Strong Disinfectant Research Articles

Off-site production of plasma-activated water for efficient disinfection: The crucial role of high valence NOx and new chemical pathways

Efficient disinfection of pathogens is a critical concern for environmental disinfection and clinical anti-infective treatment. Plasma-activated water (PAW) is a promising alternative to chemical disinfectants and antibiotics for its strong disinfection ability and not inducing any acute toxicity. Previous plasma sources are commonly placed near or fully in contact with water as possible for more efficient activation, but the risk of electrode corrosion and metal particle contamination of water threatens the safety and stability of PAW. In this work, plasma-activated gas (PAG) rich in high-valence NOx is generated by a hybrid plasma configuration and introduced into water for off-site PAW production. It is found that plasma-generated O3 dominates the gas-phase reactions for the formation of high-valence NOx. With the time-evolution of O3 concentration, the gaseous NO3 radicals are produced behind N2O5 formation, but will be decomposed before N2O5 quenching. By decoupling the roles of gaseous NO3, N2O5, and O3 in the water activation, results show that short-lived aqueous species induced by gaseous NO3 radicals play the most crucial role in PAW disinfection, and the acidic environment induced by N2O5 is also beneficial for microbial inactivation. Moreover, SEM photographs and biomacromolecule leakage assays demonstrate that PAW disrupts the cell membranes of bacteria and thus achieves inactivation. In real-life applications, an integrated device for off-site PAW production with a yield of 2 L/h and a bactericidal efficiency of >99.9 % is developed. The PAW of 50 mL produced in 3 min using this device is more effective in disinfection than 0.5 % NaClO and 3 % H2O2 with the same bacterial contact time. Overall, this work provides new avenues for efficient PAW production and deepens insights into the fundamental chemical processes that govern the reactive chemistry in PAW for environmental and biomedical applications.

The Toxic Effects of Strong Chlorin Disinfectant on Mangroves and Emission Thresholds

The Toxic Effects of Strong Chlorin Disinfectant on Mangroves and Emission Thresholds

A Volume-Adjustable Artificial Womb for Extremely Preterm Infants.

More than 13 million children are born preterm annually. Prematurity-related mortality accounts for 0.9 million deaths worldwide. The majority of those affected are Extremely Preterm Infants (gestational age less than 28weeks). Immaturity causes organ failure and specific morbidities like germinal matrix hemorrhage, bronchopulmonary dysplasia, and necrotizing enterocolitis. Artificial womb and placenta technologies address these issues. As a bridge-to-life technology, they provide a liquid environment to allow organ maturation under more physiological conditions. The proposed artificial womb can adapt to fetal growth. Volume adjustment is achieved by removing fluid from the interspace between an inner and outer chamber. Results of the in vitro tests showed a temperature constancy of 36.8°C ± 0.3°C without pressure loss over 7days. The volume of the inner sac was variable between 3.6 and 7.0L. We designed a filtration and disinfection system for this particular purpose. This system has proven strong disinfection capabilities, effective filtering of metabolic waste, and the ability to avoid phospholipid washout. The presented artificial womb has sufficient volume variability to adapt to the physiologic growth of an extremely preterm neonate over a 4-week period. We regard this as an important step in the development of this bridge-to-life technology.

臭氧杀菌技术在农业和食品行业中的应用：综述

Ozone is a strong oxidant and strong disinfectant that has a strong anti-pathogenic effect on bacteria, fungi, parasites, and viruses. Because of its high reactivity, strong permeability, low residue, and other advantages, the application of ozone is gaining more and more attention, and ozone has been widely used in water treatment, equipment disinfection, public scene disinfection, and other fields. The purpose of this review is to discuss the use of ozone technology for animal and plant protection that can be applied to agriculture, and to emphasize the need for further studies to determine the optimal concentration and application of ozone for different crops so that, in the future, ozone technology can be applied in agriculture to gain a significant competitive advantage and improve product safety.

Detection of Haloacetic Acid in Swimming Pool in Haikou and Its Influencing Factors

Chlorine disinfection is a commonly applied disinfection products due to its effectiveness, strong disinfection ability, and low cost. The objective of this study is to investigate the occurrence of haloacetic acids (HAAs), a group of disinfection byproducts, in swimming pool and spa water, and analyze its influencing factors, so as to provide reference to understand the pollution status of haloacetic acid (HAAs) disinfection byproducts in swimming pool water in Haikou, for the formulation of hygienic standards and sanitation management of HAAs in swimming pool water. The samples were collected from 18 swimming places with sanitary licenses in Haikou. For a period from April to July 2022. High performance liquid chromatography -tandem mass spectrometry (HPLC-MS) was used to detect the concentration of HAAs in swimming pool water, and its influencing factors were also analyzed. . Results indicated that the levels of average concentration of HAAs in indoor and outdoor swimming pools were 176.20 μg•L-1 and 241.53 μg•L-1, respectively. There were differences in the levels of HAAs in indoor and outdoor swimming places (p<0.05). The Pearson correlation analysis showed that the concentration of HAAs was positively correlated with free chlorine and urea (p<0.05). The water quality and sanitation of the swimming pools in this survey were somewhat poor. It is necessary to formulate the regulation of HAAs in the swimming pool sanitation standards, strengthen the water quality sanitation management, and take further effective measures to reduce the concentration of HAAs to protect swimmers.

SUBSTANTIATION OF THE ELECTROLYTE COMPOSITION IN THE ELECTROCHEMICAL SYNTHESIS OF PEROXYLIC ACID

lactic acid (PLA) is a strong disinfectant with a wide spectrum of antimicrobial activity. Its widespread use is hampered by the lack of an electrochemical technology for PLA synthesis, which will make it possible to develop local electrochemical generators for the production of disinfectants. There is no information about the standard potential of the СН3СH(OH)С(=О)ОН « СН3СH(OH)С(=О)ООН system, both in reference literature and professional scientific publications. It has been shown that the electrochemical synthesis of PLA will be combined with the processes of oxygen release and the formation of hydrogen peroxide. To inhibit side processes, an additive to a solution of lactic acid 0.5 mol dm-3 H2SO4 was used. The adsorption of sulfate ions leads to the displacement of a certain proportion of water molecules outside the boundaries between the phase boundaries. An almost 2-fold increase in the anodic current density was also noted at the potentials of electrochemical synthesis of peroxide compounds. It has-been found that a lactic acid molecule is integrated into the structure of the near-electrode layer with a carboxyl group directed towards the anode surface. The inflection of the current-voltage curve, at potentials more positive than 1.70...1.75 V, indicates the course of the combined processes of the formation of peroxide compounds, proceeding with a significant inhibition of the oxygen reaction at the Pt/PtO2 anode. The release of oxygen under these conditions occurs due to the formation and destruction of H2O2. The potential difference between the forward and reverse runs of the current-voltage curve indicates a significant effect of lactic acid on the adsorption processes on the anode surface. The results obtained confirmed the relevant the choice of the Pt/PtO2 anode for the electrochemical synthesis of PLA. The characteristics of the electrolyte for the electrochemical synthesis of PLA has been defined: 2 mol dm-3 of lactic acid, 0.5 mol dm-3 of sulfuric acid.

Peracetic acid promotes biohydrogen production from anaerobic dark fermentation of waste activated sludge

Peracetic acid (PAA), a widely used organic peroxide with strong disinfection and oxidizing effect, has recently attracted research interest in waste activated sludge (WAS) treatment to achieve sludge reduction and resource utilization. However, its impact on hydrogen accumulation from WAS dark fermentation has not been documented. This study therefore is intended to fill in this knowledge gap and clarify the underlying mechanism of PAA-promoted hydrogen generation. Batch experiments revealed that when raised PAA dosage from 0 to 8 mg/g TSS (total suspended solids), cumulative hydrogen production within 168 h fermentation increased from 1.3 to 14.2 mL/g VSS (volatile suspended solids), however, further increase PAA dosage to 10 mg/g TSS resulted in a slight decrease in hydrogen yield. Mechanism studies revealed that PAA was beneficial to sludge disintegration (10 mg/g TSS PAA increased SCOD (soluble chemical oxygen demand) by 254 %). Although PAA inhibited the activity of all microorganism involved in dark fermentation, the inhibitory effect on hydrogen consumers were much more serious than that on hydrogen producers (−45.8 % versus −5.1 % and − 7.3 %). The fermentation was found to shift from propionate type to acetate and butyrate type, favoring hydrogen production. Moreover, the methane production process was effectively inhibited by PAA, which meant less hydrogen consumption. Microbial community analysis results unveiled that PAA increased the abundances of hydrolytic bacteria (e.g., norank_f__Saprospiraceae) and hydrogen producers (e.g., Clostridium_sensu_stricto_10). These findings obtained in this work provide new insights into oxidants-involved sludge treatment process and might have important implication for WAS treatment and bioenergy production in the future.

SOLAR BASED SMART COVID PROTECTION SYSTEM

The design shown shows the precautions that can be taken around the world during the COVID 19 pandemic. Disinfectants have become one of the most important products these days. Strong disinfection is required to survive the new WHO rules and regulations. The design provided a solution to the problem mentioned. This design introduces an automatic hand disinfection and temperature detection system that allows you to disinfect your hands at any time without touching the disinfectant. The temperature sensor shows the temperature of the person when touched. Keywords:- Automatic hand sanitizer, Arduino, ultrasonic sensor, PIR sensors, TMP36, covid-19.

Green detection of trace cyanuric acid and free chlorine together via ion chromatography

Chlorinated cyanurates (CCAs) are a type of disinfectants currently used worldwide for fight of Coronavirus. However, CCAs upon dosed into water can release not only free chlorine (FC), a strong disinfectant, but also cyanurate (CYA), a persistent compound potentially harmful to human and environment. Therefore, detecting CYA and FC in water are very important not only for ensuring sufficient disinfection but also for monitoring the impacts of FC and CYA on receiving watershed. However, conventional analytical methods for them are mostly based on colorimetric methods, which have high method detection limits (MDLs) and rely on chemical reactions that are likely sensitive to coexisting chemicals. To overcome these issues, we herein proposed a facile and reaction-free method to detect CYA and FC together in just one run by ion chromatography (IC) equipped with both conductivity and ultraviolet absorbance detectors. The method features obvious advantages over colorimetric methods in being lower MDLs (3.6 μg/L for CYA and 9.0 μg/L for FC), environmental-friendly (i.e., no organic solvent involved), and more resistant to alkaline solution. With this method, trace levels of CYA (i.e., 34–44 μg/L), which were nondetectable by conventional method, were found in two river water samples, implying that the local environment was already polluted by CCAs during the pandemic period. Overall, this study demonstrates a robust tool that may assist better understanding and monitoring the fate and transport of trace CCA derivatives in water.

Natural sanitizer potential of Cuminum cyminum and applicable approach for calculation of Kováts retention index of its compounds

ABSTRACT The demand for natural agents instead of chemicals in terms of food and health safety is increasing day by day. This study aimed to investigate the potential of the methanolic extract of Cuminum cyminum (C. cyminum) in the fight against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus)and Candida (C. albicans). The chemical composition of the methanolic extract of C. cyminum was analyzed using GS-MS. Also, Kováts retention indices were calculated for the detected compounds using an applicable formula. The most basic substance was cuminic aldehyde (27.86%) and p-(Dimethoxymethyl)-isopropylbenze (18.32%). The Minimum Inhibitory Concentration (MIC) of the extract was 0.1 g/mL for S. aureus and C. albicans while it was > 0.1 for E. coli. Although the methanol extract of C. cyminum acts against all three microorganisms, the most lasting effect was on S. aureus, indicating that it can be recommended as a strong antibacterial disinfectant for S. aureus.

Slightly Acidic Electrolyzed Water to Remove Methylobacterium mesophilicum, Rhodotorula mucilaginosa and Cladosporium cladosporioides in Households

(1) Background: Slightly acidic electrolyzed water (SAEW) is an effective and safe sterilizing solution. Its active component is hypochlorous acid (HOCl) which has been proved to exhibit a strong disinfectant activity. In this research we evaluated the effectiveness of SAEW in the removal of Methylobacterium mesophilicum, Rhodotorula mucilaginosa and Cladosporium cladosporioides, responsible for pink-colored biofilm and black mold in households. (2) Methods: Two concentrations of SAEW, 20 mg/L and 40 mg/L, were tested against M. mesophilicum, R. mucilaginosa and C. cladosporioides. In vitro experiments and mesh experiments were conducted to test the effectiveness of SAEW. (3) Results: The test results showed that 40 mg/L SAEW was effective in removing R. mucilaginosa and C. cladosporioides, with the population decreasing by approximately two orders of magnitude. For M. mesophilicum, resistance towards SAEW was observed; to obtain a 1.3 order of magnitude decrease in bacterial population, washing 5 times with 40 mg/L SAEW was necessary. Mesh experiments showed that SAEW can remove black mold; (4) Conclusions: Overall results indicated that SAEW was particularly effective for R. mucilaginosa and C. cladosporioides species commonly found in Japanese households.

Wetting properties of dehydrated biofilms under different growth conditions

Biofilms are resilient to environmental conditions and often resistant even to strong disinfectants. It is crucial to investigate their interfacial properties, which can be effectively characterized by wetting analysis. Wetting phenomena on biofilm surfaces have been poorly investigated in literature, in particular a systematic study of wetting on real biofilm-coated substrates including the application of external body forces (forced wetting, i.e.: centrifugal and gravitational forces) is missing. The aim of this work is to study the role of nutrient and shear flow conditions on wetting properties of Pseudomonas fluorescens dehydrated biofilms, grown on glass substrates. An innovative device (Kerberos®), capable to study spreading/sliding behavior under the application of external body forces, is used here for a systematic analysis of wetting/de-wetting liquid droplets on horizontal substrates under the action of tangential forces. Results prove that, under different growth conditions, (i.e., nutrients and imposed flow), biofilms exhibit different wetting properties. At lower nutrient/shear flow conditions, biofilms show spreading/sliding behavior close to that of pure glass. At higher nutrient and shear flow conditions, droplets on biofilms show spreading followed by imbibition soon after deposition, which leads to peculiar droplet depinning during the rotation test. Wetting properties are derived as a function of the rotation speed from both top and side views videoframes through a dedicated image analysis technique. A detailed analysis of biofilm formation and morphology/topography is also provided here.

Discussion on effect of material on UV reflection and its disinfection with focus on Japanese Stucco for interior wall

Research has previously shown that ultraviolet light C (UV-C) can inactivate unexpected infection. However, this type of potential disinfection is dramatically reduced for the shadow area such as under desk or medical equipment. Because the UV-C reflectance ratio is low on the general wall surfaces. We compared Stucco against the other materials to investigate whether we could improve disinfection for the shadow area. The reflectance ratios of UV-C irradiation of each material were examined, with particular attention to the rates for the author’s Modified Stucco. To evaluate the disinfection effects of the UV-C reflective lighting, colonies of E. coli and of Staphylococcus hominis were cultured in an agar media and counted over a certain time period after applying UV-C irradiation from a sterilizing lamp onto the investigation materials. The author’s Modified Stucco, produced reflectance ratios that was 11 times that of white wallpaper. This demonstrated that the UV-C reflected on the Stucco wall having optimum components and their compositions inhibited the number of E. coli and S. hominis, resulting in significantly disinfection effects on white wallpapers. The space with Modified Stucco and then irradiated by a UV-C may give a strong disinfection effect.

Evaluation of N doped rGO-ZnO-CoPc(COOH)8 nanocomposite in cyanide degradation and its bactericidal activities

In the present study, an attempt has been made to design a solar light driven N-rGO-ZnO- CoPc(COOH)8 nanocomposite for the degradation of cyanide. The morphological and structural characterization of the synthesized nanocomposite was performed by XRD, FT-IR, XPS, UV–vis DRS, FESEM, TEM, EDS, PL spectra and BET surface area. The results revealed that almost 91% degradation and 86% toxicity removal occurred at 25 mgL−1 of initial cyanide concentration by the N-rGO-ZnO-CoPc(COOH)8 nanocomposite under illumination of solar light within 120 min. Analysis of free radicals reveals that the generation of OH. radicals was the predominant species in the photocatalytic degradation process. The cyanide degradation follows pseudo-first order kinetics. The estimated apparent rate constant (Kapp) of the above nanocomposite was 3 times higher than that of the ZnO photocatalyst alone together with a very good recycle activities. This might be due to the application of metallpthalocyanine photosensitizer CoPc(COOH)8 which enhances the rate of visible light absorption efficiency and activates the higher band gap ZnO photocatalyst under visible light. In addition, the presence of residual oxygen in N-rGO also promotes nucleation and anchor sites for interfacial contact between ZnO and N-rGO for effective charge transfer. Further, the N-rGO-ZnO-CoPc(COOH)8 photocatalytic system showed significant antibacterial activities against mixed culture systems. Therefore, the N-rGO-ZnO-CoPc(COOH)8 nanocomposite may be an alternative solar light driven photocatalyst system for the removal of cyanide from the wastewater along with its strong disinfectant activities.

Influence of New Compound Disinfectant From N-Dodecyl-2-(Piridin-1-Ium)Acetamide Chloride on Pathogenic Microorganisms in Poultry Houses.

With the development of large-scale and intensive poultry farming, environmental disinfection has become particularly important, and the effectiveness of disinfection depends upon the performance of the disinfectants. Quaternate ammonium salt is a group of positively charged polyatomic ions with both antibacterial and antiviral activities. In order to prepare an ideal disinfectant for poultry farms, we combined a quaternate ammonium salt N-dodecyl-2-(piridin-1-ium)acetamide chloride with two other disinfectants (chlorhexidine acetate and glutaraldehyde), respectively. The antimicrobial activity, mutagenicity, and safety of the compound disinfectants were assessed by the European Standard methods using ATCC strains and clinical isolates. The results showed that both compound disinfectants meet the requirements of microbial reduction, and their effectiveness was not affected by organic matter. Quaternary ammonium disinfectant resistance genes were not detected in the strains tested indicating that bacteria are less likely to develop resistance to these compound disinfectants. Ames test showed that there was no detectable mutagenicity in the strains treated with the compound disinfectants. In vivo experiment showed that both compound disinfectants did not have significant pathological effect in mice. The bactericidal effect of the compound disinfectants was not significantly different among strains of different sources (p>0.05). Clinical tests showed that compound disinfectant had a good bactericidal effect on the air and ground of poultry farms. These results show that quaternary ammonium salts in combination with other compounds can enhance the bactericidal effect and can be used safely in poultry feedlots. This study provides a technical reference for the development of a new quaternate ammonium compound disinfectant with strong disinfection effect and low irritation.

Controlling Growth of Multidrug-Resistant Staphylococci Isolated from Sports Mats: A Report from the Golestan Province, Iran

Background: Gyms are among the places where various human infections can spread. One of the most important strategies to prevent infection spread among athletes is the use of strong and effective disinfectants. Objectives: The aim of this study was to evaluate and compare the antiseptic properties of chlorhexidine gluconate and pomegranate peel extract on staphylococcal isolates from sports mats. Methods: This descriptive-analytical study was performed on 22 Staphylococcus aureus, and Staphylococcus epidermidis isolates from a total of 105 sports mat samples. After identification of multi-drug resistant (MDR) staphylococcal isolates, the antimicrobial effect of chlorhexidine gluconate 20% and pomegranate peel extract was evaluated by broth microdilution according to the instructions of the Clinical and Laboratory Standards Institute. Results: Overall, 14 (66.7%) S. aureus and 8 (28.6%) S. epidermidis isolates resistant to azithromycin, linezolid, ciprofloxacin, vancomycin, and aztreonam were reported as MDR strains. The minimum inhibitory concentration (MIC) of chlorhexidine gluconate, which inhibited the growth of 90% of MDR S. aureus isolates was 250 μg/mL, which was 4-fold lower than the MIC of pomegranate peel extract (MIC90 ≥ 500μg/mL) and 2-fold lower against MDR S. epidermidis isolates (MIC90 ≤ 125 μg/mL). The MIC of chlorhexidine gluconate and pomegranate peel extract against S. aureus isolates differed significantly (P = 0.037). Conclusions: Compared to pomegranate peel extract, chlorhexidine gluconate has a higher antibacterial effect on MDR staphylococcal isolates from sports mats. Further research is required to verify the efficacy of this biocide for disinfection of gyms and sports clubs.

The value of a nano-bamboo charcoal ankle guard combined with ankle-joint rehabilitation treatment on the rehabilitation effect of ankle-joint motor injury

Ankle-joint sports injuries with poor rehabilitation results can seriously affect a patient’s quality of life. Nanobamboo charcoal has a strong adsorbability and disinfection effect. It has been used in ankle guards, but the effect of nanometer-sized bamboo charcoal has not been reported thus far. In this study, 98 patients with an ankle-joint motor injury were divided into a Regular Group and Joint Group (49 cases, each) using the random number table method. The Regular Group received the conventional treatment, and the Joint Group received nano-bamboo charcoal ankle guard combined with ankle-joint rehabilitation treatment. The analysis showed that ankle function, balance function, dorsiflexion range of motion, American Orthopedic Foot Ankle Society score, and total effective rate (91.84% vs. 73.47%) in the Joint Group were all higher than those in the Regular Group, while the Visual Analog Scale and Clinical Symptom Score scores were all lower than those of the conventional group (P < 0.05). This indicates that a nano-bamboo charcoal ankle guard combined with ankle-joint rehabilitation treatment can effectively reduce pain and improve ankle-joint balance, movement, dorsiflexion range of motion, and other functioning parameters of the patients, with a significant curative effect and high clinical application value.

Mycobacterium Abscessus Masquerading as Disseminated Mycobacterium Tuberculosis Infection

Disseminated infection caused by mycobacterium abscessus is a rare condition, observed in immunodeficient or immunosuppressed individuals. We report a case of disseminated mycobacterium abscessus infection, which occurred in a nine-year-old boy with a ventriculoperitoneal shunt. He presented with features of meningitis, ascites and later developed pleural effusion. This infection closely mimics mycobacterium tuberculosis infection, which is endemic in India. Multidrug therapy with macrolides and aminoglycosides, for prolonged duration, can help to eradicate the organism. Mycobacterium abscessus infections can occur following neurosurgical interventions, with surgical shunts and prostheses acting as the portals of entry, thus prompting strong disinfection and sterilization measures in the operating room.

A need to combat COVID-19; herbal disinfection techniques, formulations and preparations of human health friendly hand sanitizers

Indigenous medicinal plants enriched with flavonoids, alkaloids, poly-phenolic compounds carry antiseptic, disinfectant and antimicrobial activities. During old era, plant extracts were used as strong antiseptics and disinfectants to get ride from microbes. We aimed to present the herbal formulations and preparations for human health hazards free hand sanitizers based on indigenous medicinal plants with reported effective results against infectious microbes along with least toxic impact on environment. Easily available plants formulations safe to human health and environment are presented with easy procedure for their preparations. Data have been collected from literature for dissemination to scientific community and common society. A recent report published on human health hazards linked with the frequent use of alcohol based hand sanitizers provoked the scientific community to prepare safe hand rubs. National Poison Data System, USA revealed 36.7% increase in alcoholic hand sanitizer exposure and toxicity in first three months of 2020 as compared to 2019. Adaptation of alternative preparations of hand sanitizers based on natural and plant resources are the possible solution to get ride off toxicity problem. There should be more detailed screenings of indigenous plants with enriched flavonoids contents for their antiseptic properties and to develop eco-friendly and effective hand sanitizers as compared to chemical formulations.

Influence of Ozone on the Biochemical Composition of Birch Sap

Studies have shown that ozone is a good oxidizer and a strong disinfectant. There are many uses for ozone in the food industry, but there is relatively little information about the influence of ozone on biochemical composition and the capacity to reduce the number of microorganisms in birch sap. In this study, sap was ozonated at different intervals for 5 min (O3: 0.087 ± 0.009 mg L−1), 10 min, 15 min, 20 min, 25 min, or 30 min (O3: 0.99 ± 0.09 mg L−1). The parameters of the birch sap were studied immediately after the ozone treatment as well as during storage for seven days at 2 °C and for five days at 20 °C. The parameters of ozonated birch sap were compared with the parameters of fresh sap (control). The microbiological analysis included total bacterial count, lactic acid bacterial count, and yeast and mold count. Birch sap color, pH, titratable acidity, and ºBrix values were also determined. Evaluation of monosaccharides, sucrose, total sugars, and ascorbic acid was carried out in fresh sap as well as sap ozonated for 30 min, immediately after ozonation. The results show the statistical significance of the inactivation of microorganisms after treatment in most cases. The microorganism counts gradually reduced with increasing intervals of ozone treatment. The best results were obtained after 25 and 30 min of ozonation. Ozone treatment did not significantly influence the pH, titratable acidity, or °Brix statistically. Values of monosaccharides, sucrose, total sugars, and ascorbic acid were influenced within the margin of error. Ozone had a significant influence on the chroma and hue angle.