Peering into lunar permanently shadowed regions with deep learning.

The lunar permanently shadowed regions (PSRs) are expected to host large quantities of water-ice, which are key for sustainable exploration of the Moon and beyond. In the near future, NASA and other entities plan to send rovers and humans to characterize water-ice within PSRs. However, there exists only limited information about the small-scale geomorphology and distribution of ice within PSRs because the orbital imagery captured to date lacks sufficient resolution and/or signal. In this paper, we develop and validate a new method of post-processing LRO NAC images of PSRs. We show that our method is able to reveal previously unseen geomorphological features such as boulders and craters down to 3 meters in size, whilst not finding evidence for surface frost or near-surface ice. Our post-processed images significantly facilitate the exploration of PSRs by reducing the uncertainty of target selection and traverse/mission planning.

The application of post-market monitoring to novel foods.

The role of post-market monitoring (PMM) in the safety assessment of novel foods is critically discussed in order to derive guidelines as to in which situations the application of PMM might be warranted. Available data sources on food consumption and health status, and the methodologies for generating such data are reviewed. The paper suggests improvements to make them more applicable for PMM purposes. It is concluded that any PMM programme must be a hypothesis-driven scientific exercise. PMM can have a role as a complement to, but not as a replacement for, a comprehensive pre-market safety assessment. Its use may be appropriate to confirm that product use is as predicted in the pre-market assessment; to provide reassurance that effects observed in the pre-market assessment occur with no greater frequency or intensity in the post-market phase than anticipated; and to investigate the significance of any adverse effects reported by consumers after market-launch. However PMM is insufficiently powerful to test the hypothesis that any effects seen in the pre-market assessment are absent in the post-market phase. Current methodologies place limitations on what PMM can achieve. PMM should only be used when triggered by or when the focus is on specific evidence-based questions.

History of safe use as applied to the safety assessment of novel foods and foods derived from genetically modified organisms.

Very few traditional foods that are consumed have been subjected to systematic toxicological and nutritional assessment, yet because of their long history and customary preparation and use and absence of evidence of harm, they are generally regarded as safe to eat. This 'history of safe use' of traditional foods forms the benchmark for the comparative safety assessment of novel foods, and of foods derived from genetically modified organisms. However, the concept is hard to define, since it relates to an existing body of information which describes the safety profile of a food, rather than a precise checklist of criteria. The term should be regarded as a working concept used to assist the safety assessment of a food product. Important factors in establishing a history of safe use include: the period over which the traditional food has been consumed; the way in which it has been prepared and used and at what intake levels; its composition and the results of animal studies and observations from human exposure. This paper is aimed to assist food safety professionals in the safety evaluation and regulation of novel foods and foods derived from genetically modified organisms, by describing the practical application and use of the concept of 'history of safe use'.

Cloning of the DNA repair genes mtcA, mtcB, uvsC, uvsD, uvsE and the leuB gene from Deinococcus radiodurans.

A gene library from Deinococcus radiodurans has been constructed in the cosmid pJBFH. A 51.5-kb hybrid cosmid, pUE40, that transduced Escherichia coli HB101 from leucine dependence to independence was selected, and a 6.9-kb fragment which carried the leuB gene from D. radiodurans was subcloned into the EcoRI site of pAT153. The DNA repair genes mtcA, mtcB, uvsC, uvsD and uvsE, which code for two D. radiodurans UV endonucleases were identified by transforming appropriate repair-deficient mutants of D. radiodurans to repair proficiency with DNA derived from the gene library. Hybrid cosmid pUE50 (37.9 kb) containing an insert carrying both the mtcA and mtcB genes was selected and 5.6- and 2.7-kb DNA fragments carrying mtcA and mtcB, respectively, i.e., the genes that code for UV endonuclease alpha, were subcloned into the EcoRI site of pAT153. The three genes uvsC, uvsD and uvsE, that code for UV endonuclease beta, were all present in the 46.0-kb hybrid cosmid pUE60. The uvsE gene in a 12.2-kb fragment was subcloned into the HindIII site of pAT153 and the size of the insert reduced to 6.1 kb by deletion of a 6.7-kb fragment from the hybrid plasmid pUE62. None of the uvs genes introduced into the UV-sensitive E. coli CSR603 (uvrA-) was able to complement its repair defect. The mtcA, uvsC, uvsD and uvsE genes were found in the 52.5-kb hybrid cosmid pUE70. It is concluded that the DNA repair genes mtcA, mtcB, uvsC, uvsD and uvsE are located within an 83.0-kb fragment of the D. radiodurans genome.

The safety and social acceptance of novel foods.

The regulatory processes employed in the UK and the European Union to assess the safety of novel foods and novel food ingredients, including those resulting from the application of recombinant DNA technology (genetically modified foods), are described. Examples are given of yeasts that have been genetically modified and can be used in food and drink manufacture and food enzymes derived from genetically modified microorganisms that have been deemed safe for use by the UK regulatory system. Social acceptance of such novel foods or food ingredients is not uniform in countries of the developed world. Consumer concerns can be based on ethical considerations (scientists "playing God") or safety worries ("more testing needs to be done"). The general acceptance of such foods and food ingredients in Europe is still unclear.

Lack of ultraviolet mutagenesis in radiation-resistant bacteria.

Ultraviolet (UV) radiation did not induce rifampicin-resistant mutants in populations of the taxonomically-related radiation-resistant bacteria Deinococcus radiodurans, D. radiopugnans, D. radiophilus and D. proteolyticus, although such mutants arose spontaneously at a low frequency and at a high frequency after treatment of cultures with N-nitroso compounds. The radiation-resistant bacteria Arthrobacter radiotolerans and P-30-A were also UV-immutable whereas the more radiation-sensitive Pseudomonas radiora was UV-mutable. We conclude that the radiation-resistant bacteria repair UV-induced DNA damage accurately and lack an error-prone pathway for the repair of such damage.

The resistance of Micrococcus radiodurans to killing and mutation by agents which damage DNA.

The resistance of Micrococcus radiodurans to the lethal and mutagenic action of ultraviolet (UV) light, ionising (gamma) radiation, mitomycin C (MTC), nitrous acid (NA), hydroxylamine (HA), N-methyl-N'-nitro-N-nitrosoguanidine (NG), ethylmethanesulphonate (EMS) and beta-propiolactone (betaPL) has been compared with that of Escherichia coli B/r. M. radiodurans was much more resistant than E. coli B/r to the lethal effects of UV light (by a factor of 33), gamma-radiation (55), NG (15) and NA (62), showed intermediate resistance to MTC (4) and HA (7), but was sensitive to EMS (1) and betaPL (2). M. radiodurans was very resistant to mutagens producing damage which can be repaired by a recombination system, indicating that it possesses an extremely efficient recombination repair mechanism. Both species were equally sensitive to mutation to trimethoprim resistance by NG, but M. radiodurans was more resistant than E. coli B/R to the other mutagens tests, being non-mutable by UV light, gamma-radiation, MTC and HA, and only slightly sensitive to mutation by NA, EMS and betaPL. The resistance of M. radiodurans to mutation by UV-light, gamma-radiation and MTC is consistent with an hypothesis that recombination repair in M. radiodurans is accurate since these mutagens may depend on an "error-prone" recombination system for their mutagenic effect in E. coli B/r. However, because M. radiodurans is also resistant to mutagens such as HA and EMS, which are mutagenic in E. coli in the absence of an "error-prone" system, we propose that all the mutagens tested may have a common mode of action in E. coli B/r, but that this mutagenic pathway is missing in M. radiodurans.

Deinococcus radiodurans UV endonuclease beta DNA incisions do not generate photoreversible thymine residues.

The ability of UV endonuclease beta of Deinococcus radiodurans to act as a pyrimidine dimer DNA glycosylase was investigated. Cell-free extracts of D. radiodurans exhibiting UV endonuclease beta activity failed to generate incisions in irradiated DNA that liberated free-thymine residues upon photoreversal with 254-nm light. This is in marked contrast to the pyrimidine dimer UV glycosylase of Micrococcus luteus that does liberate such residues. The result suggests that UV endonuclease beta incises DNA by true endonuclease action.

Identification and initial characterisation of a pyrimidine dimer UV endonuclease (UV endonuclease beta) from Deinococcus radiodurans; a DNA-repair enzyme that requires manganese ions.

An endonuclease that incises lightly ultraviolet-irradiated supercoiled plasmid DNA was identified in cell-free extracts of Deinococcus radiodurans R1 wild-type. The endonuclease was absent from strains mutant in the uvsC, uvsD or uvsE genes identifying it as 'UV endonuclease beta' responsible for the initial incision step of one excision-repair pathway for the removal of pyrimidine dimers from D. radiodurans DNA in vivo. The enzyme was purified free from contaminating nuclease activities and was partially characterised. The enzyme has an apparent molecular weight of 36 000, is ATP-independent, caffeine-insensitive and is inactivated by N-ethylmaleimide. It also has a novel requirement for manganese ions distinguishing it from all other known DNA-repair enzymes.

AP endonuclease and uracil DNA glycosylase activities in Deinococcus radiodurans.

An endonuclease specific for apurinic/apyrimidinic (AP) sites was identified and purified from extracts of Deinococcus radiodurans. The enzyme is 34.5 kD, has no activity towards normal, alkylated, uracil-containing, or UV-irradiated DNA, and is active in the presence of EDTA. The addition of up to 10 mM Mg2+ or Mn2+ did not affect activity, but higher concentrations were inhibitory. There is no associated exonuclease activity, either in the presence or absence of divalent cation. Optimal reaction conditions were 150 mM NaCl and pH 7.5. A uracil DNA glycosylase was also detected, active in the presence of EDTA, selectively removing uracil from DNA without generating other byproducts. The optimal reaction conditions were 50 mM NaCl and pH 7.5. Implications for base excision repair in D. radiodurans are discussed.

Superior labrum-biceps tendon complex lesions of the shoulder.

The detachment of the superior labrum from anterior to posterior has previously been reported. This lesion has been classified into four types. It was our impression that not all superior labrum abnormalities fit into such a classification system and that the mechanism of injury was distinctly different. During a 5-year period, 84 of 712 (11.8%) patients had significant labral abnormalities; 52 of 84 patients (6.2%) had lesions that fit within the classification system (Type II, 55%; III 4%; IV, 4%), but 32 of 84 patients (38%) had significant findings that could not be classified. These unclassifiable lesions fit into three distinct categories. Two of three patients described a traction injury to the shoulder. Only 8% sustained a fall on an outstretched arm; 75% had a preoperative diagnosis of impingement based on consistent history and provocative testing; however, when examined under anesthesia, 43% of the shoulders were considered to have increased humeral head translation when compared with the other shoulder. Recognition of superior labrum-biceps tendon detachment should prompt the surgeon to investigate glenohumeral instability as the source of a patient's complaints.

Survey of Bicycling Accidents in Boulder, Colorado.

In brief: To determine what public and individual efforts might reduce bicycling accidents and injuries, a survey was conducted during the primary cycling months (April through September) in Boulder, Colorado. Of 253 patients (87 women, 166 men, average age 22) treated for injuries in bicycling accidents, almost 30% of the accidents were caused by gravel, and nearly half involved a motor vehicle. The most frequent types of injury were abrasions, contusions, lacerations, and fractures. The survey results confirm the need for adequate head protection, satisfactory lighting, and increased awareness on the bicyclist's part. In addition, improved street maintenance will drastically reduce the number of cycling injuries and accidents.

How to make foods safer--genetically modified foods.

It is the responsibility of companies developing genetically modified foods, and of regulatory authorities that approve their marketing, to ensure that they are at least as safe as the traditional foods they are intended to replace in the diet. This requires that any novel material introduced into the food material should not be allergenic. If the novel gene has come from an allergenic source, e.g. nuts, it is necessary to demonstrate using immunological procedures applied to the IgE fractions of pooled sera from individuals with confirmed allergies that the novel protein is non-allergenic. When the novel gene is from a non-allergenic source then it is necessary to demonstrate lack of significant amino acid sequence homology to known allergens together with sensitivity to food manufacturing and digestive processes. Consumer confidence in genetically modified foods would be significantly improved if hypoallergenic varieties of crops and food products that are currently allergenic could be developed. Techniques such as antisense technology and single site amino acid substitution have been shown to have such potential.

Repair of ultraviolet radiation damage in sensitive mutants of Micrococcus radiodurans.

Various aspects of the repair of ultraviolet (UV) radiation-induced damage were compared in wild-type Micrococcus radiodurans and two UV-sensitive mutants. Unlike the wild type, the mutants are more sensitive to radiation at 265 nm than at 280 nm. The delay in deoxyribonucleic acid (DNA) synthesis following exposure to UV is about seven times as long in the mutants as in the wild type. All three strains excise UV-induced pyrimidine dimers from their DNA, although the rate at which cytosine-thymine dimers are excised is slower in the mutants. The three strains also mend the single-strand breaks that appear in the irradiated DNA as a result of dimer excision, although the process is less efficient in the mutants. It is suggested that the increased sensitivity of the mutants to UV radiation may be caused by a partial defect in the second step of dimer excision.