Characterization of a flexible a-Si:H detector for in vivo dosimetry in therapeutic x-ray beams

BACKGROUND

The increasing use of complex and high dose-rate treatments in radiation therapy necessitates advanced detectors to provide accurate dosimetry. Rather than relying on pre-treatment quality assurance (QA) measurements alone, many countries are now mandating the use of in vivo dosimetry, whereby a dosimeter is placed on the surface of the patient during treatment. Ideally, in vivo detectors should be flexible to conform to a patient's irregular surfaces.

PURPOSE

This study aims to characterize a novel hydrogenated amorphous silicon (a-Si:H) radiation detector for the dosimetry of therapeutic x-ray beams. The detectors are flexible as they are fabricated directly on a flexible polyimide (Kapton) substrate.

METHODS

The potential of this technology for application as a real-time flexible detector is investigated through a combined dosimetric and flexibility study. Measurements of fundamental dosimetric quantities were obtained including output factor (OF), dose rate dependence (DPP), energy dependence, percentage depth dose (PDD), and angular dependence. The response of the a-Si:H detectors investigated in this study are benchmarked directly against commercially available ionization chambers and solid-state diodes currently employed for QA practices.

RESULTS

The a-Si:H detectors exhibit remarkable dose linearities in the direct detection of kV and MV therapeutic x-rays, with calibrated sensitivities ranging from (0.580 ± 0.002) pC/cGy to (19.36 ± 0.10) pC/cGy as a function of detector thickness, area, and applied bias. Regarding dosimetry, the a-Si:H detectors accurately obtained OF measurements that parallel commercially available detector solutions. The PDD response closely matched the expected profile as predicted via Geant4 simulations, a PTW Farmer ionization chamber and a PTW ROOS chamber. The most significant variation in the PDD performance was 5.67%, observed at a depth of 3 mm for detectors operated unbiased. With an external bias, the discrepancy in PDD response from reference data was confined to ± 2.92% for all depths (surface to 250 mm) in water-equivalent plastic. Very little angular dependence is displayed between irradiations at angles of 0° and 180°, with the most significant variation being a 7.71% decrease in collected charge at a 110° relative angle of incidence. Energy dependence and dose per pulse dependence are also reported, with results in agreement with the literature. Most notably, the flexibility of a-Si:H detectors was quantified for sample bending up to a radius of curvature of 7.98 mm, where the recorded photosensitivity degraded by (-4.9 ± 0.6)% of the initial device response when flat. It is essential to mention that this small bending radius is unlikely during in vivo patient dosimetry. In a more realistic scenario, with a bending radius of 15-20 mm, the variation in detector response remained within ± 4%. After substantial bending, the detector's photosensitivity when returned to a flat condition was (99.1 ± 0.5)% of the original response.

CONCLUSIONS

This work successfully characterizes a flexible detector based on thin-film a-Si:H deposited on a Kapton substrate for applications in therapeutic x-ray dosimetry. The detectors exhibit dosimetric performances that parallel commercially available dosimeters, while also demonstrating excellent flexibility results.

Safety and efficacy of a feed additive consisting of 6-phytase produced by Aspergillus oryzae DSM 33737 (HiPhorius™) for all poultry, all Suidae and all fin fish (DSM Nutritional Products Ltd)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 6-phytase produced by the genetically modified strain Aspergillus oryzae DSM 33737 (HiPhorius™ 10, 40, 20L and 50L) as a zootechnical feed additive for all poultry, all Suidae and all fin fish. The FEEDAP Panel concluded that the genetic modification of the production strain does not give rise to safety concerns. Based on the no observed adverse effect level identified in a subchronic oral toxicity study in rats, the additive was considered safe for all poultry, all Suidae and all fin fish at the proposed conditions of use. The Panel also concluded that the use of the product as a feed additive is of no concern for the consumers and the environment. The liquid formulations of the additive are not skin or eye irritants. The two solid ones are not skin irritants but are eye irritants. Owing to the lack of data, the Panel cannot conclude on the skin sensitisation of the final formulations of the additive. Due to the proteinaceous nature of the active substance (6-phytase), the additive is considered a respiratory sensitiser. The Panel concludes that the additive is efficacious when included in the diet of poultry for fattening or reared for laying/breeding, reproductive Suidae, and all fin fish. Due to the lack of sufficient data, the Panel could not conclude on the efficacy for laying and reproductive poultry and growing Suidae.

Safety and efficacy of the feed additive Anpro consisting of a mixture of Sepiolite and Kieselguhr (diatomaceous earth) for all terrestrial animal species (Anpario plc)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the mixture of Sepiolite and Kieselguhr (diatomaceous earth) (Anpro) as a technological feed additive for all terrestrial animal species. According to the conventional risk assessment, due to lack of adequate data, the safety of the additive Anpro for the target species cannot be established. Based on current knowledge, there is no indication of substantial absorption of the components of the additive and therefore no concern for the consumer. The additive poses a risk by inhalation. It is not irritant to the skin or eyes but should be considered as skin sensitiser. As no suitable data in line with the requirements of the Guidance on risk assessment of nanomaterials were provided by the applicant, the potential risks associated with the presence of nanoparticles could not be assessed for the target species, the consumer and the user. The additive is safe for the environment. The FEEDAP Panel is not in the position to conclude on the efficacy of the additive for all terrestrial animal species.

Exposure to environmental pollutants and attention-deficit/hyperactivity disorder: an overview of systematic reviews and meta-analyses

Although heritability estimates suggest a role for genetic components, environmental risk factors have been described as relevant in the etiology of attention deficit/hyperactivity disorder (ADHD). Several studies have investigated the role of toxicological pollution, i.e., air pollution, heavy metals, POPs, and phthalates. Clear evidence for association of ADHD and environmental factors has not been provided yet. To answer this, we have assessed all available systematic reviews and meta-analyses that focused on the association between pollutant exposure and either ADHD diagnosis or symptoms. More than 1800 studies were screened of which 14 found eligible. We found evidence of a significant role for some pollutants, in particular heavy metals and phthalates, in the increased risk of developing ADHD symptoms. However, at the current stage, data from existing literature also do not allow to weight the role of the different environmental pollutants. We also offer a critical examination of the reviews/meta-analyses and provide indications for future studies in this field. PROSPERO registration: CRD42022341496.

Assessment of the feed additive consisting of niacinamide for all animal species for the renewal of its authorisation (Arxada Ltd)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the application for renewal of niacinamide as a nutritional additive for use in all animal species. The applicant has provided evidence that the additive currently on the market complies with the existing conditions of authorisation. There is no new evidence that would lead the FEEDAP Panel to reconsider its previous conclusions. Thus, the Panel concludes that the additive remains safe for all animal species, consumers and the environment under the authorised conditions of use. Regarding user safety, the additive is not irritant to skin but irritant to eyes. It is not a dermal sensitiser. Exposure through inhalation is likely. There is no need for assessing the efficacy of the additive in the context of the renewal of the authorisation.

Assessment of the feed additive consisting of niacin (nicotinic acid) for all animal species for the renewal of its authorisation (Arxada Ltd)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the application for renewal of niacin (nicotinic acid) as a nutritional additive for use in all animal species. The applicant has provided evidence that the additive currently on the market complies with the existing conditions of authorisation. There is no new evidence that would lead the FEEDAP Panel to reconsider its previous conclusions. Thus, the Panel concludes that the additive remains safe for all animal species, consumers and the environment under the authorised conditions of use. Regarding user safety, the additive is not irritant to skin but is irritant to eyes. It is not a dermal sensitiser. Exposure through inhalation is likely. There is no need for assessing the efficacy of the additive in the context of the renewal of the authorisation.

Safety and efficacy of a feed additive consisting of endo-1,4-β-xylanase produced by Trichoderma citrinovirideDSM 34663 (Hostazym® X) for use in all poultry species, ornamental birds, all growing Suidae and carp (Huvepharma NV)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of a feed additive containing endo-1,4-β-xylanase produced by Trichoderma citrinoviride DSM 34663 (Hostazym® X). The product is authorised as a zootechnical additive (digestibility enhancers) for use in all poultry species for fattening, for laying and reared for laying, weaned piglets, pigs for fattening and carp. The current opinion concerns the request for the renewal of the authorisation for the use in those species/categories and the extension of use to all poultry species for breeding and reared for breeding, ornamental birds, suckling piglets and minor porcine species for fattening. The applicant provided evidence that the additive in the market complies with the conditions of the authorisation. There is no new evidence that would lead the Panel to reconsider previous conclusions that the additive is safe for the target species, the consumers and the environment under the authorised conditions of use. This conclusion also applies to the target species for which a request for extension of use is made. The additive is considered not a skin corrosive or skin sensitiser, but it is an eye irritant. The Panel cannot conclude on the potential of the additive to be a skin irritant. Due to the proteinaceous nature of the active substance, the additive is considered a respiratory sensitiser. The Panel considers that the additive has the potential to be efficacious in all poultry species, ornamental birds, all growing Suidae and carp at the proposed conditions of use.

Hydrogenated amorphous silicon high flux x-ray detectors for synchrotron microbeam radiation therapy

OBJECTIVE

Microbeam radiation therapy (MRT) is an alternative emerging radiotherapy treatment modality which has demonstrated effective radioresistant tumour control while sparing surrounding healthy tissue in preclinical trials. This apparent selectivity is achieved through MRT combining ultra-high dose rates with micron-scale spatial fractionation of the delivered X-ray treatment field. Quality assurance dosimetry for MRT must therefore overcome a significant challenge, as detectors require both a high dynamic range and a high spatial resolution to perform accurately. 
Approach: In this work, a series of radiation hard a-Si:H diodes, with different thicknesses and carrier selective contact configurations, have been characterized for X-ray dosimetry and real-time beam monitoring applications in extremely high flux beamlines utilised for MRT at the Australian Synchrotron. 
Results: These devices displayed superior radiation hardness under constant high dose-rate irradiations on the order of 6000 Gy/s, with a variation in response of 10% over a delivered dose range of approximately 600 kGy. Dose linearity of each detector to X-rays with a peak energy of 117 keV is reported, with sensitivities ranging from (2.74 ± 0.02) nC/Gy to (4.96 ± 0.02) nC/Gy. For detectors with 0.8 µm thick active a-Si:H layer, their operation in an edge-on orientation allows for the reconstruction of micron-size beam profiles (microbeams). The microbeams, with a nominal full-width-half-max of 50 µm and a peak-to-peak separation of 400 µm, were reconstructed with extreme accuracy. The full-width-half-max was observed as 55 ± 1 µm. Evaluation of the peak-to-valley dose ratio and dose-rate dependence of the devices, as well as an X-ray induced charge (XBIC) map of a single pixel is also reported. 
Significance: These devices based on novel a-Si:H technology possess a unique combination of accurate dosimetric performance and radiation resistance, making them an ideal candidate for X-ray dosimetry in high dose-rate environments such as FLASH and MRT. &#xD.

Safety and efficacy of a feed additive consisting of β-mannanase produced by Aspergillus nigerCBS 120604 (Nutrixtend Optim) for use in all poultry for fattening (Kerry Ingredients & Flavours Ltd)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of a product containing β-mannanase produced by a non-genetically modified strain of Aspergillus niger (CBS 120604). The commercial name is Nutrixtend Optim and it is intended to be used as a zootechnical feed additive for all poultry for fattening. Based on a tolerance trial in chickens for fattening and the no observed adverse effect level identified in a subchronic oral toxicity study in rats, the additive was considered safe for all poultry for fattening. The Panel concluded that the use of the product as a feed additive does not give rise to concerns for consumers and the environment. The additive is considered an irritant to skin and eyes and a dermal sensitiser. Due to the proteinaceous nature of the active substance, it is also considered a respiratory sensitiser. The Panel concludes that the additive has the potential to be efficacious as a zootechnical additive at the level of inclusion in feed of chickens for fattening of 30 U β-mannanase/kg complete feed. This conclusion was extrapolated to all poultry for fattening.

Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC

Linelike features in TeV γ rays constitute a "smoking gun" for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite γ-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic telescope system reaching γ-ray energies up to 100 TeV. We improved the sensitivity to spectral lines at high energies using large-zenith-angle observations and a novel background modeling method within a maximum-likelihood analysis in the energy domain. No linelike spectral feature is found in our analysis. Therefore, we constrain the cross section for dark matter annihilation into two photons to ⟨σv⟩≲5×10^{-28}  cm^{3} s^{-1} at 1 TeV and ⟨σv⟩≲1×10^{-25}  cm^{3} s^{-1} at 100 TeV, achieving the best limits to date for a dark matter mass above 20 TeV and a cuspy dark matter profile at the Galactic Center. Finally, we use the derived limits for both cuspy and cored dark matter profiles to constrain supersymmetric wino models.

Safety and efficacy of a feed additive consisting of Streptococcus salivarius DSM 13084/ATCC BAA 1024 for dogs and cats (BLIS Technologies Limited)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of Streptococcus salivarius DSM 13084/ATCC BAA 1024 as a technological additive (functional group: acidity regulators) in feed for dogs and cats. The additive is intended for use at a proposed minimum concentration of 1 × 1011 CFU/l or kg liquid feed for dogs and cats. Due to the lack of adequate data, the FEEDAP Panel could not conclude on the safety of the additive for the target species. The additive was considered a respiratory sensitiser, but not irritant to skin. No conclusions could be drawn on the potential of the additive to be an eye irritant or a skin sensitiser. No environmental risk assessment is necessary for the use of the additive in feeds for pets. The Panel concluded that the additive has the potential to be efficacious in feeds for dogs and cats at the proposed conditions of use.

Safety of a feed additive consisting of sodium saccharin for suckling and weaned piglets, fattening pigs, calves for rearing and for fattening (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety of sodium saccharin as a sensory feed additive (flavouring compound) for suckling and weaned piglets, fattening pigs, calves for rearing and for fattening. In a previous assessment, the Panel on Additives and Products or substances used in Animal Feed (FEEDAP Panel) could not conclude on the safety of the additive for the environment because concentrations of the additive or its degradation product 4-hydroxysaccharin in groundwater above 0.1 μg/L were likely to occur. In addition, regarding user safety, sodium saccharin was considered to be potentially harmful by inhalation or by contact to skin and eyes. In the current opinion, the applicant restricted the use to suckling and weaned piglets and up to a use level of 5 mg/kg complete feed. In relation to the user safety, the additive was neither a skin or eye irritant, nor a dermal sensitiser. In the absence of data, the FEEDAP Panel could not conclude on the potential of the additive to be toxic by inhalation. Regarding the safety of the additive for the environment, the new conditions of use describe a maximum use level of 5 mg sodium saccharin/kg feed. The applicant indicated that a restriction to a lower use level due to environmental safety would be accepted and submitted an environment risk assessment based on a use level of 1.13 mg sodium saccharin/kg feed. This use level cannot be considered safe. The estimated use level that would result in a concentration in groundwater below 0.1 μg/L is of 0.022 mg sodium saccharin/kg feed. The available data do not allow to conclude on the potential effect of the degradation product 4-hydroxysaccharin in ground water.

Safety and efficacy of a feed additive consisting of endo-1,4-beta xylanase, endo-1,4-beta-glucanase and xyloglucan-specific-endo-beta-1,4-glucanase produced by Trichoderma citrinovirideDSM 33578 (Huvezym® neXo 100 G/L) for all poultry species, ornamental birds and piglets (weaned and suckling) (Huvepharma EOOD)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of the product Huvezym® neXo 100 G/L containing an endo-1,4-beta xylanase, an endo-1,4-beta-glucanase and a xyloglucan-specific-endo-beta-1,4-glucanase produced by a non-genetically modified strain of Trichoderma citrinoviride (DSM 33578) as a zootechnical additive for feed in all poultry species, ornamental birds and piglets (weaned and suckling). The information regarding the production strain did not allow to confirm its taxonomic identification. The batches used for the characterisation of the final formulations showed compliance with the minimum specifications of the additive in terms of enzyme activities but showed ratios between the enzymes lower than the ones specified for the additive. The FEEDAP Panel considered that the below-described conclusions would apply to the final formulations of the additive as per specifications with xylanase:glucanase, xylanase:xyloglucanase and glucanase:xyloglucanase ratios of 15, 15 and 1, respectively. Based on the data available, the Panel concluded that the additive is safe for the target species, consumers and the environment. Huvezym® neXo 100 G (granulated form) is neither skin corrosive nor eye irritant but should be considered a potential skin sensitiser. Huvezym® neXo 100 L (liquid) is neither skin corrosive nor sensitising and it is not an eye irritant. Due to lack of data, no conclusions can be drawn on the skin irritation of the final formulations of the additive. Due to the proteinaceous nature of the active substances, the additive is considered a respiratory sensitiser. The FEEDAP Panel concluded that the additive has the potential to be efficacious in chickens for fattening, chickens reared for laying and breeding, and all growing poultry and ornamental birds at the minimum intended level of 1,500 EPU, 100 CU and 100 XGU/kg complete feed. Owing to the lack of sufficient data, the Panel could not conclude on the efficacy of the additive for laying hens and weaned piglets.

Safety and efficacy of a feed additive consisting of 6‐phytase produced by Trichoderma reesei CBS 146250 (Axtra® PHY GOLD 30L, Axtra® PHY GOLD 30T, Axtra® PHY GOLD 65G) for all poultry species and all pigs (Danisco (UK) ltd)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 6‐phytase produced by the genetically modified strain Trichoderma reesei CBS 146250 (Axtra® PHY GOLD 30L, Axtra® PHY GOLD 30 T and Axtra® PHY GOLD 65G) as a zootechnical feed additive for all poultry species and all pigs. The FEEDAP Panel concluded that the genetic modification of the production strain does not give rise to safety concerns. Based on the no observed adverse effect level identified in a subchronic oral toxicity study in rats, the additive was considered safe for all poultry species and all pigs at the proposed conditions of use. The Panel also concluded that the use of the product as a feed additive does not give rise to concerns for consumers and the environment. Owing to the lack of data obtained with the final formulations, the Panel cannot conclude on the potential of the additive to be irritant to eyes or skin. Due to the proteinaceous nature of the active substance, it is considered a respiratory sensitiser. The panel concludes that the additive is efficacious in increasing the phosphorus utilisation when supplemented at 500 FTU/kg for all growing poultry species and all pigs, and at 300 FTU/kg in laying hens and other laying birds.

Safety and efficacy of a feed additive consisting of carmine for cats and dogs (Mars Petcare GMbH)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the re‐evaluation of the safety and efficacy of carmine (sensory additive, functional group: colourants – substances that add or restore colour in feeds) for cats and dogs. The additive consists of aluminium lakes of carminic acid (carmines), which are complexes of aluminium and carminic acid. Carminic acid, produced from the female insect Dactylopius coccus Costa, is the colouring principle and is present in the final additive at 50%. The additive does not pose a risk concerning genotoxicity and is considered safe for dogs and cats at 264 and 220 mg Carmine/kg feed, respectively (which correspond to 132 and 110 mg carminic acid/kg feed, respectively). Due to the nature of the additive, the FEEDAP Panel concluded that allergic reactions may occur in the target species following the ingestion of feeds containing the additive. The FEEDAP Panel concluded that the exposure of users by inhalation is very likely, and that carmine is a respiratory and skin sensitiser; however, due to the lack of data, a conclusion cannot be reached on the potential skin and eye irritation of the additive. The additive is considered to be efficacious in feeds for dogs and cats under the proposed conditions of use.

Safety and efficacy of a feed additive consisting of concentrated liquid l-lysine, l-lysine monohydrochloride and concentrated liquid l-lysine monohydrochloride produced by Escherichia coliNITE BP-02917 for all animal species (Metex NoovistaGo)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of concentrated liquid l-lysine, l-lysine monohydrochloride and concentrated liquid l-lysine monohydrochloride produced by Escherichia coli NITE BP-02917 as nutritional and as sensory (flavouring compound) feed additives for all animal species. The production strain did not carry ■■■■■ antimicrobial resistance genes and no viable cells of the production strain were detected in the final products. ■■■■■ However, since no sequences of concern remained in the production strain, the potential presence of that DNA did not raise safety concerns. The use of the three forms of l-lysine produced by E. coli NITE BP-02917 in supplementing feed to compensate for l-lysine deficiency in feedingstuffs was safe for the target species. This conclusion would also cover the use as a sensory additive. The FEEDAP Panel identified risks of nutritional imbalances and hygienic concerns for amino acids when administered simultaneously in feed and in water for drinking. The use of the three forms of l-lysine produced by E. coli NITE BP-02917 in animal nutrition was considered safe for the consumers and for the environment. Concentrated liquid l-lysine, l-lysine HCl and concentrated liquid l-lysine HCl were not considered to have the potential to cause respiratory toxicity, or skin sensitisation. l-Lysine HCl and concentrated liquid l-lysine HCl were not considered skin and eye irritants. Concentrated liquid l-lysine, due to its high pH, might be corrosive for skin and eyes. The three forms were considered an efficacious source of the essential amino acid l-lysine for non-ruminant animal species. For the supplemental l-lysine to be as efficacious in ruminants as in non-ruminant species, it would require protection against degradation in the rumen. The three forms of the additive were also considered efficacious as feed flavouring compounds under the proposed conditions of use.

Safety and efficacy of a feed additive consisting of Bacillus subtilis FERM BP-07462, Enterococcus lactis FERM BP-10867 and Clostridium butyricum FERM BP-10866 (BIO-THREE®) for chickens for fattening, chickens reared for laying, turkeys for fattening, turkeys reared for breeding, all avian species for rearing/fattening to slaughter and all avian species reared for laying or breeding to point of lay (TOA BIOPHARMA Co., Ltd.)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of BIO‐THREE^® when used as a feed additive for chickens for fattening, chickens reared for laying, turkeys for fattening, turkeys reared for breeding, all avian species for rearing/fattening to slaughter and all avian species reared for laying or breeding to point of lay. The product under assessment is based on viable cells/spores of Bacillus subtilis FERM BP‐07462, Enterococcus lactis FERM BP‐10867 and Clostridium butyricum FERM BP‐10866. Based on the tolerance study provided, the Panel concluded that the additive is safe for the target species under the conditions of use. The additive is safe for the consumers of products derived from animals receiving the additive. The additive is not irritant to skin and eyes. The additive is a respiratory sensitiser. No conclusions could be drawn on its potential to be a skin sensitiser. The use of the product as a feed additive is of no concern for the environment. The FEEDAP Panel was not in the position to conclude on the efficacy of BIO‐THREE^® for the target species. BIO‐THREE^® is compatible with diclazuril, decoquinate and halofuginone. No conclusions could be drawn on the compatibility of BIO‐THREE^® with monensin sodium, salinomycin sodium, narasin, robenidine hydrochloride and maduramicin ammonium.

Safety and efficacy of a feed additive consisting of guar gum for all animal species (A.I.P.G. Association for International Promotion of Gums)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of guar gum as a feed additive for all animal species. Owing the absence of information, the genotoxic potential of the additive could not be fully assessed. From the results of tolerance studies, the FEEDAP Panel concluded that guar gum is safe for salmonids at a maximum concentration of 3,000 mg/kg complete feed. Guar gum is safe up to ~ 280 mg/kg complete feed for chickens for fattening, 375 mg/kg complete feed for turkeys for fattening, 400 mg/kg complete feed for rabbits, 500 and 600 mg/kg complete feed for piglets and pigs for fattening, respectively, 1,100 mg/kg complete feed for cattle for fattening and 1,150 mg/kg complete feed for veal calves. No conclusions can be reached on the safety for long living and reproductive animals, until the genotoxic potential of the additive is fully assessed in the framework of its use as a feed additive. The use of the additive in animal nutrition is considered safe for the consumer and the environment. In the absence of data, no conclusions could be drawn on the safety of the additive for the user. Guar gum is efficacious as a gelling agent, thickener, and contributes to stabilise canned pet feed. No conclusion can be drawn on the additive as an emulsifier.

Safety and efficacy of a feed additive consisting of sepiolite for all animal species (Sepiol S.A and Tolsa, S.A)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the re‐evaluation of the authorisation of sepiolite as a feed additive for all animal species. The FEEDAP Panel considered that sepiolite is unlikely to be absorbed. Harmful amounts of residues of any chemical component in edible tissues/products, as a consequence of the use of sepiolite as a feed additive, are not expected. Sepiolite is not genotoxic and does not induce any toxicity effects following oral administration and, therefore, it was considered safe for the consumers. The additive was considered safe for dairy cows at the recommended use level with a safety factor of 2.5. The conclusion was extrapolated to other dairy ruminants but owing to the lack of sufficient data, no conclusions can be drawn on the safety of the additive for the other target species/categories. Based on the results of a chronic inhalation toxicity study, the additive is considered a respiratory irritant. Owing to the dusting potential of the additive and its silica content, handling the additive was considered a risk by inhalation for the users. It is not irritant or corrosive to skin or eyes. Due to the nickel content, it is considered a skin and respiratory sensitiser. The additive was considered safe for the environment. The FEEDAP Panel concluded that sepiolite was efficacious as a thickener‐suspending agent, binder and anticaking agent in feed for all animal species under the proposed conditions of use.

Safety and efficacy of the feed additives consisting of l‐glutamic acid and monosodium l‐glutamate monohydrate produced by Corynebacterium glutamicum NITE BP‐01681 for all animal species (METEX NOOVISTAGO)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of l‐glutamic acid and monosodium l‐glutamate monohydrate produced by fermentation using the genetically modified strain Corynebacterium glutamicum NITE BP‐01681. The additives are intended to be used in feed and water for drinking for all animal species and categories as nutritional additives (amino acids) or as sensory additives (flavouring compounds). Viable cells of the production strain and its DNA were not detected in the final additives. The additives do not give rise to any safety concern regarding the production strain. l‐Glutamic acid and monosodium l‐glutamate monohydrate produced using C. glutamicum NITE BP‐01681 are considered safe for the target species, for the consumer and for the environment. However, the Panel raised concerns on the use in water for drinking for hygienic reasons. The additives are considered not irritant to skin or eyes and not dermal sensitisers but a risk by inhalation. The Panel concluded that the additives are efficacious as nutritional additives and as flavouring compounds.

Long-term COVID symptoms, work ability and fitness to work in healthcare workers hospitalized for Sars-CoV-2 infection

BACKGROUND

COVID-19 can affect the persistence of symptoms and work ability (WA), hence the fitness to work of healthcare workers (HCW). We describe the effects of COVID-19 in hospitalized HCWs of a large Hospital in Lombardy and their implications on WA and fitness to work.

METHODS

Fifty-six HCWs of Fatebenefratelli-Sacco Hospital have been hospitalized for COVID-19 since March 2020. Clinical and fitness-to-work data were acquired from Occupational Health Surveillance Program. A structured questionnaire was administered to 53/56 HCWs 18 months after infection to investigate Long-COVID symptoms and WA.

RESULTS

Symptoms most reported at recovery (rhino-pharyngeal swab-NPS-negative) were exertional dyspnea (86.8%), asthenia (86.8%), arthro-myalgia (71.7%), sleep disorders (64.2%), resting dyspnea (62.3%), cough (56.6%). 69.6% underwent evaluation at out-patient clinics experienced in Long-COVID. Ten months after recovery, symptoms related to physical well-being decreased while memory and anxiety/depression were more persistent. At recovery, the WA score decreased from 10 to 8, and then an improvement from 8 to 9 was noted during the survey. At the return-to-work examination, fit-to-work judgements with restrictions increased from 31.4% to 58.7%; then, a slight decrease in the rate of judgements with restrictions was observed at the survey's time.

CONCLUSION

Post-COVID-19 symptoms can persist for a long time and could impact WA and fitness-to-work of HCW. Adequate health surveillance protocols should guarantee the health protection of HCW with persistent disorders after COVID-19.

Safety and efficacy of a feed additive consisting of Allura Red AC for small non-food-producing mammals and ornamental birds (Versele-Laga)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of Allura Red AC for small non-food-producing mammals and ornamental birds when used as an additive that add or restore colour in feedingstuffs. The use of Allura Red AC up to the proposed conditions of use of 500 mg/kg complete feed is considered safe for guinea pig, chinchilla, degu, hamster, gerbil and chipmunk. The following maximum safe levels (mg/kg complete feed) apply to the following species: ferrets 99, rabbits 123, canaries, budgerigars, mynah and toucans 45, lovebirds 51, cockatiels 79, cockatoos 115, amazons 145, parrots 147, yellow breast macaw 150, blue-throated macaw 173 and hyacinth macaw 214. The maximum safe level of Allura Red AC for other small non-food-producing mammal is 99 mg/kg feed and for other ornamental birds is 45 mg/kg feed. Inhalation exposure of Allura Red is regarded as hazardous. In the absence of data, the Panel cannot conclude on the potential of Allura Red to be a skin/eye irritant or a skin sensitiser. The FEEDAP Panel cannot conclude on the efficacy of the additive.

Safety and efficacy of a feed additive consisting of 3-nitrooxypropanol (Bovaer® 10) for ruminants for milk production and reproduction (DSM Nutritional Products Ltd)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of Bovaer^® 10 as a zootechnical additive for ruminants for milk production and reproduction. Systemic exposure or site of contact toxicity for the active substance 3‐nitrooxypropanol (3‐NOP), for which genotoxicity has not been fully clarified, in the target species, is unlikely based on ADME data available. Consequently, the FEEDAP Panel concluded that Bovaer^® 10 was safe for dairy cows at the maximum recommended level. However, as a margin of safety could not be established, the FEEDAP Panel could not conclude on the safety of the additive for other animal species/categories. The FEEDAP Panel considered that the consumer was exposed to 3‐nitrooxypropionic acid (NOPA), which is one of the 3‐NOP metabolites. NOPA was not genotoxic based on the studies provided. The FEEDAP Panel concluded that the use of Bovaer^® 10 in animal nutrition under the conditions of use proposed was of no concern for consumer safety and for the environment. The FEEDAP Panel concluded that the active substance 3‐NOP may be harmful if inhaled. It is irritant (but not corrosive) to skin, irritant to the eyes but it is not a skin sensitiser. As the genotoxicity of 3‐NOP is not completely elucidated, the exposure through inhalation of the additive may represent an additional risk for the user. The Panel concluded that the additive has a potential to be efficacious in dairy cows to reduce enteric methane production under the proposed conditions of use. This conclusion was extrapolated to all other ruminants for milk production and reproduction.

Safety and efficacy of a feed additive consisting on the bacteriophages PCM F/00069, PCM F/00070, PCM F/00071 and PCM F/00097 infecting Salmonella Gallinarum B/00111 (Bafasal®) for all avian species (Proteon Pharmaceuticals S.A.)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the feed additive consisting of four bacteriophages infecting Salmonella Gallinarum B/00111 (PCM F/00069, PCM F/00070, PCM F/00071 and PCM F/00097, trade name: Bafasal®) when used as a zootechnical additive in water for drinking and liquid complementary feed for all avian species. The effects sought are the reduction of the Salmonella spp. carriage in chickens for fattening, the improvement of their performance, or both. The host strain harbours an acquired antimicrobial resistance gene. No viable cells or DNA from the host organism were found in the additive. The four phages proved to be strictly lytic and to have a machinery allowing to package a unit-length of the viral genome. The manufacturing process excludes the presence of remnants from the propagation process in the final additive. Consequently, no concerns are expected from the nature and manufacture of the product. Considering this and the results of the tolerance study with chickens for fattening, the Panel concluded that Bafasal® is safe for all avian species. Considering the nature and manufacturing process of the additive, Bafasal® is not expected to pose a risk for consumers. The results of the subchronic oral toxicity study and genotoxicity studies provided support this conclusion. Exposure of users via inhalation is expected to be low, but Bafasal® should be considered a respiratory sensitiser. No conclusions were drawn on the irritancy of Bafasal® to skin and eyes or on its dermal sensitisation potential due to lack of data. Considering the nature and manufacturing process of the additive, Bafasal® is safe for the environment. The Panel was not in the position to conclude on the efficacy of Bafasal® for any avian species due to insufficient data.

Safety and efficacy of a feed additive consisting of copper chelate of ethylenediamine for all animal species (Zinpro Animal Nutrition (Europe), Inc.)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of copper chelate of ethylenediamine (Copper-EDA-Cl) as a feed additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP Panel) identified several issues related to the data provided concerning the chemical characteristics of the additive and, based on the information provided from an in vitro dissociation study, considered it unlikely that the additive consists only of copper mono-chelate of EDA but of several coexisting (copper) species. Therefore, in the absence of adequate experimental data and owing to the uncertainties identified, the Panel cannot conclude on its identity and characterisation of the additive. The FEEDAP Panel concludes that the additive is safe for chickens for fattening and reared for laying/breeding but cannot conclude on the safety for other animal species/categories. The FEEDAP Panel cannot conclude on the safety of the additive for the consumer or the environment. The FEEDAP Panel concludes that handling the additive poses a risk to users by inhalation. The additive should be considered as non-irritant for the skin but corrosive for the eyes and a skin sensitiser. The Panel notes the uncertainties on the genotoxicity potential of the additive that might have an impact on the conclusions on the safety for the user. The FEEDAP Panel concludes that the additive is efficacious in providing copper to meet the nutritional requirements of this trace element in all animal species.

Safety and efficacy of a feed additive consisting of iron chelate of ethylenediamine for all animal species (Zinpro Animal Nutrition (Europe), Inc.)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of iron chelate of ethylenediamine (Iron-EDA-Cl) as a feed additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) identified several issues related to the data provided concerning the chemical characteristics of the additive. Based on the information provided, the FEEDAP Panel considered unlikely that the additive consists only of iron monochelate of EDA, but of several coexisting (iron) species; therefore, in the absence of adequate experimental data and owing to the uncertainties identified, the Panel cannot conclude on its identity and characterisation. The FEEDAP Panel concludes that the additive is safe for poultry for fattening and reared for laying/breeding, but cannot conclude on the safety for other animal species/categories. The FEEDAP Panel cannot conclude on the safety of the additive for the consumer or the environment. The FEEDAP Panel concludes that handling the additive poses a risk to users by inhalation. The additive should be considered as non-irritant for the skin but irritant for the eyes and skin sensitiser. The FEEDAP Panel cannot conclude on the efficacy of the additive.

Safety and efficacy of the feed additive consisting of Vitamin B2/Riboflavin produced by Eremothecium ashbyiCCTCCM 2019833 for all animal species (Hubei Guangji Pharmaceutical Co., Ltd)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the feed additive Vitamin B₂/Riboflavin produced by Eremothecium ashbyi CCTCCM 2019833 for all animal species and categories. The additive contains a minimum content of riboflavin of 5%. The production strain has been characterised and data showed that viable cells are not present in the final additive. The additive is not a skin or eye irritant nor a skin sensitiser, but it is considered to be a respiratory sensitiser. The lack of data on the toxicological profile of the additive, including its genotoxic potential, did not allow the Panel to conclude on the safety of the additive for the target species, consumers and users. The FEEDAP Panel concluded that the use of the product as a feed additive poses no concerns for the environment. The additive under assessment is effective in covering the animals' requirements for vitamin B₂ when administered via feed.

Safety and efficacy of a feed additive consisting of manganese chelate of ethylenediamine for all animal species (Zinpro Animal Nutrition (Europe), Inc.)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of manganese chelate of ethylenediamine (Manganese-EDA-Cl) as feed additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) identified several issues related to the data provided concerning the chemical characteristics of the additive. Based on the information provided, the FEEDAP Panel considered unlikely that the additive consists only of manganese mono-chelate of EDA, but of several coexisting (manganese) species; therefore, the FEEDAP Panel was unable to confirm the identity of the additive. The FEEDAP Panel could not evaluate the safety for target species, consumer and environment and the efficacy of the additive owing to the uncertainties and limitations identified in the studies submitted. Concerning the safety of the additive for the users, the Panel considered that handling the additive poses a risk to users by inhalation. The additive should be considered as corrosive to eyes and a skin sensitiser.

Safety and efficacy of a feed additive consisting of zinc chelate of ethylenediamine for all animal species (Zinpro Animal Nutrition (Europe), Inc.)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of zinc chelate of ethylenediamine (Zinc-EDA-Cl) as feed additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) identified several issues related to the data provided concerning the chemical characteristics of the additive. Based on the information provided, the FEEDAP Panel considered unlikely that the additive consists only of zinc mono-chelate of EDA, but of several coexisting (zinc) species; therefore, the FEEDAP Panel was unable to confirm the identity of the additive. The FEEDAP Panel could not evaluate the safety for target species, consumer and environment and the efficacy of the additive owing to the uncertainties and limitations identified in the studies submitted. Concerning the safety of the additive for the users, the Panel considered that handling the additive poses a risk to users by inhalation. The additive should be considered as corrosive to eyes and a skin sensitiser.

Single-Nucleus and In Situ RNA-Sequencing Reveal Cell Topographies in the Human Pancreas

BACKGROUND & AIMS

Molecular evidence of cellular heterogeneity in the human exocrine pancreas has not been yet established because of the local concentration and cascade of hydrolytic enzymes that can rapidly degrade cells and RNA upon pancreatic resection. We sought to better understand the heterogeneity and cellular composition of the pancreas in neonates and adults in healthy and diseased conditions using single-cell sequencing approaches.

METHODS

We innovated single-nucleus RNA-sequencing protocols and profiled more than 120,000 cells from pancreata of adult and neonatal human donors. We validated the single-nucleus findings using RNA fluorescence in situ hybridization, in situ sequencing, and computational approaches.

RESULTS

We created the first comprehensive atlas of human pancreas cells including epithelial and nonepithelial constituents, and uncovered 3 distinct acinar cell types, with possible implications for homeostatic and inflammatory processes of the pancreas. The comparison with neonatal single-nucleus sequencing data showed a different cellular composition of the endocrine tissue, highlighting the tissue dynamics occurring during development. By applying spatial cartography, involving cell proximity mapping through in situ sequencing, we found evidence of specific cell type neighborhoods, dynamic topographies in the endocrine and exocrine pancreas, and principles of morphologic organization of the organ. Furthermore, similar analyses in chronic pancreatitis biopsy samples showed the presence of acinar-REG⁺ cells, a reciprocal association between macrophages and activated stellate cells, and a new potential role of tuft cells in this disease.

CONCLUSIONS

Our human pancreas cell atlas can be interrogated to understand pancreatic cell biology and provides a crucial reference set for comparisons with diseased tissue samples to map the cellular foundations of pancreatic diseases.

Bounds on Lorentz Invariance Violation from MAGIC Observation of GRB 190114C

On January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording the most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of the speed of light in vacuo for photons as predicted by several quantum gravity models. Based on a set of assumptions on the possible intrinsic spectral and temporal evolution, we obtain competitive lower limits on the quadratic leading order of speed of light modification.

Safety of Lancer® (lanthanide citrate) as a zootechnical additive for weaned piglets

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the additional data submitted on Lancer^® when used as a feed additive for weaned piglets. The FEEDAP Panel considered that uncertainty still remains on possible developmental neurotoxicity of Lancer^® since it was unable to identify a no observed adverse effect level (NOAEL) for this specific endpoint applying a read‐across strategy from the studies provided by the applicant. However, the FEEDAP Panel considered that the exposure to La and Ce from products of animals treated with Lancer^® at 250 mg/kg feed would not add a significant contribution to the background exposure of these elements. The FEEDAP Panel concluded that the use of Lancer^® in feed for weaned piglets (up to 120 days) according to the proposed conditions of use, does not represent a safety concern for the consumer and for the environment.

Safety and efficacy of l-histidine monohydrochloride monohydrate produced by fermentation with Escherichia coli (NITE BP-02526) for all animal species

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on l‐histidine monohydrochloride monohydrate produced by fermentation with Escherichia coli (NITE BP‐02526) when used as a nutritional additive or as a feed flavouring compound in feed and water for drinking for all animal species. The product under assessment is l‐histidine HCl H₂O produced by fermentation with a genetically modified strain of E. coli (NITE BP‐02526). The production strain and its recombinant DNA were not detected in the final products. l‐Histidine HCl H₂O does not give rise to any safety concern to the production strain. The use of l‐histidine HCl H₂O is safe for the target species when used to supplement the diet in appropriate amounts. It is safe at the proposed use level of 25 mg/kg when used as a flavouring compound for all animal species. The use of l‐histidine HCl H₂O in animal nutrition raises no safety concerns for consumers of animal products. The additive is not irritating to the skin or eyes and is not a skin sensitiser. There is a risk for persons handling the additive from the exposure to endotoxins by inhalation. The use of l‐histidine as a feed additive does not represent a risk to the environment. The additive l‐histidine HCl H₂O is regarded as an effective source of the amino acid l‐histidine when used as a nutritional additive. For the supplemental l‐histidine to be as efficacious in ruminants as in non‐ruminant species, it requires protection against degradation in the rumen. It is also considered efficacious as a feed flavouring compound under the proposed conditions of use.

Safety and efficacy of Axtra®XAP 104 TPT (endo-1,4-xylanase, protease and alpha-amylase) as a feed additive for chickens for fattening, laying hens and minor poultry species

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of Axtra® XAP 104 TPT as a zootechnical feed additive (digestibility enhancers) for poultry species. The additive contains three enzyme activities (endo-1,4-beta-xylanase, protease and alpha-amylase) produced by three different genetically modified strains. Viable cells and recombinant DNA of the strains producing the protease and amylase were not detected in the final product. Owing to the insufficient data, uncertainty remained on the presence in the additive of viable cells of the strain producing the xylanase. The results obtained in the genotoxicity and subchronic oral toxicity studies performed with the three fermentation products did not indicate safety concerns resulting from the fermentation products used in the formulation/manufacturing. However, uncertainties remain on the suitability of the test item used in the studies conducted with the xylanase; therefore, the Panel was not in the position to conclude on the toxicological potential of AXTRA ® XAP 104 TPT. Consequently, the Panel could not conclude on the safety of the additive for the target species, consumers and users. Owing to the uncertainty on the presence of viable cells of one of the production strains in the additive, the Panel could not conclude on the safety for the environment. The FEEDAP Panel concluded that AXTRA ® XAP 104 TPT is efficacious in chickens for fattening, chickens reared for laying and minor poultry species up to the point of lay at the level of 2,000 U xylanase, 200 U amylase and 4,000 U protease per kg feed. Owing to the lack of sufficient data, the Panel could not conclude on the efficacy of the additive for laying hens.

Safety and efficacy of IMP (disodium 5'-inosinate) produced by fermentation with Corynebacterium stationis KCCM 80161 for all animal species

Following a request from the European Commission, the Panel on Additives and Products or substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of disodium 5'-inosinate (IMP) produced by fermentation using Corynebacterium stationis KCCM 80161 when used as a sensory additive (flavouring compound) in feed and water for drinking for all animal species. The production strain is not genetically modified. Viable cells of the production strain were not detected in the final additive. The additive does not give rise to any safety concern regarding the production strain. IMP produced using C. stationis KCCM 80161 is considered safe for the target species, for the consumer and for the environment. IMP produced using C. stationis KCCM 80161 is considered not toxic by inhalation, not irritant to skin or eyes and not a dermal sensitiser. The FEEDAP Panel expressed reservations on the use of the additive in water for drinking due to concerns on its impact on the hygienic conditions of the water. The Panel concluded that the additive is efficacious to contribute to the flavour of feed.

Assessment of the application for renewal of authorisation of l-histidine monohydrochloride monohydrate produced with Escherichia coli NITE SD 00268 for salmonids and its extension of use to other fin fish

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on l-histidine monohydrochloride (HCl) monohydrate produced by fermentation using Escherichia coli NITE SD 00268 in the context of the renewal of the authorisation for salmonids when used as a nutritional additive. In addition, the applicant requested the extension of use of the additive for other fin fish. The applicant has provided evidence that the composition of the additive currently in the market complies with the conditions of authorisation. The production strain has been modified by conventional mutagenesis and it does not raise safety concerns. The use of l-histidine HCl monohydrate produced by fermentation using E. coli NITE SD 00268 is safe for salmonids and other fin fish when used as a nutritional additive to supplement the diet in appropriate amounts to cover the nutritional requirements, depending on the species, the physiological state of the animal, the performance level, the environmental conditions, the background amino acid composition of the unsupplemented diet and the status of some essential trace elements such as copper and zinc. The FEEDAP Panel considers the maximum total concentration of 1.7% histidine in feed for salmonids proposed by the applicant as safe. For other fin fish species, the level of 1.7% appears to cause adverse effects. Therefore, it is not possible to define a maximum concentration of histidine in fish other than salmonids as it depends on histidine nutritional requirements in the different fish species. The use of the authorised additive in salmonids production does not pose a risk for consumers, and the proposed maximum total concentration of 1.7% histidine in feed is considered safe for the consumer. l-Histidine HCl monohydrate produced using E. coli NITE SD 00268 supplemented at levels appropriate to cover the nutritional requirements of fish other than salmonids is considered safe for the consumer. The additive under assessment is not a skin irritant. In the absence of data, it is not possible to conclude on the potential of the additive to be toxic by inhalation, irritant to eyes or a skin sensitiser. The amino acid l-histidine is a natural component of plants and animals. The use of the additive under assessment in animal nutrition does not represent a risk to the environment. The additive is considered an efficacious source of the amino acid l-histidine for fish species.

Safety and efficacy of l-histidine monohydrochloride monohydrate produced using Corynebacterium glutamicum KCCM 80172 for all animal species

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on l-histidine monohydrochloride (HCl) monohydrate produced by fermentation using Corynebacterium glutamicum KCCM 80172 when used as a nutritional additive in feed and water for drinking for all animal species. The production strain is genetically modified. The production strain and its recombinant DNA were not detected in the final product. l-Histidine HCl monohydrate manufactured by fermentation using C. glutamicum KCCM 80172 does not give rise to any safety concern regarding the genetic modification. The use of l-histidine HCl monohydrate produced by fermentation using C. glutamicum KCCM 80172 is safe for the target species when used as a nutritional additive to supplement the diet in appropriate amounts to cover the requirements, depending on the species, the physiological state of the animal, the performance level, the environmental conditions, the background amino acid composition of the unsupplemented diet and the status of some essential trace elements such as copper and zinc. l-Histidine HCl monohydrate produced using C. glutamicum KCCM 80172 supplemented at levels appropriate for the requirements of the target species is considered safe for the consumer. l-Histidine HCl monohydrate produced using C. glutamicum KCCM 80172 is not irritant to skin, is a mildly irritant to eyes, and it is not a skin sensitiser. The additive does not pose a risk to users by inhalation. The use of l-histidine HCl monohydrate produced by C. glutamicum KCCM 80172 in animal nutrition is not expected to represent a risk to the environment. l-Histidine HCl monohydrate is considered an efficacious source of the essential amino acid l-histidine for non-ruminant animal species. For the supplemental l-histidine to be as efficacious in ruminants as in non-ruminant species, it would require protection against degradation in the rumen.

SiPM optical modules for the Schwarzschild-Couder Medium Size Telescopes proposed for the CTA observatory

Silicon Photomultipliers (SiPMs) are excellent devices to detect the faint and short Cherenkov light emitted in high energy atmospheric showers, and therefore suitable for use in imaging air Cherenkov Telescopes. The high density Near Ultraviolet Violet SiPMs (NUV-HD3) produced by Fondazione Bruno Kessler (FBK) in collaboration with INFN were used to equip optical modules for a possible upgrade of the Schwarzschild-Couder Telescope camera prototype, in the framework of the Cherenkov Telescope Array project. SiPMs are 6×6 mm2 devices based on 40×40 μm2 microcells optimized for photo-detection at the NUV wavelengths. More than 40 optical modules, each composed by a 4×4 array of SiPMs, were assembled. In this contribution we report on the development and on the assembly of the optical modules, their validation and integration in the camera.

Mapping transcription factor occupancy using minimal numbers of cells in vitro and in vivo

The identification of transcription factor (TF) binding sites in the genome is critical to understanding gene regulatory networks (GRNs). While ChIP-seq is commonly used to identify TF targets, it requires specific ChIP-grade antibodies and high cell numbers, often limiting its applicability. DNA adenine methyltransferase identification (DamID), developed and widely used in Drosophila, is a distinct technology to investigate protein–DNA interactions. Unlike ChIP-seq, it does not require antibodies, precipitation steps, or chemical protein–DNA crosslinking, but to date it has been seldom used in mammalian cells due to technical limitations. Here we describe an optimized DamID method coupled with next-generation sequencing (DamID-seq) in mouse cells and demonstrate the identification of the binding sites of two TFs, POU5F1 (also known as OCT4) and SOX2, in as few as 1000 embryonic stem cells (ESCs) and neural stem cells (NSCs), respectively. Furthermore, we have applied this technique in vivo for the first time in mammals. POU5F1 DamID-seq in the gastrulating mouse embryo at 7.5 d post coitum (dpc) successfully identified multiple POU5F1 binding sites proximal to genes involved in embryo development, neural tube formation, and mesoderm-cardiac tissue development, consistent with the pivotal role of this TF in post-implantation embryo. This technology paves the way to unprecedented investigation of TF–DNA interactions and GRNs in specific cell types of limited availability in mammals, including in vivo samples.

Constitutively Active SMAD2/3 Are Broad-Scope Potentiators of Transcription-Factor-Mediated Cellular Reprogramming

Reprogramming of cellular identity using exogenous expression of transcription factors (TFs) is a powerful and exciting tool for tissue engineering, disease modeling, and regenerative medicine. However, generation of desired cell types using this approach is often plagued by inefficiency, slow conversion, and an inability to produce mature functional cells. Here, we show that expression of constitutively active SMAD2/3 significantly improves the efficiency of induced pluripotent stem cell (iPSC) generation by the Yamanaka factors. Mechanistically, SMAD3 interacts with reprogramming factors and co-activators and co-occupies OCT4 target loci during reprogramming. Unexpectedly, active SMAD2/3 also markedly enhances three other TF-mediated direct reprogramming conversions, from B cells to macrophages, myoblasts to adipocytes, and human fibroblasts to neurons, highlighting broad and general roles for SMAD2/3 as cell-reprogramming potentiators. Our results suggest that co-expression of active SMAD2/3 could enhance multiple types of TF-based cell identity conversion and therefore be a powerful tool for cellular engineering.

Extracellular vesicles as potential biomarkers of acute graft-vs-host disease

Acute graft-vs-host disease (GVHD) is a serious complication after allografting. We carried out an exploratory study to investigate a potential correlation of surface antigens on extracellular vesicles (EVs) and acute GVHD. EVs were extracted from serum samples from 41 multiple myeloma patients who underwent allografting. EVs were characterized by flow cytometry using a panel of 13 antibodies against specific membrane proteins that were reported to be predictive of acute GVHD. We observed a correlation between three potential biomarkers expressed on EV surface and acute GVHD onset by both logistic regression analysis and Cox proportional hazard model. In our study, CD146 (MCAM-1) was correlated with an increased risk-by almost 60%-of developing GVHD, whereas CD31 and CD140-α (PECAM-1 and PDGFR-α) with a decreased risk-by almost 40 and 60%, respectively. These biomarkers also showed a significant change in signal level from baseline to the onset of acute GVHD. Our novel study encourages future investigations into the potential correlation between EVs and acute GVHD. Larger prospective multicenter studies are currently in progress.

Exposure to PFOA and PFOS and fetal growth: a critical merging of toxicological and epidemiological data

Toxicological and epidemiological evidence on the association between perfluorooctanoic acid (PFOA) or perfluorooctane sulfonic acid (PFOS) and birth/fetal weight was assessed. An extensive search for toxicological information in rats and mice, and a systematic search for epidemiological evidence were conducted. The linear regression coefficient (LRC) of birth weight (BrthW) on PFOA/PFOS was considered, and separate random effects meta-analyses for untransformed (i.e. not mathematically transformed) and log-transformed values were performed. Toxicological evidence: PFOA: 12 studies (21 datasets) in mice showed statistically significant lower birth/fetal weights from 5 mg/kg body weight per day. PFOS: most of the 13 studies (19 datasets) showed lower birth/fetal weights following in utero exposure. Epidemiological evidence: Sixteen articles were considered. The pooled LRC for a 1 ng/mL increase in untransformed PFOA (12 studies) in maternal plasma/serum was -12.8 g (95% CI -23.2; 2.4), and -27.1 g (95% CI -50.6; -3.6) for an increase of 1 log_e ng/mL PFOA (nine studies). The pooled LRC for untransformed PFOS (eight studies) was -0.92 g (95%CI -3.4; 1.6), and for an increase of 1 log_e ng/mL was -46.1(95% CI -80.3; -11.9). No consistent pattern emerged for study location or timing of blood sampling.

CONCLUSIONS

Epidemiological and toxicological evidence suggests that PFOA and PFOS elicit a decrease in BrthW both in humans and rodents. However, the effective animal extrapolated serum concentrations are 10²-10³ times higher than those in humans. Thus, there is no quantitative toxicological evidence to support the epidemiological association, thus reducing the biological plausibility of a causal relationship.

MBD3/NuRD facilitates induction of pluripotency in a context-dependent manner

The Nucleosome Remodeling and Deacetylase (NuRD) complex is essential for embryonic development and pluripotent stem cell differentiation. In this study, we investigated whether NuRD is also involved in the reverse biological process of induction of pluripotency in neural stem cells. By knocking out MBD3, an essential scaffold subunit of the NuRD complex, at different time points in reprogramming, we found that efficient formation of reprogramming intermediates and induced pluripotent stem cells from neural stem cells requires NuRD activity. We also show that reprogramming of epiblast-derived stem cells to naive pluripotency requires NuRD complex function and that increased MBD3/NuRD levels can enhance reprogramming efficiency when coexpressed with the reprogramming factor NANOG. Our results therefore show that the MBD3/NuRD complex plays a key role in reprogramming in certain contexts and that a chromatin complex required for cell differentiation can also promote reversion back to a naive pluripotent cell state.

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Mbd3 facilitates the initiation of neural stem cell reprogramming

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Mbd3 is also required for efficient iPSC generation from EpiSCs and preiPSCs

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Overexpression of Mbd3/NuRD facilitates reprogramming in a context-dependent manner

Bis-(2-ethylexhyl) phthalate impairs spermatogenesis in zebrafish (Danio rerio)

Bis-(2-ethylhexyl) phthalate (DEHP) is a widely used industrial additive for increasing plastic flexibility. Its metabolites are known to exert toxic effects on reproduction and development of mammals. The aim of this study was to evaluate the effects of environmentally relevant concentrations of DEHP (0.2 and 20 μg/L) on the reproductive biology of adult male zebrafish (Danio rerio). The effects of DEHP and 17β-ethynylestradiol (a positive control) were determined after one or three weeks of exposure by TUNEL assay, histomorphometric analysis and evaluation of reproductive performance. DEHP impaired reproduction in zebrafish by inducing a mitotic arrest during spermatogenesis, increasing DNA fragmentation in sperm cells and markedly reducing embryo production (up to 90%). In conclusion, relatively short-term exposure to environmentally relevant concentrations of DEHP is able to alter spermatogenesis and affect reproduction in zebrafish.

Fluorescent recovery after photobleaching (FRAP) analysis of nuclear export rates identifies intrinsic features of nucleocytoplasmic transport

A quantitative description of carrier-mediated nuclear export in live cells is presented. To this end, we fused a prototypical leucine-rich nuclear export signal (NES) to GFP as a cargo model and expressed the fluorescent chimera in live CHO-K1 cells. By modeling FRAP data, we calculate the NES affinity for the export machinery and the maximum rate of nuclear export achievable at saturation of endogenous carriers. The measured active-export time through the Nuclear Pore Complex (NPC) is 18 ms, remarkably similar to the previously determined active-import rate. Also, our results reveal that active export/import and active export/passive diffusion fluxes are uncoupled, thus complementing previous reports on active import/passive diffusion uncoupling. These findings suggest differential gating at the NPC level.

DEHP impairs zebrafish reproduction by affecting critical factors in oogenesis

Public concerns on phthalates distributions in the environment have been increasing since they can cause liver cancer, structural abnormalities and reduce sperm counts in male reproductive system. However, few data are actually available on the effects of Di-(2-ethylhexyl)-phthalate (DEHP) in female reproductive system. The aim of this study was to assess the impacts of DEHP on zebrafish oogenesis and embryo production. Female Danio rerio were exposed to environmentally relevant doses of DEHP and a significant decrease in ovulation and embryo production was observed. The effects of DEHP on several key regulators of oocyte maturation and ovulation including bone morphogenetic protein-15 (BMP15), luteinizing hormone receptor (LHR), membrane progesterone receptors (mPRs) and cyclooxygenase (COX)-2 (ptgs2) were determined by real time PCR. The expressions of BMP15 and mPR proteins were further determined by Western analyses to strengthen molecular findings. Moreover, plasma vitellogenin (vtg) titers were assayed by an ELISA procedure to determine the estrogenic effects of DEHP and its effects on oocyte growth. A significant reduction of fecundity in fish exposed to DEHP was observed. The reduced reproductive capacity was associated with an increase in ovarian BMP15 levels. This rise, in turn, was concomitant with a significant reduction in LHR and mPRbeta levels. Finally, ptgs2 expression, the final trigger of ovulation, was also decreased by DEHP. By an in vitro maturation assay, the inhibitory effect of DEHP on germinal vesicle breakdown was further confirmed. In conclusion, DEHP affecting signals involved in oocyte growth (vtg), maturation (BMP15, LHR, mPRs,) and ovulation (ptgs2), deeply impairs ovarian functions with serious consequences on embryo production. Since there is a significant genetic similarity between D.rerio and humans, the harmful effects observed at oocyte level may be relevant for further molecular studies on humans.