X-ray-induced piezoresponse during X-ray photon correlation spectroscopy of PbMg1/3Nb2/3O3

X-ray photon correlation spectroscopy (XPCS) holds strong promise for observing atomic-scale dynamics in materials, both at equilibrium and during non-equilibrium transitions. Here an in situ XPCS study of the relaxor ferroelectric PbMg1/3Nb2/3O3 (PMN) is reported. A weak applied AC electric field generates strong response in the speckle of the diffuse scattering from the polar nanodomains, which is captured using the two-time correlation function. Correlated motions of the Bragg peak are also observed, which indicate dynamic tilting of the illuminated volume. This tilting quantitatively accounts for the observed two-time speckle correlations. The magnitude of the tilting would not be expected solely from the modest applied field, since PMN is an electrostrictive material with no linear strain response to the field. A model is developed based on non-uniform static charging of the illuminated surface spot by the incident micrometre-scale X-ray beam and the electrostrictive material response to the combination of static and dynamic fields. The model qualitatively explains the direction and magnitude of the observed tilting, and predicts that X-ray-induced piezoresponse could be an important factor in correctly interpreting results from XPCS and nanodiffraction studies of other insulating materials under applied AC field or varying X-ray illumination.

[Current status of oral health literacy and its influencing factors among adult orthodontic patients]

PURPOSE

To investigate the current status of oral health literacy among adult orthodontic patients and analyze its influencing factors.

METHODS

Totally 163 adult orthodontic patients were recruited by convenience sampling method from November 2021 to February 2022 at the Department of Oral and Craniomaxillofacial Surgery, Center of Craniofacial Orthodontics in Shanghai Ninth People's Hospital. General information questionnaire, Chinese version of Health Literacy in Dentistry (HeLD-14), Chinese version of Self-Efficacy Scale for Self-care (SESS) and Social Support Rating Scale (SSRS) were applied. SPSS 21.0 software package was used for data analysis.

RESULTS

The mean score of oral health literacy in adult orthodontic patients was (48.74±5.54), and the lowest score were obtained in concern (6.80±1.19) and support (6.40±1.59) dimensions. Multiple stepwise regression analysis showed that adult orthodontic patients' consultation self-efficacy, social support utilization, family or friends' orthodontic history and objective support were the influencing factors of oral health literacy.

CONCLUSIONS

The oral health literacy in adult orthodontic patients is at a middle to high level, but concern and support literacy need to be improved. Strengthening consultation self-efficacy, objective support and utilization of social support can improve adult orthodontic patients' oral health literacy. Attention should be paid to patients who have no relatives or friends with history of orthodontic treatment.

[Research progress of vitamin D in inflammatory skin disease]

It is well known that vitamin D is engaged in calcium and phosphorus metabolism. However, vitamin D also plays an important role in other aspects over the past decades, such as immune response. Vitamin D has thus aroused the interest of the scientific community, especially the field of dermatology. The major source of vitamin D comes from the exposure of the skin to ultraviolet B. In turn, vitamin D regulates the proliferation and differentiation of keratinocytes, prevents opportunistic infection, and regulates the inflammatory response and immune response of the skin. Acne, psoriasis, atopic dermatitis, and other inflammatory skin diseases have been found to have a certain relationship with vitamin D. This article review the correlation between vitamin D and inflammatory skin diseases.

Structure, Antiferroelectricity and Energy-Storage Performance of Lead Hafnate in a Wide Temperature Range

Lead hafnate (PbHfO₃) has attracted a lot of renewed interest due to its potential as antiferroelectric (AFE) material for energy storage. However, its room temperature (RT) energy-storage performance has not been well established and no reports on the energy-storage feature of its high-temperature intermediate phase (IM) are available. In this work, high-quality PbHfO₃ ceramics were prepared via the solid-state synthesis route. Based on high-temperature X-ray diffraction data, the IM of PbHfO₃ was found to be orthorhombic, Imma space group, with antiparallel alignment of Pb²⁺ ions along the [001]_cubic directions. The polarization-electric field (P-E) relation of PbHfO₃ is displayed at RT as well as in the temperature range of the IM. A typical AFE loop revealed an optimal recoverable energy-storage density (W_rec) of 2.7 J/cm³, which is 286% higher than the reported data with an efficiency (η) of 65% at 235 kV/cm at RT. A relatively high W_rec value of 0.7 J/cm³ was found at 190 °C with an η of 89% at 65 kV/cm. These results demonstrate that PbHfO₃ is a prototypical AFE from RT up to 200 °C, making it a suitable material for energy-storage applications in a wide temperature range.

First-in-class Microbial Ecosystem Therapeutic 4 (MET4) in combination with immune checkpoint inhibitors in patients with advanced solid tumors (MET4-IO trial)

BACKGROUND

The intestinal microbiome has been associated with response to immune checkpoint inhibitors (ICIs) in humans and causally implicated in ICI responsiveness in animal models. Two recent human trials demonstrated that fecal microbiota transplant (FMT) from ICI responders can rescue ICI responses in refractory melanoma, but FMT has specific limitations to scaled use.

PATIENTS AND METHODS

We conducted an early-phase clinical trial of a cultivated, orally delivered 30-species microbial consortium (Microbial Ecosystem Therapeutic 4, MET4) designed for co-administration with ICIs as an alternative to FMT and assessed safety, tolerability and ecological responses in patients with advanced solid tumors.

RESULTS

The trial achieved its primary safety and tolerability outcomes. There were no statistically significant differences in the primary ecological outcomes; however, differences in MET4 species relative abundance were evident after randomization that varied by patient and species. Increases in the relative abundance of several MET4 taxa, including Enterococcus and Bifidobacterium, taxa previously associated with ICI responsiveness, were observed and MET4 engraftment was associated with decreases in plasma and stool primary bile acids.

CONCLUSIONS

This trial is the first report of the use of a microbial consortium as an alternative to FMT in advanced cancer patients receiving ICI and the results justify the further development of microbial consortia as a therapeutic co-intervention for ICI treatment in cancer.

[Comparison of high-flow nasal cannula oxygen therapy and non-rebreather face mask in the treatment of mild carbon monoxide poisoning]

Objective: To compare the efficacy of high-flow nasal cannula oxygen therapy (HFNC) and non-rebreather face mask (NRFM) in the treatment of mild acute carbon monoxide poisoning (ACOP) in reducing carboxyhemoglobin (COHb) , and to explore the feasibility of HFNC in the treatment of ACOP. Methods: Patients with mild ACOP with COHb >10% who were admitted to the emergency department of Northern Jiangsu People's Hospital from January 2015 to December 2020 were analyzed, and those with altered consciousness, mechanical ventilation and those requiring hyperbaric oxygen therapy were excluded. The patients were divided into HFNC group and NRFM group according to the oxygen therapy used in the emergency department. The COHb decline value and COHb half-life in the two groups were observed. Results: Seventy-one patients were enrolled, including 39 in the NRFM group and 32 in the HFNC group. The baseline COHb in the HFNC group was 24.8%±8.3%, and that in the NRFM group was 22.5%±7.1%, with no significant difference between the two groups (t=1.27, P=0.094) . At 60 min, 90 min and 120 min of treatment, COHb in both groups decreased, but the COHb in HFNC group was lower than that in NRFM group at the same time point (P<0.05) . After 1 h of treatment, the COHb decrease in the HFNC group (16.9%±4.5%) was significantly higher than that in the NRFM group (10.1%±7.8%) (t=4.32, P=0.013) . The mean half-life of COHb in the HFNC group (39.3 min) was significantly lower than that in the NRFM group (61.4 min) (t=4.69, P=0.034) . Conclusion: HFNC treatment of mild ACOP can rapidly reduce blood COHb level, it is a potential oxygen therapy method for clinical treatment of ACOP.

[Research advances in the use of dynamic navigation technology for implantation in the edentulous jaw]

The use of dynamic navigation technology in edentulous jaw implant restoration can solve many problems associated with traditional edentulous jaw implant restoration. The benefits of dynamic navigation include fine positioning guidance, restoration-guided surgery, good aesthetic results, and the possibility of simultaneous conceptual design and real-time implant guidance, as well as the transition from "blind" to "direct" vision during the implantation. It can guide clinicians and adjust the plan in real time, improve the efficiency of communication between the clinician, technician, and patient throughout the process and so on. The workflow, current clinical application and challenges, accuracy analysis, and limitations of the dynamic navigation technology in the edentulous jaw are discussed in this paper, as well as an outlook on its future development, with the goal of contributing to the clinical development of dynamic navigation-guided implantology in the edentulous jaw.

Active and passive defects in tetragonal tungsten bronze relaxor ferroelectrics

Tetragonal tungsten bronze (TTB) based oxides constitute a large family of dielectric materials which are known to exhibit complex distortions producing incommensurately modulated superstructures as well as significant local deviations from their average symmetry. The local deviations produce diffuse scattering in diffraction experiments. The structure as well as the charge dynamics of these materials are anticipated to be sensitive to defects, such as cation or oxygen vacancies. In this work, in an effort to understand how the structural and charge dynamical properties respond to these two types of vacancy defects, we have performed measurements of dielectric susceptibilities and single crystal diffraction experiments of two types of TTB materials with both 'filled' (Ba₂NdFeNb₄O₁₅and Ba₂PrFeNb₄O₁₅) and 'unfilled' (Sr_0.5Ba_0.5Nb₂O₆) cation sublattices. We also perform these measurements before and after oxygen annealing, which alters the oxygen vacancy concentrations. Surprisingly, we find that many of the diffuse scattering features that are present in the unfilled structure are also present in the filled structure, suggesting that the random fields and disorder that are characteristic of the unfilled structure are not responsible for many of the local structural features that are reflected in the diffuse scattering. Oxygen annealing clearly affected both color and dielectric properties, consistent with a diminishment of the oxygen vacancy concentration, but had little effect on observed diffuse patterns.

[Characteristics and risk factors of functional constipation in children aged 0-4 years in Xi 'an]

Objective: To investigate the epidemiology, characteristics and risk factors of functional constipation (FC) in children aged 0-4 years in Xi'an. Methods: From October, 2020 to June, 2021, a prevalence survey was conducted among 2 615 children aged 0-4 years in Xi'an by group sampling. The related factors of FC were investigated by questionnaire designed based on Rome Ⅳ diagnostic criteria.The children were divided into FC group and non-FC group. The prevalence, symptoms and signs of FC were analyzed, and its risk factors were analyzed by multivariate Logistic regression. Results: A total of 2 985 valid questionnaires were handed out, and 2 711 (90.8%) were received back. A total of 2 615 questionnaires were valid, with an effective rate of 96.5%. There were 1 338 males (51.2%) and 1 277 females (48.8%). There were 260 cases in FC group and 2 355 cases in non-FC group. The prevalence of FC in children aged 0-4 years in Xi 'an was 10.6%.There were significant differences in FC prevalence among children of different ages and sex (χ²=14.58,4.39, both P<0.05), but not in urban or rural residence (χ²=3.29, P=0.070). The main symptoms of FC group in the last month were large-diameter feces (73.5%, 191/260), painful defecation or dry and hard defecation (65.8%, 171/260). In the last month, FC group had higher incidences of the Bristol type 1, 2 and 3 stool, fecal retention, prolonged defecation, abdominal pain and incomplete defecation compared with non-FC group, with statistical significance (all P<0.05). Parental history of childhood constipation (OR=2.13, 95%CI 1.55-2.92), fever in the last month (OR=1.86, 95%CI 1.32-2.63), history of constipation (OR=3.24, 95%CI 2.46-4.26) and taking probiotics in the last month (OR=1.45, 95%CI 1.11-1.91) were risk factors of FC in children aged 0-4 years. Stratified with age, the results showed that complementary feeding earlier than 5 months of age or later than 6 months of age (OR=2.42, 95%CI 1.13-5.20), dry stools during the complementary feeding (OR=11.27, 95%CI 5.15-24.66), history of constipation (OR=2.29, 95%CI 1.23-4.29) and taking probiotics in the last month (OR=1.88, 95%CI 1.10-3.23) were risk factors of FC in children aged 0-<1 year, and breastfeeding (OR=0.53, 95%CI 0.29-0.94) was a protective factor of FC in children aged 0-<1 year. Family members' recent constipation history (OR=2.02, 95%CI 1.06-3.85) and past history of constipation (OR=3.06, 95%CI 1.74-5.38) were FC risk factors for children aged 1-<2 years. Parental history of childhood constipation (OR=3.12, 95%CI 2.00-4.85), frequency of eating vegetables less than 3 times per week (OR=3.28, 95%CI 2.00-5.38), history of constipation (OR=3.66, 95%CI 2.42-5.53) and taking antibiotics in the last month (OR=1.65, 95%CI 1.06-2.55) were risk factors for FC in children aged 2-4 years. Conclusions: FC in children aged 0-4 years in Xi'an is mainly manifested with large-diameter feces and painful defecation or dry and hard defecation in the last month. It is associated with a variety of risk factors, which are different in different age groups.

[Analysis of cerebral blood perfusion changes in patients with unilateral sudden sensorineural hearing loss based on three-dimensional pseudo-continuous arterial spin labeling]

Objective: To explore the changes of cerebral blood perfusion in patients with unilateral sudden sensorineural hearing loss (SSNHL) by using the three-dimensional pseudo-continuous arterial spin labeling (3D pCASL) technique. Methods: The clinical characteristics and ASL data of the 32 patients with unilateral SSNHL were retrospectively collected from November 2020 to June 2021 in Beijing Fuxing Hospital of Capital Medical University, among them, there were 7 males and 25 females, aged from 17 to 73 (44.9±14.4) years. According to the location of SSNHL, they were divided into the left SSNHL (L-SSNHL) group (18 cases) and the right SSNHL (R-SSNHL) group (14 cases). A total of 34 healthy volunteers, which including 14 males and 20 females, aged from 24 to 68 (46.2±14.4) years were enrolled from the local community. The parameter of cerebral blood flow (CBF) of each brain area was obtained using the CereFlow software. The Brainnetome Atlas software package based on MATLAB was used for visualization. The independent-samples t test was conducted to compare the difference of cerebral blood perfusion between the unilateral SSNHL group and healthy control (HC) group. Pearson correlation analysis was used to evaluate the correlation between changes in cerebral blood perfusion and clinical scale scores. Results: The CBF of left orbital gyrus part 5, left inferior temporal gyrus part 7, right orbital gyrus part 5, right inferior temporal gyrus part 1, right inferior temporal gyrus part 7, and right parahippocampal gyrus part 3 of the L-SSNHL group were higher than that in the HC group[(49.1±8.8) vs (31.6±10.9)ml·100g^-1·min^-1;(42.8±14.3) vs (27.1±13.6)ml·100g^-1·min^-1;(51.8±9.4) vs (27.2±11.2)ml·100g^-1·min^-1;(38.8±5.7) vs (28.0±9.2)ml·100g^-1·min^-1;(38.4±13.8) vs (23.6±10.3)ml·100g^-1·min^-1;(42.4±9.4) vs (30.1±12.6)ml·100g^-1·min^-1; all P<0.05]. The CBF of left superior frontal gyrus part 7 and left middle frontal gyrus part 3 of the L-SSNHL group were lower than that in the HC group[(48.2±7.9) vs (59.3±13.7)ml·100g^-1·min^-1;(46.4±10.3) vs (59.3±16.9)ml·100g^-1·min^-1;all P<0.05]. The CBF of left orbital gyrus part 5, right orbital gyrus part 5, right inferior temporal gyrus part 1, and right inferior temporal gyrus part 7 of the R-SSNHL group were higher than that in the HC group[(50.6±7.0) vs (31.6±10.9)ml·100g^-1·min^-1;(50.9±8.8) vs (27.2±11.2)ml·100 g^-1·min^-1;(38.0±7.2) vs (28.0±9.2)ml·100g^-1·min^-1;(35.7±8.5) vs (23.6±10.3)ml·100g^-1·min^-1;all P<0.05]; the CBF of right insular part 4 was lower than that in the HC group [(44.2±6.1) vs (54.4±11.3) ml·100 g^-1·min^-1, P=0.018]. In the L-SSNHL group, the CBF of left superior frontal gyrus part 7 and right orbital gyrus part 5 were negatively correlated with the VAS score(r=-0.83, -0.81, all P<0.05), and the CBF of right orbital gyrus part 5 was negatively correlated with the THI score(r=-0.75, P=0.013). There was no statistically significant correlation between the remaining differences in brain regions and clinical scale scores(all P>0.05). Conclusion: Changes in cerebral blood perfusion in multiple brain regions were found in patients with unilateral SSNHL by using the 3D pCASL technique.

[Analysis of information needs of patients with dentofacial deformities at different stages of treatment]

PURPOSE

To investigate the treatment experience and information needs of patients with dentofacial deformities in the process of surgical program design, surgical treatment and postoperative rehabilitation.

METHODS

Thirty-six patients with dentofacial deformities at different treatment stages from March to July 2019 were selected for semi-structured interview. Colaizzi content analysis method and QSR NVivo 12.0 software were used to analyze and code the data, as well as extract the theme and genus.

RESULTS

Three themes and eight categories were extracted, including① information needs in different treatment stages, mainly specific content of information needs at pre-operative preparation stage, orthognathic perioperative stage and post-operative rehabilitation stage; ② information support methods, i.e., diversified information support methods and patients' recognition of internet information;③ patients' cognition difference,namely the difference between patients' psychological expectation and the results of operation.

CONCLUSIONS

Due to the treatment characteristics of orthognathic surgery and individual cognitive differences of patients, there is a large demand for information support at different stages of treatment. However, the current information support mode is limited, so it is necessary to further improve and provide scientific, professional and targeted information support for patients with dentofacial deformities.

Synthesis and characterization of bulk Nd1-x Sr x NiO2 and Nd1-x Sr x NiO3

The recent reports of superconductivity in Nd_1-x Sr _x NiO₂/SrTiO₃ heterostructures have reinvigorated interest in potential superconductivity of low-oxidation state nickelates. Synthesis of Ni¹⁺-containing compounds is notoriously difficult. In the current work, a combined sol-gel combustion and high-pressure annealing technique was employed to prepare polycrystalline perovskite Nd_1-x Sr _x NiO₃ (x = 0, 0.1, and 0.2). Metal nitrates and metal acetates were used as starting materials, and the latter were found to be superior to the former in terms of safety and reactivity. The Nd_1-x Sr _x NiO₃ compounds were subsequently reduced to Nd_1-x Sr _x NiO₂ using calcium hydride in a sealed, evacuated quartz tube. To understand the synthesis pathway, the evolution from NdNiO₃ to NdNiO₂ was monitored using in situ synchrotron x-ray diffraction during the reduction process. Electrical transport properties were consistent with an insulator-metal transition occurring between x = 0 and 0.1 for Nd_1-x Sr _x NiO₃. Superconductivity was not observed in our bulk samples of Nd_1-x Sr _x NiO₂. Neutron diffraction experiments at 3 and 300 K were performed on Nd_0.9Sr_0.1NiO₂, in which no magnetic Bragg reflections were observed, and the results of structural Rietveld refinement are provided.

[Qualitative study on the decision-making of orthognathic surgery in adult patients with malocclusion]

PURPOSE

The main purpose of this study was to explore the experience associated with patient's decision to have or not have orthognathic treatment.

METHODS

Phenomenological methodology was used in this study. Ten patients were collected from January 2018 to March 2018, who were consulted in the Department of Oral and Craniomaxillofacial Surgery, Center of Craniofacial Orthodontics in Shanghai Ninth People's Hospital. They were interviewed by semi-structured, face to face in-depth interviews. Data were organized and analyzed by Colaizzi methods.

RESULTS

By reading, analysis and extraction, two topics, i.e, motivation and interference factor were obtained.

CONCLUSIONS

The treatment information service was limited. Further research is needed to improve the information services that support the treatment decision of malocclusion patients and help them to make the best choice.

Active tuning of directional scattering by combining magneto-optical effects and multipolar interferences

An efficient route is proposed to actively manipulate directional scattering based on magneto-optical (MO) effects and multipolar interferences with a coated MO cylinder. We demonstrate that the presence of an external magnetic field B contributes to breaking the degeneracy of multipoles and making them rotate. The rotated modes further interfere with each other, thus reshaping scattering profiles and introducing novel directional optical switching (OS) phenomena. As a result, we show that forward scattering (FS) and backward scattering (BS) can be flexibly altered by turning on or off the B for both s-polarization and p-polarization, and optical switching exhibits broadband performance as well. More specifically, the proposed nanostructure also operates robust and reliable functionalities when considering realistic MO materials with optical loss and dispersion; therefore, they are ideal candidates to develop reconfigurable, tunable and versatile optical devices.

Polarization management based on dipolar interferences and lattice couplings

We have achieved efficient polarization manipulations based on dipolar interferences and lattice couplings in one-dimensional cylindrical metalattices. First, we employ the scattering asymmetry factor g to quantify the directional scattering ability and find the maximum |g|_max=1/2 for a cylinder with effective excitations of electric and magnetic dipoles simultaneously. Further, the strong negative-g (gp = -0.38) for p-polarization and positive-g (gs = 0.68) for s-polarization are obtained within a narrow visible band using c-Si with experimental data. Inspired by the polarization-dependent phenomena, we design a metalattice-based linear polarizer considering lattice effects with an optimal particle arrangement. The metalattice performs near-perfect reflection for p-polarized waves but with zero reflection for s-polarized waves with large extinction ratios for transmission (17 dB) and reflection (24 dB). The perfect functionalities can be attributed to the near-field lattice couplings with dipolar interferences. And, we reveal that the polarization-dependent scattering coefficients, which are sensitive to the lattice period, can be largely tuned owing to lattice effects, therefore contributing to modifying far-field scattering patterns. More specifically, the proposed linear polarizers also show robust and reliable functionalities when considering lattice imperfections, the effects of system sizes, oblique incident angles, and the tunbility for different working wavelengths. The present study paves a way to stimulate many advanced practical implements based on multipolar interferences and lattice couplings.

[Gene cloning and prokaryotic expression of glycosyltransferase from Ligustrum quihoui]

According to the previous results from transcriptome analysis of Ligustrum quihoui, a glycosyltransferase gene(xynzUGT) was cloned by rapid amplification of cDNA ends(RACE). The full length cDNA of xynzUGT was 1 598 bp, consisting of 66 bp 5'-UTR, 1 440 bp ORF and 92 bp 3'-UTR. The ORF encoded a 480 amino-acid protein(xynzUGT) with a molecular weight of 54 826.67 Da and isoelectric point of 5.82. The structure of enzyme was analyzed by using bioinformatics method, the results showed that the primary structure contained a highly conserved PSPG box of glycosyltransferase, the secondary structure included α helix(38%), β sheet(12.1%) and random coil(49.9%), and tertiary structure was constructed by peptide chain folding to form two face-to-face α/β/α domains(often referred to as a Rossmann domains), between which a substrate binding pocket is sandwiched. The phylogenetic tree analysis indicated that xynzUGT might catalyze glycosylation of phenylpropanoids, such as tyrosol. Further simulation experiment of molecular docking between enzyme and tyrosol showed that Gly138 and Ser285 located in the binding pocket interacted with tyrosol by hydrogen bonding. SDS-PAGE analysis exhibited that the prokaryotic expression system successfully expressed recombinant xynzUGT with molecular weight of 58 370.57 Da, but it exists in the form of non-soluble inclusion bodies. Using the molecular chaperone and enzyme co-expression method, the soluble expression was promoted to some extent. The above works laid the foundation for further studying on enzymatic reaction in vitro and clarifying the functional mechanism of enzyme.

Design of metasurface polarizers based on two-dimensional cold atomic arrays

Engineering light-matter interaction using cold atomic arrays is one of the central topics in modern optics. Here we have demonstrated the capability of two-dimensional asymmetric cold atomic arrays as microscopic metasurfaces for controlling polarization states of light. The designed linear polarizer can lead to an extinction ratio over 20dB as well as a high transmittance over 0.8 for the permitted polarization at zero detuning. For detuned driving light, changing lattice constants can also achieve high performance linear polarizers. We have also accomplished a circular polarizer by manipulating the phases of transmitted light. A theoretical analysis based on Bloch theorem shows the underlying mechanism for this performance is actually attributed to cooperative effects in periodic lattices. Finally, we discuss in detail the effects of system size, lattice imperfection and nonzero driving light linewidth in practical implementation. The present study paves a way to design extremely miniaturized metasurfaces using cold atoms and other two-level systems, showing great potential in quantum information and quantum metrology sciences as well as the fundamental physics of light-matter interaction.

[The effect of tanshinone ⅡA potentiates the effects of Cisplatin in Fadu cells in vitro through downregulation of survivin]

Objective:The aim of this study is to investigate the inhibitory effect and mechanism of tanshinone ⅡA combined with cisplatin on tumor Fadu cells in pharyngeal squamous cell carcinoma. Method:Cytotoxicity was determined by CCK8 assay. Flow cytometry was used to detect apoptosis and cell cycle distribution. Western blotting was used to assess the protein expression of related signaling proteins. Result:Compared with the two single drug groups treated with Tan ⅡA and DDP respectively, the combination group showed significantly higher anti-proliferative rate (P<0.01), arrested cell cycle at S phase, and resulted in observably higher apoptotic cell fractions in human hypopharyngeal squamous cell carcinomas Fadu cells; Western blotting showed that the protein expression of cleaved caspase 3 and cleaved PARP increased ,while survivin significantly decreased in the cells treated with the combination of tanshinone ⅡA and cisplatin. Conclusion:Tanshinone ⅡA potentiates the efficacy of Cisplatin in Fadu cells, which may be attributed to the downregulation of survivin protein expression.

Designing ultrabroadband absorbers based on Bloch theorem and optical topological transition

In this Letter, we propose a method to design ultrabroadband near-perfect absorbers, consisting of a periodic dielectric-metal multilayer. In the method, the Bloch theorem and optical topological transition (OTT) of iso-frequency surfaces are employed to manipulate the start and end of the near-perfect spectral absorption band, respectively. Moreover, we design and fabricate an ultrabroadband near-perfect absorber utilizing the proposed method. The average absorption of the designed absorber is ∼95% in the focused visible and near-infrared range (0.4-2 μm). This omnidirectional and polarization-independent near-perfect absorber is promising for solar energy harvesting, emissivity control, and thermal imaging.

Néel-like domain walls in ferroelectric Pb(Zr,Ti)O3 single crystals

In contrast to the flexible rotation of magnetization direction in ferromagnets, the spontaneous polarization in ferroelectric materials is highly confined along the symmetry-allowed directions. Accordingly, chirality at ferroelectric domain walls was treated only at the theoretical level and its real appearance is still a mystery. Here we report a Néel-like domain wall imaged by atom-resolved transmission electron microscopy in Ti-rich ferroelectric Pb(Zr_1−xTi_x)O₃ crystals, where nanometre-scale monoclinic order coexists with the tetragonal order. The formation of such domain walls is interpreted in the light of polarization discontinuity and clamping effects at phase boundaries between the nesting domains. Phase-field simulation confirms that the coexistence of both phases as encountered near the morphotropic phase boundary promotes the polarization to rotate in a continuous manner. Our results provide a further insight into the complex domain configuration in ferroelectrics, and establish a foundation towards exploring chiral domain walls in ferroelectrics.

Flexible rotation of spontaneous polarization at ferroelectric domain walls is predicted in theory but lacks evidence from experiment. Here, Wei et al. image a Néel-like domain wall in Ti-rich ferroelectric Pb(Zr_1−xTi_x)O₃ crystals, providing insight in exploring chiral domain walls in ferroelectrics.

Effects of Forage:Concentrate Ratio on Growth Performance, Ruminal Fermentation and Blood Metabolites in Housing-feeding Yaks

The objective of this study was to determine the effect of forage: concentrate ratio (F:C) on growth performance, ruminal fermentation and blood metabolites of housing-feeding yaks. Thirty-two Maiwa male yaks (initial body weight = 207.99±3.31 kg) were randomly assigned to four dietary treatments (8 yaks per treatment). Experimental diets were: A, B, C, D which contained 70:30, 60:40, 50:50 and 40:60 F:C ratios, respectively. Dry matter intake and average daily gain in yaks fed the C and D diets were greater (p<0.05) than yaks fed the A and B diets. No differences were found in ruminal NH₃-N, total volatile fatty acids, acetate, butyrate, valerate, and isovalerate concentrations. The propionate concentration was increased (p<0.05) in the C and D groups compared with the A and B diets. In contrast, the acetate to propionate ratio was decreased and was lowest (p<0.05) in the C group relative to the A and B diets, but was similar with the D group. For blood metabolites, no differences were found in serum concentrations of urea-N, albumin, triglyceride, cholesterol, low density lipoprotein, alanine aminotransferase, and aspartate aminotransferase (p>0.05) among treatments. Treatment C had a higher concentration of total protein and high density lipoprotein (p<0.05) than A and B groups. In addition, there was a trend that the globulin concentration of A group was lower than other treatments (p = 0.079). Results from this study suggest that increasing the level of concentrate from 30% to 50% exerted a positive effect on growth performance, rumen fermentation and blood metabolites in yaks.

[Effects of aluminum stress on ecophysiological characteristics of male and female Populus cathayana seedlings]

This paper studied the sex-specific differences of male and female Populus cathayana seedlings in their ecophysiological characteristics and photosynthesis under the stress of aluminum (216 mg Al(3+) x kg(-1)). Under the effects of aluminum, the malonaldehyde (MDA) and soluble protein (Pr) contents of the male and female seedlings increased significantly (P < 0.001), and the males had a significantly lower MDA content and a significantly higher Pr content than the females. The peroxidase (POD) activity of the males increased but the superoxide dismutase (SOD) activity decreased significantly, while the POD and SOD activities of the females had no significant variation. The net photosynthetic rate (Pn) of both male and female seedlings decreased significantly (P = 0.001), and the transpiration rate (Tr) of the female seedlings decreased (P = 0.007) and the instant water use efficiency (WUEi) increased significantly, while no significant variations were observed in the Tr and WUEi of the male seedlings. The total chlorophyll and chlorophyll a contents and chlorophyll a/b ratio of the females decreased significantly, resulting in a significantly higher chlorophyll a/b ratio of the males. The specific leaf area (SLA) of the females decreased but that of the males increased significantly. No significant variation was observed on the leaf- and stem dry mass. Comparing with the females, the males had higher Pr and chlorophyll contents and higher active antioxidant enzymes activity to maintain higher Pn, and thus, had greater resistance against aluminum stress.

Steroidal saponins from Dioscorea panthaica and their cytotoxic activity

A new steroidal saponin, dioscoreside E (1), and a known compound, protodioscin (2), were isolated from an ethanol extract of the rhizomes of Dioscorea panthaica. The structure of 1 was established as 3-O-[bis-alpha-L-rhamnopyranosyl-(1 --> 2 and 1 --> 4)-beta-D-glucopyranosyl]-26-O-beta-D-glucopyranosyl-20(R)-methoxy-25(R)-furosta-5,22(23)-diene-3beta,26-diol, on the basis of spectral and chemical evidence. Compounds 1 and 2 showed cytotoxic activity against a panel of tumor cell lines.

Two new steroidal saponins from the rhizomes of Dioscorea panthaica and their cytotoxic activity

Two new steroidal saponins, dioscoresides C (1) and D (2), along with a new natural product, pregnadienolone 3-O-beta-gracillimatriose (3), and two known compounds, pregnadienolone 3-O-beta-chacotrioside (4) and pseudoprotodioscin (5), were isolated from the rhizomes of Dioscorea panthaica Prain et Burkill. On the basis of extensive NMR studies and chemical evidence, dioscoresides C and D were determined to be 26-O-beta-D-glucopyranosyl-3 beta,26-dihydroxy-23(S)-methoxy-25(R)-furosta-5,20(22)-dien-3-O-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranoside and 26-O-beta-D-glucopyranosyl-3 beta,26-dihydroxy-20,22-seco-25(R)-furosta-5-en-20,22-dine-3-O-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1--> 4)]-beta-D-glucopyranoside. These compounds showed mild cytotoxicity against the cancer cell lines, A375, L929, and HeLa, in a dose-dependent manner.

[A comparison of chemical composition and bioactivity of polypeptides from velvet antlers of Cervus nippon Temminck and Cervus elaphus Linnaeus]

OBJECTIVE

To compare the chemical composition and bioactivity of polypeptides(PPs) isolated from velvet antlers of sika deer (Cervus nippon Temminck) and red deer (Cervus elaphus Linnaeus).

METHOD

The two kind of polypeptides were isolated from the above mentioned velvet antlers with same technology. The chemical composition was determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and MALDI-TOF mass spectrometry. Stimulant activity of cells proliferation was measured by [3H] TdR incorporation into DNA.

RESULT

The graphs of SDS-PAGE and MALDI-TOF MS of velvet antler polypeptides (VAPPs) from Chinese and New zealand red deer were very similar, but there were obvious difference in respect of graph between sika deer and red deer. VAPPs 25-50 mg.L-1 showed marked proliferation-promoting activity for rabbit costed chondrocytes, either sika deer or red deer. However, the activity of sika deer VAPPs 12.5 mg.L-1 for epidermal cells was weaker than that of red deer (12.5 mg.L-1).

CONCLUSION

The chemical property and bioactivity of VAPPs from sika deer and red deer are significantly different.

[Metabolism of ginsenoside Rb1 and panaxadiol saponins by fungi]

AIM

To study the metabolic process of ginsenoside Rb1 (G-Rb1) and panaxadiol saponins (PDS) by fungi.

METHODS

Ten strains of fungi were incubated with G-Rb1 and PDS at a certain temperature with shaking. A portion was taken out at different time and mixed up with butanol. The butanol extract was analysed by thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and electrospray ionazition mass spectrometry (ESI-MS).

RESULTS

It was found that there were ginsenoside-Rd (G-Rd), ginsenoside-F2 (G-F2), compound K (CK) and 20(S) protopanaxadiol (Ppd) metabolites beside the prodrug G-Rb1 induced by fungi (No. 1, 2, 3, 6, 8, 9).

CONCLUSION

The six strains of fungi have different degrees of ability to metabolize G-Rb1 and PDS. The possible metabolic process could be as follows: G-Rb1 (or PDS)-->G-Rd-->G-F2-->CK-->Ppd.

[Studies on metabolism of oxymatrine by human intestinal bacteria]

OBJECTIVE

To study the oxymatrine metabolism induced by human intestinal bacteria and its absorbed metabolites in blood.

METHOD

TLC and HPLC were used to examine oxymatrine and its metabolites, and UV, IR, NMR and MS were used to confirm the chemical structures of the metabolites.

RESULT

Oxymatrine was transformed into matrine by human intestinal bacteria metabolism in vitro. Rats were given orally oxymatrine 100 mg.kg-1 and were decapitated 3 hours after administration, and their blood was taken to examine serum metabolites by TLC and HPLC, which revealed that oxymatrine and matrine were absorbed into blood.

CONCLUSION

Oxymatrine will be transformed into matrine when it is given orally and both of the alkaloids can be absorbed to blood.

[Research on the transformation of ginsenoside Rg1 by intestinal flora]

OBJECTIVE

The decomposition of Ginsenoside Rg1(Rg1) by intestinal bacteria in rats or human was investigated both in vitro and in vivo.

METHOD

The decompositions were investigated by means of thin-layer chromatography and Electron spurt ion mass.

RESULT

It was found that Rg1 was converted into two metabolites [Rh1 and 20(S)-protopanaxatriol(20S-Ppt)] by human intestinal bacteria in vitro, while three compounds [Rh1, F1, and 20(S)-Ppt] were detected in rat intestinal bacteria metabolism in vitro and in vivo.

CONCLUSION

The decomposition and/or metabolism of Rg1 in rat and human digestive tract was confirmed. The mode of metabolism in rat is Rg1-->Rh1(F1)-->Ppt, while in human it is Rg1-->Rh1-->Ppt.

[Isolation and identification of steroidal saponins from Dioscorea panthaica Prain et Burkill]

AIM

To investigate the chemical constituents of the rhizomes of Dioscorea panthaica Prain et Burkill and look for new active compounds.

METHODS

The compounds were isolated with silica gel and HPLC, and their structures were elucidated on the basis of chemical evidences and spectral analysis (IR, ESI-MS, 1HNMR, 13CNMR, DEPT, 1H-1H COSY, HMQC, HMBC, NOESY).

RESULTS

Three steroidal saponins were isolated from the rhizomes of Dioscorea panthaica. They were elucidated as 26-O-beta-D-glucopyranosyl-3 beta, 26-diol-23(S)-methoxy-25(R)-delta 5,20(22)-diene-furosta-3-O-[alpha-L-rhamnopyranosyl-(1-->2)- O-alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranoside (I), pseudoprotodioscin (II), 26-O-beta-D-glucopyranosyl-3 beta, 26-diol-25 (R)-delta 5,20(22)-diene-furosta-3-O-alpha-L-rhamnopyranosyl- (1-->2)-O-beta-D-glucopyranoside (III).

CONCLUSION

Compound I is a new steroidal saponin and was named as dioscoreside C. Compound II and III were obtained from this genus for the first time.

Effects of polysaccharides (FI0-b) from mycelium of Ganoderma tsugae on proinflammatory cytokine production by THP-1 cells and human PBMC (I)

AIM

To compare the effects of water-soluble polysaccharides, FI0-b, and its formic acid-modified derivative, FI0-b-H, on production of human proinflammatory cytokines.

METHODS

The polysaccharides were modified by formic acid. Cytokine production was quantitated by radioimmunoassay. mRNA for cytokines was measured by semi-quantitative RT-PCR.

RESULTS

FI0-b and FI0-b-H 4, 40, and 400 mg/L significantly downregulated interleukin-1 alpha (IL-1 alpha) production by THP-1 cells induced by lypopolysaccharide (LPS) 1 or 10 mg/L and phorbol myristate acetate (PMA) 200 nmol/L. At lower stimulation with LPS 10 mg/L and PMA 200 nmol/L, both polysaccharides significantly upregulated tumor necrosis factor alpha (TNF alpha) production by THP-1 cells. However, at higher stimulation with LPS 100 mg/L and PMA 200 nmol/L, they downregulated TNF alpha production. FI0-b-H downregulated interleukin-8 (IL-8) production by THP-1 cells at a lower-dose of LPS 1 mg/L and PMA 200 nmol/L, but upregulated IL-8 production at a higher-dose of LPS 10 mg/L and PMA 200 nmol/L. Production of cytokines (IL-1 alpha and TNF alpha) was transcriptionally or post-transcriptionally regulated by FI0-b and FI0-b-H.

CONCLUSION

The water-soluble polysaccharides of Ganoderma tsugae mycelium have bidirectional immunomodulatory effects on cytokine production in different stimulatory conditions in a dose-dependent manner. Compared with FI0-b, FI0-b-H has more marked effects on human proinflammatory cytokine production.

Effects of polysaccharides (FI0-c) from mycelium of Ganoderma tsugae on proinflammatory cytokine production by THP-1 cells and human PBMC (II)

AIM

To study the effects of water-soluble polysaccharides. FI0-c, and its sulfated derivative, FI0-c-S, on production of human proinflammatory cytokines, interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor alpha (TNF alpha).

METHODS

The herbal polysaccharides were modified by chlorosulfornic acid in dimethyl sulfoxide (Me2SO). Cytokine production was measured by radioimmunoassay, mRNA for the cytokines was measured by semi-quantitative RT-PCR.

RESULTS

FI0-c 4 mg/L itself induced IL-1 alpha production by THP-1 cells without stimulants, such as lipopolysaccharides (LPS) and phorbol myristate acetate (PMA). On the other hand, FI0-c and FI0-c-S inhibited the IL-1 alpha production by THP-1 cells with these stimulants. FI0-c and FI0-c-S significantly upregulated TNF alpha production by THP-1 cells without stimulants or at a low dose of LPS 10 mg/L and PMA 200 nmol/L, whereas these polysaccharides markedly downregulated the TNF alpha production by a high dose of LPS 100 mg/L and PMA. Human peripheral blood mononuclear cells (PBMC) responded to FI0-c and FI0-c-S in IL-1 alpha and TNF alpha production in a fashion similar to THP-1 cell responses. FI0-c 4 mg/L downregulated high-dose LPS- and PMA-induced IL-1 alpha or TNF alpha mRNA and their protein production by THP-1 cells.

CONCLUSION

The water-soluble polysaccharides of Ganoderma tsugae mycelium have bidirectional immunomodulatory effects on cytokine production in different cell stimulatory conditions. Chemical modification of this polysaccharide changed the intensity of regulatory effect on cytokine production.

Metabolism of ginsenoside Rg1 by intestinal bacteria. II. Immunological activity of ginsenoside Rg1 and Rh1

AIM

To compare the effect of ginsenoside Rg1 and its metabolite Rh1 on proinflammatory cytokines and their mRNA expression by THP-1 cells.

METHODS

Human peripheral blood mononuclear cells (PBMC) were incubated with Rg1 and Rh1 at concentrations of 0.1, 1, 10, and 100 mg/L, and the cell proliferation was measured 24 h after incubation. Radioimmunoassay (RIA) was used to detect the production of proinflammatory cytokines, TNF alpha, IL-1 alpha, and IL-8. TNF alpha mRNA level was detected by reverse transcription polymerase chain reaction (RT-PCR) after administration of Rg1 and Rh1.

RESULTS

Rg1 and Rh1 (at concentration of 0.1, 1, 10, 100 mg/L) had no effect on PBMC proliferation. Rh1 1 mg/L could upregulate the productions of TNF (and IL-8 induced by lipopolysaccharides (LPS) 10 mg/L plus phorbol myristate acetate (PMA) 200 nmol/L, however, Rg1 showed an inhibitory effect on TNF alpha production induced by LPS 100 mg/L. Rg1 1 mg/L and Rh1 100 mg/L enhanced the production of IL-1 alpha level in THP-1 cells in the presence of LPS 10 mg/L. RT-PCR revealed that Rh1 stimulated TNF alpha mRNA expression in suitable stimulatory conditions.

CONCLUSION

Rg1 and Rh1 have different effects on the production of cytokines produced THP-1 cells stimulated by LPS and PMA.

Oxidative modification of neurogranin by nitric oxide: an amperometric study

Neurogranin (Ng) is a neuron-specific protein kinase C (PKC) substrate, which contains four cysteine (Cys) residues. Recently, it has been shown that Ng is a redox-sensitive protein and is a likely target of nitric oxide (NO) and other oxidants [F.-S. Sheu, C.W. Mahoney, K. Seki, K.-P. Huang, Nitric oxide modification of rat brain neurogranin affects its phosphorylation by protein kinase C and affinity for calmodulin, J. Biol. Chem. 271 (1996) 22407-22413: J. Li, J.H. Pak, F.L. Huang, K.-P. Huang, N-methyl-D-aspartate induces neurogranin/RC3 oxidation in rat brain slices, J. Biol. Chem. 274 (1999) 1294-1300]. In this study, we directly examine the redox reactions between dissolved NO and Cys as well as between NO and bacterial expressed Ng in its reduced form, at concentrations approximate to the physiological levels in phosphate buffer solution (PBS) under aerobic conditions. The reaction kinetics are measured directly by our newly developed electrochemical sensor. Our sensor is based on the chemical modification of electrode with immobilized nanoparticles of transition metal palladium (Pd) which serves as catalytic centers for the electrochemical oxidation of thiol and NO selectively and quantitatively at different potentials. It detects Cys and Ng in a linear range from nano to micromolar concentration at + 450 mV, vs. a saturated calomel reference electrode (SCE), while the detection of NO at the sensor can be optimally achieved at + 700 mV (vs. SCE) with a linear current-to-concentration range of nM to microM. It thus provides a selective control to monitor two reactants independently. With this sensor as a detector, we found that (1) the oxidation of either Cys or Ng by NO is a fast reaction which reaches a near completion within 1-2 min at its physiological concentration; and (2) after the completion of reaction, NO is mostly, if not all, regenerated, an observation consistent with the reaction mechanism involving the formation of S-nitrosothiol as an intermediate. The reaction kinetics of both NO to Cys and NO to Ng implies that NO can achieve local action on cellular proteins in addition to its effect on targets located in neighboring cells via concentration-gradient-dependent diffusion.

Velvet antler polypeptides promoted proliferation of chondrocytes and osteoblast precursors and fracture healing

AIM

To study the effects of velvet antler (VA) total polypeptides (VATP) and VA polypeptides, VAP-A, VAP-B, and VAP-C on proliferation of chondrocytes and osteoblast precusors.

METHODS

Chondrocytes (rabbit and human fetus) and osteoblast precusors (chick embryo) were incubated in the culture medium containing VATP or VAP-A, VAP-B, and VAP-C. [3H]TdR incorporation into DNA was measured. Fracture healing-promoting action of VATP was determined in rats.

RESULTS

VATP 50-200 mg.L-1 and VAP-B 12.5, 25, and 50 mg.L-1 showed most marked proliferation-promoting activity for rabbit costed chondrocytes and increased incorporation of [3H]TdR from (73 +/- 9) Bq (control group) to (272 +/- 55), (327 +/- 38), and (415 +/- 32) Bq, respectively (P < 0.01). The activity of VAP-A was weaker than that of VAP-B, and VAP-C had no activity. VATP 10 and 20 mg.kg-1 by local injection into the cross-section fracture area accelerated healing of radial fracture. The healing rate of VATP-treated group was higher (75%) than that of control group (25%) (P < 0.05).

CONCLUSION

VATP accelerated fracture healing by stimulating proliferation of chondrocytes and osteoblast precursors.

[Anti-inflammatory effects of pilose antler peptide]

Pilose antler peptide (PAP:MW:7200; amino acid residue:68) isolated from the antlers of Cervus nippon temminck 10 and 20 mg.kg-1 i.p. produced inhibitions towards acute and chronic inflammations in a dose-dependent manner. PAP reduced ascorbic acid and cholesterol contents in adrenal glands and decreased the serum hydrocortisone level of rats. The reduction of ascorbic acid and cholesterol contents were unaffected by the pretreatment of dexamethasone. PAP also showed an anti-inflammatory action on the swelling of carrageenan-induced hind paw in adrenalectomized rats. The results suggest that the anti-inflammatory effects of PAP do not depend absolutely on pituitary-adrenal system.

The effect of pressure on ultrasonic testing sensitivity of hot steel blooms by pressure contact method

The effect of exerted pressure of the buffer rod on the sensitivity of ultrasonic testing of hot steel blooms by the pressure contact method is discussed. The formula describing their linear relation is introduced. Results show that, at a given temperature, sensitivity increases linearly with pressure until a certain pressure is reached where sensitivity is rather insensitive to pressure variations. However, this pressure region is not always used. The proper choice of exerted pressure for practical use is analyzed.

[A tablet of Tripterygium wilfordii in treating lupus erythematosus]

Twenty-three cases of lupus erythematosus, including 15 cases of SLE and 8 cases of DLE treated with Tripterygium wilfordii (TW, three tablets thrice a day, each tablet contains 5 gm of crude TW) were reported. As controls, 19 cases of SLE were treated with prednisone alone at the same time. 9/15 cases in the former group and 6/19 in the latter got improvement after treatment. There was no significant difference between the two groups (P greater than 0.10). However, TW had beneficial effects to remission of arthralgia (7/10 in the former group and 7/15 in the latter group) and erythematosus rash (6/8 in the former group and 5/12 in the latter). Clinically, four out of eight cases of DLE improved after treatment with TW. TW had some toxic effects, such as decrease of peripheral blood leukocyte and kidney damage. Since the toxic dose and effective dose could be quite close, special attention should be paid when the drug was being used, especially on those patients with nephropathy. So the authors suggested that the indication of TW could include the patients of DLE and SLE without nephropathy.

Biochemical changes related to aging in the senescence-accelerated mouse

Several biochemical parameters reflecting the degree of senescence were compared between senile-prone (P) and resistant (R) strains of male senescence-accelerated mouse (SAM) at 11 to 12 months of age. Plasma testosterone in SAM-P amounted to half the concentration in SAM-R. In the liver and brain of SAM-P, the content of malondialdehyde (MDA) and the activity of monoamine oxidase B (MAO-B) were significantly higher than those in SAM-R. Moreover, large amounts of fluorescent lipofuscin were detected in the SAM-P liver. Compared with SAM-R, both membrane and cytosolic fractions from the SAM-P liver contained small amounts of protein and showed less activity of superoxide dismutase (SOD). The present findings suggest that the male SAM-P rapidly acquires biochemical changes which are considered to be part of the normal aging process.

Induction of rat hepatic cytochromes P-450 by environmental nitropolycyclic aromatic hydrocarbons

Nitrated polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that result from various incomplete combustion processes. We have examined the activity of hepatic microsomal enzymes in rats pretreated with a series of environmentally occurring nitrated PAHs including: 1- and 4-nitropyrene, 1,3-, 1,6- and 1,8-dinitropyrene, 6-nitrochrysene, 7-nitrobenz[a]anthracene, 3-nitrofluoranthene, and 1-, 3-, and 6-nitrobenzo[a]pyrene. None of the compounds increased the cytochrome P-450 content more than 2-fold. 1,8-Dinitropyrene, 6-nitrochrysene, and 1- and 3-nitrobenzo[a]pyrene significantly increased arylhydrocarbon hydroxylase activity 2- to 8-fold higher than solvent-treated controls. The induction of 7-ethoxycoumarin O-deethylase activity paralleled that found with arylhydrocarbon hydroxylase. The maximum induction of aminopyrine N-demethylase was only 1.5-fold, and none of the nitrated PAHs caused significant increases in epoxide hydrase or NADPH-cytochrome c reductase. 1-Nitropyrene reductase activity was induced by each of the compounds with the exception of 6-nitrobenzo[a]pyrene. The greatest increase was caused by 1-nitrobenzo[a]pyrene followed by 1,3-dinitropyrene, 3-nitrobenzo[a]pyrene and 6-nitrochrysene. These data suggest that nitrated PAHs may potentiate the effects of subsequent exposures to various chemical carcinogens.