ultraviolet-C Irradiation Research Articles

Dose-dependent physiological effects of UV-C radiation on seashore paspalum

Positive effects of ultraviolet-C (UV–C) radiation on plants have been documented in previous literature with a focus on extending shelf life and reducing disease development. However, its effect on plant growth habits has been scarcely explored, especially in turfgrass where a compact shoot growth is a desirable trait. Seashore paspalum (Paspalum vaginatum) is a warm-season perennial turfgrass requiring low fertilizer and pesticide inputs. This project aimed to test the effects of different doses of UV-C radiation on growth and performance of seashore paspalum cv. Seastar. Here, we provide evidence of dose-dependent effects. Lower UV-C doses (6 s and 1 min daily) improved the performance of seashore paspalum, as manifested by higher tiller density, reduced clipping yields, increased chlorophyll level on selected dates as well as enhanced photosynthetic efficiency compared to control. Contrastingly, higher doses (6 min and 30 min daily) resulted in severe damage with 30-min treatment being lethal to seashore paspalum, causing marked declines in all measured parameters. This is the first time that UV-C-induced growth response was reported in turf. Conclusions drawn from this study would shed light into the effects of UV-C radiation on the growth and performance of seashore paspalum and offer exciting potential for the utilization of UV-C at non-lethal dosage in turfgrass management.

Germicidal efficacy of continuous and pulsed ultraviolet-C radiation on pathogen models and SARS-CoV-2

Ultraviolet radiation’s germicidal efficacy depends on several parameters, including wavelength, radiant exposure, microbial physiology, biological matrices, and surfaces. In this work, several ultraviolet radiation sources (a low-pressure mercury lamp, a KrCl excimer, and four UV LEDs) emitting continuous or pulsed irradiation were compared. The greatest log reductions in E. coli cells and B. subtilis endospores were 4.1 ± 0.2 (18 mJ cm−2) and 4.5 ± 0.1 (42 mJ cm−2) with continuous 222 nm, respectively. The highest MS2 log reduction observed was 2.7 ± 0.1 (277 nm at 3809 mJ cm−2). Log reductions of SARS-CoV-2 with continuous 222 nm and 277 nm were ≥ 3.4 ± 0.7, with 13.3 mJ cm−2 and 60 mJ cm−2, respectively. There was no statistical difference between continuous and pulsed irradiation (0.83–16.7% [222 nm and 277 nm] or 0.83–20% [280 nm] duty rates) on E. coli inactivation. Pulsed 260 nm radiation (0.5% duty rate) at 260 nm yielded significantly greater log reduction for both bacteria than continuous 260 nm radiation. There was no statistical difference in SARS-CoV-2 inactivation between continuous and pulsed 222 nm UV-C radiation and pulsed 277 nm radiation demonstrated greater germicidal efficacy than continuous 277 nm radiation. Greater radiant exposure for all radiation sources was required to inactivate MS2 bacteriophage. Findings demonstrate that pulsed irradiation could be more useful than continuous UV radiation in human-occupied spaces, but threshold limit values should be respected. Pathogen-specific sensitivities, experimental setup, and quantification methods for determining germicidal efficacy remain important factors when optimizing ultraviolet radiation for surface decontamination or other applications.Graphical abstract

Ultraviolet-C lamp control system designed to estimate deactivation of the coronavirus disease

To prevent the transmission of the coronavirus disease (COVID-19), one approach involves the application of disinfectants containing specific chemical compounds. Nonetheless, an overabundance of chemicals may yield adverse effects on both humans and the environment. Therefore, alternative methods are needed to prevent the spread of the virus without endangering humans and the environment. One method that minimizes the use of chemicals is ultraviolet-C (UV-C) light. The method used in this study is to make a UV-C lamp control system based on the internet of things (IoT). Then conduct experiments on the spread of UV-C radiation using a system that has already been built. Based on the research that has been done, a disinfectant system has been successfully designed using two Philips 30 W UV-C lamps with Wemos D1 mini microcontroller and Blynk application. The results of data collection show that the highest ultraviolet-C radiation irradiation on the intended object is 0.017 mW/cm<sup>2</sup> with a distance between the two is 1.5 m.

UV-C pretreatment of wastewater-grown algal biomass for recover of biofuel precursors

In the present study, ultraviolet radiation C (UV-C) was used as a pretreatment tool for the optimal recovery of biofuel precursors from algae Chlorella vulgaris. The pretreatment efficiency of UV-C with fixed light intensity (1.173 mWcm−2) on 1.5 gL-1 algal biomass was observed at 0, 0.5, 1, 2, 5, 10, and 20 h of irradiation by measuring the released sugar content and soluble chemical oxygen demand (sCOD). The UV-C pretreated algal cells were also analyzed through impedance spectroscopy, fluorescence microscope, and digital images to assess the degree of cell wall disintegration. The released sugar content reached a maximum of 73.61 mg L-1 at 10 h of exposure, whereas the maximum sCOD of 190 mg L-1 was achieved at 20 h exposure. Image analysis indicated that the chlorophyll content declined exponentially from 7.21 to 0.14 µgmL-1 with UV-C exposure. An increase in UV-C exposure time resulted in decreased impedance and increased conductance. The SYTOX green fluorescence also increased with 10 h of exposure, followed by a decline. Therefore, the cell wall stability gets compromised and the permeability increases with increment in UV-C exposure. This triggers extensive release in cell wall sugar content with exposure. Further exposure destabilizes the cell wall leading to discreet breakage. This breakage disperses internal content to bulk liquid, causing elevated sCOD with reduced sugar content. The present study showed that UV-C to be a potential pretreatment strategy to release precursors to derive biofuels such as biohydrogen, bioethanol and others.

Methods for SARS-CoV-2 hospital disinfection, in vitro observations

IntroductionEscalation of chemical disinfection during the COVID-19 pandemic raised occupational hazard concerns. Alternative and potentially safer methods such as ultraviolet-C (UVC) irradiation and ozone are desirable, notwithstanding the lack of standardized criteria for their use in the healthcare environment. AimCompare the virucidal activity of 70% ethanol, sodium dichloroisocyanurate (NaDCC), chlorhexidine, ozonated water, UVC-222 nm, UVC-254 nm against three SARS-CoV-2 variants of concern cultured in vitro. MethodsInactivation of three SARS‐CoV‐2 variants (alpha, beta, gamma) by the following chemical methods was tested: ethanol 70%, NaDCC (100 ppm, 500 ppm, 1000 ppm), chlorhexidine (2%, 1% and 0.5%), ozonated water 7 ppm. For irradiation, a je2Care 222nm UVC Lamp was compared to a Sylvania G15 UV254 nm lamp on SARS-CoV-2 variants. ResultsViral inactivation by >3 log was achieved with ethanol, NaDCC and chlorhexidine. The minor virucidal effect of ozonated water was <1 log. Virus treatment with UVC-254 nm reduced viral activity by 1-5 logs with higher inactivation after exposure for 3 minutes compared to 6 seconds. For all three variants, under equivalent conditions, exposure to UVC-222 nm did not achieve time-dependent inactivation as was observed with treatment with UVC-254 nm. ConclusionThe virucidal activity on replication-competent SARS-CoV-2 by conventional chemical methods, including chlorhexidine at concentrations as low as 0.5%, was not matched by UVC irradiation, and to an even lesser extent by ozonated water treatment.

UV-C LED-induced cyclobutane pyrimidine dimer formation, lesion repair and mutagenesis in the biofilm-forming diatom, Navicula incerta

The use of ultraviolet-C (UV-C) irradiation in marine biofouling control is a relatively new and potentially disruptive technology. This study examined effects of UV-C exposure on the biofilm-forming diatom, Navicula incerta. UV-C-induced mutations were identified via Illumina HiSeq. A de novo genome was assembled from control sequences and reads from UV-C-exposed treatments were mapped to this genome, with a quantitative estimate of mutagenesis then derived from the frequency of single nucleotide polymorphisms. UV-C exposure increased cyclobutane pyrimidine dimer (CPD) abundance with a direct correlation between lesion formation and fluency. Cellular repair mechanisms gradually reduced CPDs over time, with the highest UV-C fluence treatments having the fastest repair rates. Mutation abundances were, however, negatively correlated with CPD abundance suggesting that UV-C exposure may influence lesion repair. The threshold fluence for CPD formation exceeding CPD repair was >1.27 J cm−2. Fluences >2.54 J cm−2 were predicted to inhibit repair mechanisms. While UV-C holds considerable promise for marine antifouling, diatoms are just one, albeit an important, component of marine biofouling communities. Determining fluence thresholds for other representative taxa, highlighting the most resistant, would allow UV-C treatments to be specifically tuned to target biofouling organisms, whilst limiting environmental effects and the power requirement.

Destructive effects of UVC radiation on Drosophila melanogaster: Mortality, fertility, mutations, and molecular mechanisms.

The detrimental effects of ultraviolet C (UVC) radiation on living organisms, with a specific focus on the fruit fly Drosophila melanogaster, were examined. This study investigated the impact of heightened UVC radiation exposure on D. melanogaster by assessing mortality and fertility rates, studying phenotypic mutations, and investigating the associated molecular mechanisms. The findings of this study revealed that UVC radiation increases mortality rates and decreases fertility rates in D. melanogaster. Additionally, phenotypic wing mutations were observed in the exposed flies. Furthermore, the study demonstrated that UVC radiation downregulates the expression of antioxidant genes, including superoxide dismutase (SOD), manganese-dependent superoxide dismutase (Mn-SOD), zinc-dependent superoxide dismutase (Cu-Zn-SOD), and the G protein-coupled receptor methuselah (MTH) gene. These results suggest that UVC radiation exerts a destructive effect on D. melanogaster by inducing oxidative stress, which is marked by the overexpression of harmful oxidative processes and a simultaneous reduction in antioxidant gene expression. In conclusion, this study underscores the critical importance of comprehending the deleterious effects of UVC radiation, not only to safeguard human health on Earth, but also to address the potential risks associated with space missions, such as the ongoing Emirate astronaut program.

Mechanisms of SARS-CoV-2 Inactivation Using UVC Laser Radiation.

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) has had a tremendous impact on humanity. Prevention of transmission by disinfection of surfaces and aerosols through a chemical-free method is highly desirable. Ultraviolet C (UVC) light is uniquely positioned to achieve inactivation of pathogens. We report the inactivation of SARS-CoV-2 virus by UVC radiation and explore its mechanisms. A dose of 50 mJ/cm2 using a UVC laser at 266 nm achieved an inactivation efficiency of 99.89%, while infectious virions were undetectable at 75 mJ/cm2 indicating >99.99% inactivation. Infection by SARS-CoV-2 involves viral entry mediated by the spike glycoprotein (S), and viral reproduction, reliant on translation of its genome. We demonstrate that UVC radiation damages ribonucleic acid (RNA) and provide in-depth characterization of UVC-induced damage of the S protein. We find that UVC severely impacts SARS-CoV- 2 spike protein's ability to bind human angiotensin-converting enzyme 2 (hACE2) and this correlates with loss of native protein conformation and aromatic amino acid integrity. This report has important implications for the design and development of rapid and effective disinfection systems against the SARS-CoV-2 virus and other pathogens.

COVID-19 infection prevention and control management during hyperbaric oxygen therapy: a best practice implementation project.

This implementation project compared standard operating procedures, accepted preventive measures, and disinfection procedures between the initial stage of the COVID-19 pandemic (first wave: March 15 to May 31, 2020) and the later stages of the pandemic (second and third waves: September 1, 2020 to January 31, 2021). This project sought to improve compliance with international evidence-based guidelines and clinical standards for the prevention and control of COVID-19 infection during hyperbaric oxygen therapy taking into account the conditions of the local hospital. Guided by the JBI evidence implementation framework, seven evidence-based audit criteria were developed for the prevention and control of COVID-19 infection during hyperbaric oxygen therapy. A questionnaire was used to measure compliance in baseline and follow-up audits. Differences between the baseline and follow-up audits were noted for criteria 6 and 7. Criterion 6 increased from 0% to 100% as the hyperbaric facility was equipped with certified ultraviolet-C radiation for air disinfection during the later period, but this equipment was not available in the initial period of the pandemic. Criterion 7 dropped from 100% in the baseline audit to 0% in the follow-up audit because of a significant increase in the operational burden of the treatment capacity of the facility, which made it impossible to comply with the recommended distancing between patients. Differences were found in preventive measures, disinfection procedures, work organization, and approach to care strategy. The project objectives were met and the implementation strategies proved effective. Larger sample sizes would need be needed to confirm the reproducibility of the results.

Validation of In-Room UV-C-Based Air Cleaners

The risks to human health posed by airborne pathogens can be mitigated by the use of ultraviolet-C (UV-C) radiation. In general, UV-C-based systems should be applied in a manner that allows effective inactivation of airborne pathogens, while controlling human exposure to below defined limits. Among the methods used to apply UV-C radiation in indoor settings to meet these objectives are UV-C-based air cleaners. These devices can be effective for the control of airborne pathogens, but methods are needed to quantify and validate their performance. To address this need, an experiment-based method and a mathematical model were developed to quantify the effects of UV-C-based air cleaners on the concentration of an aerosolized, viral challenge agent. The method and model were demonstrated to allow quantification of disinfection efficacy and to allow translation of the results from the test environment to the application environment. The primary figure-of-merit from these tests was the clean air delivery rate (CADR), which is commonly used to characterize the disinfection efficacy of these devices. The ability of a validated air cleaner to improve indoor air quality in application settings is simulated based on the measured value of CADR from laboratory tests and the mathematical model.

Radiant Reinforcement: Enhancing Composite Polymer Magnet Materials Mechanical Properties with UVC Medical Disinfection.

Magnetic polymer composites have recently attracted considerable interest, primarily because of their promising applications, especially in the biomedical industry. The aim of this study is to investigate the impact of ultraviolet C (UVC) irradiation as a disinfection method on the mechanical characteristics of composite polymer magnets. Tensile and compression tests were conducted following the standards set by ASTM D3039 and ASTM D3410, respectively. In addition, energy dispersive spectroscopy (EDS) was used to determine the effect of the disinfection method on the amount of carbon, oxygen, and iron within the surface of the composite polymer magnet material. The UVC's irradiation impact was statistically assessed by a t-test. The results of the tensile tests demonstrated a significant increase in the transition force, measuring 0.41 kN and 0.58 kN before and after UVC exposure, respectively. Similarly, the outcomes of the compression tests showed a notable increase in yield force, registering 4.9 kN and 6 kN before and after UVC treatment. This suggests that the composite magnetic material has gained a higher capacity to withstand compressive loads than tensile loads. Finally, the EDS analysis revealed the carbon mass percentage was 71.69% prior to UVC radiation exposure, with it increasing to 78.56%, following exposure. This suggests that the composite material exhibited improved hardness. These findings highlight that UVC irradiation has a beneficial impact on both the mechanical and chemical properties of the composite magnet material, which support its use as a disinfection method in clinical settings.

Targeted metabolomic and transcriptomic reveal the regulation of UV–C on phenolics biosynthesis of peach fruit during storage

Phenolic compounds are important secondary metabolites in peach fruit and play positive roles in plant resilience and human diets. To investigate the regulation of Ultraviolet-C (UV–C) irradiation on phenolics biosynthesis of peach fruit, the targeted metabolomic and transcriptomic were used to analyze polyphenolic metabolites and their gene expression patterns. The metabolomic results showed that a total of 45 phenolics were identified in the peach pulp. Total phenolic content was significantly increased by UV–C irradiation and 35 individual phenolics responded observably to UV–C treatment. In particular, UV–C irradiation dramatically increased the content of 2,6-dihydroxybenzoic acid, luteolin, quercitrin, astragalin, narcissin, nicotiflorin, sorhamnetin-3-O-glucoside and hesperidin. The HCT1, CYP98A1/3, COMT1 and CHS2/3 genes in phenylpropanoid metabolic pathway and the CHI1/3, F3′H1/3, P2′GT1/2/3/4, UFGT3 and DFR2/3 genes in flavonoid metabolic pathway were significantly regulated by UV–C irradiation. Overall, the present study revealed that phenolics biosynthesis is regulated by UV–C irradiation at the level of metabolites and molecule supported by targeted metabolomic and transcriptomic results.

Enhancing post-harvest quality of sapota using ultraviolet-C irradiation: A study on efficacy and effects.

Ultraviolet-C (UV-C) radiation has been identified as a promising method for enhancing the shelf life of fruits and vegetables by reducing microbial count and boosting their defence mechanisms. In this study, the impact of UV-C radiation on the physical, biochemical, and microbial properties of sapota fruits was investigated by subjecting them to different doses (2.5, 5, 7.5, and 10 kJ m-2; 12 ± 1°C; 85-90% relative humidity) to enhance their shelf life. The results revealed that higher doses of UV-C radiation resulted in significantly lower weight loss and higher firmness compared to untreated samples and samples treated with lower doses. Furthermore, UV-C-treated fruits displayed a delayed increase in total soluble solids, total sugar, and reduced sugar content compared to the untreated fruit during storage. The UV-C-treated fruits also exhibited a delayed decline in ascorbic acid and titratable acidity during storage. The treated fruits exhibited significantly higher phenolic content than the untreated fruits. Additionally, significantly lower decay and microbial count were observed in fruits treated with higher doses than in those treated with lower doses. The samples treated with a dose of 7.5 and 10 kJ m-2 had a shelf life of 25 days compared to 14 days for the control fruits.

Ultraviolet-C irradiation of wheat grains induces seedling resistance to leaf rust and powdery mildew disease

Ultraviolet-C (UV-C) irradiation of grains activated the antioxidant system and wheat seedlings’ resistance to leaf rust and powdery mildew disease under greenhouse conditions. Two wheat cultivars (Gemmeiza-12 and Sids-1) with dry and germinated grains were treated with UV-C at three exposure times (5, 10, and 15 minutes). The results indicated that the percentages of disease severity and infection type for leaf rust and powdery mildew on wheat seedlings were significantly reduced when exposed to UVC at all exposure times compared to the untreated control. The most effective treatments for both cultivars were obtained in seedlings grown from germinated grains treated with UV-C for 10 minutes. Furthermore, UV-C irradiation treatments improved plant resistance to infection by activating certain defense genes, thereby increasing the production of resistance compounds that support defense mechanisms against pathogens. Our results demonstrated that UV-C for 10 minutes can induce resistance in wheat seedlings while also increasing total chlorophyll, total phenolic compounds, phenylalanine ammonia-lyase, and peroxidase activity. In addition, phenylalanine ammonia-lyase mRNA expression levels were significantly increased in seedlings growing from germinated grains treated with UV-C for 10 minutes, as compared to both infected and uninfected controls. These findings demonstrate the potential for additional UV-C radiation treatments to enhance disease resistance.

Moist heat as a promising method to decontaminate N95 masks: A large scale clinical study comparing four decontamination modalities—moist heat, steam, ultraviolet-C irradiation, and hydrogen peroxide plasma

BackgroundEarly in the COVID-19 pandemic, there was a global shortage of masks. Although mask reprocessing was practiced, no clinical study has assessed systematically the impact of repeated cycles of wear and decontamination on the integrity of N95 filtering facepiece respirators (FFRs). MethodsWe evaluated mask fit assessed by qualitative respirator fit test (QRFT) after each cycle of wear and decontamination, as well as four measures of mask integrity—bacterial filtration efficacy, particle filtration efficacy, differential pressure, and splash resistance through five cycles of wear and decontamination using one of the four modalities (moist heat, steam, ultraviolet-C irradiation, and hydrogen peroxide plasma). ResultsA total of 60.6% (hydrogen peroxide plasma) to 77.5% (moist heat) of the FFRs passed five cycles of wear and decontamination, as assessed by the wearers passing QRFT all five times. Moist heat-decontaminated FFRs retained all technical measures of integrity through all five cycles. ConclusionsThis is the first large-scale study to assess systematically the impact (clinically and quantitatively) on N95 FFR integrity of repeated cycles of wearing followed by decontamination.Our results suggest that moist heat is a promising method for decontaminating N95 FFRs. Performing QRFT after every cycle of wear and decontamination ensures wearer safety. Although there is currently no mask shortage, reprocessing may reduce medical waste and improve sustainability.

The new 222-nm far ultraviolet-C lowers bacterial contamination to endoscopists during esophagogastroduodenoscopy.

This study aimed to clarify the disinfectant efficacy of the 222-nm far ultraviolet-C (UV-C) during esophagogastroduodenoscopy using bacterial cultures. The endoscopists performed esophagogastroduodenoscopy wearing a gown with a tryptic soy agar medium plate on their epigastric region and were divided into two groups: 222-nm far UV-C irradiation (UV group) and non-UV irradiation (non-UV group). As a control group, tryptic soy agar medium plates were placed about 110 cm above the floor. The incidence of bacterial contamination was determined by positive bacterial culture. The cultured bacteria were identified by 16S rRNA sequencing. Additionally, the actual UV exposure dose was measured using the UV-indicator card which changed colors upon exposure to 222 nm far UV-C. The bacterial culture positivity in the UV group (5.03%) was significantly lower than that in the non-UV group (25.76%), p < 0.0001. Most of the bacteria identified in the UV and non-UV groups were normal constituents of the oral flora, including Streptococcus salivarius and Staphylococci. Conversely, pathogenic microbes were found in the control group. The actual exposure doses of 222-nm far UV-C at the endoscopists' face, neck, and epigastric region were 2.09±0.29, 5.89±0.49, and 7.36±0.58 mJ/cm2, respectively. The 222-nm far UV-C irradiation reduced bacterial contamination for endoscopists. It can be used with conventional physical coverings to provide more effective infection control.

The impact of UV-C radiation on the sugar metabolism of the red flour beetle Tribolium castaneum herbst (coleoptera; tenebrionidae)

Purpose Ultraviolet-C (UV-C) is known to induce morphological abnormality in various parts of the red flour beetle, Tribolium castaneum, including its wings, antennae, eyes, legs, and reproductive organs. However, little is known about the effects of UV-C on T. castaneum’s sugar content and enzyme activity. Material and methods We investigated the concentrations of glucose and trehalose as well as changes in trehalase activity in different developmental stages following UV-C radiation at different exposure periods (1, 2, 4, 8, 16, 32, and 64 min). In addition, the larval mortality and body weight were examined. Results A reduction in glucose content was recorded in 10-, 15- and 20-day-old larvae and trehalase enzyme activity was recorded in 5- and 10-day-old larvae, whereas an increase in trehalose content was found in adults irradiated with UV-C. In addition, UV-C radiation for 1–64 min caused larval mortality on the first and subsequent days post-irradiation. Moreover, UV-C irradiated larvae exhibited lower body weight, which aligned with the reduction of trehalase activity and glucose content from days 1–6 post-exposure, and the degree of these reductions corresponded to the exposure times. Conclusion UV-C affected sugar content through the reduction of trehalase activity, and glucose declination may cause mortality in T. castaneum; however, further research is needed to provide a better understanding of the impact of UV-C on sugar metabolism.

Modeling a UVC irradiation standalone system for inactivating Mycobacterium tuberculosis from indoor spaces.

After the outbreak of the COVID-19 pandemic, a rise in demand has occurred for efficient designs of disinfection systems that utilize ultraviolet-C (UVC) radiation to inactivate airborne microorganisms effectively. This paper proposes what we believe to be a novel standalone system for inactivating Mycobacterium tuberculosis (which requires a higher dosage value than SARS-CoV-2) from a medium size room of 12.5f t×12.5f t×9f t. The structure consists of a UVC source at the center and a spiral pathway guiding the air around the UVC source, thus increasing the residence time of the aerosol particle. The top and bottom louvre and a hollow cylindrical cover (comprising four external cover segments) enclose the UVC source and prevent the danger of direct exposure to indoor occupants. The whole system is modeled in SolidWorks, and flux leakage was examined using the RayViz tool in SolidWorks. Optical/radiometric analysis in ray tracing software TracePro provided the UVC flux value at different locations of the standalone system. Flow simulation carried out in SolidWorks helped calculate aerosol particles' residence time at different airflow trajectories. The designed standalone system demonstrated the capability of delivering 1.87 times more dosage than is required to inactivate Mycobacterium tuberculosis from the ambient air. The standalone system achieves a ventilation rate, i.e.,air changes per hour value of 10, according to guidelines from the Council of Scientific & Industrial Research, India.

Ultraviolet-C irradiation has no short-term, direct effects on cyclamen mite (Phytonemus pallidus (Banks)) in strawberry

Cyclamen mite is a nearly global pest of strawberry, inhabiting concealed spaces within folded leaves and flower buds emerging from plant crowns. It feeds on new plant tissue causing leaf discoloration and deformation, stunted plants, fruit bronzing and cracking, and yield losses at high population levels. Because ultraviolet-C (UV-C) irradiation is a promising new tool for disease and pest management in strawberry, and because there are few control options for cyclamen mite, we tested the direct, short-term effects of UV-C on cyclamen mite populations in potted strawberry plants in a controlled environment. Results from three experiments showed few differences in cyclamen mite populations on controls versus plants treated with UV-C (0.237 W m−1) for 3 or 4 weeks. In the second experiment, using a different strawberry cultivar and directing the UV-C from above the plant crown only, there was indication of a mild effect that may be due to some direct mortality and/or indirectly to plant defenses. However, longer-term studies will need to be conducted to determine whether pre-infestation exposure to UV-C can enable strawberry plants to better resist or tolerate cyclamen mite populations. Direct mortality did not occur as in previous experiments with pests, like twospotted spider mite, that live primarily on opened leaves.

Effect of gamma and Ultraviolet-C sterilization on BMP-7 level of indigenously prepared demineralized freeze-dried bone allograft.

The presence of bone morphogenetic proteins in demineralized freeze-dried bone allograft (DFDBA) are responsible for developing hard tissues in intraosseous defects. The most common mode of sterilization of bone allografts, i.e., Gamma rays, have dramatic effects on the structural and biological properties of DFDBA, leading to loss of BMPs. Ultraviolet-C radiation is a newer approach to sterilize biodegradable scaffolds, which is simple to use and ensures efficient sterilization.However, UV-C radiation has not yet been effectively studied to sterilize bone allografts. This study aimed to compare and evaluate the effectiveness of Gamma and Ultraviolet-C rays in sterilizing indigenously prepared DFDBA and assess their effect on the quantity of BMP-7 present in the allograft. DFDBA samples from non-irradiated, gamma irradiated, and UV-C irradiated groups were tested for BMP-7 level and samples sterilized with gamma and UV-C rays were analysed for sterility testing.The estimated mean BMP-7 level was highest in non-irradiated DFDBA samples, followed by UV-C irradiated, and the lowest in gamma irradiated samples. Our study concluded that UV-C rays effectively sterilized DFDBA as indicated by negative sterility test and comprised lesser degradation of BMP-7 than gamma irradiation.