Transport of functional group modified polystyrene nanoplastics in binary metal oxide saturated porous media.

Metal oxides exist in porous media in the form of composite metal oxides, which can significantly affect the transport and transformation of pollutants in the soil environment. In this study, binary metal oxide porous media were prepared to explore the effects of solution chemistry, and the presence of binary metal oxides on the transport of functional group modified polystyrene nanoplastics (PSNPs) in saturated porous media. The results show that the existence of binary metal oxides significantly affects the migration ability of PSNPs in saturated porous media. The increase of ionic strength and the presence of multivalent cations affect the transport capacity of PSNPs in porous media. The types of binary metal oxides affect the migration of PSNPs in saturated porous media. The surface roughness and electrostatic interaction are important factors affecting the retention of PSNPs on the surface of binary metal oxide saturated porous media. The surface morphology has a more far-reaching impact. In addition, DLVO theory cannot fully explain the interaction between PSNPs and saturated porous media in the presence of Al3+. This study's results help provide some theoretical support for the migration of microplastics in the soil environment.

Transport of degradable/nondegradable and aged microplastics in porous media: Effects of physicochemical factors.

The degradable properties of degradable plastics allow them to form microplastics (MPs) faster. Therefore, degradable MPs may easily be transported in the underground environment. Research on degradable MPs transport in porous media is necessary and urgent. In this study, polylactic acid (PLA) and polyvinyl chloride (PVC) were selected to compare the transport differences between degradable and nondegradable MPs under different factors (flow rates, ionic strengths (ISs), pH, and coexisting cations) through column experiments, and UV irradiation was used to further simulate the effect of aging on different types of MPs. Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to characterize functional groups and to determine the surface elements of MPs, respectively. The results showed that MPs were more mobile at higher flow rate, lower IS, higher pH, and monovalent cations. The order of transport capacity of MPs was PVC < aged PVC < PLA < aged PLA. This result was mainly attributed to the more negative Zeta potential and higher dispersion stability of aged PLA and PLA, which were caused by abundant O-functional groups. Compared with PVC, the O/C ratio of PLA increased significantly after aging, indicating that PLA was more prone to aging. The advection-dispersion-equation (ADE) fitted the transport data of MPs well. The interaction energy of MPs and quartz sand was accurately predicted by the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. This work contributes to a comprehensive understanding of the transport of degradable MPs in the environment.

Interactions of pristine and aged nanoplastics with heavy metals: Enhanced adsorption and transport in saturated porous media.

Interactions of nanoplastics (NPs) with other contaminants are attracting attention, and it is essential to investigate the interaction of aged plastics with heavy metals. We obtained aged nanopolystyrene by UV radiation and investigated the effects of aged NPs on the adsorption and cotransport of Pb-(II) and Cd-(II). The results showed that the UV-aged NPs led to the enhanced adsorption capacity of heavy metals due to the increase in oxygen-containing functional groups, and the promotion of transport by the aged NPs to heavy metals was stronger than that of the pristine NPs. Furthermore, the heavy metals retained in the columns could be freed by the NPs, and the aged NPs were more capable of freed of heavy metals as carriers. In conclusion, the radiation of NPs is correlated with their ability to promote heavy metal transport, and the oxygen content on the surface of NPs plays an essential role in this process to promote the transport of heavy metals in porous media. The ADR equation and DLVO theory simulates the transport behaviour of NPs well. This study is expected to provide a new perspective for assessing the potential risk of aged NPs in soil-groundwater systems.

Removal of Pb (II) and V (V) from aqueous solution by glutaraldehyde crosslinked chitosan and nanocomposites.

In this paper, new adsorbents with high mechanical strength chitosan-graphene oxide (CS-GO) and chitosan-titanium dioxide (CS-TiO2) were synthesized by using glutaraldehyde as crosslinking agent, and the adsorption behavior of Pb (II) and V (V) on them were investigated. The materials were characterized by scanning electron microscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The effects of initial metal ion concentration and contact time on the removal of V (V) and Pb (II) by CS-GO and CS-TiO2 were investigated. Characterization results showed that the hydroxyl group of GO/TiO2 reacted with the amino group of chitosan. A comparison of the kinetic models against experimental data showed that the kinetics react system was best described by the pseudo-second-order model. indicating that chemical adsorption was the main adsorption force. the Langmuir adsorption model and Freundlich model agreed well with the experimental data. The removal capacity of Pb (II) by CS-GO and CS-TiO2 were lower than those of V (V). The uncross-linked -OH and CO were the main adsorptive sites for Pb (II) removal, while uncross-linked -OH and -NH2 played an important role in removing V (V). These findings provided insights on the removing lead and vanadium pollution.

Novel Zn-Fe engineered kiwi branch biochar for the removal of Pb(II) from aqueous solution.

In this study, a novel adsorbent made from kiwi branch biochar modified with Zn-Fe (KB/Zn-Fe) was compared with original biochar to the Pb(II)'s adsorptivity from waste water. The adsorbent was synthetized by liquid-phase deposition. Batches of sorption tests were performed, and the biochars' representative properties were tested. Characterizations revealed the physicochemical properties of biochars and showed that the KB/Zn-Fe composites were successfully synthesized. The Langmuir model and pseudo-second-order kinetic model were proven to satisfactorily fit the original biochar and KB/Zn-Fe. The KB/Zn-Fe showed Langmuir maximum adsorption ability to Pb (II) in aqueous solution of 161.29 mg g-1, compared with 36.76 mg g-1 for original biochar. The adsorption ability of Pb(II) decreased and the Pb(II) removal efficiency increased with increasing biochar dose. The effect of co-existence of NO3- to the absorptive capacity of KB/Zn-Fe on Pb(II) was unremarkable, but Cl- could increase the absorptive capacity. Multiple Pb(II) adsorption mechanisms by KB/Zn-Fe include surface precipitation of metal hydroxides, complexation with active functional groups and ion-exchange. This work provides guidance for future production of biochar with efficient adsorption ability, which could be used to remove Pb(II) ions from wastewater.

Efficient removal of Cd (II) from aqueous solution by chitosan modified kiwi branch biochar.

Production of cost-efficient composite materials from low-cost modified biochar for the removal of Cd (II) from wastewater is much needed to meet the growing needs of industrial wastewater treatments. A novel chitosan-modified kiwi branch biochar (CHKB) was fabricated as low-cost modified biochar for the removal of Cd (II) from aqueous solution. Batch adsorption and characterization experiments indicated that the modification of kiwi biochar (KB) by chitosan remarkably improved its adsorption performance. The results revealed that the adsorption isotherms can be best described by a Langmuir model and that a pseudo-second-order model fits the Cd (II) adsorption kinetics well, which indicates that it is a monolayer process controlled by chemisorption. CHKB exhibited a Langmuir maximum adsorption capacity of Cd (II) (126.58 mg g-1), whereas that of KB was only 4.26 mg g-1. The adsorption ability of CHKB was improved by increasing the surface area and an abundance of surface functional groups (-OH, -NH, CO, etc.). The cation exchange, electrostatic interaction, surface complexation, and precipitation were the main mechanisms in the sorption of Cd (II) on CHKB. Excellent adsorption performance, low cost, and environmental-friendliness made CHKB a fantastic adsorbent for the removal of Cd (II) in wastewater.

Effects of physicochemical factors on the transport of aged polystyrene nanoparticles in saturated porous media.

Plastic debris, particularly nanoplastics, have attracted substantial attention as an emerging pollutant of global concern. The aging process caused by UV could dramatically alter the physicochemical properties of polystyrene plastics and affect their fate and transport in the subsurface environment. We researched the effects of diverse factors, including flow rate, ionic strength (IS), and cation valence on the transport of aged polystyrene nanoparticles (PSNPs) in saturated porous media and found that their mobility was greatly enhanced by the aging process at all other experimental conditions except coexistence with Al3+. Interestingly, we found that the aged PSNPs were polymerized due to the coexistence with Al3+, which led the aged PSNPs to exhibit weaker mobility than the pristine. Zeta potential and particle size measurements, FTIR spectroscopy, and XPS were employed to characterize the PSNPs, and the results suggest that UV radiation provides O-containing functional groups for the PSNPs. The experimental results correspond well with the ADR model and the values of Smax and k closely reflect the deposition of the PSNPs in sand columns. Moreover, the Derjaguin-Landau-Verwey-Overbeek (DLVO) theoretical calculation accurately reflects the interaction of the pristine and aged PSNPs and quartz sand. Overall, due to the processes that PSNPs possibly undergo in the environment, their mobility may fluctuate dramatically. These findings help remedy knowledge deficiency regarding nanoplastic mobility being affected by aging processes, further underscore the critical influence of the aging process on the potential risks and environmental fates of nanoplastics.

Calcium Carbonate@silica Composite with Superhydrophobic Properties.

In this paper, spherical calcium carbonate particles were prepared by using CaCl2 aqueous solution + NH3·H2O + polyoxyethylene octyl phenol ether-10 (OP-10) + n-butyl alcohol + cyclohexane inverse micro emulsion system. Then, nanoscale spherical silica was deposited on the surface of micron calcium carbonate by Stöber method to form the composite material. Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and structure of the composite material. It is found that the surface of the composite material has a micro-nano complex structure similar to the surface of a "lotus leaf", making the composite material show hydrophobicity. The contact angle of the cubic calcium carbonate, spherical calcium carbonate and CaCO3@SiO2 composite material were measured. They were 51.6°, 73.5°, and 76.8°, respectively. After modification with stearic acid, the contact angle of cubic and spherical CaCO3 were 127.1° and 136.1°, respectively, while the contact angle of CaCO3@SiO2 composite was 151.3°. These results showed that CaCO3@SiO2 composite had good superhydrophobicity, and the influence of material roughness on its hydrophobicity was investigated using the Cassie model theory.

Dual feedback based bipolar current source with high stability for driving voice coil motors in wide temperature ranges.

Bipolar current sources with a stability better than 0.1% in the temperature range of -30 to +70 °C are demanded for driving voice coil motors applied in a new ultra-quiet satellite platform, but almost none of the existing designs satisfy the harsh requirements. This paper presents a possible solution, which is essentially a floating-load, bipolar current source circuit with a dual feedback path. The key circuit is a composite amplifier (co-amp) composed of a high precision amplifier for error correction and a high power amplifier for load driving. The first feedback path comprises a specially designed four-wire current-sense resistor for current-to-voltage conversion and a discrete instrumentation amplifier for amplifying the converted voltage and closing the loop. The second feedback path is a proposed compensation network for loop stability. Error budgets for evaluating current stability and choosing key components of the circuit are comprehensively studied based on a derived rigorous current equation. Loop-stability problems attributable to the inductive load and the high open-loop gain of the co-amp are analyzed, and the proposed dual feedback compensation method is verified by theory, simulation, and measurement. All these contributions are demonstrated by three implemented prototypes with an output of up to ±2 A. The measured results agree well with theoretical predictions. The best and the worst stability performances of the three prototypes at +2 and -2 A are, respectively, 394 and 986 ppm in the temperature range of -30 to +70 °C, which are close to the theoretical value of 776 ppm.

Effect of surfactants on the transport of polyethylene and polypropylene microplastics in porous media.

The transport of microplastics in porous media is attracting increasing attention. However, to date, research is limited to polystyrene microplastics. Meanwhile, surfactants can promote solid dispersion to form a stable suspension, possibly allowing microplastics to migrate when attached to a surfactant, which would increase the scope and degree of microplastic pollution, further endangering human health and the stability of the ecological environment. Therefore, in this study, the transport behavior of microplastics in porous media was explored in the presence of surfactants. Herein, polyethylene (PE) and polypropylene (PP) were evaluated while dispersed by two ionic surfactants: cationic surfactant-cetyltrimethylammonium bromide (CTAB) and anionic surfactant-sodium dodecylbenzenesulfonate (SDBS). The influence of different factors (surfactant concentration, ionic strength, pH, flow rate, and multivalent cations) on the transport of microplastics in porous media was explored via quartz sand packed-column experiments. Our experimental results show that the transport abilities of PE and PP increased with increasing surfactant concentration when the surfactant concentration was less than the critical micelle concentration (CMC). In the presence of CTAB and SDBS, physicochemical factors had different effects on the transport of microplastics mainly by controlling Zeta potential, advection diffusion and CMC. The mobility of PE and PP decreased with increasing ionic strength, cation valence and pH, and decreasing flow rate. However, the mobility of PE and PP under CTAB is much greater than that of PE and PP under SDBS, because quartz sand can absorb more CTAB molecules through electrostatic attraction to weaken the collision between microplastics and quartz sand. Further, the transport ability of PP was greater than that of PE under all conditions considered. Notably, the Extended-Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory formed by adding osmotic, elastic, and hydrophobic force could well described the migration behavior of microplastics in CTAB and SDBS well. This research highlights that surfactant has a significant impact on the transport ability of microplastics, and provides a comprehensive understanding of the migration and fate behaviors of microplastics affected by surfactants, which is necessary to prevent and reduce the environmental hazards of microplastics.

Preparation, characterization and application of CS@PDA@Fe3O4 nanocomposite as a new magnetic nano-adsorber for the removal of metals and dyes in wastewater.

This study aimed to develop a novel magnetic chitosan/dopamine/Fe3O4 nano-adsorber (CS@PDA@Fe3O4) for the removal of heavy metal ions and organic dye molecules from aqueous solution. CS@PDA@Fe3O4 was prepared by surface modification of PDA/Fe3O4 nanoparticles with chitosan using IPTES as the cross-linker. The surface structure, composition, and properties of the CS@PDA@Fe3O4 nano-adsorber were characterized by elemental (EDS), spectroscopic (XRD, XPS, and FT-IR), magnetic intensity (VSM), surface and morphological (TEM and SEM) analyses. In order to study its adsorption behavior, equilibrium and kinetics studies were carried out through batch experiments. Additionally, the influences of the pH value, initial concentration, adsorbent dose, and contact time were also evaluated. The CS@PDA@Fe3O4 nano-adsorber exhibited high adsorption capacity especially for Cu(ii), with a maximum adsorption capacity of 419.6 mg g-1. The experimental data were well described by the Langmuir isotherm kinetic models.

Pinewood outperformed bamboo as feedstock to prepare biochar-supported zero-valent iron for Cr6+ reduction.

In this work, pinewood and bamboo were pyrolyzed at 600 °C to prepare PBC and BBC-supported zerovalent iron (ZVI), respectively. Raman spectra suggested PBC was more intensively carbonized than BBC as indicated by higher ID/IG ratio. XRD and TEM confirmed nanoscaled ZVI was well dispersed in PBC but soldered in chain-structure in BBC. Maximal chromate (Cr(VI)) sorption capacity followed the order of PBC/ZVI (5.93 g kg-1)>BBC/ZVI (3.61 g kg-1)>BBC (3.55 g kg-1)>PBC (2.59 g kg-1). Desorption and XPS of four Cr-spent sorbents suggested reduction accounted for 79-88% of overall Cr(VI) detoxification. Greater Cr(VI) reduction of BBC than PBC indicated greater tendency of BBC to donate electrons. However, Cr(VI) reduction by PBC/ZVI was 1.7 times greater than BBC/ZVI, corresponding to greater electron transfer of PBC/ZVI (2.5 µA e-) than BBC/ZVI (0.5 µA e-). Thus, PBC is more conducible to transfer electrons as evidenced by Tafel and Amperometric analyses. Demineralization of pristine BC enhanced the difference between PBC/ZVI and BBC/ZVI regarding Cr(VI) reduction, suggesting the dominant role of biopolymers in biomass in terms of electron transfer capacity. Three model biopolymers were compared which indicated lignin-BC had lower electron transfer rates than cellulose-BC and hemicellulose-BC. BC prepared by lignin extracted from pinewood exhibited higher corrosion rate and lower electrical resistance than that from bamboo. Thus, unfavorable lignin in bamboo compromised electron transfer of BBC and Cr(VI) reduction by BBC/ZVI.

The transport of graphitic carbon nitride in saturated porous media: Effect of hydrodynamic and solution chemistry.

Understanding transport behavior of graphitic carbon nitride (g-C3N4) in porous media plays an important role in preventing its possible causing the underground environmental problems. The transport behavior of g-C3N4 in porous media were investigated by packed column experiments at different flow rates, ionic strengths (ISs), pHs and multivalent cations. The experimental results showed that the transport ability of g-C3N4 decreased with the IS increasing, and most of the g-C3N4 was retained in the sand column for the IS greater than 0.0001 M. The flow rate had little effect on the transport behavior of g-C3N4, and the recovery of g-C3N4 increased slightly with increasing flow rate. In addition, the migration ability of g-C3N4 under acidic conditions was drastically reduced compared with neutral alkaline conditions. Moreover, it was found that 1.51%, 30.33%, 34.91%, and 60.54% of g-C3N4 was retained in the column when g-C3N4 was leached through the quartz sand column at Al3+, Ca2+, Mg2+, and K+, which was consistent with the Schulze-Hardy rule. Finally, FTIR spectrum showed that the infrared absorption peak of the g-C3N4 mixed quartz sand were shifted to certain degrees under different conditions, which confirmed that hydrogen bond was formed in the transport of carbon nitride with the quartz sand surface. This study provides a new perspective on the role of hydrogen bond in the transport and fate of nanomaterials.

Co-transport of Pb(II) and oxygen-content-controllable graphene oxide from electron-beam-irradiated graphite in saturated porous media.

It is essential to investigate the role of the surface oxygen content of graphene oxide (GO) in transport processes. In this study, GO was prepared using flake graphite with different radiation doses. The effects of the flow rate and ionic strength (IS) on the migration and co-transport of GO and Pb(II) ions were investigated via laboratory packed-column experiments. The experimental results showed that the mobility of GO in saturated porous media decreased with increasing flow rate. Further, the mobility of GO with a radiation dose of 18 kGy was lower than that of GOs with other radiation doses for an IS below 0.01 M. Regarding the co-transport of irradiated GO and Pb(II) in porous media, the greater the radiation dose, the stronger was the ability of GO to promote Pb(II) transport. The surface oxygen content promoted the ability of GO to remove Pb(II). However, radiation doses exceeding a certain range inhibited the release of Pb(II). The transport of GO in saturated porous media was successfully simulated with the advection-dispersion-reaction (ADR) equation. This study is expected to provide a new perspective on the potential risks of GO due to surface changes during its transport in the environment.

Co-transport of graphene oxide and heavy metal ions in surface-modified porous media.

The ability to predict the transport of heavy metal ions in porous media with different surface characteristics is crucial to protect groundwater quality and public health. In this study, the effects of graphene oxide (GO) on co-transport and remobilization of Pb2+ and Cd2+ in humic acid (HA), smectite, kaolinite, and ferrihydrite-coated sand media were evaluated via laboratory packed-column experiments. Scanning electron microscope and energy dispersive X-ray analysis showed that the surface morphology of the coated sands was quite different and that ∼56.7-89.9% of the surface was covered by the coating and the major elemental components were C, O, Si, Al, and Fe. GO exhibited high mobility in HA, kaolinite, and smectite-coated sand, but showed high retention in ferrihydrite-coated sand. While GO reduced the transport of Pb2+ and Cd2+, both metal ions also reduced the mobility of GO in coated-sand columns. Elution experiments revealed that GO led to the remobilization and release of the previously sorbed Pb2+ and Cd2+ from the coated sand. However, GO could not release Pb2+ and Cd2+ from smectite-coated sand columns, probably because smectite has stronger adsorption affinity to the heavy metals than GO. Derjaguin-Landau-Verwey-Overbeek calculations were employed and explained the GO transport behavior in the columns well. Furthermore, the advection-dispersion-reaction equation simulated the cotransport of Pb2+ and Cd2+ with GO in the coated sand well. These results are expected to provide insight into the potential impact of coexisting nanomaterials with contaminants in vulnerable soil and groundwater systems.

Removal of V (V) and Pb (II) by nanosized TiO2 and ZnO from aqueous solution.

The removal of V (V) and Pb (II) by TiO2 and ZnO nanoparticles from aqueous solution was studied with batch experiments. Atomic force microscopy (AFM), fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface properties including functional groups of the adsorbent as well as to explore adsorption mechanisms. Factors influencing V (V) and Pb (II) removal such as initial metal ion concentration and contact time were investigated. The kinetics of V (V) and Pb (II) removal occurred quickly and > 90% of the metals was removed within 30 min for both nanoparticles. Maximum adsorption of V (V) and Pb (II) onto TiO2 and ZnO nanoparticles was observed at temperature of 298 K and pH 6.5 ±â€¯0.1. The removal characteristics of the metals by the two nanoparticles were similar. A comparison of the kinetic models against experimental data showed that the kinetics react system was best described by the pseudo-second-order model. V (V) and Pb (II) reacted with functional groups, which led to the formation of polytype Pb-O bond and hydroxyl-vanadium complexes. The experimental data also confirmed the formation of heavy metal-OH sorption complexes on the adsorbent surfaces. This research enhanced current understanding of the removal of V (V) and Pb (II) by nanosized TiO2 and ZnO from contaminated water.

Graphene oxide-facilitated transport of Pb2+ and Cd2+ in saturated porous media.

This paper provides an overview of the effect of graphene oxide (GO) on sorption, transport, and remobilization of Pb2+ and Cd2+ ions in saturated porous media. The affinity of GO to Pb2+ and Cd2+ ions was investigated via kinetic and isothermal sorption experiments. Laboratory packed-column experiments were also conducted to investigate the cotransport of Pb2+ and Cd2+ ions with GO across a quartz sand matrix. In addition, the Pb2+- and Cd2+-preequilibrated sand column was sequentially flushed with GO to test its remobilization effect on these ions. GO exhibited a high affinity toward both Pb2+ and Cd2+ ions with maximum sorption capacities of 1428.57 and 911.43mgg-1, respectively. On the other hand, while GO improved the transport ability of Pb2+ and Cd2+, both ions reduced the mobility of GO in saturated porous media. Data from the elution experiment revealed that the high affinity of GO toward the metal ions led to the remobilization of the presorbed Pb2+ and Cd2+ ions onto the quartz sand surfaces and their concurrent migration across the sand column. XDLVO (Extended Derjaguin-Landau-Verwey-Overbeek) calculations were employed to interpret the GO transport behavior in the column wells. The cotransport of Pb2+ and Cd2+ ions with GO in the saturated quartz sand was successfully simulated by the advection-dispersion-reaction equation. Findings from this study provide an insight on the potential implications of remobilization and spread of pollutants by nanomaterials existing in vulnerable ecosystems.

Carboxymethyl cellulose stabilized ZnO/biochar nanocomposites: Enhanced adsorption and inhibited photocatalytic degradation of methylene blue.

Biochar(BC)-supported nanoscaled zinc oxide (nZO) was encapsulated either with (nZORc/BC) or with no (nZOR/BC) sodium carboxymethyl cellulose (CMC). The X-ray diffraction and ultraviolet (UV)-visible-near infrared spectrophotometry revealed that nZO of 16, 10, and 20 nm with energy band gaps of 2.79, 3.68 and 2.62 eV were synthesized for nZOR/BC, nZORc/BC and nZO/BC, respectively. The Langmuir isotherm predicted saturated sorption of methylene blue (MB) was 17.01 g kg-1 for nZORc/BC, over 19 times greater than nZOR/BC and nZO/BC. Under UV irradiation, 10.9, 61.6, 83.1, and 41.6% of MB were degraded for nZORc/BC, nZO/BC, nZOR/BC and BC. The scavenging experiment revealed hydroxyl radical dominated CMC degradation. Exogenous CMC (2 g L-1) increased MB sorption from 10.6% to 73.1%, but decreased MB degradation from 80.7% to 41.1%, relative to nZOR/BC. Thus, CMC could increase MB sorption by electrostatic attraction and other possible mechanisms. The compromised MB degradation may be ascribed to reduced availability of hydroxyl and superoxide radicals to degrade MB, and increased band gap energy of ZnO.

Analysis of epithelial-mesenchymal transition markers in the histogenesis of hepatic progenitor cell in HBV-related liver diseases.

BACKGROUND: The origin and heterogeneity of hepatic progenitor cells (HPCs) remain unclear. This study aimed to investigate the involvement of epithelial-mesenchymal transition (EMT) in the histogenesis of HPCs. METHODS: Surgical liver specimens from patients with HBV-related hepatitis and cirrhosis were investigated with double immunofluorescence labeling to detect antigens associated with HPCs and EMT. Ductular reactions were subjected to quantitative reverse transcription PCR following isolation by laser capture microdissection. Electron microscopic examination was performed to find an ultrastructural evidence of EMT. RESULTS: The number of EpCAM-positive HPCs was proportional to the disease severity. The S100A4 expression of HPCs was firstly observed in mild hepatitis and increased significantly in moderate hepatitis, but decreased in severe hepatitis and cirrhosis. The levels of MMP-2, Twist, and Snail increased in direct proportion to the number of HPCs. Some hepatocytes adjacent to portal tracts in cirrhosis showed positivity for MMP-2. Although CK7 and E-cadherin levels decreased in mild and moderate hepatitis, HPCs re-expressed both of them in severe hepatitis and cirrhosis. However, HPCs expressed neither vimentin nor αSMA. The relative mRNA expression levels of EpCAM and EMT-associated markers supported immunohistochemical results. Electron microscopic examination demonstrated the existence of intercellular junctions among HPCs, cholangiocytes, and intermediate hepatocyte-like cells. CONCLUSION: We provided preliminary evidence for the involvement of EMT in the histogenesis of HPCs from cholangiocytes in HBV-related liver diseases. HPCs may re-transdifferentiate into hepatocytes, and the differentiation direction depends, at least in part, on interactions between HPCs and the surrounding microenvironment, especially the non-resolving inflammation caused by HBV infection.

Cutaneous clear cell/signet-ring cell squamous cell carcinoma arising in the right thigh of a patient with type 2 diabetes: combined morphologic, immunohistochemical, and etiologic analysis.

BACKGROUND: The clear cell/signet-ring cell variant of cutaneous squamous cell carcinoma (cSCC) is extremely rare. Its carcinogenesis has consistently been linked to ultraviolet radiation and HPV in the literature. However, there is little definite information about the contribution of diabetes mellitus (DM) to cSCC. CASE PRESENTATION: A 78-year-old Chinese woman with type 2 DM presented with a mushroom-like lump in her right thigh. Histological findings revealed that the lesion was mainly composed of clear cells and signet-ring cells. The septa of vacuoles in cytoplasm displayed positivity for periodic acid schiff (PAS) and cytokeratins such as AE1/AE3, CK5/6, CK14, and CK19. Malignant cells did not express CK7, CK8, CK18, CK20, p16, p53, or c-erbB-2, and the Ki-67 index was less than 5 %. We further explored the etiology of clear cell/signet-ring cell cSCC using human papillomavirus (HPV) type-specific PCR and genotyping and confirmed that the patient was not infected with HPV. Nucleus positivity for p63 indicated the involvement of the p53 family in the lesion. Meanwhile, the expression of fibroblast growth factor receptor-2 (FGFR2), a downstream effector of p63, was upregulated in tumor cells. CONCLUSIONS: This study provides the first report on the clear cell/signet-ring cell variant of cSCC found in the right thigh of a patient with type 2 DM. Metabolic imbalance in addition to conventional pathogens such as UV and HPV may contribute to the development of the lesion via p63/FGFR2 axis.