of eye-measurement methods. The students in the experimental group carried out improved demonstration by the use of digital intraoral scan with 3D measurement data. The students in both groups were provided with two resin teeth to conduct full crown tooth preparation on head model dental simulators. The teeth prepared before and after demonstration were scored by Chinese Stomatological Association Group Standards, with a total score of 100 points. Analysis of covariance was performed to comparatively analyze the scores related to the tooth surfaces, and convergence angle between two groups. RESULTS: Analysis of two prepared teeth (tooth #11 and #16) in two groups showed that there was a statistical significant difference in the mean score between the control group and experimental group (tooth #11, P = 0.0039) (tooth #16, P = 0.0120).The demonstration of the tooth #16 showed that there were statistical significant differences in the scores related to buccolingual surface (P = 0.0205) and proximal surface (P = 0.0023) between the control group and experimental group; There was a statistical significant difference in the score related to the convergence angle of buccolingual surface between the control group and experimental group (P = 0.0265). CONCLUSION: The digital methods can effectively improve the quality of tooth preparations and has a pedagogical advantage for posterior teeth, which present greater operational challenges.

Intense Broadband Emission in the Unconventional 3D Hybrid Metal Halide via High-Pressure Engineering.

Developing hybrid metal halides with self-trapped exciton (STE) emission is a powerful and promising approach to achieve single-component phosphors for wide-color-gamut display and illumination. Nevertheless, it is difficult to generate STEs and broadband emission in the classical and widely used 3D systems, owing to the great structural connectivity of metal-halogen networks. Here, high pressure is implemented to achieve dual emission and dramatical emission enhancement in 3D metal halide of [Pb3 Br4 ][O2 C(CH2 )2 CO2 ]. The pressure-induced new emission is ascribed to the radiation recombination of STEs from the Pb2 Br2 O2 tetrahedra with the promoted distortion through the isostructural phase transition. Furthermore, the wide range of emission chromaticity can be regulated by controlling the distortion order of different polyhedral units upon compression. This work not only constructs the relationship between structure and optical behavior of [Pb3 Br4 ][O2 C(CH2 )2 CO2 ], but also provides new strategies for optimizing broadband emission toward potential applications in solid-state lighting.

Harvesting Multicolor Photoluminescence in Nonaromatic Interpenetrated Metal-Organic Framework Nanocrystals via Pressure-Modulated Carbonyls Aggregation.

Interpenetrated metal-organic frameworks (MOFs) with nonaromatic ligands provide a unique platform for adsorption, catalysis, and sensing applications. However, nonemission and the lack of optical property tailoring make it challenging to fabricate smart responsive devices with nonaromatic interpenetrated MOFs based on ligand-centered emission. In this paper, the pressure-induced aggregation effect is introduced in nonaromatic interpenetrated Zn4O(ADC)4(Et3N)6 (IRMOF-0) nanocrystals (NCs), where carbonyl groups aggregation results in O─O distances smaller than the sum of the van der Waals radii (3.04 Å), triggering the photoluminescence turn-on behavior. It is noteworthy that the IRMOF-0 NCs display an ultrabroad emission tunability of 130 nm from deep blue (440 nm) to yellow (570 nm) upon release to ambient conditions at different pressures. The eventual retention of through-space n-π* interactions in different degrees via pressure treatment is primarily responsible for achieving a controllable multicolor emission behavior in initially nonemissive IRMOF-0 NCs. The fabricated multicolor phosphor-converted light-emitting diodes based on the pressure-treated IRMOF-0 NCs exhibit excellent thermal, chromaticity, and fatigue stability. The proposed strategy not only imparts new vitality to nonaromatic interpenetrated MOFs but also offers new perspectives for advancements in the field of multicolor displays and daylight illumination.

Inactivation of Bacillus cereus spores by ohmic heating: Efficiency and changes of spore biological properties.

Bacillus cereus spores pose a significant concern during food processing due to their high resistance to environmental stress. Ohmic heating (OH) is an emerging and alternative heating technology with potential for inactivating such spores. This study evaluated the inactivation effects and the biological property changes of Bacillus cereus spores during OH treatments. OH effectively inactivated spores in milk, orange juice, broth, rice soup, and buffer solution in less time than oil bath heating (OB). A decrease in NaCl content improved spore inactivation at the same temperature. Spores were more sensitive to acid at 80-85 °C with OH treatment. Furthermore, OH at 10 V/cm and 50 Hz could reduce the spore resistance and inhibit an increase in spore hydrophobicity and spore aggregation. Both heating methods resulted in significant dipicolinic acid (DPA) leakage and damage to the cortex and inner membranes of the spores. However, OH at 10 V/cm and 50 Hz had the lowest DPA leakage and inflicted the least damage to the inner membrane. The damage to the spore's inner membrane was considered the primary reason for inactivation by OB and OH treatments. Still, OH at 10 V/cm and 50 Hz might also block the germination or outgrowth of treated spores or cause damage to the spore core.

Identifying the Potential Apoptotic Metabolites in Postmortem Beef Muscle by Targeted Metabolomics.

Apoptotic cells may release specific metabolites to act as messengers during the apoptotic process. This study represents the first attempt to identify potential apoptotic metabolites in postmortem muscle. Ninety potential apoptotic metabolites in beef were selected and analyzed through targeted metabolomics, with 84 of them exhibiting significant differences over the postmortem time. Following the addition of the mitochondria-targeted antiapoptotic agent mitoquinone to postmortem muscle, metabolomic analysis revealed that 73 apoptotic metabolites still underwent significant changes, even against the backdrop of altered apoptosis. Of these 73 apoptotic metabolites, 54 exhibited similar trends at various treatment times with adding mitoquinone, including lipids (6), amino acids (27), nucleosides (11), and carbohydrate and energy metabolism (10). Mitoquinone significantly reduced the levels of most apoptotic metabolites, and inhibition of apoptosis resulted in a significant decrease in the levels of numerous apoptotic metabolites. Consequently, these apoptotic metabolites are considered complementary to apoptosis in postmortem muscle, with their increased levels potentially promoting apoptosis. Noteworthy apoptotic metabolites, such as glycerol 3-phosphate, serine, AMP, ATP, GMP, and creatine, were identified as active signaling molecules that attract and recruit phagocytes during apoptosis, assisting in recognizing apoptotic cells by phagocytes. This study provides, for the first time, insights into potential apoptotic metabolites in postmortem muscle, contributing to a better understanding of meat biochemistry.

Self-Trapped Exciton Emission Enhancement in 3D Cationic Lead Halide Hybrids Via Phase Transition Engineering.

Three-dimensional (3D) cationic lead halide hybrids constructed by organic ions and inorganic networks via coordination bonds are a promising material for solid-state lighting due to their exceptional environmental stability and broad-spectrum emission. Nevertheless, their fluorescence properties are hindered by the limited lattice distortion from extensive connectivity within the inorganic network. Here, a dramatic 100-fold enhancement of self-trapped exciton (STE) emission is achieved in 3D hybrid material [Pb2Br2][O2C(CH2)4CO2] via pressure-triggered phase transition. Notably, pressure-treated material exhibits a 110 nm redshift with 1.5-fold enhancement compared to the initial state after pressure was completely released. The irreversible structural phase transition intensifies the [PbBr3O3] octahedral distortion, which is highly responsible for the optimization of quenched emission. These findings present a promising strategy for improving the optical properties of 3D halide hybrids with relatively high stability and thus facilitate their practical applications by pressure-driven phase transition engineering.

Odontogenic Keratocyst in Maxillary Sinus with Ectopic Third Molar: A Case Report.

BACKGROUND Odontogenic keratocyst (OKC) is a common odontogenic cyst, and it occurs more frequently in the mandible, with the posterior region of the dental arch, the angle, or the ramus being the most commonly affected sites. Odontogenic keratocyst occurring within the maxillary sinus is extremely rare, accounting for only about 1% of cases. CASE REPORT A 20-year-old female patient without any clinical symptoms underwent an oral examination, during which a dense dental shadow was identified within the maxillary sinus, surrounded by a low-density shadow. Physical examination revealed absence of the left maxillary third molar, with intact mucosa. The patient reported no history of tooth extraction. X-ray and cone-beam computed tomography revealed a high-density image within the left maxillary sinus, resembling a tooth and surrounded by a soft-tissue shadow, which exhibited a greater density in comparison to conventional odontogenic cysts. The initial diagnosis was odontogenic keratocyst in the maxillary sinus with an ectopic maxillary third molar. Surgical enucleation of the cyst and extraction of the impacted tooth were carried out utilizing the Caldwell-Luc approach. Histopathological analysis confirmed the presence of OKC. No significant recurrence was noted during the 6 months of follow-up. CONCLUSIONS Odontogenic keratocysts in the maxillary sinus with ectopic third molar are rare and may not have any symptoms in the early stage. Surgery can be performed using the Caroler-Luke approach to achieve ideal treatment results. In view of the high recurrence rate of OKC, close follow-up should be conducted after surgery.

Blue light emission enhancement and robust pressure resistance of gallium oxide nanocrystals.

Exploration of pressure-resistant materials largely facilitates their operation under extreme conditions where a stable structure and properties are highly desirable. However, under extreme conditions, such as a high pressure over 30.0 GPa, fluorescence quenching generally occurs in most materials. Herein, pressure-induced emission enhancement (PIEE) by a factor of 4.2 is found in Ga2O3 nanocrystals (NCs), a fourth-generation ultrawide bandgap semiconductor. This is mainly attributed to pressure optimizing the intrinsic lattice defects of the Ga2O3 nanocrystals, which was further confirmed by first-principles calculations. Note that the bright blue emission could be stabilized even up to a high pressure of 30.6 GPa, which is of great significance in the essential components of white light. Notably, after releasing the pressure to ambient conditions, the emission of the Ga2O3 nanocrystals can completely recover, even after undergoing multiple repeated pressurizations. In addition to stable optical properties, synchrotron radiation shows that the Ga2O3 nanocrystals remain in the cubic structure described by space group Fd3m upon compression, demonstrating the structural stability of the Ga2O3 nanocrystals under high pressure. This study pays the way for the application of oxide nanomaterials in pressure anti-counterfeiting and pressure information memory devices.