Waste expanded polystyrene modified with H2SO4/biodegradable chelating agent for reuse: As a highly efficient adsorbent to remove fluoroquinolone antibiotic from water.

Untreated wastewater containing fluoroquinolone antibiotics poses serious hazards to aquatic species and human health; therefore, treatment of waste expanded polystyrene (EPS) is a crucial environmental matter. In this study, waste EPS was modified with a H2SO4/biodegradable chelating agent, [S,S]-ethylenediamine-N,N'-disuccinic acid (EDDS), and used for highly efficient adsorption of the fluoroquinolone antibiotic ciprofloxacin. When ciprofloxacin of 25 mg/L was used, the H2SO4-modified EPS (EPSH2SO4) adsorbed 60.5% of the ciprofloxacin. During sulfonation, adding a low dose of EDDS markedly improved the adsorption ability of EPSH2SO4+EDDS. The optimal modification conditions were 95% H2SO4, 0.002 M EDDS, 80 °C, and 40 min. The increased adsorbent doses enhanced the adsorption. Approximately 0.2 g/L of EPSH2SO4+EDDS could effectively adsorb 97.8% of the ciprofloxacin (554.3 mg/g) within 30 min. Solution pH0 greatly influenced the adsorption, and the most suitable pH0 was 6. The Langmuir isotherm accurately described the adsorption behaviors of both EPSH2SO4 and EPSH2SO4+EDDS (R2 = 0.997-0.998). The adsorption ability of EPSH2SO4+EDDS (qmax = 1250 mg/g) was 32 times higher than that of EPSH2SO4 (qmax = 38.6 mg/g). A total of 1 M HCl effectively regenerated the exhausted adsorbent. The optimal solid/liquid ratio and time were 0.08 g/20 mL and 60 min, respectively. The regenerated EPSH2SO4+EDDS maintained a high adsorption ability (87.2%) after 10 regeneration cycles. The results thus indicate that the EPSH2SO4+EDDS adsorption-regeneration process is a potential approach to remove ciprofloxacin from water.

Oxidative degradation of tetramethylammonium hydroxide (TMAH) by UV/persulfate and associated acute toxicity assessment.

Tetramethylammonium hydroxide (TMAH) is widely used in high-tech industries as a developing agent. Ultraviolet (UV) light-activated persulfate (PS, S2O82-) can be used to generate strongly oxidative sulfate radicals, and it also exhibits the potential to treat TMAH-containing wastewater. This study initially investigated the effect of S2O82- concentration and UV strength on the UV/S2O82- process for the degradation of TMAH in a batch reactor. The results suggested that 15 watts (W) of UV-activated S2O82- at concentrations of 10 or 50 mM resulted in pseudo-first-order TMAH degradation rate constants of 3.1-4.2 × 10-2 min-1, which was adopted for determining the hydraulic retention time (HRT) in a continuous stirred tank reactor (CSTR). The operating conditions (15 W UV/10 mM S2O82-) with a HRT of 129 min resulted in stable residual concentrations of S2O82- and TMAH at approximately 2.6 mM and 20 mg L-1 in effluent, respectively. Several TMAH degradation intermediates including trimethylamine, dimethylamine, and methylamine were also detected. The effluent was adjusted to a neutral pH and evaluated for its biological acute toxicity using Cyprinus carpio as a bioassay organism. The "bio-acute toxicity unit" (TUa) was determined to be 1.41, which indicated that the effluent was acceptable for being discharged into an aquatic ecosystem.

Effects of Reductants on Phytoextraction of Chromium (VI) by Ipomoea aquatica.

Reductants are often used to reduce Cr(VI) in chemical treatments, yet the effects of the reductants on Cr(VI) phytoremediation are not fully understood. This study investigates the effects of different reductants on Cr(VI) phytoremediation by Ipomoea aquatica in simulated solution with 3 mg L(-1) of Cr(VI), pH0 of 6, and an incubation time of 5 days. Results indicate that the applications of S2O3(2-), Fe0, and Fe2+ at low doses notably increased root Cr concentrations, which were obviously higher than that those in the control (Cr6+ alone). However, high reductant concentrations decreased bioaccumulation of Cr in the roots and shoots of the plant. Statistical results indicate that Cr concentrations were significantly and negatively correlated with Fe concentrations in the roots and shoots of the plant (p<0.05). This suggest that Fe accumulation inhibited Cr accumulation in the plant. A Cr(VI) concentration of 3 mg L(-1) caused short, brown lateral roots with tip necrosis, leaf chlorosis, and noticeable shoot wilting. The leaf necrosis and shoot wilting is caused by oxidative damage of lateral roots by Cr(VI) rather than by the reactive oxygen species generated by the oxidative stress. Addition of the reductants effectively reduced these plant injuries.

Study of the endoparasitic fauna of commensal rats and shrews caught in traditional wet markets in Taichung City, Taiwan.

BACKGROUND: Rats live in close proximity to human populations. Feral rodents are known to transmit diseases and act as reservoir hosts to many zoonotic parasites that pose health risks to humans. The aim of this study is to investigate endoparasitic infections in commensal rats and shrews caught in traditional wet markets in Taichung City, Taiwan. METHODS: A total of 51 commensal wild rodents and shrews were caught in traditional wet markets in Taichung City, including 32 Rattus norvegicus, 11 R. rattus, and eight Suncus murinus. All tissues, organs, and intestinal contents were carefully examined after euthanasia for the detection of parasites. RESULTS: The overall prevalence of infection was 94.1%, and the infection rates in R. norvegicus, R. rattus, and S. murinus were 93.8%, 90.9%, and 100.0%, respectively. Four cestodes (Taenia taeniaeformis, Hymenolepis diminuta, H. nana, and Raillietina celebensis), seven nematodes (Angiostrongylus cantonensis, Capillaria hepatica, Heterakis spumosa, Nippostrongylus brasiliensis, Strongyloides ratti, Syphacia muris, and Trichosomoides crassicauda), and one protozoan (Sarcocystis spp.) were detected. CONCLUSION: Our findings indicate that commensal rodents and shrews found in the traditional wet markets of Taichung City are hosts to various zoonotic parasites and, therefore, pose a serious health risk to humans and domestic animals in Taiwan.

Evaluation of acute toxicity and teratogenic effects of disinfectants by Daphnia magna embryo assay.

Three common disinfectants were selected in this study to investigate their toxicity to Daphnia magna. The methods used in this study included the traditional acute toxicity test, new embryo toxicity test, and teratogenic test. The study concluded that the acute toxicity of the three disinfectants to young daphnids and embryos were hypochlorite > formaldehyde > m-cresol. The effects on growth mostly occurred in the late stages of organogenesis. Of the organs, the Malpighian tube was the most sensitive to disinfectants during embryonic organogenesis. After exposure of the disinfectants to sunlight for 4 h, acute toxicity and teratogenic effects of hypochlorite on young daphnids decreased by 30% and 71%, respectively, while those of formaldehyde decreased by 35% and 49%, respectively. In addition, comparing toxic endpoints of the three disinfectants with and without sunlight exposure, the embryo tests were equally sensitive to the three-week reproduction test in this study.

Effects of UV irradiation on humic acid removal by ozonation, Fenton and Fe°/air treatment: THMFP and biotoxicity evaluation.

Effects of UV irradiation on humic acid (HA) removal by Fe(0)/air, ozonation and Fenton oxidation were investigated. The trihalomethane forming potential (THMFP) and toxicity of treated solutions were also evaluated. The experimental conditions were ozone of 21 mg min(-1), H(2)O(2) of 8 × 10(-4)M, Fe(0) of 20 g L(-1), air flow of 5 L min(-1), and UVC of 9 W. Results indicated that Fe(0)/air rapidly removed HA color (>99%) and COD (90%) within 9 min. 51-81% of color and 43-50% of COD were removed by ozonation and Fenton oxidation after 60 min. Both UV enhanced ozone and Fenton oxidation removed HA, but the Fe(0)/air process did not. Spectrum results showed all processes effectively diminished UV-vis spectra, except for ozonation. The THMFP of Fe(0)/air-treated solution (114 µg L(-1)) was much lower than those of Fenton- (226 µg L(-1)) and ozonation-treated solutions (499 µg L(-1)). Fe(0)/air with UV irradiation obviously increased the THMFP of treated solution (502 µg L(-1)). The toxicity results obtained from Vibrio fischeri light inhibition test indicated that the toxicity of Fe(0)/air-treated solution (5%) was much lower than that of ozonation- (33%) and Fenton-treated solutions (31%). Chlorination increased the solution toxicity. The correlation between biotoxicity and chloroform in the chlorinated solution was insignificant.

Evaluation of acute toxicity and teratogenic effects of plant growth regulators by Daphnia magna embryo assay.

This study selected common plant growth regulators (Atonik, Cytokinin, Ethephon, Gibberellic acid and Paclobutrazol) to investigate their biological toxicity to the waters of the important biological indicator Daphnia magna. The methods used in this study included traditional neonate acute toxicity test, new Daphnia embryo toxicity test, and teratogenic embryo test. The study concluded that the acute toxicity of the five PGRs to Daphnia neonate had EC(50) value range of 1.9-130.5 mg l(-1), while acute toxicity of PGRs on Daphnia embryo had EC(50) value range of 0.2-125 mg l(-1); the Daphnia embryos' LOEC values (0.05-48 mg l(-1)) for the five PGRs were lower than embryo EC(50) values. The toxic ratios of 48 h EC(50) (neonate)/48 h LOEC (embryo) for 5 PGRs were 19-512 times. The study found that teratogenic effects of Paclobutrazol and Cytokinin induced in embryo were higher than those of most other PGRs. Microscopic observation of the teratogenic effects showed that all 5 PGRs induced malformations of the second antenna, rostrum, Malpighian tube, sensory bristles, and tail spine as well as function loss and death.

Effects of dissolved oxygen on dye removal by zero-valent iron.

Effects of dissolved oxygen concentrations on dye removal by zero-valent iron (Fe(0)) were investigated. The Vibrio fischeri light inhibition test was employed to evaluate toxicity of decolorized solution. Three dyes, Acid Orange 7 (AO7, monoazo), Reactive Red 120 (RR120, diazo), and Acid Blue 9 (AB9, triphenylmethane), were selected as model dyes. The dye concentration and Fe(0) dose used were 100 mg L(-1) and 30 g L(-1), respectively. Under anoxic condition, the order for dye decolorization was AO7>RR120>AB9. An increase in the dissolved oxygen concentrations enhanced decolorization and chemical oxygen demand (COD) removal of the three dyes. An increase in gas flow rates also improved dye and COD removals by Fe(0). At dissolved oxygen of 6 mg L(-1), more than 99% of each dye was decolorized within 12 min and high COD removals were obtained (97% for AO7, 87% for RR120, and 93% for AB9). The toxicity of decolorized dye solutions was low (I(5)<40%). An increase in DO concentrations obviously reduced the toxicity. When DO above 2 mg L(-1) was applied, low iron ion concentration (13.6 mg L(-1)) was obtained in the decolorized AO7 solution.

Treatment and toxicity evaluation of methylene blue using electrochemical oxidation, fly ash adsorption and combined electrochemical oxidation-fly ash adsorption.

Treatment of a basic dye, methylene blue, by electrochemical oxidation, fly ash adsorption, and combined electrochemical oxidation-fly ash adsorption was compared. Methylene blue at 100 mgL(-1) was used in this study. The toxicity was also monitored by the Vibrio fischeri light inhibition test. When electrochemical oxidation was used, 99% color and 84% COD were removed from the methylene blue solution in 20 min at a current density of 428 Am(-2), NaCl of 1000 mgL(-1), and pH(0) of 7. However, the decolorized solution showed high toxicity (100% light inhibition). For fly ash adsorption, a high dose of fly ash (>20,000 mgL(-1)) was needed to remove methylene blue, and the Freundlich isotherm described the adsorption behavior well. In the combined electrochemical oxidation-fly ash adsorption treatment, the addition of 4000 mgL(-1) fly ash effectively reduced intermediate toxicity and decreased the COD of the electrochemical oxidation-treated methylene blue solution. The results indicated that the combined process effectively removed color, COD, and intermediate toxicity of the methylene blue solution.

Phytoremediation of Cr(III) by Ipomonea aquatica (water spinach) from water in the presence of EDTA and chloride: effects of Cr speciation.

Wastewater is often co-contaminated with chromium, chelating agents, and chloride. Influences of Cr(3+) speciation on Cr phytoremediation by Ipomonea aquatica were investigated. MINEQL+ was employed to estimate Cr speciation. Statistic regression was used to investigate the relationships between Cr speciation and accumulation. I. aquatica accumulated high Cr concentration (13,217 mg kg(-1)) in the root at Cr(3+) of 10 mg l(-1) and EDTA of 10(-4) M after 14 d growth. Pearson correlation analysis indicates that root Cr concentration significantly correlated with Cr-EDTA speciation (r = 0.67, p < 0.05) and Cr-Cl speciation (r = 0.91, p < 0.01). Shoot Cr concentration also significantly correlated with Cr-Cl speciation (r = 0.97, p < 0.01). An increase in Cl(-) concentration to 1.72 x 10(-4) M enhanced root Cr concentration; however, the accumulation of root Cr was inhibited at high Cl(-) concentration (5.76 x 10(-5) M). Microscopic image showed that a high portion of Cr(3+) accumulated on the root surface.

Treatment of Reactive Black 5 by combined electrocoagulation-granular activated carbon adsorption-microwave regeneration process.

Treatment of an azo dye, Reactive Black 5 (RB5) by combined electrocoagulation-activated carbon adsorption-microwave regeneration process was evaluated. The toxicity was also monitored by the Vibrio fischeri light inhibition test. GAC of 100 g L(-1) sorbed 82% of RB5 (100 mg L(-1)) within 4h. RB5-loaded GAC was not effectively regenerated by microwave irradiation (800 W, 30s). Electrocoagulation showed high decolorization of RB5 within 8 min at pH(0) of 7, current density of 277 A m(-2), and NaCl of 1 g L(-1). However, 61% COD residue remained after treatment and toxicity was high (100% light inhibition). GAC of 20 g L(-1) effectively removed COD and toxicity of electrocoagulation-treated solution within 4h. Microwave irradiation effectively regenerated intermediate-loaded GAC within 30s at power of 800 W, GAC/water ratio of 20 g L(-1), and pH of 7.8. The adsorption capacity of GAC for COD removal from the electrocoagulation-treated solution did not significantly decrease at the first 7 cycles of adsorption/regeneration. The adsorption capacity of GAC for removal of both A(265) (benzene-related groups) and toxicity slightly decreased after the 6th cycle.

Enhancement of Rhodamine B removal by low-cost fly ash sorption with Fenton pre-oxidation.

The removal of a basic dye, Rhodamine B (RhB), by fly ash adsorption, Fenton oxidation, and combined Fenton oxidation-fly ash adsorption were evaluated. Even though fly ash is a low cost absorbent, a high dose of fly ash was needed to remove RhB. Only 54% of RhB was removed by 80 g L(-1) fly ash. Solution pH did not significantly affect the RhB sorption by fly ash after 8h. Fenton reagents at H(2)O(2) dose of 6 x 10(-3)M and pH 3 rapidly decolorized 97% of RhB within 2 min, and 72% of COD removal was obtained at 30min reaction time. Spectrum analysis result showed that a large area of UV spectrum at 200-400 nm remained after Fenton reaction. The addition of 1gL(-1) fly ash effectively removed COD from Fenton-treated solution, and the UV absorption spectrum at 220-400 nm totally vanished within 2h. COD removal of RhB by the combined Fenton oxidation and fly ash sorption process was 98%. The COD removal capacity of fly ash for Fenton-treated RhB solution was 41.6 times higher than that for untreated RhB solution. The results indicated that the combined process is a potential technique for RhB removal.

Surveillance of endoparasitic infections and the first report of Physaloptera sp. and Sarcocystis spp. in farm rodents and shrews in central Taiwan.

A total of 95 rodents and shrews including 82 Rattus norvegicus, 7 Rattus rattus, and 6 Suncus murinus were trapped from different localities of Taichung, Taiwan. The overall prevalence of parasites was 93.7%. The infection rates for R. norvegicus, R. rattus, and S. murinus were 93.9%, 85.7%, and 100%, respectively. The rats were infected with four cestodes, Taenia taeniaeformis (48.4%), Hymenolepis diminuta (38.9%), Hymenolepis nana (5.3%), and Raillietina celebensis (45.3%); ten nematodes, Angiostrongylus cantonensis (16.8%), Capillaria hepatica (49.5%), Gongylonema neoplasticum (1.1%), Heterakis spumosa (35.8%), Nippostrongylus brasiliensis (57.9%), Physaloptera sp. (1.1%), Strongyloides ratti (81.1%), Syphacia muris (2.1%), Trichosomoides crassicauda (29.5%), and Trichurus sp. (1.1%), and one protozoan, Sarcocystis spp. (33.7%). Physaloptera sp. from S. murinus and Sarcocystis spp. from both R. norvegicus and R. rattus were reported for the first time in Taiwan. The importances of zoonotic species were discussed.

Degradation of azo and anthraquinone dyes by a low-cost Fe 0/air process.

Degradation of two different kinds of dyes, anthraquinone Reactive Blue 4 (RB4) and azo Reactive Black 5 (RB5), by low-cost zero valent iron (Fe(0)) in a N(2) bubbling system (Fe(0)/N(2) process) and air bubbling system (Fe(0)/air process) was investigated. The operating parameters, including initial solution pH, dye concentration and Fe(0) dose, were also evaluated. The Fe(0)/air process shows a higher decolorization rate compared to the Fe(0)/N(2) process. Both RB4 and RB5 solutions at 100 mg L(-1) were rapidly decolorized by Fe(0)/air process within 9 and 3 min, respectively, at initial solution pH 3, Fe dose of 50 g L(-1) and air flow rate of 5 L min(-1). The optimal initial solution pH was 3. The Fe(0)/N(2) process removed only <17% of COD. However, significant COD removals were achieved for RB 4 (87%) and RB5 (43%) by the Fe(0)/air process after 9 min of treatment. Spectra analysis results indicated that the Fe(0)/N(2) process destroyed only the anthraquinone group (A(594)) for the RB4 solution and decreased the azo (A(596)) and naphthalene group (A(310)) for the RB5 solution. However, the Fe(0)/air process rapidly removed A(594), A(370), A(296) (anthraquinone group) and A(256) (aromatic and dichlorotriazine group) for RB4, and A(597) and A(310) (naphthalene group) for RB5. The results indicated that the low-cost Fe(0)/air process is a potential technique for rapid degradation of RB4 and RB5 solutions.

Rapid recovery of dilute copper from a simulated Cu-SDS solution with low-cost steel wool cathode reactor.

Copper-surfactant wastewaters are often encountered in electroplating, printed circuit boards manufacturing, and metal finishing industries, as well as in retentates from micellar-enhanced ultrafiltration process. A low-cost three-dimensional steel wool cathode reactor was evaluated for electrolytic recovery of Cu ion from dilute copper solution (0.2mM) in the presence of sodium dodecyl sulfate (SDS), octylphenol poly (ethyleneglycol) 9.5 ether (TX), nonylphenol poly (oxyethylene) 9 ether (NP9) and polyoxyethylene (20) sorbitan monooleate (TW) and also mixed surfactants (anionic/nonionic). The reactor showed excellent copper recovery ability in comparison to a parallel-plate reactor. The reactor rapidly recovered copper with a reasonable current efficiency. 93% of copper was recovered at current density of 1 A m(-2) and pH 4 in the presence of 8.5mM SDS. Initial solution pH, cathodic current density, solution mixing condition, SDS concentration, and initial copper concentrations significantly influenced copper recovery. The copper recovery rate increased with an increase in aqueous SDS concentrations between 5 and 8.5mM. The influences of nonionic surfactants on Cu recovery from SDS-Cu solution depended not only on the type of surfactants used, but also on applied concentrations. From the copper recovery perspective, TX at 0.1mM or NP should be selected rather than TW, because they did not inhibit copper recovery from SDS-Cu solution.

Phytoextraction of cadmium by Ipomoea aquatica (water spinach) in hydroponic solution: effects of cadmium speciation.

Phytoextraction is a promising technique to remediate heavy metals from contaminated wastewater. However, the interactions of multi-contaminants are not fully clear. This study employed cadmium, Triton X-100 (TX-100), and EDTA to investigate their interactions on phytotoxicity and Cd phytoextraction of Ipomoea aquatica (water spinach) in simulated wastewater. The Cd speciation was estimated by a chemical equilibrium model and MINEQL+. Statistic regression was applied to evaluate Cd speciation on Cd uptake in shoots and stems of I. aquatica. Results indicated that the root length was a more sensitive parameter than root weight and shoot weight. Root elongation was affected by Cd in the Cd-EDTA solution and TX-100 in the Cd-TX-100 solution. Both the root length and the root biomass were negatively correlated with the total soluble Cd ions. In contrast, Cd phytoextraction of I. aquatic was correlated with the aqueous Cd ions in the free and complex forms rather than in the chelating form. Additionally, the high Cd bioconcentration factors of I. aquatica (375-2227 l kg(-1) for roots, 45-144 l kg(-1) for shoots) imply that I. aquatica is a potential aquatic plant to remediate Cd-contaminated wastewater.

Degradation of Reactive Black 5 using combined electrochemical degradation-solar-light/immobilized TiO2 film process and toxicity evaluation.

The combined electrochemical oxidation-solar-light/immobilized TiO2 film process was conducted to degrade an azo dye, Reactive Black 5 (RB5). The toxicity was also monitored by the Vibrio fischeri light inhibition test. The electrochemical oxidation rapidly decolorized RB5 (55, 110 microM) with a supporting electrolyte of 2 gl(-1) NaCl at current density 277Am(-2) and pH 4. However, TOC mineralization and A(310) removal were low. Additionally, the treated solution showed high biotoxicity. RB5 at 110 microM significantly retarded the de-colorization efficiency by using the solar-light/immobilized TiO2 film process. The combined electrochemical oxidation-solar-light/immobilized TiO2 process effectively increased the removal of color, A(310), and TOC. The toxicity was also significantly reduced after 3h of solar irradiation. The results indicated that the low-cost combined process is a potential technique for rapid treatment of RB5.

Screening long-time plating effluent qualities by sorbent sorption with XRF analysis.

Long-term monitoring of plating effluent quality traditionally requires dense frequency sampling and analysis for multiple elements are needed. An effective and rapid approach was developed to monitor long-time plating effluent quality. The approach employs the placement of low-cost sorbents (chitosan, zeolite and granular activated carbon) in plating effluents followed by analysis of multiple-element X-ray fluorescence (XRF). Three plating effluents were selected in this study. Laboratory Freundlich isotherm sorption experiments were also conducted to describe the relationships of metal concentrations on sorbents and in effluents. Results indicated that chitosan was a suitable sorbent to estimate the Zn, Ni and Cr concentrations in plating effluents. Granular activated carbon was suitable for Cu concentration monitoring in effluents. The accumulation of metals onto sorbents with different sorption periods (1-3 days) was also investigated.

First Thelazia callipaeda infestation report in a dog in Taiwan.

An ocular Thelazia callipaeda infestation was found in a male domestic dog in Taiwan during regular examination. This is the first report of the parasite from pet animal in Taiwan. The infested dog showed normal bodily condition but slight conjunctival congestion. This parasite has been reported in humans in southeast Asia, China and Korea. In 1998, first human case was reported in the central area of Taiwan. The dogs infected with T. callipaeda may have important implication in the infestation of this parasite to humans as reservoir hosts.

Demonstration of vector competence of Culex quinquefasciatus (Diptera: Culicidae) for Setaria digitata.

In Taiwan, Setaria digitata infection causes a lumber paralysis in increasing number of cattle. Culex quinquefasciatus is one of the predominant mosquitoes, and it has been suspected that C. quinquefasciatus acts as a vector to Setaria nematodes prevalence but this was not confirmed. C. quinquefasciatus, Aedes albopictus and A. aegypti of various strains were investigated using an artificial infection system to evaluate their vector competence. After blood feeding at day 14, the number of larvae (stage III) per infected mosquito in A. aegypti (Liverpool strain), A. aegypti (Kaohsiung strain), A. aegypti (Tungan strain), C. quinquefasciatus (Taichung strain) and A. albopictus (Taichung strain) was 1.3 +/- 0.1, 1.3 +/- 0.1, 1.4 +/- 0.1, 1.0 +/- 0.0 and 0 +/- 0.0 (mean +/- S.E.M), respectively. The vector efficiency index of A. aegypti (Liverpool) was the highest among mosquitoes whereas A. albopictus showed a complete refractoriness to the infection. In conclusion, C. quinquefasciatus demonstrates its potential competence for serving as a transmission vector of S. digitata. This mosquito might therefore be responsible, at least in part, for the prevalence of cattle lumbar paralysis in Taiwan. This is the first report of C. quinquefasciatu demonstrating its vector competence for S. digitata.