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Abstract Key message Primary remains of Eucalyptus (E. urophylla × E. grandis) plantations following clear-cutting are the stumps and coarse roots. A chrono-sequence approach revealed that the biomass of coarse roots is higher than that of stumps, while they have a smaller rate of biomass loss than stumps. This implies that coarse roots serve as long-term stock for nutrients (carbon, nitrogen, and phosphorus). Context A significant quantity of stumps and coarse roots persist in the forest floor following the clear-cutting of Eucalyptus plantations in China. The decomposition of these stumps and coarse roots is a crucial aspect of the nutrient stocks in plantation ecosystems. Aims We described the stock and decomposition dynamics of stumps and coarse roots on Eucalyptus plantations, as well as the nutrient loss rate associated with them. Methods We used a chrono-sequence of 0–6-year-old clear-cutting stands of Eucalyptus plantations in southern China. The biomass and nutrient stocks of these samples were assessed at different times of decomposition. Results The highest biomass of stump-root system was 33.8 Mg·ha−1, with nutrient stocks were 16.3 Mg·ha−1, and 63.0 kg·ha−1, and 6710.9 g·ha−1, for C, N, and P. The coarse roots accounted for 81–96% of the biomass of the stump-root system. The loss rate of biomass and nutrients from stumps was higher than that of coarse roots. This suggests that the decomposition of coarse roots could serve as a long-term source of nutrients, thereby improving the nutrient status of the plantations. Conclusion Stumps and coarse roots serve as significant nutrient stocks that decay at varying rates. The loss of nutrients must be considered while analyzing the decomposition dynamics following clear-cutting in Eucalyptus plantations.

[This corrects the article DOI: 10.1371/journal.pone.0298700.].

Silkworms are insects with important economic value, and mulberry leaves are the food of silkworms. The quality and quantity of mulberry leaves have a direct impact on cocooning. Mulberry leaves are often infected with various diseases during the growth process. Because of the subjectivity and time-consuming problems in artificial identification of mulberry leaf diseases. In this work, a multi-scale residual network fusion Squeeze-and-Excitation Networks (SENet) is proposed for mulberry leaf disease recognition. The mulberry leaf disease dataset was expanded by performing operations such as brightness enhancement, contrast enhancement, level flipping and adding Gaussian noise. Multi-scale convolution was used instead of the traditional single-scale convolution, allowing the network to be widened to obtain more feature information and avoiding the overfitting phenomenon caused by the network piling up too deep. SENet was introduced into the residual network to enhance the extraction of key feature information of the model, thus improving the recognition accuracy of the model. The experimental results showed that the method proposed in this paper can effectively improve the recognition performance of the model. The recognition accuracy reached 98.72%. The recall and F1 score were 98.73% and 98.72% respectively. Compared with some other models, this model has better recognition effect and can provide technical reference for intelligent mulberry leaf disease detection.

Abstract Background Clinical instructional strategies and the climate in which teaching and learning take place have a significant impact on the quality of dental education. Therefore, this study aimed to evaluate the impact of early microsurgery training on the skills of dental intern students who are planning to join an oral and maxillofacial surgical field (DIS) as compared with junior residents within an oral and maxillofacial surgery department who had no microsurgery experience (JR). Methods A total of 100 trainees, 70 were DIS, while the other 30 were JR. The average age was 23.87 ± 2.05 years for DIS group and 31.05 ± 3.06 for JR group. All trainees attended a microsurgical course (theoretical and practical parts) for seven days within a Microvascular Laboratory for Research and Education of a university-affiliated tertiary hospital. Two blinded examiners had assessed the performance of trainees independently using a specific scoring system. The independent sample t-test was used to compare the effect of microsurgery training between DIS and JR groups. The significance level was set at 0.05. Results The DIS group had showed higher attendance rate than JR group (p

Background: Pectus excavatum is not rare in China. Many treatments for this disease have proved to have many shortcomings. Nuss procedure has been a ground-breaking technology, but it also has some disadvantages. Hence, this study was conducted to review our experience in the use of modified Nuss procedure in our hospital. Methods: Data from 259 patients suffered from pectus excavatum between August 2020 and August 2021 who were treated with modified Nuss procedure was analyzed retrospectively. Result: Age was from 3 to 37 years. The average was 15.54 years. The male was 213 cases and the female was 46 cases. The time patients or their family members found pectus excavatum varied. 10 cases had been repaired previously when patients were admitted in our hospital. The clinical symptoms also varied. Each case had an improvement in Haller index. The average of the postoperative hospitalization was 3.97 days. Most cases were inserted 1 bar. Complication rate was also very low. All patients or their parents or their guardians were satisfied with the appearance of the chest wall after operation. There was no death in the whole observation period. Conclusion: From our experience, this modified Nuss procedure have obtained optimistic outcomes with more minimal invasion and low complication rate. This surgical method may be applied to many other hospitals in the future.

Summary: The multi-scale modeling of lithium-ion battery (LIB) is difficult and necessary due to its complexity. However, it is difficult to capture the aging behavior of batteries, and the coupling mechanism between multiple scales is still incomplete. In this paper, a simplified electrochemical model (SEM) and a kinetic Monte Carlo (KMC)-based solid electrolyte interphase (SEI) film growth model are used to study the multi-scale characteristics of LIBs. The single-particle SEM (SP-SEM) is described for macro scale, and a simple and self-consistent multi-particle SEM (MP-SEM) is developed. Then, the KMC-based SEI model is established for micro-scale molecular evolution. And, the two models are coupled to construct the full-cycle multi-scale model. After modeling, validation is performed by using a commercial 18650-type LIB. Finally, the effect of parameters on the SEI model is studied, including qualitative trend analysis and quantitative sensitivity analysis. The growth of SEI film with different particle sizes is studied by MP-SEM coupling simulation.

Abstract Background The surgical extraction of impacted third molars is one of the most common procedures in oral and maxillofacial surgery, which associated with several postoperative complications. The aim of this clinical trial was to estimate the implication of concentrated growth factor (CGF) on postoperative sequelae after the completely impacted lower third molar extraction. Materials and methods A total of 74 sides of 37 participants who had completely bilateral impacted lower third molars were enrolled in this split-mouth, randomized single‑blind, clinical trial. Surgical extraction was undertaken on both sides of the mandible. Randomization was achieved by opaque, sealed envelopes. The postoperative outcomes including wound healing, swelling and pain were clinically assessed at different-time intervals(1st, 3rd and 7th days). A p-value

AimThe aim of this clinical trial was to assess the impact of autologous concentrated growth factor (CGF) as a socket-filling material and its ridge preservation properties following the lower third molar extraction.Materials and methodsA total of 60 sides of 30 participants who had completely symmetrical bilateral impacted lower third molars were enrolled. The primary outcome variables of the study were bone height and width, bone density, and socket surface area in the coronal section. Cone beam computed tomography images were obtained immediately after surgery and three months after surgery as a temporal measure. Follow-up data were compared to the baseline using paired and unpaired t-tests.ResultsCGF sites had higher values in height and width when compared to control sites (Buccal wall 32.9 ± 3.5 vs 29.4 ± 4.3 mm, Lingual wall 25.4 ± 3.5 vs 23.1 ± 4 mm, and Alveolar bone width 21.07 ± 1.55vs19.53 ± 1.90 mm, respectively). Bone density showed significantly higher values in CGF sites than in control sites (Coronal half 200 ± 127.3 vs -84.1 ± 121.3 and Apical half 406.5 ± 103 vs 64.2 ± 158.6, respectively). There was a significant difference between both sites in the reduction of the periodontal pockets.ConclusionCGF application following surgical extraction provides an easy, low-cost, and efficient option for alveolar ridge preservation. Thus, the use of CGF by dentists during dental extractions may be encouraged, particularly when alveolar ridge preservation is required.Clinical trial registrationTCTR identification, TCTR20221028003.

This article proposes a multiscan joint noncoherent detection method of small targets in high-resolution sea clutter with spatial–temporally structural textures induced by large-scale swells and waves, which is composed of intrascan noncoherent integration at each spatial resolution cell followed by interscan integration on a radial velocity template. The main contributions of the article are as follows. First, a concept of noncoherent radial velocity spectrum (NCRVS) is proposed to model the nonhomogeneity of multiscan integration of sea clutter with structural textures. In the NCRVS, the noncoherent intrascan integration and the interscan integration by passing the retrospective filter bank are fully combined. Second, the NCRVS of sea clutter has different statistics at individual radial velocity bins and the lognormal distributions are used to fit their statistics and an outlier-robust analytical bipercentile estimator is constructed for parameter estimation. Third, based on the lognormal-distributed NCRVS model, a double-channel multiscan joint detector (DC-MJD) is proposed, where the intrascan noncoherent integration channel is used to find floating or low radial velocity targets and the whitening plus intrascan noncoherent integration channel is used to find target with high radial velocity. Simulated data and measured X-band radar data are used to verify the DC-MJD detector. In comparison with the existing three multiscan detectors, the DC-MJD detector improves the detection probability by 96% in the measured data with a test target.

BackgroundMena, a cytoskeletal regulatory protein, is involved in actin-based regulation of cell motility and adhesion, and contributes to tumor invasion and metastasis. However, the role of Mena in oral squamous cell carcinoma remains unclear. This is the first research focusing on the prognostic value of Mena in OSCC. In this study, we aimed to investigate the correlation between Mena expression and clinicopathological significance, as well as prognostic value in OSCC.MethodsMena gene expression profiles of OSCC and normal tissues were collected from Oncomine, TCGA, and GEO databases. Biological function was analyzed through GO, KEGG and GSEA enrichment. Further, the expression level of Mena and tumor-related markers in 151 OSCC specimens was examined by IHC staining based on tissue microarray. Kaplan-Meier analysis was used to assess the prognostic performance of Mena in OSCC.ResultMena was generally upregulation in various malignancies, especially OSCC. The functional analyses indicated that Mena was involved in the assembly and regulation of actin, cell movement, and EMT. IHC staining revealed that high expression of Mena in OSCC was correlated with Lymphatic metastasis, TNM stage, E-cadherin, Vimentin, and MMP-2, but insignificantly Ki67. Kaplan-Meier analysis demonstrated that elevated expression of Mena was significantly associated with poor overall survival and disease-free survival of OSCC patients.ConclusionMena could be a novel biomarker for predicting the prognosis of OSCC patients, which supports a theoretical basis for developing molecular target therapy.

Abstract Promising cancer treatment requires the assistant of drug delivery systems (DDS) with the aim to increase the accumulation of drugs in tumor tissue. Herein, a hybrid DDS was successfully developed to integrate chondroitin sulfate (CS) and calcium carbonate (CC) in to one system. Anticancer drug adriamycin (Adr) was preloaded into CC nanoparticles to obtain Adr‐loaded CC nanoparticles (CC/Adr). The resulted CS‐CC/Adr nanoparticles as a biocompatible DDS was able to specifically target cancer cells to enhance the chemotherapy of lung cancer due to the surface modification of CS. Intracellular uptake as well as in vivo imaging results revealed the obtained CS‐CC/Adr nanoparticles (size of ~100 nm) showed CS mediated tumor specific accumulation into A549 and LLC cells than unmodified CC/Adr, in which the CD44 receptor might be involved, which finally resulted in stronger anticancer capability than Adr or CC/Adr. As a result, CS‐CC/Adr nanoparticles could be further extended to clinical administration in our future works.

Golden pompano, Trachinotus ovatus, is a perciform fish with great economic value and is widely cultured in the coastal areas of China. The wide occurrence of bacterial, parasitic and viral diseases has seriously threatened the sustainable development of the golden pompano culture industry. Janus kinases (JAKs) play important roles in most cytokine-mediated inflammatory responses, antiviral immune responses, autoimmune responses and disease pathologies. The present study aimed to obtain the full-length cDNA sequences of JAKs (JAK1, JAK2a, JAK3 and TYK2) from golden pompano and investigate their roles following stimulation with lipopolysaccharide (LPS), polyriboinosinic-polyribocytidylic acid (poly I:C) and Vibrio alginolyticus using RT-PCR, RACE-PCR and real-time qPCR methods. All four JAK proteins of golden pompano shared similar conserved domains, had high identities and clustered well with their teleost counterparts in phylogenetic analysis. Furthermore, these four genes were expressed in all examined tissues from healthy fish and induced in head kidney (HK), spleen, liver and gill post LPS, poly I:C and V. alginolyticus stimulation. Knowledge of the roles of JAKs in the immune response to different microbial pathogens provides a basis for further understanding of these functions.

Abstract Background The red swamp crayfish Procambarus clarkii is a freshwater species that possesses high adaptability, environmental tolerance, and fecundity. P. clarkii is artificially farmed on a large scale in China. However, the molecular mechanisms of ovarian development in P. clarkii remain largely unknown. In this study, we identified four stages of P. clarkii ovary development, the previtellogenic stage (stage I), early vitellogenic stage (stage II), middle vitellogenic stage (stage III), and mature stage (stage IV) and compared the transcriptomics among these four stages through next-generation sequencing (NGS). Results The total numbers of clean reads of the four stages ranged from 42,013,648 to 62,220,956. A total of 216,444 unigenes were obtained, and the GC content of most unigenes was slightly less than the AT content. Principal Component Analysis (PCA) and Anosim analysis demonstrated that the grouping of these four stages was feasible, and each stage could be distinguished from the others. In the expression pattern analysis, 2301 genes were continuously increase from stage I to stage IV, and 2660 genes were sharply decrease at stage IV compared to stages I-III. By comparing each of the stages at the same time, four clusters of differentially expressed genes (DEGs) were found to be uniquely highly expressed in stage I (136 genes), stage II (43 genes), stage III-IV (49 genes), and stage IV (22 genes), thus exhibiting developmental stage specificity. Moreover, in comparisons between adjacent stages, the number of DEGs between stage III and IV was the highest. GO enrichment analysis demonstrated that nutrient reservoir activity was highest at stage II and that this played a foreshadowing role in ovarian development, and the GO terms of cell, intracellular and organelle participated in the ovary maturation during later stages. In addition, KEGG pathway analysis revealed that the early development of the ovary was mainly associated with the PI3K-Akt signaling pathway and focal adhesion; the middle developmental period was related to apoptosis, lysine biosynthesis, and the NF-kappa B signaling pathway; the late developmental period was involved with the cell cycle and the p53 signaling pathway. Conclusion These transcriptomic data provide insights into the molecular mechanisms of ovarian development in P. clarkii. The results will be helpful for improving the reproduction and development of this aquatic species.

Abstract High mobility group box 1 (HMGB1) has been known to involve in the pathogenesis of many inflammatory diseases. The aim of this study was to establish animal model of acute rhinosinusitis (ARS), and determine whether ethyl pyruvate (EP) attenuate inflammatory response of sinonasal mucosa by inhibiting HMGB1 in ARS animals. Thirty-six Sprague Dawley (SD) rat were used as follows: six normal controls without intervention (group 1); thirty rats were used for establishment of ARS rats model by nasal insertion of Merocel sponge, and model rats without any treatments (group 2), treated with nasal drops of sterile saline (group 3), 10 μl EP (group 4), and 20 μl EP (group 5), twice a day for 5 days, respectively. Bacterial culture was done regularly and the main bacterial strains were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry. HMGB1 expression in sinonasal mucosa was detected by immunohistochemistry and RT-PCR. Serum levels of HMGB1, IL-6, and TNF-α were determined by ELISA. Data from 29 of 36 rats that had completed research were analyzed. Bacterial colony formation unit (CFU) of nasal secretion was significantly higher in each group of ARS rats compared with controls (p

In high-resolution maritime surveillance radars, sea clutter exhibits highly spatial heterogeneity due to modulation of long waves with wavelengths longer than the width of one range cell. Compound-Gaussian model (CGM) fails to characterize the heterogeneous high-resolution sea clutter in both amplitude distribution and Doppler spectrum. In this article, a bi-phase compound-Gaussian mixture model (BP-CGMM) is proposed to characterize the heterogeneous sea clutter. In the BP-CGMM, spatial resolution cells are grouped into two disjoint sets, and the sea clutter in each set is represented by one CGM with inverse Gamma-distributed texture. The spectral heterogeneity indicates that sea clutter vectors at spatially adjacent resolution cells in one set share the same speckle covariance matrix, while that at two adjacent spatial cells separated in the two sets often have different speckle covariance matrices. The BP-CGMM is validated by a mass of measured high-resolution sea clutter data. Moreover, under the BP-CGMM, a detection method based on batch test is given to detect sea-surface small targets, which is composed of scene segmentation, by the aid of Bayesian threshold and morphological filtering, and adaptive generalized likelihood ratio test linear-threshold detector (GLRT-LTD) separately in each set. The detection method is verified by measured data with small targets under test. The experimental results show that it attains better detection performance than the adaptive GLRT-LTD under the CGM of sea clutter.

Topologically ordered phases of matter elude Landaus symmetry-breaking theory, featuring a variety of intriguing properties such as long-range entanglement and intrinsic robustness against local perturbations. Their extension to periodically driven systems gives rise to exotic new phenomena that are forbidden in thermal equilibrium. Here, we report the observation of signatures of such a phenomenon-a prethermal topologically ordered time crystal-with programmable superconducting qubits arranged on a square lattice. By periodically driving the superconducting qubits with a surface code Hamiltonian, we observe discrete time-translation symmetry breaking dynamics that is only manifested in the subharmonic temporal response of nonlocal logical operators. We further connect the observed dynamics to the underlying topological order by measuring a nonzero topological entanglement entropy and studying its subsequent dynamics. Our results demonstrate the potential to explore exotic topologically ordered nonequilibrium phases of matter with noisy intermediate-scale quantum processors.

Introduction: Low molecular weight heparin (LMWH), a natural sulfated glycosaminoglycan with an affinity for proangiogenic factors, is produced by chemical or enzymatic depolymerization of unfractionated heparin (UFH). Known for its anticoagulant effects, LMWH has recently been reported to have a strong anti-inflammatory effect on colitis, myocarditis, and airway inflammation. However, as a newly-developed drug, its anti-inflammatory mechanism in upper respiratory tract inflammation has not been well-studied.Methods: SD rats were randomly divided into control and experimental groups. The experimental group was established by building an acute nasal sinusitis model with expansion sponges mixed with Streptococcus pneumoniae. Then the experimental group rats were subcutaneously injected with different concentrations of LMWH. After seven consecutive days of injection, some rats were sacrificed, and blood and nasal mucosa samples were taken to determine their inflammation status. The remaining acute sinusitis rats were randomly selected for a week of nasal irrigation with normal saline or saline mixed with different concentrations of LMWH. One week later, rats were sacrificed, and samples of blood and nasal mucosa were taken to determine the inflammation status.Results: Rat nasal mucosa in the model group had obvious inflammation. The degree of nasal mucosa inflammation damage in the experimental group was lower than in the experimental control group, proving that LMWH has a protective effect on the nasal mucosa and that the effect correlates with dosage. Irrigation of the nose with saline mixed with LMWH can improve the anti-inflammatory effect. Protein related to the TLR4-MyD88-NF-κB signaling pathway was activated in the acute sinusitis rat model, and LMWH can significantly inhibit its expression.Conclusion: This is the first report of the anti-inflammatory effect of LMWH in acute upper respiratory tract inflammation, together with an explanation of its anti-inflammatory mechanism. The findings contribute a theoretical basis for its potential anti-tumor effect.

Abstract Background The poorly differentiated renal cell carcinoma (RCC) with rhabdomyosarcomatous sarcomatoid differentiation shows a severely aggressive biological behavior characterized by rapid disease progression. Preoperative identification of the subtype with the prognostic factors and imaging features of sarcomatoid renal cell carcinoma (SRCC) would be of great clinical significance. Case presentation A 45-year-old male patient presented a nine day history of gross hematuria without any other symptoms. A computed tomography (CT) and a full-body fluorine-18 fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) - computed tomography (CT) scan urogram were performed. An initial diagnosis identified a space-occupying lesion of the right kidney, retroperitoneal and right renal hulum lymph node metastases, as well as a space-occupying lesion of the third thoracic vertebra (T3). A right radical nephrectomy was performed. Pathologic analysis revealed poorly differentiated RCC with rhabdomyosarcomatous sarcomatoid differentiation that extends into the renal sinus and the ureteral (T3N1M1). Five days later, the Magnetic Resonance imaging (MRI) evidenced a diffused osseous metastatic disease in the thoracic and lumbar vertebra and multiple retroperitoneal lymph node metastases. The disease progressed quickly to multiple organ dysfunction syndrome (MODS) in half a month and the patient died of respiratory failure two days later. The patient refused any chemoradiotherapy in the hospital. Conclusions Our case presents a SRCC with severe, aggressive, and rapid disease progression. Classifying SRCC imaging features by CT, MRI as well as PET-CT techniques could potentially be helpful for preoperative identification of the subtype. The prognostic factors of SRCC would be of great clinical interest.

In view of the lack of applicability of the existing equivalent evaporation duct feature calculation scheme in China's sea area and the requirement of the evaporation duct model test, this study used the actual sounding data in China's coastal areas and studied the applicability of the three computational schemes proposed by J.F. Howell, S.P. Oncley, and G.J. Steeneveld in different sea areas and different seasons by comparing the error and standard deviation. The applicability of the sea area shows that the best calculation scheme for the equivalent evaporating duct feature in the South China Sea is the scheme proposed by G.J. Steeneveld et al., while the optimal calculation method for the East China Sea is the scheme proposed by S.P. Oncley et al.; the seasonal applicability shows that the scheme proposed by G.J. Steeneveld et al. has the best-fitting results in the spring, while in the summer and winter, the scheme proposed by S.P. Oncley et al. fits best. These results provide a theoretical basis for the follow-up study.

The potential value of multiplexed positron emission tomography (PET) tracers in mice with turpentine-induced inflammation was evaluated and compared with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) for glucose metabolism imaging. These PET tracers included [18F]fluoromethylcholine ([18F]FCH) for choline metabolism imaging, (S-[11C]methyl)-D-cysteine ([11C]DMCYS) for amino acid metabolism imaging, [11C]bis(zinc(II)-dipicolylamine) ([11C]DPA-Zn2+) for apoptosis imaging, 2-(4-N-[11C]-methylaminophenyl)-6-hydroxybenzothiazole ([11C]PIB) for β amyloid binding imaging, and [18F]fluoride (18F−) for bone metabolism imaging. In mice with turpentine-induced inflammation mice, the biodistribution of all the tracers mentioned above at 5, 15, 30, 45, and 60 min postinjection was determined. Also, the time-course curves of the tracer uptake ratios for inflammatory thigh muscle (IM) to normal uninflammatory thigh muscle (NM), IM to blood (BL), IM to brain (BR), and IM to liver (LI) were acquired, respectively. Moreover, PET imaging with the tracers within 60 min postinjection on a clinical PET/CT scanner was also conducted. [18F]FDG and 18F− showed relatively higher uptake ratios for IM to NM, IM to BL, IM to BR, and IM to LI than [18F]FCH, [11C]DPA-Zn2+, [11C]DMCYS and [11C]PIB, which were highly consistent with the results delineated in PET images. The results demonstrate that 18F− seems to be a potential PET tracer for inflammation imaging. [18F]FCH and [11C]DMCYS, with lower accumulation in inflammatory tissue than [18F]FDG, are not good PET tracers for inflammation imaging. As a promising inflammatory tracer, the chemical structure of [11C]DPA-Zn2+ needs to be further optimized.

Radiolabeled cyclic arginine-glycine-aspartic (RGD) peptides can be used for noninvasive determination of integrin αvβ3 expression in tumors. In this study, we performed radiosynthesis and biological evaluation of a new 18F-labeled RGD homodimeric peptide with one 8-amino-3,6-dioxaoctanoic acid (PEG2) linker on the glutamate β-amino group (18F-FP-PEG2-β-Glu-RGD2) as a symmetric PET tracer for tumor imaging. Biodistribution studies showed that radioactivity of 18F-FP-PEG2-β-Glu-RGD2 was rapidly cleared from blood by predominately renal excretion. MicroPET-CT imaging with 18F-FP-PEG2-β-Glu-RGD2 revealed high tumor contrast and low background in A549 human lung adenocarcinoma-bearing mouse models, PC-3 prostate cancer-bearing mouse models, and orthotopic transplanted C6 brain glioma models. 18F-FP-PEG2-β-Glu-RGD2 exhibited good stability in vitro and in vivo. The results suggest that this tracer is a potential PET tracer for tumor imaging.

We have previously reported that N-(2-[18F]fluoropropionyl)-L-methionine ([18F]FPMET) selectively accumulates in tumors. However, due to the poor pharmacokinetics of [18F]FPMET in vivo, the potential clinical translation of this observation is hampered. In this study, we rationally designed and synthesized [18F] or [11C]labeled N-position L-glutamic acid analogues for tumor imaging. N-(2-[18F]fluoropropionyl)-L-glutamic acid ([18F]FPGLU) was synthesized with a 30±10% (n = 10, decay-corrected) overall radiochemical yield and a specific activity of 40±25 GBq/μmol (n = 10) after 130 min of radiosynthesis. In vitro cell experiments showed that [18F]FPGLU was primarily transported through the XAG(-) system and was not incorporated into protein. [18F]FPGLU was stable in urine, tumor tissues, and blood. We were able to use [18F]FPGLU in PET imaging and obtained high tumor to background ratios when visualizing tumors tissues in animal models.

A previously engineered Methanocaldococcus jannaschii tRNA(CUA Tyr)-tyrosyl-tRNA synthetase pair orthogonal to Escherichia coli was modified to become orthogonal in mammalian cells. The resulting tRNA(CUA Tyr)-tyrosyl-tRNA synthetase pair was able to suppress an amber codon in the green fluorescent protein, GFP, and in a foldon protein in mammalian cells. The methodology reported here will allow rapid transformation of the much larger collection of existing tyrosyl-tRNA synthetases that were already evolved for the incorporation of an array of over 50 unnatural amino acids into proteins in Escherichia coli into proteins in mammalian cells. Thus we will be able to introduce a large array of possibilities for protein modifications in mammalian cells.