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The synthesis of novel water-soluble polymers with biodegradability is an effective way to mitigate their negative environmental impacts. In this study, semi-aromatic copolyester poly(butylene succinate-co-butylene terephthalate) (PBST) with exceptional biodegradability is used as the resin matrix. Anionic sodium 1-3-isophthalate-5-sulfonate (SIPA) is introduced as a fourth monomer to prepare random poly(butylene succinate-co-butylene terephthalate-co-butylene 5-sodiosulfoisophthalate) (PBSTS) copolyesters by melt copolymerization. The incorporation of ionic groups enhances the hydrophilicity and water absorption of the copolyesters, resulting in water-soluble materials that exhibit ionic and temperature responsivity. Furthermore, the ionized biodegradable copolyesters demonstrate distinct pH-dependent degradation, which is accelerated at pH = 5.5 and 8.5 but inhibited at pH = 7.2. Degradation assessments in simulated body fluids reveal that the PBSTS copolyesters exhibit significant degradation in gastric fluids at pH = 1.5 with minimal degradation in intestinal fluids at pH = 6.8 and in body fluids at pH = 7.0. This unique degradation performance highlights the potential of these materials for addressing the challenges associated with selective drug delivery and localized controlled release in the human body.
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Due to the detrimental effect of formaldehyde on DNA, ethanol has replaced formalin as the primary preservative for animal specimens. However, short-term formalin fixation of specimens might be applied during field collection. In an increasing number of studies, DNA extraction and sequencing have been successfully conducted from formalin-fixed specimens. Here the DNA from five specimens of Triplophysadalaica (Kessler, 1876) were extracted and performed high-throughput sequencing. Four of the specimens underwent short-term fixation with formalin and were subsequently transferred to ethanol. One was continuously stored in ethanol. No significant difference of DNA quality and amount were observed among these samples. Followed by assembly and annotation, five mitochondrial genomes ranging in length from 16,569 to 16,572 bp were obtained. Additionally, previously published data of other individuals or species were included to perform phylogenetic analyses. In the reconstructed trees, all eight individuals of T.dalaica form a monophyletic group within the Triplophysa branch. The group is divided into three clades: (1) samples from the Yellow River, (2) those from the Yangtze River, and (3) those from the Haihe River, and the Lake Dali Nur. This study sheds initial light on the phylogeographic relationships among different populations of T.dalaica, and will support the research about its evolutionary history in the future.
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[This corrects the article DOI: 10.3389/fpls.2022.887179.].
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BACKGROUND: Mucopolysaccharidosis (MPS) IIIB, also known as Sanfilippo Syndrome B, is a devastating childhood disease. Unfortunately, there are currently no available treatments for MPS IIIB patients. Yet, animal models of lysosomal storage diseases have been valuable tools in identifying promising avenues of treatment. Enzyme replacement therapy, gene therapy, and bone marrow transplant have all shown efficacy in the MPS IIIB model systems. A ubiquitous finding across rodent models of lysosomal storage diseases is that the best treatment outcomes resulted from intervention prior to symptom onset. Therefore, the aim of the current study was to identify early markers of disease in the MPS IIIB mouse model as well as examine clinically-relevant behavioral domains not yet explored in this model. METHODS: Using the MPS IIIB mouse model, we explored early developmental trajectories of communication and gait, and later social behavior, fear-related startle and conditioning, and visual capabilities. In addition, we examined brain structure and function via magnetic resonance imaging and diffusion tensor imaging. RESULTS: We observed reduced maternal isolation-induced ultrasonic vocalizations in MPS IIIB mice relative to controls, as well as disruption in a number of the spectrotemporal features. MPS IIIB also exhibited disrupted thermoregulation during the first two postnatal weeks without any differences in body weight. The developmental trajectories of gait were largely normal. In early adulthood, we observed intact visual acuity and sociability yet a more submissive phenotype, increased aggressive behavior, and decreased social sniffing relative to controls. MPS IIIB mice showed greater inhibition of startle in response to a pretone with a decrease in overall startle response and reduced cued fear memory. MPS IIIB also weighed significantly more than controls throughout adulthood and showed larger whole brain volumes and normalized regional volumes with intact tissue integrity as measured with magnetic resonance and diffusion tensor imaging, respectively. CONCLUSIONS: Together, these results indicate disease markers are present as early as the first two weeks postnatal in this model. Further, this model recapitulates social, sensory and fear-related clinical features. Our study using a mouse model of MPS IIIB provides essential baseline information that will be useful in future evaluations of potential treatments.
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Mucopolisacaridosis III , Humanos , Animales , Adulto , Niño , Mucopolisacaridosis III/genética , Mucopolisacaridosis III/patología , Imagen de Difusión Tensora , Encéfalo , Modelos Animales de Enfermedad , Resultado del TratamientoRESUMEN
OBJECTIVES: To observe the effects of electroacupuncture (EA) on the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/cAMP response element binding protein (CREB) signaling pathway-related proteins and hippocampal neuron apoptosis in diabetic cognitive impairment (DCI) rats, and to explore the mechanisms of EA in treating DCI. METHODS: Adult male SD rats were randomly divided into normal, model, and EA groups, with 12 rats in each group. The animal model of DCI was replicated using a high-fat, high-sugar diet combined with low-dose streptozotocin. The EA group received EA stimulation at "Yishu" (EX-B6), "Zusanli" (ST36), "Baihui" (GV20), and "Dazhui" (GV14). Blood glucose contents of the rats in each group were measured. The Morris water maze test was used to assess the learning and memory abilities of rats. Transmission electron microscopy was used to observe the ultrastructure of hippocampal CA1 neurons. Nissl staining was used to observe the pathological changes in hippocampal CA1 neurons. TUNEL staining was used to detect the apoptosis in hippocampal CA1 neurons. Western blot was used to detect the protein expression levels of p-PI3K/PI3K and p-Akt/Akt, as well as CREB, p-CREB, cysteine aspartate pro-tease (Caspase)-3, B-cell lymphoma-2 (Bcl-2), and Bcl-2 related X protein (Bax) in the hippocampal tissue of rats. RESULTS: Compared with the normal group, the rats' random blood glucose contents were significantly increased (P<0.01), the escape latency prolonged (P<0.01), and the original platform crossing counts reduced (P<0.01) in the model group. Significant damage to hippocampal CA1 neurons, a significantly increased neuronal apoptosis index (P<0.01), decreased ratio of p-PI3K/PI3K and p-Akt/Akt and expression of CREB, p-CREB and Bcl-2 proteins, increased expression of Caspase-3 and Bax proteins (P<0.01) were observed in the hippocampal tissue of rats in the model group. Compared with the model group, the rats in the EA group showed decreased random blood glucose content (P<0.01), shortened escape latency (P<0.01), increased original platform crossing counts (P<0.01), improved quantity and pathological morphology and ultrastructure of hippocampal CA1 neurons, reduced neuronal apoptosis index (P<0.01), increased ratio of p-PI3K/PI3K and p-Akt/Akt, and expression of CREB, p-CREB and Bcl-2 proteins (P<0.05, P<0.01) in the hippocampal tissue, and decreased expression of Caspase-3 and Bax proteins (P<0.01). CONCLUSIONS: EA can improve the learning and memory abilities of rats with DCI, and the mechanism may be related to the regulation of the expression of PI3K/Akt/CREB signaling pathway-related proteins, which attenuates the neuronal apoptosis in the hippocampus of rats, and improves the neural function.
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Disfunción Cognitiva , Diabetes Mellitus , Electroacupuntura , Ratas , Masculino , Animales , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas Sprague-Dawley , Fosfatidilinositol 3-Quinasas/genética , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismo , Caspasa 3/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Fosfatidilinositol 3-Quinasa/metabolismo , Glucemia , Transducción de Señal , Hipocampo/metabolismo , Apoptosis , Disfunción Cognitiva/genética , Disfunción Cognitiva/terapiaRESUMEN
Despite six decades of the use of exogenous oxytocin for management of labor, little is known about its effects on the developing brain. Motivated by controversial reports suggesting a link between oxytocin use during labor and autism spectrum disorders (ASDs), we employed our recently validated rat model for labor induction with oxytocin to address this important concern. Using a combination of molecular biological, behavioral, and neuroimaging assays, we show that induced birth with oxytocin leads to sex-specific disruption of oxytocinergic signaling in the developing brain, decreased communicative ability of pups, reduced empathy-like behaviors especially in male offspring, and widespread sex-dependent changes in functional cortical connectivity. Contrary to our hypothesis, social behavior, typically impaired in ASDs, was largely preserved. Collectively, our foundational studies provide nuanced insights into the neurodevelopmental impact of birth induction with oxytocin and set the stage for mechanistic investigations in animal models and prospective longitudinal clinical studies.
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PURPOSE: Distinguishing recurrent brain tumor from treatment effects, including late time-to-onset radiation necrosis (RN), presents an on-going challenge in post-treatment imaging of neuro-oncology patients. Experiments were performed in a novel mouse model that recapitulates the relevant clinical histologic features of recurrent glioblastoma growing in a RN environment, the mixed tumor/RN model. The goal of this work was to apply single-voxel deuterium (2H) magnetic resonance spectroscopy (MRS), in concert with administration of deuterated glucose, to determine if the metabolic signature of aerobic glycolysis (Warburg effect: glucose â lactate in the presence of O2), a distinguishing characteristic of proliferating tumor, provides a quantitative readout of the tumor fraction (percent) in a mixed tumor/RN lesion. PROCEDURES: 2H MRS employed the SPin-ECho full-Intensity Acquired Localized (SPECIAL) MRS pulse sequence and outer volume suppression at 11.74 T. For each subject, a single 2H MRS voxel was placed over the mixed lesion as defined by contrast enhanced (CE) 1H T1-weighted MRI. Following intravenous administration of [6,6-2H2]glucose (Glc), 2H MRS monitored the glycolytic conversion to [3,3-2H2]lactate (Lac) and glutamate + glutamine (Glu + Gln = Glx). RESULTS: Based on previous work, the tumor fraction of the mixed lesion was quantified as the ratio of tumor volume, defined by 1H magnetization transfer experiments, vs. the total mixed-lesion volume. Metabolite 2H MR spectral-amplitude values were converted to metabolite concentrations using the natural-abundance semi-heavy water (1HO2H) resonance as an internal concentration standard. The 2H MR-determined [Lac] / [Glx] ratio was strongly linearly correlated with tumor fraction in the mixed lesion (n = 9), Pearson's r = 0.87, and 77% of the variation in the [Lac] / [Glx] ratio was due to tumor percent r2 = 0.77. CONCLUSIONS: This preclinical study supports the proposal that 2H MR could occupy a well-defined secondary role when standard-of-care 1H imaging is non-diagnostic regarding tumor presence and/or response to therapy.
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Glioblastoma , Animales , Ratones , Humanos , Deuterio , Glioblastoma/diagnóstico por imagen , Espectroscopía de Resonancia Magnética , Modelos Animales de Enfermedad , Ácido Láctico/metabolismo , Necrosis , Glucosa , Imagen por Resonancia MagnéticaRESUMEN
PURPOSE: Tail-vein catheterization and subsequent in-magnet infusion is a common route of administration of deuterium (2 H)-labeled substrates in small-animal deuterium (D) MR studies. With mice, because of the tail vein's small diameter, this procedure is challenging. It requires considerable personnel training and practice, is prone to failure, and may preclude serial studies. Motivated by the need for an alternative, the time courses for common small-molecule deuterated substrates and downstream metabolites in brain following subcutaneous infusion were determined in mice and are presented herein. METHODS: Three 2 H-labeled substrates-[6,6-2 H2 ]glucose, [2 H3 ]acetate, and [3,4,4,4-2 H4 ]beta-hydroxybutyrate-and 2 H2 O were administered to mice in-magnet via subcutaneous catheter. Brain time courses of the substrates and downstream metabolites (and semi-heavy water) were determined via single-voxel DMRS. RESULTS: Subcutaneous catheter placement and substrate administration was readily accomplished with limited personnel training. Substrates reached pseudo-steady state in brain within â¼30-40 min of bolus infusion. Time constants characterizing the appearance in brain of deuterated substrates or semi-heavy water following 2 H2 O administration were similar (â¼15 min). CONCLUSION: Administration of deuterated substrates via subcutaneous catheter for in vivo DMRS experiments with mice is robust, requires limited personnel training, and enables substantial dosing. It is suitable for metabolic studies where pseudo-steady state substrate administration/accumulation is sufficient. It is particularly advantageous for serial longitudinal studies over an extended period because it avoids inevitable damage to the tail vein following multiple catheterizations.
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Encéfalo , Cola (estructura animal) , Ratones , Animales , Óxido de Deuterio , Deuterio , Cola (estructura animal)/metabolismo , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismoRESUMEN
Aquaporin-4 (AQP4) is a water channel protein that links the astrocytic endfeet to the blood-brain barrier (BBB) and regulates water and potassium homeostasis in the brain, as well as the glymphatic clearance of waste products that would otherwise potentiate neurological diseases. Recently, translational readthrough was shown to generate a C-terminally extended variant of AQP4, known as AQP4x, which preferentially localizes around the BBB through interaction with the scaffolding protein α-syntrophin, and loss of AQP4x disrupts waste clearance from the brain. To investigate the function of AQP4x, we generated a novel AQP4 mouse line (AllX) to increase relative levels of the readthrough variant above the ~15% of AQP4 in the brain of wild-type (WT) mice. We validated the line and assessed characteristics that are affected by the presence of AQP4x, including AQP4 and α-syntrophin localization, integrity of the BBB, and neurovascular coupling. We compared AllXHom and AllXHet mice to WT and to previously characterized AQP4 NoXHet and NoXHom mice, which cannot produce AQP4x. An increased dose of AQP4x enhanced perivascular localization of α-syntrophin and AQP4, while total protein expression of the two was unchanged. However, at 100% readthrough, AQP4x localization and the formation of higher order complexes were disrupted. Electron microscopy showed that overall blood vessel morphology was unchanged except for an increased proportion of endothelial cells with budding vesicles in NoXHom mice, which may correspond to a leakier BBB or altered efflux that was identified in NoX mice using MRI. These data demonstrate that AQP4x plays a small but measurable role in maintaining BBB integrity as well as recruiting structural and functional support proteins to the blood vessel. This also establishes a new set of genetic tools for quantitatively modulating AQP4x levels.
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BACKGROUND: Coronary chronic total occlusion (CTO) interventions are more complex than general percutaneous coronary intervention (PCI) procedures. However, only a few nursing methods are specifically applied to patients undergoing CTO interventions. And the conventional nursing effect is not ideal, urgent need to explore more effective nursing methods. The checklist is a simple and effective tool for error management and performance improvement that has been widely used in many fields. But there have been no reports of the checklist being used to improve care for CTO patients. OBJECTIVE: This study aimed to investigate the effectiveness of a checklist-based nursing care process in patients undergoing Coronary chronic total occlusion (CTO) interventions, including duration of care, patient anxiety, improved patient satisfaction, and occurrence of adverse events. METHODS: A total of 120 CTO patients undergoing percutaneous coronary intervention (PCI) were selected at our hospital and divided into an intervention group (n = 60, adopted the checklist-based nursing care process for patient care) and a control group (n = 60, adopted nursing care according to the existing workflow) according to different nursing interventions. After surgery, the nurse in charge of the patient completed the nursing according to the "List of postoperative care for CTO patients" filled in by the patient within 24 h after surgery, conducted a doctor satisfaction survey, recorded adverse events, and completed the postoperative Self-Rating Anxiety Scale (SAS) score and patient satisfaction survey before the patient was discharged. Subsequently, the Qc team checks the completion of the patient's checklist for safety and the completion of the questionnaire. Finally, the differences between the two groups in preoperative nursing time, incidence of adverse events caused by nurses' omission or inadequate guidance, patient anxiety, and doctor and patient satisfaction were compared. RESULTS: The intervention grouphad significantly shorter preoperative nursing care time and significantly lower the total number of adverse events than the control group (P < 0.05).The postoperative Self-Rating Anxiety Scale (SAS) score of the intervention group was significantly lower than that of the control group (P < 0.05).The satisfaction of doctors and patients in the intervention groupwas significantly higher than that in the control group (P < 0.05). CONCLUSION: The application of the checklist-based nursing care process in patients with CTO intervention can significantly reduce the preoperative nursing care time, reduce patient anxiety, improve patients' and doctors' satisfaction with nursing care, and effectively reduce the occurrence of adverse events caused by nurses' omissions or inadequate instructions. TRIAL REGISTRATION: The protocol of the trial was registered retrospectively of Chinese Clinical Trial Registry (registration number ChiCTR2200056804, reg date17/02/2022).
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Oclusión Coronaria , Atención de Enfermería , Intervención Coronaria Percutánea , Humanos , Oclusión Coronaria/diagnóstico por imagen , Oclusión Coronaria/cirugía , Resultado del Tratamiento , Intervención Coronaria Percutánea/efectos adversos , Estudios Retrospectivos , Lista de Verificación , Enfermedad Crónica , Sistema de Registros , Angiografía Coronaria , Factores de RiesgoRESUMEN
Phenotypic heterogeneity in monogenic neurodevelopmental disorders can arise from differential severity of variants underlying disease, but how distinct alleles drive variable disease presentation is not well understood. Here, we investigate missense mutations in DNA methyltransferase 3A (DNMT3A), a DNA methyltransferase associated with overgrowth, intellectual disability, and autism, to uncover molecular correlates of phenotypic heterogeneity. We generate a Dnmt3aP900L/+ mouse mimicking a mutation with mild to moderate severity and compare phenotypic and epigenomic effects with a severe R878H mutation. P900L mutants exhibit core growth and behavioral phenotypes shared across models but show subtle epigenomic changes, while R878H mutants display extensive disruptions. We identify mutation-specific dysregulated genes that may contribute to variable disease severity. Shared transcriptomic disruption identified across mutations overlaps dysregulation observed in other developmental disorder models and likely drives common phenotypes. Together, our findings define central drivers of DNMT3A disorders and illustrate how variable epigenomic disruption contributes to phenotypic heterogeneity in neurodevelopmental disease.
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ADN (Citosina-5-)-Metiltransferasas , ADN Metiltransferasa 3A , Animales , Ratones , ADN (Citosina-5-)-Metiltransferasas/genética , ADN (Citosina-5-)-Metiltransferasas/metabolismo , Epigénesis Genética , Epigenómica , Mutación/genéticaRESUMEN
BACKGROUND: Mortality rates after pancreaticoduodenectomy (PD) have significantly decreased in specialized centers. However, postoperative morbidity, particularly delayed gastric emptying (DGE), remains the most frequent complication following PD. AIM: To identify risk factors associated with DGE after the PD procedure. METHODS: In this retrospective, cross-sectional study, clinical data were collected from 114 patients who underwent PD between January 2015 and June 2018. Demographic factors, pre- and perioperative characteristics, and surgical complications were assessed. Univariate and multivariate analyses were performed to identify risk factors for post-PD DGE. RESULTS: The study included 66 males (57.9%) and 48 females (42.1%), aged 33-83 years (mean: 62.5), with a male-to-female ratio of approximately 1.4:1. There were 63 cases (55.3%) of PD and 51 cases (44.7%) of pylorus-preserving pancreatoduodenectomy. Among the 114 patients who underwent PD, 33 (28.9%) developed postoperative DGE. Univariate analysis revealed significant differences in four of the 14 clinical indexes observed: pylorus preservation, retrocolonic anastomosis, postoperative abdominal complications, and early postoperative albumin (ALB). Logistic regression analysis further identified postoperative abdominal complications [odds ratio (OR) = 4.768, P = 0.002], preoperative systemic diseases (OR = 2.516, P = 0.049), and early postoperative ALB (OR = 1.195, P = 0.003) as significant risk factors. CONCLUSION: Postoperative severe abdominal complications, preoperative systemic diseases, and early postoperative ALB are identified as risk factors for post-PD DGE.
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Two new Sinolachnus species from China, Sinolachnusrubusis Qiao & Li, sp. nov. feeding on Rubus sp. from Shaanxi and Sichuan Provinces, and Sinolachnusyunnanensis Qiao & Li, sp. nov. feeding on Elaeagnus sp. from Yunnan Province, are described and illustrated. Keys to Sinolachnus species distributed in China are presented. All examined specimens are deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
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Objective: Thyroid cancer is the third most prevalent cancer among females. Genetic testing based on next-generation sequencing may provide an auxiliary diagnosis to reduce cytologically diagnostic uncertainty. However, commercial multigene tests are not widely available and are not well-tested in the Chinese population. Methods: In this study, we designed a multigene testing panel and evaluated its performance in 529 cytologically indeterminate thyroid nodules (Bethesda III, IV and V). The molecular data of the DNA mutations and RNA fusions of fine needle aspiration samples were reviewed in conjunction with a clinical diagnosis, pathological reports, and definitive surgery for retrospective analysis. Then, the molecular risk stratification was investigated for its accuracy in malignant risk prediction. Results: The overall combined consistency revealed substantial agreement (Kappa = 0.726) with the sensitivity, specificity, positive predictive value, and negative predictive values of 97.80%, 82.14%, 98.99%, and 67.65%, respectively. The most common aberration was BRAFV600E (82.59%), followed by NRAS mutants (4.07%), RET fusions (3.70%), and KRAS mutants (3.15%). Two cases (0.44%) were categorized into a high-risk group, 426 cases (94.67%) were categorized into a BRAF-like group with totally histopathologic papillary patterned tumors, and 22 cases (4.89%) were categorized into a RAS-like group with 14 papillary and eight follicular patterned tumors when the cohort concurrent aberrations were excluded. Potentially aggressive features may be related to concurrent molecular alterations of BRAFV600E with TERTQ302R, and AKT1L52R, NRASG12C, NRASQ61R, and CCDC6-RET fusions. Conclusions: This study provided a multigene panel for identifying benign nodules from cytologically indeterminate thyroid nodules to avoid unnecessary surgery. We provide further evidence for using molecular risk stratification as a promising predictor of disease outcomes. The results of this study may be limited by the extremely high prevalence of cancer in the cohort for clinical reference.
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Neoplasias de la Tiroides , Nódulo Tiroideo , Femenino , Humanos , Nódulo Tiroideo/diagnóstico , Proteínas Proto-Oncogénicas B-raf , Estudios Retrospectivos , Neoplasias de la Tiroides/diagnóstico , Medición de RiesgoRESUMEN
Aquaporin-4 (AQP4) is a water channel protein that links astrocytic endfeet to the blood-brain barrier (BBB) and regulates water and potassium homeostasis in the brain, as well as the glymphatic clearance of waste products that would otherwise potentiate neurological diseases. Recently, translational readthrough was shown to generate a C-terminally extended variant of AQP4, known as AQP4x, that preferentially localizes around the BBB through interaction with the scaffolding protein α-syntrophin, and loss of AQP4x disrupts waste clearance from the brain. To investigate the function of AQP4x, we generated a novel mouse AQP4 line (AllX) to increase relative levels of the readthrough variant above the ~15% of AQP4 in the brain of wildtype (WT) mice. We validated the line and assessed characteristics that are affected by the presence of AQP4x, including AQP4 and α-syntrophin localization, integrity of the BBB, and neurovascular coupling. We compared AllXHom and AllXHet mice to wildtype, and to previously characterized AQP4 NoXHet and NoXHom mice, which cannot produce AQP4x. Increased dose of AQP4x enhanced perivascular localization of α-syntrophin and AQP4, while total protein expression of the two were unchanged. However, at 100% readthrough, AQP4x localization and formation of higher-order complexes was disrupted. Electron microscopy showed that overall blood vessel morphology was unchanged except for increased endothelial cell vesicles in NoXHom mice, which may correspond to a leakier BBB or altered efflux that was identified in NoX mice using MRI. These data demonstrate that AQP4x plays a small but measurable role in maintaining BBB integrity as well as recruiting structural and functional support proteins to the blood vessel. This also establishes a new set of genetic tools for quantitatively modulating AQP4x levels.
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The design and production of materials with excellent mechanical properties and biodegradability face significant challenges. Poly (butylene terephthalate-co-caprolactone) copolyesters (PBTCL) is obtained by modifying the engineering plastic polybutylene terephthalate (PBT) with a simple one-pot process using readily biodegradable ε-caprolactone (ε-CL). The material has mechanical properties comparable to those of commercial biodegradable copolyester PBAT. Besides, this copolyester exhibited remarkable degradability in natural environments such as soil and ocean, for example, PBTCL1.91 lost >40 % of its weight after 6 months of immersion in the Bohai Sea. The effect and diversity of specific microorganisms acting on degradation in the ocean were analyzed by 16 s rDNA gene sequencing. Theoretical calculations such as Fukui function and DFT, and experimental studies on water-soluble intermediates and residual matrixes produced after degradation, confirmed that the insertion CL units not only act as active sites themselves susceptible to hydrolysis reactions, but also promote the reactivity of ester bonds between aromatic segments. This work provides insight for the development of novel materials with high performance and environmental degradability.
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The genus Cavariella is distinguished from other Macrosiphini genera (Aphididae, Aphidinae) because it has a supra-caudal process on abdominal tergite VIII which possesses two setae distally. It is Holarctic in distribution, and half of its species are Asian. The Chinese fauna of this genus, 17 species, have been restudied, morphologically and through DNA barcodes. As a result: Cavariellahidaensis Takahashi is transferred to Elatobium; Cavariellasculptura Qiao & Xu, sp. nov. is described from specimens collected on Torilis and Cryptotaenia (Apiaceae); Cavariellacessana Zhang, Chen, Zhong & Li, syn. nov. and Cavariellalargispiracula Zhang, Chen, Zhong & Li, syn. nov. are respectively junior synonyms of Cavariellaaquatica (Gillette & Bragg) and Cavariellasapporoensis Takahashi; Cavariellagilgiana Zhang, Chen, Zhong & Li and Cavariellalhasana Zhang are confirmed as valid species and complete descriptions are provided; Cavariellabhutanensis Chakrabarti & Das, Cavariellanigra Basu, Cavariellapastinacae (Linnaeus), and Cavariellapustula Essig are recorded for the first time from China. Additionally, keys for species of Cavariella known in China are provided and modifications to the key by Blackman and Eastop of aphid species on Angelica (Aphids on World's Plants) are presented.
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Biodegradable plastics have emerged as a potential solution to the mounting plastic pollution crisis. However, current methods for evaluating the degradation of these plastics are limited in detecting structural changes rapidly and accurately, particularly for PBAT, which contains worrying benzene rings. Inspired by the fact that the aggregation of conjugated groups can endow polymers with intrinsic fluorescence, this work found that PBAT emits a bright blue-green fluoresces under UV irradiation. More importantly, we pioneered a degradation evaluation approach to track the degradation process of PBAT via fluorescence. A blue shift of fluorescence wavelength as the thickness and molecular weight of PBAT film decreased during degradation in an alkali solution was observed. Additionally, the fluorescence intensity of the degradation solution increased gradually as the degradation progressed, and was found to be exponentially correlated with the concentration of benzene ring-containing degradation products following filtration with the correlation coefficient is up to 0.999. This study proposes a promising new strategy for monitoring the degradation process with visualization and high sensitivity.
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Allocotaphis Börner, 1950 (Hemiptera, Homoptera, Aphididae, Aphidinae, Macrosiphini) and its three species are fully revised. The history of the descriptions of the involved taxa is critically presented. Descriptions of the known morphs of these species and complete information on the biology and distribution of the species are presented. Three subjective synonymies are established: Spinaphis L.K. Ghosh, 1986 syn. n. and Longisiphoniella Chakrabarti, Saha & Mandal, 1988 syn. n. of Allocotaphis Börner, 1950, and Longisiphoniella subterranea Chakrabarti, Saha & Mandal, 1988 syn. n. of Allocotaphis multisetosa (L.K. Ghosh, 1986) comb. n. An hypothesis for the formation of the genus and the speciation that took place within it is proposed.