Correlated optical convolutional neural network with "quantum speedup".

Compared with electrical neural networks, optical neural networks (ONNs) have the potentials to break the limit of the bandwidth and reduce the consumption of energy, and therefore draw much attention in recent years. By far, several types of ONNs have been implemented. However, the current ONNs cannot realize the acceleration as powerful as that indicated by the models like quantum neural networks. How to construct and realize an ONN with the quantum speedup is a huge challenge. Here, we propose theoretically and demonstrate experimentally a new type of optical convolutional neural network by introducing the optical correlation. It is called the correlated optical convolutional neural network (COCNN). We show that the COCNN can exhibit "quantum speedup" in the training process. The character is verified from the two aspects. One is the direct illustration of the faster convergence by comparing the loss function curves of the COCNN with that of the traditional convolutional neural network (CNN). Such a result is compatible with the training performance of the recently proposed quantum convolutional neural network (QCNN). The other is the demonstration of the COCNN's capability to perform the QCNN phase recognition circuit, validating the connection between the COCNN and the QCNN. Furthermore, we take the COCNN analog to the 3-qubit QCNN phase recognition circuit as an example and perform an experiment to show the soundness and the feasibility of it. The results perfectly match the theoretical calculations. Our proposal opens up a new avenue for realizing the ONNs with the quantum speedup, which will benefit the information processing in the era of big data.

FTO-mediated epigenetic upregulation of LINC01559 confers cell resistance to docetaxel in breast carcinoma by suppressing miR-1343-3p.

This study was to explore the regulatory effect of long non-coding RNA LINC01559 on Docetaxel resistance in breast carcinoma (BCa) and its underlying mechanism. In the present study, we found that LINC01559 expression was elevated and LINC01559 overexpression facilitated docetaxel resistance in BCa cells. Moreover, it was revealed that the upregulation of LINC01559 in BCa cells was induced by FTO-mediated demethylation in an m6A-YTHDF2-dependent manner. Additionally, Dual-luciferase reporter assay confirmed the binding ability between LINC01559 and miR-1343-3p, and Pearson correlation analysis showed a negative correlation between them. Particularly, miR-1343-3p inhibition partly abolished the suppression on docetaxel resistance in BCa cells caused by LINC01559 knockdown. To sum up, FTO-mediated epigenetic upregulation of LINC01559 promoted cell resistance to Docetaxel in BCa by negatively regulating miR-1343-3p.

Laguerre Gaussian mode holography and its application in optical encryption.

Holography provides an approach to reconstructing both intensity and phase information, and has many applications for microscopic imaging, optical security, and data storage. Recently, the azimuthal Laguerre-Gaussian (LG) mode index, orbital angular momentum (OAM), has been implemented in holography technologies as an independent degree of freedom for high-security encryption. The radial index (RI) of LG mode, however, has not been implemented as an information carrier in holography. Here we propose and demonstrate the RI holography by using strong RI selectivity in the spatial-frequency domain. Furthermore, the LG holography is realized theoretically and experimentally with the (RI, OAM) spanning from (1, -15) to (7, 15), which leads to a 26bit LG-multiplexing hologram for high-security optical encryption. Based on LG holography, a high-capacity holographic information system can be constructed. In our experiments, a LG-multiplexing holography with a span of 217 independent LG channels has been realized, which is inaccessible at present for the OAM holography.

High-Dimensional Entanglement-Enabled Holography.

As an important imaging technique, holography has been realized with different physical dimensions of light, including polarization, wavelength, and time. Recently, quantum holography has been demonstrated by utilizing polarization entangled state with the advantages of high robustness and enhanced spatial resolution, comparing with classical holography. However, the polarization is only a two-dimensional degree of freedom, which greatly limits the capacity of quantum holography. Here, we propose a method to realize high-dimensional quantum holography by using high-dimensional orbital angular momentum (OAM) entanglement. A high-capacity OAM-encoded quantum holographic system can be obtained by multiplexing a wide range of OAM-dependent holographic images. Proof-of-principle experiments with four- and six-dimensional OAM entangled states have been implemented and verify the feasibility of our idea. Our experimental results also demonstrate that the high-dimensional quantum holography shows a high robustness to classical noise. What is more, the level of security of the holographic imaging encryption system can be greatly improved in our high-dimensional quantum holography.

Effect of traditional Chinese manual therapy on alleviating pain and dysfunction of lumbar disc herniation: a randomized controlled pilot study.

OBJECTIVE: To investigate the effect of traditional Chinese manual therapy (TCMT) in alleviating pain and dysfunction in patients with lumbar disc herniation (LDH). METHODS: Sixty-six patients with LDH were recruited as the study cohort and randomly assigned to an observation group and a control group. The patients in the observation group underwent TCMT, whereas those in the control group underwent conventional lumbar traction (LT). The observed indexes comprised primary index, which referred to clinical efficacy, and secondary indexes, which include Simplified McGill Pain Questionnaire, Oswestry Disability Index (ODI), range of motion (ROM) of the lumbar spine, difference in muscle tone (MT) and pressure pain threshold (PPT) of the bilateral erector spinae, and serum inflammatory factor levels. RESULTS: The total effective rate was significantly higher in the observation group than in the control group (96.67% vs. 66.67%, P < 0.001). Compared with the control group after treatment, patients in the observation group had significantly lower ODI, pain rating index, visual analog scale and present pain intensity scores (all P < 0.05), and had significantly smaller differences in MT and PPT of the bilateral erector spinae (both P < 0.001), but had remarkably greater ROM of the lumbar spine (P < 0.001). In addition, interleukin (IL)-6, IL-8, and interferon-γ concentrations in the observation group were significantly lower than those in the control group after treatment (all P < 0.05). CONCLUSION: TCMT has positive effects on alleviating pain and improving dysfunction of patients with LDH and helps in reducing serum inflammatory factor levels.

High capacity topological coding based on nested vortex knots and links.

Optical knots and links have attracted great attention because of their exotic topological characteristics. Recent investigations have shown that the information encoding based on optical knots could possess robust features against external perturbations. However, as a superior coding scheme, it is also necessary to achieve a high capacity, which is hard to be fulfilled by existing knot-carriers owing to the limit number of associated topological invariants. Thus, how to realize the knot-based information coding with a high capacity is a key problem to be solved. Here, we create a type of nested vortex knot, and show that it can be used to fulfill the robust information coding with a high capacity assisted by a large number of intrinsic topological invariants. In experiments, we design and fabricate metasurface holograms to generate light fields sustaining different kinds of nested vortex links. Furthermore, we verify the feasibility of the high-capacity coding scheme based on those topological optical knots. Our work opens another way to realize the robust and high-capacity optical coding, which may have useful impacts on the field of information transfer and storage.

[Clinical Characteristics and Prognosis of Children with Myelodysplastic Syndrome].

OBJECTIVE: To analyze the clinical characteristics and prognosis of 40 children with myelodysplastic syndrome (MDS), and provide ideas for clinical diagnosis and treatment. METHODS: The clinical characteristics, risk stratification, and different treatment regimens of 40 cases with MDS admitted in Department of Hematology of Children's Hospital of Soochow University from January 1, 2011 to December 31, 2017 was retrospectively analyzed. Kaplan-Meier survival curve were used to estimate 3-year overall survival (OS) rate and event-free survival (EFS) rate. RESULTS: In 40 cases, the ratio of male to female was 1.4∶1.0, male was more than female, and median age was 6.0 years old. Among them, refractory cytopenia (MDS-RCC) was the most common type, and 11 cases were chromosomal abnormalities, 21 cases genetic abnormalities. Fifteen cases accepted hematopoietic stem cell transplantation (HSCT) treatment, while 25 cases did not but drug therapy alone. The 3-year OS rate of the cases who accepted HSCT or not was (72.2±12.2)% and (35.3±10.2)% (P=0.039), 3-year EFS rate was (65.0±12.9)% and (19.2±8.4)% (P=0.012), respectively. Cox regression analysis showed that age < 7 years old (P=0.0333), initial diagnosed platelet < 50×109/L (P=0.007), presence of complex karyotypes and/or gene mutations (P=0.0002), and treatment without HSCT (P=0.016) were the high-risk factors of prognosis. All the children were classified according to IPSS, WPSS and IPSS-R, while analysis result showed that the above three risk assessment had limitations for risk assessment of MDS in children, they could not comprehensively assess the prognosis of children with MDS. CONCLUSION: MDS-RCC in children is more common. Cox multivariate analysis shows that age < 7 years old, initial diagnosed platelet < 50×109/L, presence of complex karyotypes and/or gene mutation, and treatment without HSCT are the high-risk factors of prognosis in children with MDS. HSCT is the most effective treatment to cure children with MDS at present. The current methods such as IPSS-R commonly used in assessment of prognosis in children with MDS show obvious limitation.

Prevalence and Genotype Distribution of Human Papillomavirus Among Healthy Females in Beijing, China, 2016-2019.

OBJECTIVE: Human papillomavirus (HPV) infection, especially with high-risk HPV (HR-HPV) genotypes, is closely associated with cervical cancer. This study aimed to observe the epidemiological characteristics of HPV infection among healthy women in Beijing, China. MATERIALS AND METHODS: Cervical specimens were collected from 29,436 healthy women, who underwent health check-ups in Peking Union Medical College Hospital between 2016 and 2019. A commercial kit was used for the detection of 15 HR-HPV and two low-risk HPV (LR-HPV) genotypes. RESULTS: A total of 3586 (12.18%) participants tested positive for HPV, 3467 of which were infected with HR-HPVs. The most prevalent genotypes were HPV52, 58, 16, 51, and 56. Moreover, while infection with a single genotype (9.84%) was more prevalent, HPV16+52 was the most common combination in those infected with multiple HPVs. Furthermore, the highest infection rate among age groups was in women aged <25 years (20.92%). No significant difference in the prevalence was observed from 2016 to 2019. However, HPV incidence in Beijing was significantly different than that in all other areas in China, except for Zhengzhou (p < 0.05). CONCLUSION: Our findings could serve as potential reference for better understanding of the epidemiological characteristics of HPV infection in Beijing.

Simultaneous adsorption of Cr(VI) and phenol by biochar-based iron oxide composites in water: Performance, kinetics and mechanism.

The pollution of heavy metals and organic compounds has received increased attention in recent years. In the current study, a novel biochar-based iron oxide composite (FeYBC) was successfully synthesized using pomelo peel and ferric chloride solution through one-step process at moderate temperature. Results clearly demonstrate that FeYBC exhibited more efficient removal of Cr(VI) and/or phenol compared with the pristine biochar, and the maximum adsorption amounts of Cr(VI) and phenol by FeYBC could reach 24.37 and 39.32 mg g-1, respectively. A series of characterization data suggests that several iron oxides such as Fe2O3, Fe0, FeOOH and Fe3O4 were formed on the FeYBC surface as well as oxygen-containing groups. Thermodynamics study indicates that Cr(VI) and phenol adsorption by FeYBC were endothermic and exothermic processes, respectively. Langmuir adsorption isotherm and pseudo-second order models could better explain the Cr(VI) and phenol adsorption behaviors over FeYBC. The Cr(VI) adsorption might be primarily achieved through the ion exchange and surface complexation and reduction, whereas the π-π interaction and electron donor-acceptor complex mainly contributed to phenol adsorption. The findings indicate that the biochar-based iron oxide composites material was an efficient adsorbent for the remediation of industrial effluents containing Cr(VI) and phenol.

[Effects of manual loading on calcitonin gene-related peptide and nerve growth factor in rats with chronic low back pain].

OBJECTIVE: To observe the analgesic effect of manipulation loading on chronic low back pain (CLBP) model rats and the expression of inflammatory factors in psoas major muscle tissue, and to explore the improvement of manipulation on local inflammatory microenvironment. METHODS: Thirty two SPF male SD rats weighing 340-360g were randomly divided into blank group, sham operation group, chronic low back pain model group and treatment group, with 8 rats in each group. In the model group, L4-L6 lumbar vertebrae were implanted with external link fixation system (ELFS). After implantation of ELFS, the treatment group received manualintervention with 5N force and 2Hz frequency on both sides of the spine, 15 min / time, once a day, for 14 consecutive days. Paw with drawl threshold (PWT) and paw withdrawl latency (PWL) was measured before modeling and on the 1st, 3rd, 7th, 10th and 14th day after intervention. At the end of the treatment cycle, the concentrations of calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) in psoas muscle were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: There was no significant difference in PWT and PWL between the blank group and the sham operation group after modeling (P>0.05);after modeling, PWT and PWL in the CLBP model group and the treatment group were significantly decreased(P<0.01);PWT in the treatment group was not significantly improved than that in the CLBP model group on the 1st and 3rd day after manual loading(P>0.05);on the 7th day after manual loading, the pain threshold value in the treatment group was higher than that in the CLBP model group, but there was no significant difference There was no significant difference between the two groups (P=0.056>0.05). On the 10th and 14th day of treatment, the mechanical pain threshold of the treatment group began to rise, and it was statistically significant compared with CLBP model rats (P<0.05, P< 0.01);on the 1st and 3rd day after manual treatment, the PWL of the treatment group was not significantly improved compared with CLBP model group (P>0.05);on the 7th day, the PWL of the treatment group was significantly higher than that of CLBP model group, there was statistical significance (P=0.016<0.05). Manual loading improved thermal hyperalgesia in CLBP rats until the end of the experiment. The contents of CGRP and NGF in psoas major muscle of CLBP model group were higher than those of blank group and sham operation group (P<0.01). After treatment, the contents of CGRP and NGF decreased significantly(P<0.01). CONCLUSION: Local massage loading has analgesic effect on CLBP rats, at the same time, it can inhibit the content of CGRP and NGF in psoas muscle tissue of CLBP rats, and improve the local inflammatory microenvironment.

NOD2 induces VCAM-1 and ET-1 gene expression via NF-κB in human umbilical vein endothelial cells with muramyl dipeptide stimulation.

OBJECTIVES: Endothelial dysfunction is involved in various aspects of vascular biology and different stages of cardiovascular diseases (CVDs). Nucleotide-binding oligomerization domain-containing protein (NOD) 2, a pivotal innate immune receptor for muramyl dipeptide (MDP), has been reported to be a central regulator in CVDs. Previously, we reported that NOD2 played a leading role in MDP-triggered oxidative stress in endothelial cells (ECs). However, whether NOD2 participates in the regulatory mechanism of vascular cell adhesion molecule­1 (VCAM-1) and endothelin­1 (ET-1) expression was not elucidated. METHODS: Human umbilical vein endothelial cells (HUVECs) were stimulated with MDP for 12 h. mRNA expression of VCAM­1 and ET­1 was detected using real time polymerase chain reaction (PCR). Scrambled control small interfering RNA (siRNA) and NOD2 siRNA were transfected into HUVECs using Lipofectamine 2000 reagent (Invitrogen, Waltham, MA, USA). Furthermore, pyrrolidine dithiocarbamate was adopted to investigate the effect of nuclear factor κB (NF-κB) on NOD2-mediated VCAM­1 and ET­1 gene expression in MDP-treated HUVECs. RESULTS: Data showed that MDP significantly increased VCAM­1 and ET­1 mRNA expression, which was dependent on NOD2. In addition, NF-κB inhibition suppressed NOD2-mediated gene expression of VCAM­1 and ET­1. CONCLUSION: Collectively, we confirmed NOD2 aggravated VCAM­1 and ET­1 gene expression through NF-κB in HUVECs treated with MDP.

Theoretical analysis based on mirror symmetry for tightly focused vector optical fields.

A theoretical analysis based on mirror symmetry is proposed to analyze and predict the symmetry in intensity, phase and polarization distributions of the tightly focused vector optical field (VOF). We extend the analysis to more cases including more complicated polarization states and weak focusing cases. We further show the symmetric tightly focused fields of the eccentric cylindrical VOF and the redesigned VOF with a radially variant polarization state, which are achieved by redesigning the polarization state of the incident VOF based on the symmetry analysis. We also take the laser fabrication as an example to further show how to apply this symmetry analysis in a specific application area. Such a theoretical analysis can improve the calculation efficiency, provide new insights into the tight focusing process and offer a convenient way to engineer the field distributions in the focal plane, which may have potential applications in areas needing flexibly controllable tightly focused fields, such as laser fabrication, optical trapping, and optical storage.

Pancharatnam-Berry geometric phase memory based on spontaneous parametric down-conversion.

Phase memory is an effect in which the interaction between a coherent pump beam and a nonlinear crystal generates photon pairs via the spontaneous parametric down-conversion process, then the down-converted photons (signal and idler) can carry the phase information of the pump beam. There has been much research on the memory of the dynamic phase so far; however, there is no report on the memory of non-dynamic phase, to the best of our knowledge. Here we acquire a Pancharatnam-Berry (PB) geometric phase in a physical system when light travels along a trajectory in polarization-state space. Induced coherence occurs in a cascaded scheme composed of two nonlinear crystals, when the idler photons in both crystals are aligned to be indistinguishable. A NOON ($N\; = \;{2}$N=2) state is established when blocking the two idler photons. We explore the PB geometric phase memory of the NOON state and induced coherence. We find that the first-order interference of the two-photon state or signal photons can be controlled by introducing the PB geometric phase to the pump light. This may facilitate precise control of the phase of the down-converted photons.

Removal of U(VI) from aqueous and polluted water solutions using magnetic Arachis hypogaea leaves powder impregnated into chitosan macromolecule.

In this study m-AHLPICS (magnetic Arachis hypogaea leaves powder impregnated into chitosan) was prepared and utilized as an adsorbent to remove U(VI) from aqueous and real polluted wastewater samples. m-AHLPICS was characterized by using the BET, XRD, FTIR, SEM with elemental mapping and magnetization measurements. Different experimental effects such as pH, dose, contact time, and temperature were considered broadly. Chitosan modified magnetic leaf powder (m-AHLPICS) exhibits an excellent adsorption capacity (232.4 ± 5.59 mg/g) towards U(VI) ions at pH 5. Different kinetic models such as pseudo-first-order, and pseudo-second-order models were used to know the kinetic data. Langmuir, Freundlich and D-R isotherms were implemented to know the adsorption behavior. Isothermal information fitted well with Langmuir isotherm. Kinetic data followed by the pseudo-second-order kinetics (with high R2 values, i.e., 0.9954, 0.9985 and 0.9971) and the thermodynamic data demonstrate that U(VI) removal using m-AHLPICS was feasible, and endothermic in nature.

Impregnation of magnetic - Momordica charantia leaf powder into chitosan for the removal of U(VI) from aqueous and polluted wastewater.

Uranium (U(VI)) is radioactive and the primary raw material in the production of nuclear energy. Hence the research associated with uranium removal gained a lot of importance because to reduce the threat of uranium contamination to ecology and its environment surroundings. Thus, economically as well as environmentally friendly sorbents with a good sorption capacity have to be acquired for the removal of U(VI) pollutants from the aqueous and polluted sea samples. In this study magnetic- Momordica charantia leaf powder impregnated into chitosan (m-MCLPICS) was prepared through the impregnation method. After preparation the adsorbent undergone through various characterizations such as BET, XRD, FTIR, SEM with elemental mapping, and VSM analysis. The specific surface area (93.12 m2/g), pore size (0.212 cm3/g) and pore volume (15.35 nm) of m-MCLPICS was obtained from the BET analysis. A pH value of 5 and 0.5 g of adsorbent dose were selected as an optimum values for U(VI) removal. Kinetic data follows the pseudo-second-order model, and the equilibrium data fitted well with the Langmuir isotherm model. ΔG° (-1.6999, -2.4994, -3.5476 and -4.5147 kJ/mol), ΔH0 (25.1 kJ/mol) and ΔS0 (0.089 kJ/mol K) indicates that the U(VI) sorption process is feasible, spontaneous and endothermic.

Synergistic oxidation of Bisphenol A in a heterogeneous ultrasound-enhanced sludge biochar catalyst/persulfate process: Reactivity and mechanism.

Recently, clean-up of resistant organic compounds has attracted growing attention. In this study, a novel heterogeneous ultrasound-enhanced sludge biochar catalyst/persulfate (BC/PS/US) process was firstly developed for the degradation of bisphenol A (BPA) in water. The results revealed that BC/PS/US process could successfully achieve a positively synergistic effect between sonochemistry and catalytic chemistry on the degradation of BPA compared to its corresponding comparative process. Nearly 98% of BPA could be degraded within 80 min at optimum reaction conditions. The coexisting substances including Cl-, SO42- and NO3- had no obvious inhibition on the BPA degradation, whereas HCO3- and humic acid (HA) had significant inhibition effects on that. PS decomposition of BC/PS/US process was superior to that of BC/PS or US/PS process. Both SO4- and HO participated in the degradation of BPA, but SO4- was predominant radical in the BC/PS/US process. A possible pathway of BPA degradation was proposed, and the BPA molecule was attacked by SO4- and degraded into five kinds of intermediate products through hydroxylation and demethylation processes. This study helps to comprehend the application of sludge biochar catalyst as a persulfate activator for the degradation of organic compounds under ultrasound irradiation, and provides a new strategy in wastewater treatment.

Manipulation of eight-dimensional Bell-like states.

High-dimensional Bell-like states are necessary for increasing the channel capacity of the quantum protocol. However, their preparation and measurement are still huge challenges, especially for the latter. Here, we prepare an initial eight-dimensional Bell-like state based on hyperentanglement of spin and orbital angular momentum (OAM) of the first and the third orders. We design simple unitary operations to produce eight Bell-like states, which can be distinguished completely in theory among each other. We propose and illustrate a multiple projective measurement scheme composed of only linear optical elements and experimentally demonstrate that all the eight hyperentangled Bell-like states can be completely distinguished by our scheme. Our idea of manipulating the eight Bell-like states is beneficial to achieve the 3-bit channel capacity of quantum protocol, opening the door for extending applications of OAM states in future quantum information technology.

Modification of chitosan macromolecule and its mechanism for the removal of Pb(II) ions from aqueous environment.

It is well-known that heavy metals are non-biodegradable and have been showing remarkable impacts on the environment, public health and economics. Because of high toxic tendency, lead (Pb), is one of the foremost considerable hazardous metal with high environmental impacts. Chitosan is a polysaccharide, and can be utilized in wastewater treatment because of its good sorption ability. Amino and hydroxyl groups (C-3 position) on chitosan can serve as electrostatic interaction and complexation sites for metal cations. Chemical crosslinking can effectively enhance the stability of chitosan in acidic media. Hence a novel, cost-effective and eco-friendly ZnO incorporated into aminated chitosan Schiff's base (ACSSB@ZnO) has been synthesized, characterized (BET, XRD, FTIR, SEM, TEM and 1H NMR), and utilized as an adsorbent for the removal of Pb(II) ions from the aqueous environment. The various operating parameters, such as pH (2-8), agitation speed (30-180), adsorbent dose (0.1-0.8 g), contact time (0-140 min), metal ion concentration and temperature (303-323 K) were investigated. The maximum sorption capacity of Pb(II) onto ACSSB@ZnO was found to be 55.55 mg/g. The equilibrium, and kinetic studies suggested that the adsorption process followed the Langmuir isotherm and Pseudo-Second-Order model. Thermodynamic data showed that the sorption process was feasible, spontaneous, and endothermic.

Compact, robust, and high-efficiency generator of vector optical fields.

We design and realize a generator that can convert an orbital angular momentum (OAM) state into a vector polarization state. The generator is integrated by several commonly used optical elements and easy to make or glued. Compared with traditional interferometric ways for generating the vector optical fields, this integrated generator has compact and robust advantages and especially a high-efficiency of 87%.

Photocatalytic removal of phenanthrene and algae by a novel Ca-Ag3PO4 composite under visible light: Reactivity and coexisting effect.

In this study, the feasibility of a novel Ca-Ag3PO4 composite with visible light irradiation for the phenanthrene (PHE) degradation and algae inactivation in artificial seawater was firstly investigated. The experimental findings revealed that Ag3PO4 phase was sucessfully formed on the Ca-based material, and the presence of Ca-based material could effectively keep Ag3PO4 particles stable. An excellent performance on PHE degradation or algae inactivation was observed from Ca-Ag3PO4 composite under visible light irradiation. The degradation of PHE or inactivation of algae not only could be efficiently achieved in the single mode, but also could be successfully achieved in the coexisting mode. Above 96% of PHE and algae were simultaneously removed within 12 h in the Ca-Ag3PO4/visible light system. It was further observed that the degradation of PHE and/or inactivation of algae increased with the increase of Ca-Ag3PO4 dosage. HO was the primary radical responsible for PHE degradation, whereas HO and Ag+ released from Ca-Ag3PO4 mainly contributed to the algae inactivation. A possible mechanism involving the catalytic removal of PHE and algae by Ca-Ag3PO4 under visible light irradiation was proposed. This study provides helpful guide for the simultaneous removal of various pollutants in real seawater.