UV Transmission Research Articles

High-Performance Radiative Cooling Sunscreen.

Radiative cooling is a zero-energy-consumption cooling technology that shows great potential for outdoor human thermal management. To keep human skin comfortable in hot days, we herein develop a radiative cooling (RC) sunscreen that exhibits a low ultraviolet (UV) transmissivity (4.86%), a high solar reflectivity (90.19%), and a high mid-infrared emissivity (92.09%) to effectively provide both UV protection and skin cooling. As a result, the RC sunscreen exhibits a high cooling performance for decreasing the human skin temperature by 2.3-6.1 °C more than commercial sunscreens and 4.2-6.0 °C more than bare skin in a variety of outdoor scenarios in summer (e.g., low-humidity sunny days, high-humidity sunny days, and high-humidity cloudy days). In addition, the RC sunscreen also shows a good UV stability (12 h, 125 W), a high water resistance (106°), a long working life (30 days), and a good biocompatibility, thereby exhibiting promising commercial potentials in the sunscreen market.

Optimizing Na2EDTA Concentration for Enhanced Properties of SILAR - Deposited CTS Thin Films

Abstract This study investigates the impact of varying Na2EDTA concentrations on the properties of copper tin sulfide (CTS) thin films deposited on soda lime glass substrates using the successive ionic layer adsorption and reaction (SILAR) method. The aim is to optimize CTS thin film growth for photovoltaic technology applications. CTS thin films were prepared using SILAR with Na2EDTA concentrations of 0.01M, 0.04M, and 0.07M, resulting in samples CTS01, CTS04, and CTS07. Characterization techniques included XRD, SEM, EDAX, FTIR, I-V curves, transmittance spectra, and Tauc plots. The results reveal significant variations in film properties with changing Na2EDTA concentration. XRD patterns indicate polycrystalline films with an orthorhombic CTS phase. SEM images show smooth, dense films with localized clusters. FTIR spectra detect hydrocarbon chains, aromatic rings, and hydroxyl or ether groups. The I-V curves of three samples (CTS01, CTS04, and CTS07) show a voltage-dependent transition from semiconducting to ohmic behavior. The CTS01 exhibits superior conductivity (3.13x10-5/Ωm), while the samples' resistance and conductivity values show an inverse relationship. Transmittance curves display low UV transmittance and high visible transmittance,suggests that the samples are highly absorptive in the UV range and become more transparent in the visible range, indicating potential applications in optical filtering and photovoltaic devices. Tauc plots estimate band gap energies of 3.66, 3.89, and 3.23 eV, indicating high band gap energies suitable for buffer layers in solar cells. The correlation between band gap energy and crystallite size as a function of Na2EDTA concentration is also observed. The study demonstrates the importance of optimizing Na2EDTA concentration for achieving high-quality CTS thin films with desirable properties for photovoltaic applications. The findings highlight the potential of CTS thin films for solar cells, optical filtering, and photonic devices.

A “core-shell” structure imparting both gas barrier and UV shielding properties for a PLA/ PGA/ PBS ternary blend film

The core-shell structure enhances polymer blend systems by orderly assembly and leveraging complementary properties. This study aims to enhance the flexibility and barrier properties of polylactic acid (PLA, L) by blending it with polyglycolic acid (PGA, G) for gas barrier and polybutylene succinate (PBS, B) for flexibility. Encapsulating PGA in a core-shell structure using PBS resolves PGA's rapid hydrolysis issue. The theoretical models predicting dispersion patterns based on spreading coefficients and interfacial tensions were validated through SEM observations, confirming the formation of a core-shell structure in the 5L1G4B ternary blend. Compared to the PLA/PBS binary blend film, samples with PGA (5L1G4B and 4L1G5B) exhibit higher elongation at break and tearing strength. For instance, the elongation at break of the 5L1G4B sample increases from 272.3 % of 6L4B to 470.85 %. The 5L1G4B showed comparable oxygen and carbon dioxide barrier properties to the 6L4B sample. The 5L1G4B and 4L1G5B samples show <2 % UV transmittance in the UVA region, indicating excellent UV shielding. The 5L1G4B blend film, with its mechanical properties, oxygen barrier, UV resistance, and biodegradability, is ideal for outer layer packaging film and has the potential to replace LDPE in packaging juice and dairy product bottles.

A new strategy to prepare bio-based polylactic acid modifier for multi-functionality: Dopamine-grafted modified lignin

Currently, to address the performance deficiencies associated with high brittleness, inadequate thermal stability, and susceptibility to hydrolysis in polylactic acid (PLA), it is common practice to incorporate multiple or high proportions of additives. However, this approach raises concerns regarding interface compatibility, energy consumption, and environmental impact. In this context, we introduce an environmentally friendly, bio-based PLA modifier that is facile to prepare and facilitates multi-functional applications at a minimal dosage. The presence of a benzene ring structure in lignin endows the material with ultraviolet (UV) resistance, thermal stability, and hydrophobic characteristics, while the exceptional adhesion properties of polydopamine (PDA) enhance interfacial compatibility. A novel biomass polylactic acid modifier, designated as OL@PDA, has been synthesized by modifying low-molecular-weight lignin (OL) with PDA. Comparative analysis of OL@PDA/PLA composite materials reveals a 14.08 % increase in tensile strength and a 42.00 % enhancement in elongation at break relative to pure PLA. The incorporation of the lignin-derived benzene ring structure effectively transforms PLA from a hydrophilic to a hydrophobic material. Furthermore, the UV transmittance at 400 nm (T400 nm%) is recorded at 65.8 % for pure PLA, which significantly decreases to below 5 % for OL@PDA/PLA composites. The integration of OL@PDA as a modifier in PLA materials yields comprehensively performance enhancements while maintaining a low additive concentration.

Plasma synthesis and characteristics of nanocomposite coatings based on PVA and chitosan with incorporated nanoparticles for the healing of skin wounds

This study investigated the impact of new composites based on PVA and chitosan on wound healing in mice. Metal or metal oxide nanoparticles were synthesized without reagents by creating an impulse discharge between metal electrodes in a polymer dispersion. Polymer composites and coatings were then prepared using these nanoparticles. The composites were analyzed using various techniques, including UV spectroscopy, X-ray diffraction, scanning and transmittance electron microscopy, and infrared spectroscopy. The maximum concentration of nanoparticles in the composite was 3.5%. The average diameter of the nanoparticles was approximately 50-60 nm. The inclusion of Ag and ZnO nanoparticles accelerated the healing process by approximately 25%.

Bio-Based Polyurethane Composites with Adjustable Fluorescence and Ultraviolet Shielding for Anti-Counterfeiting and Ultraviolet Protection.

Polyurethane and its composites play an important role in innovative packing materials including anticounterfeiting and ultraviolet protection, however, they are mainly derived from petroleum resources that are not sustainable. In this study, a 100% biobased thermoplastic polyurethane (Bio-TPU) was synthesized using biobased poly(trimethylene ether) glycol, pentamethylene disocyanate, and 1,4-butanediol. Subsequently, biobased tannic acid (TA) was employed to prepare biobased composites. The structures and properties of Bio-TPU and its composites were systematically evaluated. The results showed that the Bio-TPU/TA composite films had excellent and controllable fluorescence and UV-shielding properties. The fluorescence colors of the Bio-TPU/TA composite films could be adjusted to blue, green, and yellow by varying the TA content and adding coupling agents. Moreover, the UV transmittance of the Bio-TPU/TA composites decreased from 79.25 to 5.43% below 400 nm with an increasing TA content, indicating an excellent ultraviolet-barrier performance. Consequently, biobased TPU/TA composite films can be utilized as innovative anticounterfeiting materials and UV-shielding protection films. This study is expected to facilitate sustainable development in the polyurethane industry and broaden the high-end applications of polyurethane such as fashion, electronics, food manufacturing, pharmaceuticals, and finance.

Evaluation of the UV Protection Properties of Para-Aramid Woven Fabrics with Various Specialty Core Yarns.

Para-aramid fibers, known for their remarkable strength and thermal stability, are frequently employed in protective textiles for military and aerospace applications. However, continuous exposure to ultraviolet (UV) radiation can damage their protective characteristics. This study analyzes the ultraviolet protection factor (UPF) and UV transmittance of woven fabrics produced from 30/2 Ne spun para-aramid yarns in the warp and 10 Ne core-spun yarns in the weft. The weft yarns consisted of three sheath fibers-para-aramid, meta-aramid, and polyester-in combination with different specialty core materials. The results show significant differences in UPF before and after UV exposure, with para-aramid sheaths giving the highest improvement. UV exposure caused structural changes in the fibers, resulting in increased UV protection, particularly in fabrics with para-aramid sheaths. This study concludes that the combination of para-aramid fibers with specific core materials significantly enhances UV protection, making them well-suited for applications in high UV exposure environments.

Transparent X-ray Shielding Solutions with Various Metal Ions.

We fabricated transparent, Pb-free X-ray shielding materials using solvated ions in a polar solvent. Previous materials have been based on dispersions of metal-containing particles such as barium sulfate (BaSO4) in a matrix. Comparisons of suspensions of metal-based particles and solutions of metal ions in a solvent enable better understanding of interactions such as reflection, scattering, and absorption between X-rays and substances. The X-ray shielding properties of a solution of solvated metal ions were similar to or better than those of suspensions of metal-containing particles. In addition, the metal-ion solutions exhibited high transparency. The most effective material among those investigated for X-ray shielding was barium bromide (BaBr2), which exhibits high solubility in polar solvents. X-ray shielding of 92% was confirmed at a tube voltage of 120 kV, along with ∼90% UV transmittance at a visible-light wavelength of 400 nm. Thus, both high X-ray shielding performance and high transparency were achieved.

Glass Surface Nanostructuring by Soft Lithography and Chemical Etching.

Due to its high durability and transparency, soda lime glass holds a huge potential for several applications such as photovoltaics, optical instrumentation and biomedical devices, among others. The different technologies request specific properties, which can be enhanced through the modification of the surface morphology with a nanopattern. Here, we report a simple method to nanostructure a glass surface with soft lithography and wet-chemical etching in potassium hydroxide (KOH) solutions. Glass samples etched with a polymeric mask showed a nanopattern with stripes of widths between 220 and 450 nm and modulated heights between 50 and 200 nm. For different solution concentrations or etching times, the obtained nanopatterns led to an increase or reduction of the water contact angle. The largest increment, ~20 degrees, was achieved by etching the glass for 180 min with 30% KOH concentration, while a super-hydrophilic glass (~9° contact angle) was achieved when etching for 90 min with the same concentration. Optical characterization showed a very low influence of the nanostructured pattern on glass transparency and an increment in UV transmittance for some cases.

The relationship between contact lens ultraviolet light transmittance and myopia progression: a large-scale retrospective cohort study.

The prevalence of myopia is increasing dramatically around the world, and many studies have suggested the possibility that ultraviolet (UV) light is effective to prevent the onset and progression of myopia. However, UV is a risk factor for diseases that cause refractive errors such as cataract and pterygium. In this study, we evaluated the relationship between UV exposure and myopia progression. The dataset consisted of a total of 337 396 eyes of patients in the 12-to-29-year age range, who were prescribed soft contact lenses (SCL) for refractive error at Okada Eye Clinic in Japan between 2002 and 2011. They were tracked over a five-year period and did not change the type of SCL. In this retrospective cohort study based on medical records, we divided patients into two groups, one prescribed SCL with UV protection (UV-SCL), and another prescribed SCL without UV protection (UV+SCL). Change in refractive power over five years was measured and results compared. It was -0.413 diopter (D) in the UV-SCL group and -0.462 D in the UV+SCL group. Thus, the progression of myopia was slower in the UV-SCL group. The results were also analyzed separately by gender and degree of myopia at the time of initial prescription, which all showed significant differences (P<0.001). Results suggest that UV exposure may advance myopia. Further research is needed to investigate the underlying mechanisms that could explain this.

Preparation and study of polyvinylidene fluoride film with high UV aging resistance

Abstract Polyvinylidene fluoride materials were widely used in the preparation of solar panel films due to their excellent weather resistance and heat resistance. In this work, Polyvinylidene fluoride films with UV absorbers (PF/UV films) were prepared by customized extrusion equipment. The properties of these films were demonstrated with a scanning electron microscope (SEM), water contact angle (WCA), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and tensile strength tester. Furthermore, the SEM observation suggested that PF/UV films had smooth surfaces without significant defects. The WCA results illustrated that PF/UV films had better hydrophobicity than polyvinylidene fluoride films. The TGA and DSC curves indicated that the initial decomposition temperature and the melting temperature of the PF/UV film were 365.1°C and 169.2°C, respectively. Furthermore, the results of UV transmittance indicated that the UV aging resistances of PF/UV film were higher than that of polyvinylidene fluoride film.

The Production of Melanin Pigments From Some Pathogenic Fungi in Response to L-Tyrosine Under Laboratory Conditions

Background: This study aims to evaluate response of plant pathogenic fungi to the amino acid L-tyrosine through the production of melanin. Methods: Potato dextrose broth (PDB) and PDB with 1% L-tyrosine were used for current evaluation. Melanin was produced, extracted and characterized from pathogenic fungi that infected rice in Iraq. Results: Results indicated that L-tyrosine was used as a source of the precursor by fungi belonging to Bipolaris. spicifera R15, Alternaria. alternata R18, Exserohilum. rostratum R19, Alternaria. alternate R20, and Alternaria. tenuissima R23, also produced higher levels of condensed black pigment. While, fungi like Nigrospora oryzae R9, Curvularia lunata R7, C lunata R21 and A tenuissima R24 were used more than one pathway for melanin production. UV transmittance increased significantly from 600 nm to 300 nm whereas absorbance decreased at 260 and 280 nm for all of the studied fungi. Analysis of FT-IR spectra and related assignment group of resolved that melanin extracted from B. spicifera R15 (3408.22), A. alternate R20 (3392.79), and A. tenuissima R24 (3387). Wavenumbers 2924 cm−1 and 2854 cm−1 were found in E. rostratum R19, A. alternative R20, and A. tenuissima R24 melanin extracts, respectively. Meanwhile, B. spicifera R15 revealed a single peak at 2929 cm−1. 3007.02 cm−1, 3072.6 cm−1, 3074.53 cm−1, 2920.3 cm−1, 2704.2 cm−1, and 1861.31 cm−1 are also assigned wavenumbers. Conclusion: Melanin-like pigments are produced via L-tyrosine-dependent and independent pathways. All colors extracted from fungal hyphae were morphologically and chemically identical to melanin. A UV scan and FT-IR analysis revealed differences in the physical appearance of building units and the structure of the melanin pigment produced by plant pathogenic fungi.

Fabrication and characterization of long-lasting antifungal film containing cinnamaldehyde-loaded complex coacervation microcapsules based on gelatin and gum Arabic

A novel long-acting antifungal active film was successfully created, as an alternative to conventional chemical food preservatives. The antifungal films incorporated with cinnamaldehyde (CA) microcapsules achieved long-lasting antifungal activity, mitigated yellowing caused by the direct addition of CA, and showed improved flexibility properties. CA multinuclear microcapsules were produced using gelatin with a Bloom value of 200 and gum arabic, resulting in increased encapsulation efficiency (99.86 %), good dispersibility and enhanced antifungal ability (inhibition zone diameter of 32 mm). These microcapsules can be incorporated into films as a sustained-release antifungal agent. Compared to unencapsulated CA, the addition of 1 % CA microcapsules reduced the ultraviolet transmittance (<36.40 %) of the film while maintaining visible-light transmittance (36.40 %–65.20 %), and improving its elongation at break (23.49 %). The water vapor permeability of the film was not affected by the inclusion of CA microcapsules below 0.25 %. Moreover, microcapsules can enhance the thermal properties of the film. Antifungal films incorporated with 0.5 %–2 % microcapsules may offer better long-acting inhibition against A. brasiliensis. This study presents a new promising pathway for food storage.

One-step fabrication of multifunctional TPU/TiO2/HDTMS nanofiber membrane with superhydrophobicity, UV-resistance, and self-cleaning properties for advanced outdoor protection

This study successfully fabricated thermoplastic polyurethane (TPU)-titanium dioxide (TiO2)-hexadecyltrimethoxysilane (HDTMS) composite nanofibrous membrane (CNM), exhibiting superhydrophobicity, robust UV resistance, and anti-fouling properties, via electrostatic spinning technology. The nanofibrous membranes' (NM) microstructures were meticulously characterized using techniques such as field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), Raman scattering spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and 3D optical profiling. Performance evaluations included water contact angle measurement, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and uniaxial tensile and UV transmission tests. Results indicate that the CNM has an average fiber diameter of 179.28 nm, a static water contact angle (WCA) of 166.2 ± 0.5°, a sliding angle of 3.5 ± 0.8°, and a surface energy of 9.18 ± 0.6 mN/m. It also demonstrates commendable thermal stability with a tensile strength of 3.9 MPa, an elongation at break of 145.80 %, and an ultraviolet protection factor (UPF) of 1485 ± 13.2. It has considerable mechanical stability and can withstand 4000 tensile or 5000 compression cycles. The anti-fouling and moisture permeability tests reveal the membrane's superior functional performance. These attributes suggest a wide application potential for the CNM in anti-fouling outdoor protective clothing, sports footwear, and related fields.

Study of Factors Affecting UV-Induced Photo-Degradation in Different Types of Polyethylene Sheets.

Enhancing the degradability of polyethylene plastics could provide a potential solution to the overwhelming crisis of plastic waste. Conventional studies have focused on the degradation of polyethylene thin films. This study investigated UV-induced photo-degradation according to ASTM D5208-14 in polyethylene sheets with thicknesses ranging from 0.4 to 1.2 mm. The impacts of sample thickness, metal pro-oxidants, polyethylene resin types and foaming were explored through the characterization of the carbonyl index, molecular weight, tensile properties and crystallinity. As pro-oxidants, single iron or manganese stearate demonstrated a concentration-dependent trend in accelerating the photo-degradation of polyethylene sheets. The thickness, foaming and resin type-such as low-density polyethylene (LDPE) and high-density polyethylene (HDPE)-significantly impacted the rate of photo-oxidation. Thick polyethylene sheets (1.2 mm) exhibited a heterogenous and depth-dependent degradation profile. As the photo-degradation progressed, the enhanced crystallinity, reduced UV transmittance and formation of crosslinks were able to prevent further oxidative cleavage of the polyethylene chain. This study investigated the time course and factors affecting the photo-degradation of polyethylene sheets, which could provide insights into the formulation design of photo-degradable polyethylene plastics.

Preparation and properties of sustainable superhydrophobic cotton fabrics modified with lignin nanoparticles, tannic acid and methyltrimethoxysilane

Functional superhydrophobic cotton fabrics find extensive applications in both textile and non-textile domains. Nonetheless, fabric treatment typically relies on fluorine-containing compounds, inorganic nanoparticles and potentially hazardous organic solvents, posing environmental risks during fabrication and disposal. To address this issue, endeavours are underway to develop environmentally sustainable and cost-effective methods and materials for imparting superhydrophobic properties to cotton fabric surfaces. Here, we prepared lignin nanoparticles (LNP) utilising deep eutectic solvents and facilitated their surface adhesion to cotton fabrics through the self-polymerisation of tannic acid (TA) under alkaline conditions for the construction of micro-/nanostructures on the fabric surface. Subsequently, methyltrimethoxysilane (MTMS) was employed to confer superhydrophobic properties to the fabrics using a combination of thermal chemical vapour deposition techniques, resulting in a contact angle of approximately 164.3° and a sliding angle of 8.52°. Owing to the combined effect of TA and LNP, the modified fabrics exhibited excellent ultraviolet (UV) shielding ability (UV transmittance < 1 %, UV protection factor = 50 + ) and photothermal conversion (54.2 °C in 150 s). In short, micro-/nanostructures with surface hydrophilicity were constructed on the surface of cotton fabrics using two hydrophilic biomaterials, i.e. TA, which is similar to polydopamine but lighter in colour and less expensive, and LNP as sustainable colloidal particles. Subsequently, their surface roughness was further enhanced, and superhydrophobic properties were imparted through modification with the low surface energy substance MTMS. This method not only promotes the high-value utilisation of lignin but also serves as a reference for constructing superhydrophobic structures using biomass hydrophilic materials on cellulose substrates. The prepared superhydrophobic fabric suggests potential applications in water and stain repellence, self-cleaning, outdoor UV protection and the management of marine oil spill pollution.

Polymer hydrogel electronics with adhesive, self-healing, and anti-ultraviolet capabilities for machine learning-promoted electrophysiological detection

While adjustable mechanical properties, diverse biochemical features, and good ionic conductivity enabled by molecular engineering, polymer hydrogels as ionic skins (i-skins) are still limited by multiple challenges in the practical human health monitoring and health diagnosis, such as undesirable ductility and contact adhesion, poor functionality, and insufficient sensing ability. In view of this, the strategy of multiple dynamic interactions was proposed, and a mussel characteristic double-network polymer composite hydrogel (PG-BT2) with tannic acid and borax as dynamic media was reasonably designed. Due to the dynamic reversible interactions from the crosslinked network combined with special functional groups, the obtained PG-BT2 hydrogel attains remarkable stretchability with >1200 % elongation and good toughness of 268.6 kJ/m−3, and also possesses favorable versatility (e.g., self-healing time <2 s, adhesion strength of 4.62 kPa to pigskin, and UV transmittance of 15.3 % at 365 nm). Additionally, the i-skin derived from the PG-BT2 hydrogel exhibits excellent sensing properties, including a low interface contact resistance of 8.3 kΩ at 1 kHz, fast response/recovery time of 0.657 s/0.348 s, and a wide sensing range of 0–1100 % strain. By combining the hydrogel-based i-skin patch with the wireless circuit connected to a Bluetooth module, the constructed sensor system is capable of accurately monitoring micro-expressions and multi-joint movements. The portable system is also demonstrated to capture high-fidelity signals of electrocardiograms available for training artificial intelligence, achieving differentiation and recognition of blood pressure status, which will greatly benefit health management and intelligent medicine.

The Influence of Different Phase Function Combinations on Communication Quality in NLOS Communication Model

Wireless ultraviolet communication is a new type of communication technology, which uses the atmosphere as the transmission medium, and uses the scattering effect of atmospheric molecules and aerosol particles to change the propagation direction of the optical signal carrying information, bypass the blocking obstacles and finally reach the receiving end. The study of the scattering characteristics of ultraviolet light requires the use of scattering phase function. The scattering phase function is the ratio of the scattering energy in the unit solid angle in a specific direction to the average scattering energy in all directions. The scattering of ultraviolet light by the atmosphere is usually divided into two cases : Rayleigh scattering and Mie scattering. Therefore, the scattering phase function is also divided into two cases : Rayleigh scattering phase function and Mie scattering phase function. The scattering phase function in this paper is obtained by the weighted average of the two. There are many empirical formulas for Rayleigh scattering phase function and Mie scattering phase function. In this paper, the ultraviolet light of 266 nm wavelength is taken as an example to simulate and analyze the variation trend of scattering coefficient with wavelength and visibility, and the influence of the combination of different scattering phase functions on the received light power per unit area in the process of ultraviolet atmospheric transmission.

Efficacy of UVC-LED radiation in bacterial, viral, and protozoan inactivation: an assessment of the influence of exposure doses and water quality

Ultraviolet light-emitting diodes (UV-LEDs) have demonstrated the ability to inactivate microorganisms in water, offering an environmentally safer alternative to the conventional mercury lamp, in UV applications. While several studies have explored the microbiological effect of UVC-LEDs (200nm-280nm), limited information exists regarding their effects on waters with critical qualities. These critical qualities encompass bacteria, viruses, and protozoa – drinking water quality indicators defined by the World Health Organization for small water systems. For the first time, this work reports on the Escherichia coli, PhiX-174, MS2, and Cryptosporidium oocysts inactivation using a bench-scale UVC-LED (280 nm) water disinfection system. UV doses at a wavelength of 280 nm (UV280) of up to 143.4 mJ/cm2 were delivered under two quality-critical water conditions: filtered water (UV transmittance at 280 nm – UVT280 90.2 %) and WHO challenge water (UVT 15.7 %). Results revealed microbiological reductions dependent on exposure time and UVT. For UV280 dose of 16.1 mJ/cm2, 2.93-3.70 log E. coli reductions were observed in UVT 90.2 % and 15.7 %, 3.49-4.21 log for PhiX-174, 0.63-0.78 log for MS2, and 0.02-0.04 log for Cryptosporidium oocysts. Significantly higher UV280 doses of 143.4 mJ/cm2 led to reductions of 3.94-5.35 log for MS2 and 0.42-0.46 log for Cryptosporidium oocysts. Statistical analysis revealed that the sensitivity among the organisms to UV280 exposure was E. coli = PhiX-174 > MS2 >> Cryptosporidium oocysts. Although experiments with WHO challenge water posed greater challenges for achieving 1 log reduction compared to filtered water, this difference only proved statistically significant for PhiX-174 and MS2 reductions. Overall, UVC-LED technology demonstrated notable efficacy in microbiological inactivation, achieving significant reductions based on WHO scheme of evaluation for POU technologies in both bacteria and viruses even in critical-quality waters. The findings emphasize the potential for extending the application of UVC-LED as a viable solution for household water treatment.

Impact on the incorporation of metals in physicochemical and antimicrobial properties in films based on arrowroot starcha

New biodegradable packaging has been developed from renewable sources, mainly of vegetable origin. Arrowroot starch has been recently used to produce high-quality biodegradable films capable of behaving well when incorporating oils, extracts, metal, and metal nanocomposites. The study aimed to verify the impact of incorporating metals in the sulfate and chloride forms in a biopolymeric matrix from arrowroot starch in terms of biodegradability, physicochemical and microbiological parameters. Different arrowroot films were produced to incorporate solutions with a concentration of 1 Mol L-1 of sulfate and chloride metals. The action of biodegradability in soil, UV transmittance, and visible light were observed in UV-Vis spectrophotometry and antimicrobial action on Escherichia coli, Staphylococcus aureus, Salmonella serovar Typhimurium, and Salmonella serovar Enteritidis. Good results were obtained, such as biodegradability time between 81.70 to 100 % (30 days), a low transmission rate of UV radiation and visible light between 250 to 890 nm, high capacity for bacterial inhibition between 22.08 to 10.05 mm for E. coli, among 25.59 to 11.10 mm for S. aureus, between 22.14 to 11.66 mm for S. serovar Typhimurium and between 21.11 to 8.26 mm for S. serovar Enteritidis. It is concluded that the biodegradable films of arrowroot starch incorporated with metals showed potential in all the evaluated tests, thus characterizing possible new products for different uses, such as low time available in the environment, preservation of the characteristics of special products, and antimicrobial capacity.