RESUMEN
Systematic studies1-4 have revealed hundreds of ultra-compact dwarf galaxies (UCDs5) in the nearby Universe. With half-light radii rh of approximately 10-100 parsecs and stellar masses M* ≈ 106-108 solar masses, UCDs are among the densest known stellar systems6. Although similar in appearance to massive globular clusters7, the detection of extended stellar envelopes4,8,9, complex star formation histories10, elevated mass-to-light ratio11,12 and supermassive black holes13-16 suggest that some UCDs are remnant nuclear star clusters17 of tidally stripped dwarf galaxies18,19, or even ancient compact galaxies20. However, only a few objects have been found in the transient stage of tidal stripping21,22, and this assumed evolutionary path19 has never been fully traced by observations. Here we show that 106 galaxies in the Virgo cluster have morphologies that are intermediate between normal, nucleated dwarf galaxies and single-component UCDs, revealing a continuum that fully maps this morphological transition and fills the 'size gap' between star clusters and galaxies. Their spatial distribution and redder colour are also consistent with stripped satellite galaxies on their first few pericentric passages around massive galaxies23. The 'ultra-diffuse' tidal features around several of these galaxies directly show how UCDs are forming through tidal stripping and that this evolutionary path can include an early phase as a nucleated ultra-diffuse galaxy24,25. These UCDs represent substantial visible fossil remnants of ancient dwarf galaxies in galaxy clusters, and more low-mass remnants probably remain to be found.
RESUMEN
The stability of aqueous zinc metal anodes is still constrained by their severe dendrite growth. Optimizing electric field distribution and crystallography to modulate the diffusion and deposition behavior of zinc ions can effectively suppress dendrite growth. However, the fabrication strategy to directly endow specific textured zinc anodes with gradient electric field distribution is still lacking. Herein, a strategy combining crystal reconstruction of commercial zinc foil with graphene oxide (GO) protective layer is proposed to construct an in situ gradient electric field-enhanced strong (002) textured GO@ZnO/Zn(002) anode. Based on the experimental and theoretical results, the GO protective layer can regulate a wide-range homogeneous Zn2+ ions flow, while the dense and uniform ZnO/Zn(002) nanoneedles /nanoparticles can enhance localized polarized electric field to accelerate rapid localized transfer of Zn2+ ions and guide them toward directional deposition along (002) plane. Therefore, the hierarchical GO@ZnO/Zn(002) anode enables the symmetric cell to operate continuously and stably for 5700 and 4200 h at 2 and 4 mA cm-2, respectively, which is comparable to or better than most high-end Zn anodes. This work presents new insights into the zinc foil reconstruction and gradient electric field fabrication strategy, offering a scalable approach for the development of long-term stable metal anodes.
RESUMEN
Urgent calls for reversible cycling performance of silicon (Si) requires an efficient solution to maintain the silicon-electrolyte interface stable. Herein, a conductive biphenyl-polyoxadiazole (bPOD) layer is coated on Si particles to enhance the electrochemical process and prolong the cells lifespan. The conformal bPOD coatings are mixed ionicelectronic conductors, which not only inhibit the infinite growth of solid electrolyte interphase (SEI) but also endow electrodes with outstanding ion/electrons transport capacity. The superior 3D porous structure in the continuous phase allows the bPOD layers to act like a sponge to buffer volume variation, resulting in high structural stability. The in situ polymerized bPOD coating and it-driven thin LiF-rich SEI layer remarkably improve the lithium storage performance of Si anodes, showing a high reversible specific capacity of 1600 mAh g-1 even after 500 cycles at 1 A g-1 along with excellent rate capacity of over 1500 mAh g-1 at 3 A g-1 . It should be noticed that a long cycle life of 800 cycles with 1065 mAh g-1 at 3 A g-1 can also be achieved with a capacity retention of more than 80%. Therefore, we believe this unique polymer coating design paves the way for the widespread adoption of next-generation lithium-ion batteries.
RESUMEN
A new fluorescent cytosine analog "tsC" containing a trans-stilbene moiety was synthesized and incorporated into hemiprotonated base pairs that comprise i-motif structures. Unlike previously reported fluorescent base analogs, tsC mimics the acid-base properties of cytosine (pKa ≈ 4.3) while exhibiting bright (ε × Φ ≈ 1000 cm-1 M-1) and red-shifted fluorescence (λem = 440 â 490 nm) upon its protonation in the water-excluded interface of tsC+:C base pairs. Ratiometric analyses of tsC emission wavelengths facilitate real-time tracking of reversible conversions between single-stranded, double-stranded, and i-motif structures derived from the human telomeric repeat sequence. Comparisons between local changes in tsC protonation with global structure changes according to circular dichroism suggest partial formation of hemiprotonated base pairs in the absence of global i-motif structures at pH = 6.0. In addition to providing a highly fluorescent and ionizable cytosine analog, these results suggest that hemiprotonated C+:C base pairs can form in partially folded single-stranded DNA in the absence of global i-motif structures.
Asunto(s)
Citosina , Humanos , Concentración de Iones de Hidrógeno , Citosina/química , Secuencia de Bases , Emparejamiento Base , Dicroismo Circular , Conformación de Ácido NucleicoRESUMEN
BACKGROUND: Renal surface nodularity (RSN) is a subclinical biomarker of renal injury and may be associated with arterial hypertension. PURPOSE: To explore the association of RSN with arterial hypertension compared to normotensive patients. MATERIAL AND METHODS: A total of 205 inpatients with or without high blood pressure (HBP vs. control group) who underwent abdominal computed tomography (CT) scans were included. Their clinical characteristics included age, sex, HBP course, HBP grade, history of diabetes mellitus (DM), and renal function (estimated glomerular filtration rate [eGFR]). The HBP group included HBP/+DM and HBP/-DM based on the presence or absence of DM. The CT-based RSN grade was scored from 0 to 2 by two radiologists, respectively, where RSN grade 0 indicated smooth renal surface, grade 1 was mild RSN, and grade 2 was marked RSN. RESULTS: The inter-rater agreement on RSN was good (Kappa = 0.76). The age-specific rate of RSN grade 1-2 was bigger in the HBP group than in the control group (42.86% [40%-49.22%] vs. 2.18% [0.00%-22.5%]; P = 0.005). RSN grade was associated with HBP course (P < 0.02). The rates of RSN grade 1-2 and of RSN grade 2 were bigger in the HBP/+DM group than those in the HBP/-DM group (48.84% vs. 37.84%, and 18.61% vs. 1.35%, respectively; all P = 0.001). Neither HBP course nor HBP grade correlated with rate of RSN grade (P > 0.05). The eGFR was similar among the RSN grades in HBP or between the HBP and control groups (P > 0.05). CONCLUSION: RSN was associated with HBP compared to normotensive patients.
Asunto(s)
Hipertensión , Humanos , Hipertensión/complicaciones , Hipertensión/diagnóstico por imagen , Presión Sanguínea/fisiología , Riñón/diagnóstico por imagen , Riñón/fisiología , BiomarcadoresRESUMEN
Herein, we report a novel renewable pH-responsive starch-based flocculant (CIAT-ST) via etherifying 2-chloro-4,6-isopropylamino-[1,3,5]-triazine (CIAT) onto the starch backbones for decontamination and reuse of highly saline effluents. The obtained CIAT-ST shows a unique pH-sensibility and reversibility in response to a subtle pH change due to a pH-controllable surface charge density of polymer chains. The level of residual CIAT-ST in the solution can be facilely monitored by using UV-vis detection. The dye flocculation performance of CIAT-ST was evaluated by using a batch experiment. The results exhibited that the dye removal was highly dependent on the solution pH (optimal pH was 2), the flocculation equilibrium can be achieved within 5 min, and the maximum flocculation capacity of CIAT-ST for K-2BP and KN-B5 were calculated to be 2452.6 ± 23.9 and 792.7 ± 14.1 mg/g, respectively. The multiple flocculation mechanisms, including charge neutralization, bridging and charge patching, may participate in the flocculation process. Adjustment in pH-mediated hydrophilicity-hydrophobicity switch of flocculant facilitates readily recovery and then sequentially reused three times while retaining satisfying flocculation efficiency. A significant contribution was also confirmed that the highly saline effluents after flocculation and sedimentation were reused in three successive dyeing processes without sacrificing fabric quality (ΔE* < 1) due to relatively low polymer residuals, and the efficiency of salt reuse for consecutive regeneration processes could be achieved above 85%. The present work could provide alternative thoughts for the reutilization of spent flocculant and clarified saline wastewater, which is also an efficient and sustainable strategy for textile wastewater management.
Asunto(s)
Almidón , Aguas Residuales , Floculación , Concentración de Iones de Hidrógeno , TextilesRESUMEN
Ganoderma, as a Chinese traditional medicine, has multiple bioactivities. However, industrial production was limited due to low yield during Ganoderma fermentation. In this work, sucrose was found to greatly enhance intracellular polysaccharide (IPS) content and specific extracellular polysaccharide (EPS) production rate. The mechanism was studied by analyzing the activities of enzymes related to polysaccharide biosynthesis. The results revealed that sucrose regulated the activities of phosphoglucomutase and phosphoglucose isomerase. When glucose and sucrose mixture was used as carbon source, biomass, polysaccharide and ganoderic acids (GAs) production was greatly enhanced. A sucrose fed-batch strategy was developed in 10-L bioreactor, and was scaled up to 300-L bioreactor. The biomass, EPS and IPS production was 25.5, 2.9 and 4.8 g/L, respectively, which was the highest biomass and IPS production in pilot scale. This study provides information for further understanding the regulation mechanism of Ganoderma polysaccharide biosynthesis. It demonstrates that sucrose fed-batch is a useful strategy for enhancing Ganoderma biomass, polysaccharide and GAs production.
Asunto(s)
Biomasa , Reactores Biológicos , Polisacáridos Fúngicos/biosíntesis , Reishi/crecimiento & desarrollo , Triterpenos/metabolismoRESUMEN
To expand the selection of raw material for fabricating extracorporeal membrane oxygenation (ECMO) and promote its application in lung disease therapy, polyether ether ketone hollow fiber membrane (PEEK-HFM) with designable pore characteristics, desired mechanical performances, and excellent biocompatibility was selected as the potential substitute for existing poly (4-methyl-1-pentene) hollow fiber membrane (PMP-HFM). To address the platelet adhesion and plasma leakage issues with PEEK-HFM, a natural anticoagulant heparin was grafted onto the surface using ultraviolet irradiation. Additionally, to explore the substitutability of the heparin layer while considering cost and scalability, a heparin-like layer composed of copolymers of acrylic acid and sodium p-styrenesulfonate was also constructed on the surface of PEEK-HFM Even though the successful grafting of heparin and heparin-like layers on the PEEK-HFM surface reduced the pore parameters, improvements in surface hydrophilicity also prevented the platelet-adhesion phenomenon and improved the anticoagulant behaviour, making it a viable alternative for commercial PMP-HFMs in ECMO production. Furthermore heparin-modified and heparin-like modified PEEK-HFMs demonstrated similar performance, indicating that synthetic layers can effectively replace natural heparin. This study holds practical and instructive significance for future research and the application of membranes in the development of oxygenators.
Asunto(s)
Benzofenonas , Oxigenación por Membrana Extracorpórea , Heparina , Membranas Artificiales , Polietilenglicoles , Polímeros , Heparina/química , Oxigenación por Membrana Extracorpórea/métodos , Polímeros/química , Polietilenglicoles/química , Humanos , Adhesividad Plaquetaria/efectos de los fármacos , Cetonas/química , Materiales Biocompatibles/química , Permeabilidad , Ensayo de Materiales , Aire , AnimalesRESUMEN
The dilemma of employing high-capacity battery materials and maintaining the electrodes' electrical and mechanical integrity requires a unique binder system design. Polyoxadiazole (POD) is an n-type conductive polymer with excellent electronic and ionic conductive properties, which has acted as a silicon binder to achieve high specific capacity and rate performance. However, due to its linear structure, it cannot effectively alleviate the enormous volume change of silicon during the process of lithiation/delithiation, resulting in poor cycle stability. This paper systematically studied metal ion (i.e., Li+, Na+, Mg2+, Ca2+, and Sr2+)-crosslinked PODs as silicon anode binders. The results show that the ionic radius and valence state remarkably influence the polymer's mechanical properties and the electrolyte's infiltration. Electrochemical methods have thoroughly explored the effects of different ion crosslinks on the ionic and electronic conductivity of POD in the intrinsic and n-doped states. Attributed to the excellent mechanical strength and good elasticity, Ca-POD can better maintain the overall integrity of the electrode structure and conductive network, significantly improving the cycling stability of the silicon anode. The cell with such binders still retains a capacity of 1770.1 mA h g-1 after 100 cycles at 0.2 C, which is â¼285% that of the cell with the PAALi binder (620.6 mA h g-1). This novel strategy using metal-ion crosslinking polymer binders and the unique experimental design provides a new pathway of high-performance binders for next-generation rechargeable batteries.
RESUMEN
PURPOSE: Patients with chronic hepatitis B (CHB) remain at risk for hepatocellular carcinoma during antiviral therapy. We aimed to clarify the values of alpha-fetoprotein (AFP), lectin-reactive fraction of AFP (AFP-L3), and des-γ-carboxyprothrombin (DCP) for early warning of HCC. METHODS: A total of 1348 CHB patients received antiviral therapy and follow-up every 26 weeks. Eighty-four patients with HCC were age-, sex-, and cirrhosis-matched with 168 controls. AFP, AFP-L3, and DCP were compared between the groups from 104 weeks before HCC diagnosis (- 104 w) to the time of diagnosis (0 w). RESULTS: Of the 84 HCC patients, 60 (71.4%) had early-stage HCC, AFP increased from - 26 w, and AFP-L3 and DCP increased from - 78 w. However, levels were unchanged in controls. ΔAFP, ΔAFP-L3, and ΔDCP showed similar abilities for predicting HCC (P > 0.05). Receiver operating characteristic curve analysis showed that AFP had better diagnostic performance for HCC than AFP-L3, DCP, or their combination. The cut-off values of AFP, AFP-L3, and DCP were 5.3 ng/mL, 1.05%, and 31.5 mAU/mL, respectively. Notably, lower AFP values were required to diagnose HCC in patients with detectable HBV DNA (4.1 ng/mL) or elevated alanine aminotransferase (5.2 ng/mL). CONCLUSIONS: Changes in AFP, AFP-L3, and DCP can help to predict HCC in CHB patients receiving antiviral therapy. A lower AFP value is needed to diagnose HCC, especially in patients with detectable HBV DNA or elevated alanine aminotransferase.
RESUMEN
The application effect of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) based on the improved fuzzy C-mean clustering (GA-PFCM) algorithm in analyzing premenopausal and postmenopausal invasive breast carcinoma was discussed. 159 patients with breast carcinoma were selected and divided into the postmenopausal group (71 patients) and the premenopausal group (88 patients) according to their menstrual status. The magnetic resonance images of the two groups were processed and analyzed using GA-PFCM algorithm, and the imaging characteristics and relevant parameters of DCE-MRI examination of the two groups were analyzed. Besides, the sensitivity, specificity, and accuracy of the diagnosis of invasive breast carcinoma by DCE-MRI examination were investigated. The results showed that the percentage of patients with lobulated lumps, patients with burrs on lesion edge, and patients with uniformly enhanced tumors in the premenopausal group was larger than that in the postmenopausal group (P < 0.05). In the postmenopausal group, TCI of 33 patients was shown as platform curves, and that of 34 patients was shown as outflow curves. In the premenopausal group, TCI of 39 patients was shown as platform curves, and that of 41 patients was shown as outflow curves with a high proportion. The number of patients with peak height time ranging between 130 s and 260 s and of patients with early signal enhancement rate ranging between 100% and 200% was large. In contrast, the number of patients with ADC value higher than 1.2 × 10-3 was the least. In this research, there were 128 patients with positive invasive breast carcinoma and 31 with negative invasive breast carcinoma by pathological examination. Based on DCE-MRI examination, there were 121 patients with positive invasive breast carcinoma and 38 with negative invasive breast carcinoma. The sensitivity, specificity, and accuracy of invasive breast carcinoma by DCE-MRI were 91.41%, 87.1%, and 90.57%, respectively. In addition, the positive and negative predictive values reached 96.69% and 71.05%, respectively. In summary, GA-PFCM algorithm can be applied in the processing and segmentation of DCE-MRI images, and DCE-MRI could better diagnose invasive breast carcinoma with positive guiding value.
Asunto(s)
Neoplasias de la Mama , Medios de Contraste , Algoritmos , Neoplasias de la Mama/diagnóstico , Análisis por Conglomerados , Imagen de Difusión por Resonancia Magnética/métodos , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Menopausia , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
Highly-efficient separation of adsorbent and pollutant from chemical sludge is urgent for the recycled materials and chemical resources and minimization of sludge production in industry. Herein, an effortless and cost-efficient salt/water system is developed for efficient zwitterionic polymer/dye separation from chemical sludge. To achieve this aim, a novel salt-tolerant zwitterionic polymer (STZP) is synthesized through etherifying 2-chloro-4,6-bis(4-carboxyphenyl amino)-1,3,5-triazine onto corn starch. It is found that "all-surface-area" adsorption of dye can be achieved by in-situ sol-gel transition of STZP. Spent polymer fluid and solid-state dye can be easily regenerated and separated from sewage sludge by a simple salt/water system. At a high NaCl concentration (225 g/L), the separation factor between zwitterionic polymer and dye is up to 50.4, which is 50 times larger than that of salt-free solution. More importantly, the regenerated polymer fluids exhibit an outstanding reusability ability and can maintain over 92.8% decoloration efficiency for dyeing effluent after multiple adsorption-desorption cycles. This study thus provides a technically feasible and economically acceptable strategy for the recycling and reuse of polymer from hazardous textile sludge waste, greatly promising to achieve zero emissions toward conventional adsorption units.
Asunto(s)
Industria Textil , Contaminantes Químicos del Agua , Adsorción , Colorantes , Polímeros , Aguas del Alcantarillado , AguaRESUMEN
Objective: To evaluate the early chemotherapy response in patients with lung cancer using semiquantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Methods: Twenty-two patients with lung cancer treated with chemotherapy were subjected to DCE-MRI at two time points: before starting treatment and after one week of therapy. The image data were collected by DCE-MRI, and the semiquantitative parameters including positive enhancement integral (PEI), signal enhancement ratio (SER), maximum slope of increase (MSI), and time to peak (TTP) were calculated. After chemotherapy, the parameters and relevant variations between the responders and nonresponders were compared with Mann-Whitney U tests. Student's t-test for paired samples was used to evaluate the temporal changes between pre- and posttreatment images. Results: The patients were categorized as 13 responders and 9 nonresponders based on the tumor response evaluation. After chemotherapy, the PEI, SER, and MSI were significantly increased in responders compared with the pretreatment values (P < 0.05), while no obvious decrease in TTP was observed (P > 0.05). However, 9 nonresponders showed no significant changes in PEI, SER, MSI, and TTP values, as compared with those of pretreatment (P > 0.05). Moreover, the increase of PEI was more dramatically in responders than in nonresponders (P < 0.05), but no significantly differences were observed in SER, MSI, and TTP (P > 0.05). Conclusion: Semiquantitative analysis of DCE-MRI could provide a reliable noninvasive method for assessing early chemotherapy response in lung cancer patients.
Asunto(s)
Aumento de la Imagen , Neoplasias Pulmonares , Medios de Contraste , Humanos , Aumento de la Imagen/métodos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/tratamiento farmacológico , Imagen por Resonancia Magnética/métodosRESUMEN
OBJECTIVE: To assess the value of helical CT in the diagnosis of liver diseases. METHODS: 59 patients with different liver diseases were examined by two-phase or multi-phase dynamic helical CT. RESULTS: Small hepatocellular carcinoma showed a higher density in the arterial phase, and a lower density in the portal vein phase. Large hepatic carcinoma showed a mixed pattern of higher-density in the arterial phase, and a lower density in the portal vein phase. Metastasis carcinoma showed an "oxeye sign" in the portal vein phase. Hemangioma was not obviously enhanced in the early arterial phase, marginally enhanced in the arterial phase, and equally-densed in the balanced phase. CONCLUSION: Two-phase helical CT is of value in improving the detection rate of or determining the features of hepatic diseases by two-phase helical dynamic scan (2.0-3.0 ml/s speed, and delay time 25-30 s and 70-85 s).
Asunto(s)
Carcinoma Hepatocelular/diagnóstico por imagen , Carcinoma/diagnóstico por imagen , Carcinoma/secundario , Hemangioma/diagnóstico por imagen , Neoplasias Hepáticas/diagnóstico por imagen , Tomografía Computarizada Espiral , Adulto , Anciano , Femenino , Neoplasias de la Vesícula Biliar/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Invasividad Neoplásica/diagnóstico por imagenRESUMEN
The destruction of DDT formulations and DDT contaminated soil was conducted by feeding wastes into the flue gas chamber at the kiln inlet of two different preheater/precalciner cement kilns in China. The concentration of DDT, PCDD/PCDFs and HCB were measured in the flue gas of the main stack, in the solid material under baseline conditions and when feeding DDT-wastes. The destruction efficiency and the destruction and removal efficiency for DDT were in the range of 99.9335%-99.9998% and 99.9984%-99.9999%, respectively. The emissions of PCDD/PCDFs and HCB in the flue gas varied in the range of 0.0019-0.0171 ng I-TEQ/Nm(3) and 0.0064-0.0404 µg/Nm(3), respectively. The emission factor for PCDD/PCDF and HCB varied from 0.0137 to 0.0281 µg/ton and from 17.32 to 109.34 µg/ton of clinker, respectively. The concentration of PCDD/PCDFs and HCB in solid samples decreased as follows: cement kiln dust, 4.1-5 ng I-TEQ/kg and 0.70-0.71 µg/kg, respectively; >raw meal, 0.82-0.97 ng I-TEQ/kg and 0.18 µg/kg, respectively; >cement clinker, 0.09-0.22 ng I-TEQ/kg and 0.14-0.18 µg/kg, respectively. This study indicates that the feeding of DDT and POPs-wastes to the lower temperature part of a cement kiln system possibly to create a buildup of trace not-destroyed compounds in the system and might cause emissions; the technical feasibility and the environmental acceptability of this practice need to be investigated thoroughly.
Asunto(s)
DDT/química , Restauración y Remediación Ambiental/métodos , Incineración , Contaminantes del Suelo/química , China , DDT/análisis , Contaminantes del Suelo/análisisRESUMEN
Medical waste is one special kind of hazardous wastes. If mishandled, it could cause disease spread and secondary pollution of dioxin. China produced huge amount medical wastes due to large population. Through a decade, medical waste centralized disposal sector rapidly developed with both incineration and non-incineration technology. With fully consideration advanced foreign technology, a set of Best Available Technology system of China gradually formed suitable for Chinese national conditions. This article placed emphasis on best available technology system of medical wastes centralized incineration facilities, and analyzed the application of technique retrofit of medical wastes centralized incineration facilities incorporated with case study.
RESUMEN
Based on the requirement of National Implementation Plan for the Stockholm Convention on Persistent Organic Pollutants (NIP), six industries including pulp and paper industry have been set as the priority key sectors to implement the best available technology and best environmental practice (BAT/BEP) within a specific time for UPOPs reduction. Non-wood pulping has always played important role in virgin pulp production in China, its elemental chlorinated bleaching process has been confirmed as main source of Dioxin emission for the sector. As the signature party of Stockholm Convention and long time existing country of non-wood pulping, identification of Dioxin emission situation is significant importance to China to committee the obligation of Stockholm Convention. The Dioxin concentrations in outflow water of bamboo, straw, reed, and bagasse pulping processes (chlorination alkaline extraction hypochlorite, CEH) are 41.8 pg x L(-1), 72.7 pg x L(-1), 7.46 pg x L(-1), and 19.7 pg x L(-1) respectively, which are all around the national waste water discharge standard (30 pg x L(-1)). But relevant data will easily exceed national standard while the limitation of unit water consumption for pulp making is decreased. So the application of best available techniques/best environmental practices (BAT/BEP) is very necessary to improve relevant mills up to the above standard, and proceed the sector meeting the national and international requirements for Dioxin emission. At the same time, the text calculates emission factors on bamboo, straw, reed and bagasse pulp making process through whole process monitoring, which will provide meaningful reference for increasing relevant factors in UNEP Toolkit.