Hydrogeochemical characterization and groundwater quality assessment in intruded coastal brine aquifers (Laizhou Bay, China)

The aquifer in the coastal area of the Laizhou Bay is affected by salinization processes related to intense groundwater exploitation for brine resource and for agriculture irrigation during the last three decades. As a result, the dynamic balances among freshwater, brine, and seawater have been disturbed and the quality of groundwater has deteriorated. To fully understand the groundwater chemical distribution and evolution in the regional aquifers, hydrogeochemical and isotopic studies have been conducted based on the water samples from 102 observation wells. Groundwater levels and salinities in four monitoring wells are as well measured to inspect the general groundwater flow and chemical patterns and seasonal variations. Chemical components such as Na⁺, K⁺, Ca²⁺, Mg²⁺, Sr²⁺, Cl^-, SO₄^2-, HCO₃^-, NO₃^-, F^-, and TDS during the same period are analyzed to explore geochemical evolution, water-rock interactions, sources of salt, nitrate, and fluoride pollution in fresh, brackish, saline, and brine waters. The decreased water levels without typical seasonal variation in the southeast of the study area confirm an over-exploitation of groundwater. The hydrogeochemical characteristics indicate fresh-saline-brine-saline transition pattern from inland to coast where evaporation is a vital factor to control the chemical evolution. The cation exchange processes are occurred at fresh-saline interfaces of mixtures along the hydraulic gradient. Meanwhile, isotopic data indicate that the brine in aquifers was either originated from older meteoric water with mineral dissolution and evaporation or repeatedly evaporation of retained seawater with fresher water recharge and mixing in geological time. Groundwater suitability for drinking is further evaluated according to water quality standard of China. Results reveal high risks of nitrate and fluoride contamination. The elevated nitrate concentration of 560 mg/L, which as high as 28 times of the standard content in drinking water is identified in the south region. In addition, the nitrate and ammonia data of the Wei River suggests decreasing nitrification rate in the study area from inland to estuary. High fluoride concentration, larger than 1 mg/L, is also detected in an area of about 50% of the study region. The saltwater intrusion is analyzed to be responsible for part of dissolution of minerals containing fluoride. Therefore, water treatment before drinking is needed in urgent to reduce the health expose risk.

Inhibition of AMPA receptor and CaMKII activity in the lateral habenula reduces depressive-like behavior and alcohol intake in rats

Depression is a well-known risk factor for developing relapse drinking, but the neuronal mechanisms underlying the interactions between depression and alcohol use disorders remain elusive. Accumulating evidence has associated depression with hyperactivity of the lateral habenula (LHb), an epithalamic structure in the brain that encodes aversive signals. Glutamate receptors contribute substantially to the excitability of LHb neurons. Glutamatergic synapses in LHb neurons largely express GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) that can be modulated by Ca²⁺/calmodulin-dependent protein II (CaMKII). In the current study, we tested the hypothesis that withdrawal from repeated cycles of ethanol drinking triggers an increase in LHb AMPAR and CaMKII activity concomitant with depression-like symptoms, and their inhibitions bring a reduction in depressive-like behaviors and alcohol consumption. Western blotting revealed a higher level of phosphorylated AMPAR GluA1 subunit at a CaMKII locus (GluA1-Ser831) in the LHb of ethanol-withdrawn rats than that of age-matched naïve counterparts. In ethanol-withdrawn rats, pharmacological inhibition of LHb AMPAR activity significantly mitigated the depressive-like behavior and ethanol drinking and seeking behaviors, but affected neither sucrose intake nor locomotor activity; and inhibition of LHb CaMKII activity, or chemogenetic inhibition of LHb activity produced similar effects. Conversely, activation of LHb AMPARs induced depressive-like behaviors in ethanol-naïve rats. These results demonstrate that CaMKII-AMPAR signaling in the LHb exemplifies a molecular basis for depressive-like symptoms during ethanol withdrawal and that inhibition of this signaling pathway may offer a new therapeutic approach to address the comorbidity of alcohol abuse and depression.

Changes in the expression of Col IV, gelatinase and TIMP-1 in oral leukoplakia

Type IV collagen (Col IV) is an important protein in the basement membrane (BM), which can regulate the attachment of epithelium and the lamina propria. To test the hypothesis that Col IV may play a significant role in the progression of oral leukoplakia, we have observed the morphology and distribution of Col IV in 40 patients with oral leukoplakia (epithelial hyperplasia and dysplasia). The results showed that the expression of Col IV in the BM was continuous in normal oral mucosa, while it was non-continuous or fragmented in epithelial dysplasia by immunofluorescent staining. Consequently, to analyze the correlated factors of the Col IV destruction, the expressions of gelatinase (MMP-2 and MMP-9) and tissue inhibitor of metalloproteinases -1 (TIMP-1) were detected in oral leukoplakia tissues by immunochemical staining. Then statistical analyses were performed to determine their correlations with Col IV levels. The statistics showed that the decreasing of Col IV was closely related to the increasing of MMP-9 in both epithelial hyperplasia and dysplasia (P < 0.05), while MMP-2 expression was closely related to the increasing of Col IV expression in epithelial dysplasia (P < 0.05). Therefore, monitoring changes in the expression of Col IV, gelatinase and TIMP-1 is a useful technique for assessing prognosis of oral leukoplakia.

Using the multi-objective optimization replica exchange Monte Carlo enhanced sampling method for protein-small molecule docking

Background

In this study, we extended the replica exchange Monte Carlo (REMC) sampling method to protein–small molecule docking conformational prediction using RosettaLigand. In contrast to the traditional Monte Carlo (MC) and REMC sampling methods, these methods use multi-objective optimization Pareto front information to facilitate the selection of replicas for exchange.

Results

The Pareto front information generated to select lower energy conformations as representative conformation structure replicas can facilitate the convergence of the available conformational space, including available near-native structures. Furthermore, our approach directly provides min-min scenario Pareto optimal solutions, as well as a hybrid of the min-min and max-min scenario Pareto optimal solutions with lower energy conformations for use as structure templates in the REMC sampling method. These methods were validated based on a thorough analysis of a benchmark data set containing 16 benchmark test cases. An in-depth comparison between MC, REMC, multi-objective optimization-REMC (MO-REMC), and hybrid MO-REMC (HMO-REMC) sampling methods was performed to illustrate the differences between the four conformational search strategies.

Conclusions

Our findings demonstrate that the MO-REMC and HMO-REMC conformational sampling methods are powerful approaches for obtaining protein–small molecule docking conformational predictions based on the binding energy of complexes in RosettaLigand.

The Probabilistic Profitable Tour Problem

A new routing problem is introduced and named as the probabilistic profitable tour problem in this paper. The problem is defined on a complete graph where profits are associated with the vertices and travel costs are associated with the edges. Each vertex (customer) has a probability of requiring a visit on a given day. The tour starts and ends at a fixed vertex, and each vertex can never be visited more than one time. Once a vertex is visited, an associated profit is collected and the corresponding travel cost occurs. The objective is to find a subset of vertices and an a priori tour through those vertices that maximizes the difference between the expected profits and the expected travel costs. The problem is confronted by some big e-tailing companies who need to determine, among the set of all potential customers, the customers to be served by themselves and outsource the unselected customers. The problem under study is shown to be NP-hard in this paper. The authors provide a non-linear mathematical formulation for it. Consequently, a genetic algorithm is developed to solve this problem. The computational experiments carried out on small- and moderate-size instances show a good performance of the proposed algorithm.

Zwitterionic copolymers bearing phosphonate or phosphonic motifs as novel metal-anchorable anti-fouling coatings

Developing a facile but efficient anti-fouling surface coating is highly required for metallic implants. Here, we report two kinds of zwitterionic copolymers (both random and block) bearing phosphonic/phosphonate motifs/segments as novel metal anchorable antifouling coatings. Through conventional free radical polymerization and reversible addition-fragmentation chain transfer (RAFT) polymerization, three types of zwitterionic-phosphonic random copolymers with varying mol. ratios (9 : 1, 8 : 2, and 6 : 4) and a phosphonate-zwitterionic block copolymer were precisely prepared based on zwitterionic sulfobetaine methacrylate (SBMA) and phosphonate/phosphonic methacrylate. As evidenced by XPS and water contact angle tests, the two kinds of copolymers with distinguished presenting manners of the metal-anchorable phosphonate/phosphonic motifs were all successfully immobilized on the Ti substrates through a facile one-step post-functionalization. The immobilized copolymers equally exhibited strong inhibition of protein adsorption, platelet adhesion, and bacterial adhesion, endowing significantly improved antifouling ability to the metallic substrates. This work not only provides a novel approach to improve the antifouling ability of Ti substrates, the utilization of phosphonic/phosphonate based copolymers as efficient metal-anchorable coatings may offer a new platform for versatile surface functionalization of many metallic substrates.

Current and future perspective on antimicrobial and anti-parasitic activities of Ganoderma sp.: an update

Medicinal mushroom Ganoderma sp. is considered to be a key source for the production of therapeutic agents. Our current review indicates that a limited number (<19%; 79 out of >430) of isolated compounds have been tested and known to be active against several microorganisms and parasites. In this review, we aim to summarise all the antimicrobial and anti-parasitic works on Ganoderma sp. displayed on web of science, google scholar and endnote X7 from 1932 to August 2016. We further present and discuss the structure of active compounds against microorganisms and parasites. In addition, we also discuss the possible further research to identify lead compounds from Ganoderma sp. as a novel strategy to combat the potential global emergence of bad bugs and parasites.

Comparative Genomics Unravels the Functional Roles of Co-occurring Acidophilic Bacteria in Bioleaching Heaps

The spatial-temporal distribution of populations in various econiches is thought to be potentially related to individual differences in the utilization of nutrients or other resources, but their functional roles in the microbial communities remain elusive. We compared differentiation in gene repertoire and metabolic profiles, with a focus on the potential functional traits of three commonly recognized members (Acidithiobacillus caldus, Leptospirillum ferriphilum, and Sulfobacillus thermosulfidooxidans) in bioleaching heaps. Comparative genomics revealed that intra-species divergence might be driven by horizontal gene transfer. These co-occurring bacteria shared a few homologous genes, which significantly suggested the genomic differences between these organisms. Notably, relatively more genes assigned to the Clusters of Orthologous Groups category [G] (carbohydrate transport and metabolism) were identified in Sulfobacillus thermosulfidooxidans compared to the two other species, which probably indicated their mixotrophic capabilities that assimilate both organic and inorganic forms of carbon. Further inspection revealed distinctive metabolic capabilities involving carbon assimilation, nitrogen uptake, and iron-sulfur cycling, providing robust evidence for functional differences with respect to nutrient utilization. Therefore, we proposed that the mutual compensation of functionalities among these co-occurring organisms might provide a selective advantage for efficiently utilizing the limited resources in their habitats. Furthermore, it might be favorable to chemoautotrophs' lifestyles to form mutualistic interactions with these heterotrophic and/or mixotrophic acidophiles, whereby the latter could degrade organic compounds to effectively detoxify the environments. Collectively, the findings shed light on the genetic traits and potential metabolic activities of these organisms, and enable us to make some inferences about genomic and functional differences that might allow them to co-exist.

Enhanced Functional Connectivity between the Bilateral Primary Motor Cortices after Acupuncture at Yanglingquan (GB34) in Right-Hemispheric Subcortical Stroke Patients: A Resting-State fMRI Study

Increasing neuroimaging researches in stroke rehabilitation had revealed the neural mechanisms of rehabilitation therapy. However, little was known about the neural mechanisms of acupuncture therapy in subcortical stroke patients. The aim of this study was to investigate the changes of functional connectivity (FC) between the bilateral primary motor cortices (M1s) after acupuncture intervention in right subcortical stroke patients. Twenty right-hemispheric subcortical stroke patients and 20 healthy subjects were recruited to undergo one functional magnetic resonance imaging (fMRI) scanning. The scanning consisted of resting-state fMRI before and after needling at Yanglinquan (GB34), and task-evoked fMRI. The most significant active point during the left passive thumb-to-index task was chosen as the seed point. The seed-based FC analysis of the bilateral M1s was performed. Stroke patients revealed decreased FC between the bilateral M1s compared with healthy subjects, and the decreased FC was significantly enhanced after acupuncture at GB34. Acupuncture could increase the intrinsically decreased FC between the bilateral M1s which provided further insight into the neural mechanisms of acupuncture for motor function recovery in stroke patients.

Atomic-scale investigation of a new phase transformation process in TiO2 nanofibers

Crystallography of phase transformation combining transmission electron microscopy (TEM) with in situ heating techniques and X-ray diffraction (XRD) can provide critical information regarding solid-state phase transitions and the transition-induced interfaces in TiO₂ nanomaterials theoretically and experimentally. Two types of reduced titanium oxides (Ti₃O₅, Ti₆O₁₁) are found during ex situ and in situ heating of TiO₂ (B) nanofibers with a specific morphology of the {100} single form (SF) in air and vacuum. The results indicate that the phase transformation process from TiO₂ (B) follows the TiO₂ (B) → Ti₃O₅ → Ti₆O₁₁ → anatase sequence for the nanofibers with the {100} SF. The occurrence of such a phase transition is selective to the morphology of TiO₂ (B) nanofibers. The corresponding orientation relationships (COR) between the four phases are revealed according to the TEM characterization. Four types of coherent interfaces, following the CORs are also found. They are TiO₂ (B)/Ti₃O₅, TiO₂ (B)/Ti₆O₁₁, Ti₆O₁₁/anatase and TiO₂ (B)/anatase respectively. The habit plane for the TiO₂ (B) to Ti₃O₅ transition is calculated as the {100}_TB by using the invariant line model. The detailed atomic transformation mechanism is elucidated based on the crystallographic features of the four phases.

Feasible attack on detector-device-independent quantum key distribution

Recently, to bridge the gap between security of Measurement-device-independent quantum key distribution (MDI-QKD) and a high key rate, a novel protocol, the so-called detector-device-independent QKD (DDI-QKD), has been independently proposed by several groups and has attracted great interest. A higher key rate is obtained, since a single photon bell state measurement (BSM) setup is applied to DDI-QKD. Subsequently, Qi has proposed two attacks for this protocol. However, the first attack, in which Bob's BSM setup is assumed to be completely a "black box", is easily prevented by using some additional monitoring devices or by specifically characterizing the BSM. The second attack, which combines the blinding attack and the detector wavelength-dependent efficiency, is not explicitly discussed, and its feasibility is not experimentally confirmed. Here, we show that the second attack is not technically viable because of an intrinsically wavelength-dependent property of a realistic beam splitter, which is an essential component in DDI-QKD. Moreover, we propose a feasible attack that combines a well-known attack-detector blinding attack with intrinsic imperfections of single-photon detectors. The experimental measurement and proof-of-principle test results confirm that our attack can allow Eve to get a copy of quantum keys without being detected and that it is feasible with current technology.

[The clinical characteristics and treatment strategies of differentiated thyroid carcinoma in adolescents and children]

Objective:To study the clinical characteristics and treatment strategies of differentiated thyroid carcinoma in adolescents and children.Method:From 1983 to 2014, total 2936 patients with the thyroid cancer were collected in our hospital, among which there were 85 patients of adolescents and children with 61 female and 24 male. The age was from 9 to 21 years old (median 18.3 years). There were 12 cases less than 14 years.The pathologic diagnoses were papillary carcinoma 76 cases and follicular carcinoma 9 cases. The clinical material, history of disease, clinical presentation, TNM classification, histopathological features, treatment method, and the final follow-up results were analyzed and studied. Result:Overall survival rate was 100%, follow-up from 0.5 to 31 years(medium 10.9 years), 10 year progression free survival rate was 87.1%. There was no mortality and 8(9.4%)cases occurred recurrence,who followed by surgery and resumed finally. There were 20 cases found extrathyroid extention, including 8 cases less than 14 years and 12 cases older than 15 years. The extrathyroid extention rate was significantly higher in cases of lower years(66.7%)than other group(16.4%)(P<0.01). Forty-nine(57.6%) cases were found lymphanods metastases, among them ≤14 years metastases rate 92.0%（11/12）significantly more than ≥15 years metastases rate 52.1%(38/73) (P<0.05). Three patients suffered with pulmonary metastases and all of them were ≤14 years patients. All of 85 patients were received surgery treatment included total, subtotal and oneside thyroidectomy. The neck lymph nodes were underwent modefied, radical or no neck dissection. Fifteen patients were received 131I therapy postoperatively, the dosage was 50～170 mCi. All of 85 patients were received TSH suppression therapy. 13 cases(15.3%) occurred complications,such as laryngeal recurrent nerve paralysis and hypoparathyroidism commonly. Conclusion:Majority of thyroid cancer for adolescents and children are papillary and follicular carcinoma. The histopathologic feature has significant invasion beyond thyroid capsula, and metastasis to the lymphanods and distante area,especially ≤14 years patients significant more than ≥15 years. The prognosis is favorable, it is few death from thyroid cancer. The treatment means is surgery to resect all of the disease, sometimes should perform total or neartotal thyroidectomy if there are distant metastasis and extensive invasion. It should pay attention to preserve the function of recurrent laryngeal nerve and parathyroid gland. Most of them can be performed unilateral lobectomy if the tumor located oneside thyroid gland. The lymphanode metastasis should be undertaken modified neck dissection, make effort to avoid radical neck dissection. It should be carful to use 131I internal radiation therapy and avoid the excessive treatment.

Effect of the R92H and A379V genotypes of platelet-activating factor acetylhydrolase on its enzyme activity, oxidative stress and metabolic profile in Chinese women with polycystic ovary syndrome

Background

The G994T polymorphism in platelet-activating factor acetylhydrolase (PAF-AH) gene is associated with the risk of polycystic ovary syndrome (PCOS). The aim of this study was to investigate the relationship between R92H and A379V variants of the PAF-AH gene and the risk of PCOS and to evaluate the effects of the genotypes on PAF-AH activities and clinical, metabolic and oxidative stress indexes in Chinese women.

Methods

A total of 862 patients with PCOS based on the Rotterdam consensus criteria and 750 control women from a population of Chinese Han nationality in the Chengdu area were studied from 2006–2015. PAF-AH genotypes were determined by PCR and restriction fragment length polymorphism analysis. Plasma PAF-AH, high-density lipoprotein (HDL)-associated PAF-AH (H-PAF-AH) and apolipoprotein (apo) B-containing lipoprotein-associated PAF-AH (apoB-PAF-AH) activities were measured using the trichloroacetic acid precipitation procedure with PAF C-16 as a substrate. Circulating markers of oxidative stress, including serum total oxidant status, total antioxidant capacity, oxidative stress index and malondialdehyde levels, and clinical and metabolic parameters were also analyzed.

Results

No significant differences were observed in the frequencies of R92H and A379V genotypes and alleles of the PAF-AH gene between PCOS and control groups (P > 0.05). Compared with patients with the 92RR genotype, patients with H allele of R92H (RH + HH genotype) had significantly higher plasma PAF-AH and apoB-PAF-AH activities (P < 0.05) and tended to exhibit increased H-PAF-AH activity (P = 0.063) after adjusted for age and BMI. However, when serum LDL-C, HDL-C, TG and HOMA index were added as covariates, the comparisons no longer remained statistical significance (P > 0.05). There were no significant differences in clinical, hormonal, metabolic and circulating oxidative stress parameters and the frequencies of PAF-AH G449T genotype according to PAF-AH R92H or A379V genotyping in patients with PCOS and control women.

Conclusions

There were no significant associations between R92H and A379V variants of PAF-AH gene and risk of PCOS in Chinese women. The increased plasma PAF-AH and apoB-PAF-AH activities in patients with H allele of R92H are related to the R92 → H variation, changes in plasma lipoprotein levels, insulin resistance, aging, and gaining weight and thus may be involved in the pathogenesis of PCOS and the increased risks of future cardiovascular diseases.

Tunable terahertz reflection of graphene via ionic liquid gating

We report a highly efficient tunable THz reflector in graphene. By applying a small gate voltage (up to ±3 V), the reflectance of graphene is modulated from a minimum of 0.79% to a maximum of 33.4% using graphene/ionic liquid structures at room temperature, and the reflection tuning is uniform within a wide spectral range (0.1-1.5 THz). Our observation is explained by the Drude model, which describes the THz wave-induced intraband transition in graphene. This tunable reflectance of graphene may contribute to broadband THz mirrors, deformable THz mirrors, variable THz beam splitters and other optical components.

Electroacupuncture Attenuates Hyperalgesia in Rats Withdrawn from Chronic Alcohol Drinking via Habenular Mu Opioid Receptors

BACKGROUND

Hyperalgesia or increased sensitivity to pain is often found in alcoholics during alcohol withdrawal and may contribute to relapse drinking. Alternative therapies such as acupuncture and electroacupuncture (EA), through mechanisms involving opioid receptors, may reduce pain and substance dependence and withdrawal syndromes. The lateral habenula (LHb), an epithalamic structure rich in mu opioid receptors (MORs), is a critical target for both drugs of abuse and pain. We previously observed hyperalgesia in rats withdrawn from chronic ethanol (EtOH) drinking and found that EA at the acupoint Zusanli (ST36) reduced EtOH intake. This raised question of whether EA can alleviate hyperalgesia during alcohol withdrawal and, if so, whether the mechanism involves MORs in the LHb.

METHODS

We trained male rats to drink EtOH using the intermittent access 20% EtOH 2-bottle free-choice drinking paradigm for 8 weeks, after which the alcohol supply was discontinued. We measured pain sensitivity using radiant heat (a light beam directed at the hind paw of rats) and compared the paw withdrawal latencies (PWLs) with and without EA at ST36.

RESULTS

The PWLs were significantly shorter in rats at 24, 48, and 72 hours and 7 days after the discontinuation of EtOH when compared to EtOH-naïve rats. After a single administration of 2-Hz EA for 20 minutes at ST36, the PWLs at 24 hours after the withdrawal of EtOH were significantly greater than those of the sham group (2-Hz EA at the tail). Furthermore, the effect of EA on PWLs was significantly attenuated by bilateral intrahabenula infusion of the MOR antagonist naltrexone.

CONCLUSIONS

These results suggest that EA can alleviate hyperalgesia during EtOH withdrawal through a mechanism involving MORs in the habenula. Based on this, EA could be of potential value as a therapy for hyperalgesia in alcohol dependence.

[Determination of Impurity Elements in Rosin with Inductively Coupled Plasma Mass Spectrometry]

An analytical method for the content determining of impurity elements in rosin was established. After being dissolved and diluted in ethanol, the rosin was analyzed directly with inductively coupled plasma mass spectrometry (ICP-MS). Some experiment conditions were optimized, such as the RF power, carrier gas flow, sample amount, and increase the temperature of plasma center channel, to improve the ionization efficiency. Proper oxygen concentration was added in plasma to make sure organic carbon been complete burned, resulting in carbon deposits eliminate and signal stable. Though equipment turn and isotopes selection can effectively eliminate interferences caused by oxide and doubly charged ions mass spectrums. A large amount of isobars and polyatomic ion interference were avoided. The collision reaction cell (CRC) technology was used to further eliminate the mass spectra interference, with He collision model and H2 reaction model, respectively. The results showed that detection limits of different impurity elements were within the range from 0.002 to 0.035 μg·g-1, and the recoveries of real added sample were between the range from 94.00% to 106.00%, and relative standard deviation is less than 3.34%. This method enables to detect rosin dissolved in ethanol directly and needs no special sample preparation equipment. This simple, fast and accurate approach provides us a new analysis method for the quality valuation of impurity elements in rosin.

Persulfate-assisted photodegradation of diethylstilbestrol using monoclinic BiVO4 under visible-light irradiation

In this study, the photosynergistic performance of BiVO₄ with persulfate (PS) is demonstrated under visible light irradiation for the first time. Diethylstilbestrol (DES) was selected as a reluctant compound, and factors including dosages of PS and catalyst, solution pHs, initial concertration of DES, and inorganic anions were evaluated. The morphology and chemical state of bismuth vanadate (BiVO₄) was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), and ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy (DRS). It was found that the degradation of DES was promoted in either acid or alkaline solutions. The increase of PS and BiVO₄ dosages was beneficial to the reactions, while incremental concentration of DES showed the inhibiting effect. By scavenging h_VB⁺, Cl^- was able to make the promotion, differentiated from the exsiting HCO- 3. Moreover, the photocatalytic mechanism for the BiVO₄/PS/vis-light system was proposed by using several probe compounds (isopropanol, tert-butanol, and 1,4-benzoquinone), which consists of h+ VB/e- CB generation and recombination on the surface of BiVO₄ as well as free radical oxidation in the solutions. The study provides a distinctive method to treat organic contaminants using visible light in the aqueous environment.