Safer school with near-UV technology: novel applications for environmental hygiene

Systems capable of disinfecting air and surfaces could reduce the risk of infectious diseases transmission. Aim: to evaluate the effectiveness of near-UV LED ceiling lamps, with a wavelength of 405 nm, in improving environmental hygiene. Between November and December 2020, we conducted an experimental study having a pre-post design in a kindergarten room in Siena where 4 ceiling lamps with 405 nm LED technology were installed. Twice per day, sampling was performed before (T0) and after treatment with near-UV (T1). We used between 8 and 12 pairs of contact plates to sample at various random spots each day. Air samplings were also performed. The plates were incubated at 22 and 36 °C. Significance was set at 95% (p < 0.05). The mean level of Colony Forming Unit (CFU) at T(0) was 249 (95% CI 193.1 - 305.0) at 36 °C and 535.2 (374.3 - 696.1) at 22 °C. The reduction was significant at T(1): by 65% at 36 °C and, 72% at 22 °C. Also, for air contamination: 95.3% (98.4-92.3). A dose threshold of about 5 J/cm² was identified to have an 80% CFU abatement and remains nearly constant. The advantage of being able to use this technology in the presence of people is very important in the context of controlling environmental contamination.

Graphical abstract

Can a UV-C box help cinema industry by hygienizing video-cameras?

Background

UV-C has proven to be an effective microbiocide method for disinfecting objects in domestic and work environments. Aim of this study was to test the biocidal efficiency of an UVC box on a real video-camera.

Methods

In February 2021, a descriptive study on a parallelepiped-shaped UVC box, produced by Cartoni S.p.a., was conducted at the University of Siena. The box has 10 UV-C lamps (254 nm at 0.9 Watt/each) and all six mirrored reflective walls. It was specifically engineered for disinfecting equipments for film makers. A real professional camera was used to assess the level of disinfection. Contamination was obtained inoculating 1.5x107CFU/mL of S. Aureus ATCC 43300 on five 20 cm2 plastic carriers positioned in five different spots (referred as spots A, B, C, D, E), both directly (spot A), and indirectly (by reflected light, spots B, C, D, E) exposed to a UV-C light source. After a cycle of 3 minutes' exposition to UV-C: all carriers were transferred on empty Petri dishes; 10 mL D/E medium was added, transferred into a 50 ml Falcon and spun for 40 minutes at 4500 rpm; the supernatant was then removed and 100 µl of it was incubated into a Petri dish (with a generic growth medium) at 36 °C for 48 h. The experiment was run in triplicate. The mean logarithmic reduction and its 95% confidence interval were calculated from the replicates data and compared with positive controls (1.5x107CFU/mL).

Results

Mean logarithmic reduction compared to positive control was in spot A: 6.33 log10(C.I. 5.90-6.75), spot B: 4.74 log10(C.I. 4.11-5.33), spot C: 4.83 log10(C.I. 4.75-4.91), spot D: 4.89 log10(C.I. 4.12-5.65), spot E: 5.00 log10(C.I. 4.79-5.21).

Conclusions

These experiments showed that after 3 minutes of UV-C exposure there is a significant reduction in the bacterial load, 4 to 6 log10 (99.99% to 99.9999% reduction), on the carriers. The results also highlight the ability of the UV-C box to disinfect all infected spots, including those irradiated by reflected light.

Key messages

UV-C Box devices are effective in decreasing bacterial contamination on shared work tools in cinema industries, regardless of the direct or indirect exposition to the UV-C source. UV-C box's speed in hygienizing shared work tools can help cinema industry professionals to work in a safer and cleaner environment.

Efficacy of nearuv-a to inactive microbial growth

Background

Microbes are less able to develop resistance towards antimicrobial blue light (aBL), at 405nm, towards disinfectants/antibiotics. In addition, Near UV-A light (nUV) is less harmful to host cell compared to UV-C irradiation. This study aimed to assess the efficiency aBL in reducing microbial growth on surfaces.

Methods

This cross-sectional study, run between July-October 2020. Petri dishes were contaminated with P. Aeruginosa, E. Coli, S. Aureus, S. Typhimurium, K. Pneumoniae at a concentration of 1.5x104 CFU/mL and were placed at 2 and 3m of distances from the light source having an irradiance of 967,39 and 497,33 µW/cm2 for 12 hours. The air confined the room was sampled for two weeks with two air samplers (SAS), before and after the exposition to the nUV light source to estimate the reduction of the environmental microbial contamination. The analysis was conducted using Stata software. Final results were expressed as logarithmic reduction mean with 95% confidence interval.

Results

The highest microbial reduction was reached 2m directly under the light. Significant (p &lt; 0.05) log-reduction were achieved for S. Typhimurium, 2.93 (IC 2.44-3.40), K.Pneumoniae, 2.30 (IC 2.14-2.46), S.Aureus, 3.98 (IC 3.78-4.12), E.Coli, 3.83 (IC 3.17-4.50), P. Aeruginosa, 3.86 (IC 3.22-4.48). At 3m of distance from the light source, it was observed a significant logarithmic reduction for S. Aureus, 3.49 (IC 3.34-3.65), and P. Aeruginosa, 3.80 (IC 3.11-4.47). In the air tests, we observed a mean percentage microbial reduction of about 70% after 12 h of exposure to nUV light.

Conclusions

nUV has proven to contrast microbial growth on the plates. It is possible to implement this technology in the environment for controlling microbial presence in “ad hoc” scenario but also in common areas. Mitigating the energy, it is possible to use this technology in presence of persons.

Key messages

In this experimental study, nearUV-A has proven to be efficient to reduce the microbial growth and to disinfect air and surface. NearUV light (nUV) can be use as an innovative technology for decreasing bacterial contamination, also in presence of people.

There is no planet B: masks UVC disinfection to rise to the environmental challenge during COVID-19

Background

Since the outbreak of Sars-CoV-2 public health measures have been adopted globally, most notably the use of face masks has become essential and often mandatory. As a result, about 3.4 billion single-use face masks are estimated to be discarded daily worldwide. Due to waste mismanagement, the COVID-19 pandemic is severely impacting the environment, the ecosystem and therefore human health. We aimed to assess if UV-C light is an efficient tool for proper mask disinfection, to guarantee their safe reuse and reduce their waste.

Methods

In October 2020 we conducted a cross sectional study on KN95 masks. Various operators wore the masks during their shift in the laboratory for 8, 16 and 24h. Contact plates were used to measure microbial contamination on both surfaces of the masks at time T(0). Then, masks were placed into a UV-C box (volume of 0.012 m3, 40 UVC LED at 270nm at 3mW) for a treatment of 3 minutes. We repeated the sampling at time T(1). We incubated all plates at 36 °C and read them after 48h. We performed descriptive and inferential (Wilcoxon matched pair test) analysis with Stata. Significance level was set at p < 0.05.

Results

We always observed greater contamination on internal surfaces than external ones. At T(0) the medians of CFU on samples of internal surface were 212.7 (CI 95% 0-480.2) at 8h, 311.7 (0-683.1) at 16h and 404.7 (0-736.1) at 24h; at T(1), CFU reduced (p < 0.05) and were respectively 3.2 (0-6.2), 2 (0-5.9) and 50.6 (0-164.7). At T(0) the medians of CFU on external surface were 23.7 (0-48.4), 53.2 (0-143) and 24.3 (0-71.8); at T(1) they respectively reduced (p < 0.05) to 8.7 (0-25.2), 18.2 (0-70), 2.3 (0-6.1).

Conclusions

Results showed that UV-C is effective in mask disinfection although an uncomplete abatement of the microbial load. It could be due to the limited UV-C dose or to its difficulty to penetrate among the meshes of the mask. Further investigation is needed to find a sustainable solution for mask use.

Key messages

UV-C seems a valid disinfection tool for used KN95 masks.

The development of strategies for proper disinfection of masks should be carried out to guarantee reusability and reduce waste production.

Wind of change: better air for microbial environmental control

Background

COVID19 outbreak highlighted air disinfection's importance. All bacteria and viruses tested to date (including various coronaviruses) respond to UV-C disinfection. This study aims to assess the effectiveness of an UVC disinfection system for air in a real working context.

Methods

This descriptive study was carried out in November 2020 in an office of the Department of Molecular and Developmental Medicine at the University of Siena. The disinfecting air system, Cleaning Air T12, produced by Italia Iso Group, has 12 lamps of 6.9 Watt of UVC/each, two inlet grills in its bottom and 2 outlet grills in the superior part. The volume of air that the system treat is of 210m3/h. The experiments were run over several days during the activities of 3-5 subjects working for several hours. Real time microbial air samplings were run during the tests switching the system ON and OFF. To verify microbial time variation, initial samplings (phase 1) had the system OFF, then ON (phase 2) and finally OFF again (phase 3). Petri dishes were incubated at 36 and 22 C°. Statistical analysis was executed with Stata 16. Significance level was set at p &lt; 0.05.

Results

The longest test highlighted that during phase 2, after 8 minutes from the end of phase 1, the system acted significantly (p = 0.001) on the reduction of environmental contamination up to a mean of 70 (95% C.I. 64 - 77) CFU/500 liters (about 70% at 22 °C) and 50% at 36 °C. In phase 3 the mean values became 171 (144 - 198) CFU/500 liters at 22C° and 259 (228-291) at 36 °C.

Conclusions

The system was able to significantly reduce the environmental contamination in real time. The experimental tests show how, as soon as the device is turned OFF after at least half an hour of operation, air healthiness drops dramatically within 10 minutes, bringing the levels of microbial contamination (induced by the presence of the operators in the room) to levels even higher than 150%.

Key messages

In order to convey a correct and truthful message about the disinfection capabilities of an air purification system, testing the device under real operating would be necessary. Testing the device under real operating conditions, with and without the presence of people in controlled environments, would be necessary before the final product is placed on the market.

Multicentre validation of point-of-care screening tool for heart failure: single-lead ECG recorded by smart stethoscope predicts low ejection fraction using artificial intelligence

Background/Introduction

Artificial intelligence (AI) applied to 12-lead ECG can identify left ventricular ejection fraction (EF) ≤35% with a sensitivity and specificity of 86.3% and 85.7%, respectively. Whether AI algorithms trained on 12-lead can accurately predict EF from single-lead ECGs (recorded by a smart stethoscope) remains unknown. This could facilitate point-of-care screening for low EF during routine clinical examination.

Purpose

First independent multicentre real-world UK National Health Service (NHS) prospective validation of 12-lead-ECG-trained AI algorithm applied to single-lead ECG recorded by a smart stethoscope, with AI algorithm tuned to detect EF ≤40%.

Methods

Prospective recruitment of unselected patients attending for echocardiography across six urban NHS hospital sites (UK). In addition to transthoracic echocardiogram (routine care), all participants had 15 seconds of supine, single-lead ECG recorded at six different positions (figure), encompassing standard anatomical positions for cardiac auscultation. A convolutional neural network (CNN) previously trained on 35,970 independent pairings of 12-lead-ECG and echocardiograms was retrained to use the single-lead ECG as input. Accuracy of CNN detection of low EF (binary ≤40%) is reported at a threshold of 0.5 against gold-standard; echo-determined percentage EF.

Results

Among 353 patients recruited (mean age 63±17; 58% male, 43.1% non-white), 309 (87.5%) had an EF &gt;40%, and 44 (12.5%) had EF ≤40%. The best single recording position in isolation was position 3 (sensitivity 57.9% [42.2–73.6], specificity 86.3% [82.2–90.3]). Taking any of the six positions performed during the examination as predicting EF ≤40%, this achieved a sensitivity of 81.2% and specificity of 61.5%.

Conclusion(s)

In this first prospective multicentre validation study the retrained AI algorithm reliably detected low EF from single-lead ECGs acquired using a novel ECG-enabled stethoscope in standard auscultation positions. The ability to identify patients with possible low EF during routine physical examination addresses a significant unmet clinical need in point-of-care ruling in/out of heart failure, and has potential to provide broader population-level screening for asymptomatic cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Health Research, Accelerated Access Collaborative & NHSX: Artificial Intelligence in Health & Social Care Award

Framework for large-scale automatic curation of heterogeneous cardiac MRI (ACUR MRI)

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): UKRI CDT in AI for Healthcare http://ai4health.io and British Heart Foundation

Background 

Data curation is an important process that structures and organises data, supporting research and the development of artificial intelligence models. However, manually curating a large volume of medical data is a time-consuming, repetitive and costly process that puts additional strain on clinical experts. The curation becomes more complex and demanding as more data sources are used. This leads to an introduction of disparity in the data structure and protocols. 

Purpose 

Here, we propose an automatic framework to curate large volumes of heterogenous cardiac MRI scans acquired across different sites and scanner vendors. Our framework requires minimal expert involvement throughout and works directly on DICOM images from the scanner or PACS.  The resulting structured standardised data allow for straightforward image analysis, hypothesis testing and the training and application of artificial intelligence models. 

Methods 

It is broken down into three main components

anonymisation, cataloguing and outlier detection (see Figure 1). Anonymisation automatically removes any identifiable patient information from the DICOM image attributes. These data are replaced with anonymised labels, whilst maintaining relevant longitudinal information from each patient. DICOM attributes are also used to automatically group the different images according to imaging sequence (e.g. CINE, Delayed-Enhancement, T1 maps), acquisition geometry (e.g. short-axis, 2-chamber, 4-chamber) and imaging attributes (e.g. slice thickness, TE, TR), for easier querying. The sorting characteristics are flexible and can easily be defined by the user. Finally, we detect and flag, for subsequent manual inspection, any outliers within those groups, based on the similarity levels of chosen DICOM attributes. This framework additionally offers interactive image visualisation to allow users to assess its performance in real time. 

Results 

We tested the performance of ACUR CMRI on 26,668 CMR image series (723,531 images) from 858 patient examinations, which took place across two sites in four different scanners. With an average execution time per patient of 100 seconds, ACUR was able to sort imaging data with 1191 different sequence names into 43 categories. The framework can be freely downloaded from https://bitbucket.org/cmr-ai-working-group/acur/. 

Conclusions 

We present ACUR, an automatic framework to curate large volumes of heterogeneous cardiac MRI data. We show how it can quickly and automatically curate data, grouping it according to desired imaging characteristics defined in DICOM attributes. The proposed framework is flexible and ideally suited as a pre-processing tool for large biomedical imaging data studies.

Gigantea: Uncovering New Functions in Flower Development

GIGANTEA (GI) is a gene involved in multiple biological functions, which have been analysed and are partially conserved in a series of mono- and dicotyledonous plant species. The identified biological functions include control over the circadian rhythm, light signalling, cold tolerance, hormone signalling and photoperiodic flowering. The latter function is a central role of GI, as it involves a multitude of pathways, both dependent and independent of the gene CONSTANS(CO), as well as on the basis of interaction with miRNA. The complexity of the gene function of GI increases due to the existence of paralogs showing changes in genome structure as well as incidences of sub- and neofunctionalization. We present an updated report of the biological function of GI, integrating late insights into its role in floral initiation, flower development and volatile flower production.

Genetic Transformation in Peach (Prunus persica L.): Challenges and Ways Forward

Almost 30 years have passed since the first publication reporting regeneration of transformed peach plants. Nevertheless, the general applicability of genetic transformation of this species has not yet been established. Many strategies have been tested in order to obtain an efficient peach transformation system. Despite the amount of time and the efforts invested, the lack of success has significantly limited the utility of peach as a model genetic system for trees, despite its relatively short generation time; small, high-quality genome; and well-studied genetic resources. Additionally, the absence of efficient genetic transformation protocols precludes the application of many biotechnological tools in peach breeding programs. In this review, we provide an overview of research on regeneration and genetic transformation in this species and summarize novel strategies and procedures aimed at producing transgenic peaches. Promising future approaches to develop a robust peach transformation system are discussed, focusing on the main bottlenecks to success including the low efficiency of A. tumefaciens-mediated transformation, the low level of correspondence between cells competent for transformation and those that have regenerative competence, and the high rate of chimerism in the few shoots that are produced following transformation.

Biochemical study of the effect of stress conditions on the mandelonitrile-associated salicylic acid biosynthesis in peach

Salicylic acid (SA) plays a central role in plant responses to environmental stresses. In a recent study, we suggested a third pathway for SA biosynthesis from mandelonitrile (MD) in peach plants. This pathway is an alternative to the phenylalanine ammonia-lyase pathway and links SA biosynthesis and cyanogenesis. In the present work, using biochemical approaches, we studied the effect of salt stress and Plum pox virus (PPV) infection on this proposed SA biosynthetic pathway from MD. Peach plants were submitted to salt stress and Plum pox virus (PPV) infection. We studied the levels of SA and its intermediates/precursors (phenylalanine, MD, amygdalin and benzoic acid) in in vitro shoots. Moreover, in peach seedlings, we analysed the content of H₂ O₂ -related enzymes, SA and the stress-related hormones abscisic acid and jasmonic acid. We showed that the contribution of this SA biosynthetic pathway from MD to the total SA pool does not seem to be important under the stress conditions assayed. Nevertheless, MD treatment not only affected the SA content, but also had a pleiotropic effect on abscisic acid and jasmonic acid levels. Furthermore, MD modulates the antioxidative metabolism via SA-dependent or -independent redox-related signalling pathways. Even though the proposed SA biosynthetic pathway seems to be functional under stress conditions, MD, and hence cyanogenic glycosides, may be operating more broadly than by influencing SA pathways and signalling. Thus, the physiological function of the proposed SA biosynthetic pathway remains to be elucidated.

The Salt-Stress Response of the Transgenic Plum Line J8-1 and Its Interaction with the Salicylic Acid Biosynthetic Pathway from Mandelonitrile

Salinity is considered as one of the most important abiotic challenges that affect crop productivity. Plant hormones, including salicylic acid (SA), are key factors in the defence signalling output triggered during plant responses against environmental stresses. We have previously reported in peach a new SA biosynthetic pathway from mandelonitrile (MD), the molecule at the hub of the cyanogenic glucoside turnover in Prunus sp. In this work, we have studied whether this new SA biosynthetic pathway is also present in plum and the possible role this pathway plays in plant plasticity under salinity, focusing on the transgenic plum line J8-1, which displays stress tolerance via an enhanced antioxidant capacity. The SA biosynthesis from MD in non-transgenic and J8-1 micropropagated plum shoots was studied by metabolomics. Then the response of J8-1 to salt stress in presence of MD or Phe (MD precursor) was assayed by measuring: chlorophyll content and fluorescence parameters, stress related hormones, levels of non-enzymatic antioxidants, the expression of two genes coding redox-related proteins, and the content of soluble nutrients. The results from in vitro assays suggest that the SA synthesis from the MD pathway demonstrated in peach is not clearly present in plum, at least under the tested conditions. Nevertheless, in J8-1 NaCl-stressed seedlings, an increase in SA was recorded as a result of the MD treatment, suggesting that MD could be involved in the SA biosynthesis under NaCl stress conditions in plum plants. We have also shown that the plum line J8-1 was tolerant to NaCl under greenhouse conditions, and this response was quite similar in MD-treated plants. Nevertheless, the MD treatment produced an increase in SA, jasmonic acid (JA) and reduced ascorbate (ASC) contents, as well as in the coefficient of non-photochemical quenching (qN) and the gene expression of Non-Expressor of Pathogenesis-Related 1 (NPR1) and thioredoxin H (TrxH) under salinity conditions. This response suggested a crosstalk between different signalling pathways (NPR1/Trx and SA/JA) leading to salinity tolerance in the transgenic plum line J8-1.

Current achievements and future directions in genetic engineering of European plum (Prunus domestica L.)

In most woody fruit species, transformation and regeneration are difficult. However, European plum (Prunus domestica) has been shown to be amenable to genetic improvement technologies from classical hybridization, to genetic engineering, to rapid cycle crop breeding ('FasTrack' breeding). Since the first report on European plum transformation with marker genes in the early 90 s, numerous manuscripts have been published reporting the generation of new clones with agronomically interesting traits, such as pests, diseases and/or abiotic stress resistance, shorter juvenile period, dwarfing, continuous flowering, etc. This review focuses on the main advances in genetic transformation of European plum achieved to date, and the lines of work that are converting genetic engineering into a contemporary breeding tool for this species.

Metabolomics and Biochemical Approaches Link Salicylic Acid Biosynthesis to Cyanogenesis in Peach Plants

Despite the long-established importance of salicylic acid (SA) in plant stress responses and other biological processes, its biosynthetic pathways have not been fully characterized. The proposed synthesis of SA originates from chorismate by two distinct pathways: the isochorismate and phenylalanine (Phe) ammonia-lyase (PAL) pathways. Cyanogenesis is the process related to the release of hydrogen cyanide from endogenous cyanogenic glycosides (CNglcs), and it has been linked to plant plasticity improvement. To date, however, no relationship has been suggested between the two pathways. In this work, by metabolomics and biochemical approaches (including the use of [13C]-labeled compounds), we provide strong evidences showing that CNglcs turnover is involved, at least in part, in SA biosynthesis in peach plants under control and stress conditions. The main CNglcs in peach are prunasin and amygdalin, with mandelonitrile (MD), synthesized from phenylalanine, controlling their turnover. In peach plants MD is the intermediary molecule of the suggested new SA biosynthetic pathway and CNglcs turnover, regulating the biosynthesis of both amygdalin and SA. MD-treated peach plants displayed increased SA levels via benzoic acid (one of the SA precursors within the PAL pathway). MD also provided partial protection against Plum pox virus infection in peach seedlings. Thus, we propose a third pathway, an alternative to the PAL pathway, for SA synthesis in peach plants.

Lifestyle and eating habits in a business community

PURPOSE

The present study verified, using a validated questionnaire, the presence of unhealthy aspects of lifestyle and chronic degenerative conditions in a working community.

METHODS

A cohort from a working community in Italy was investigated using of the INRAN (Istituto Nazionale di Ricerca per gli Alimenti e Nutrizione) questionnaire dedicated to the eating habits and Physical Activity Stages of Change.

RESULTS

Most of the 93 subjects (56 females and 37 males, aged 42.0±0.7) recruited reported low levels of physical activity (70 subjects). Slightly more than 50% of the subjects undertook physical activity more than once a week, while 13% did it only once. Food intolerances were reported by 7 subjects (8%), with a high consumption of fruits, cereals and dairy products, low consumption of fish and alcohol, and meat consumption in the normal range. There was a high satisfaction in general quality of life.

CONCLUSION

Questionnaire investigations play a role to identify the presence of degenerative chronic conditions in working communities. The self-reported perception of quality of life does not necessarily agree with the lifestyle habits found. Awareness of this aspect could be helpful to plan lifestyle interventions and promote healthy living habits.

Ectopic expression of cytosolic superoxide dismutase and ascorbate peroxidase leads to salt stress tolerance in transgenic plums

To fortify the antioxidant capacity of plum plants, genes encoding cytosolic antioxidants ascorbate peroxidase (cytapx) and Cu/Zn-superoxide dismutase (cytsod) were genetically engineered in these plants. Transgenic plum plants expressing the cytsod and/or cytapx genes in cytosol have been generated under the control of the CaMV35S promoter. High levels of cytsod and cytapx gene transcripts suggested that the transgenes were constitutively and functionally expressed. We examined the potential functions of cytSOD and cytAPX in in vitro plum plants against salt stress (100 mm NaCl). Several transgenic plantlets expressing cytsod and/or cytapx showed an enhanced tolerance to salt stress, mainly lines C5-5 and J8-1 (expressing several copies of sod and apx, respectively). Transformation as well as NaCl treatments influenced the antioxidative metabolism of plum plantlets, including enzymatic and nonenzymatic antioxidants. Transgenic plantlets exhibited higher contents of nonenzymatic antioxidants glutathione and ascorbate than nontransformed control, which correlated with lower accumulation of hydrogen peroxide. Overall, our results suggest that transformation of plum plants with genes encoding antioxidant enzymes enhances the tolerance to salinity.

Cu/Zn superoxide dismutase and ascorbate peroxidase enhance in vitro shoot multiplication in transgenic plum

In this study we examined the role of antioxidant metabolism in in vitro shoot multiplication. We generated transgenic plum plantlets overexpressing the cytsod and cytapx genes in cytosol under the control of the constitutive promoter CaMV35S. Three transgenic lines with up-regulated sod at transcriptional levels that showed silenced cytapx expression displayed an elevated in vitro multiplication rate. By contrast, a transgenic line harboring several copies of cytapx and with elevated APX enzymatic activity did not show any improvement in plant vigor, measured as the number of axillary shoots and shoot length. All of the lines with elevated micropropagation ability exhibited intensive H2O2 accumulation, monitored by 3,3'-diaminobenzidine (DAB) staining as well as by colorimetric analysis, providing direct in vitro evidence of the role of H2O2 and antioxidant genes in in vitro shoot multiplication.

Criticality and strong intermittency in the Lorentz channel

We demonstrate the emergence of criticality due to power-law cross correlations in an ensemble of noninteracting particles propagating in an infinite Lorentz channel. The origin of these interparticle long-range correlations is the intermittent dynamics associated with the ballistic corridors in the single particle phase space. This behavior persists dynamically, even in the presence of external driving, provided that the billiard's horizon becomes infinite at certain times. For the driven system, we show that Fermi acceleration permits the synchronization of the particle motion with the periodic appearance of the ballistic corridors. The particle ensemble then acquires characteristics of self-organization as the weight of the phase space regions leading to critical behavior increases with time.

Interactive DICOM image transmission and telediagnosis over the European ATM network

The European High-Performance Information Infrastructure in Medicine, n(o)B3014 (HIM3) project of the Trans-European Network--Integrated Broadband Communications (TEN-IBC) program, started on March 1996 and finished on February 1997, aimed to test the medical usability of the European asynchronous transfer mode (ATM) network in medical image transmission. The Department of Radiology, University of Pisa, Pisa, Italy, and St-Luc University Hospital, Brussels, Belgium, involved in the project as healthcare partners in the radiological domain, established several connection sessions finalized to test the usability of Digital Imaging and Communication (DICOM) image transmission and interactive telediagnosis tools in the daily radiological practice. The Pisa site was connected to the Italian ATM pilot (Sirius Network) through the Tuscany metropolitan area network (MAN), while St-Luc University Hospital was connected to Belgium ATM network through the Brussels MAN. By means of international connections provided by the European JAMES project, a link between the two sites was established, connecting both national ATM networks. Due to the large variety of hardware present in the medical centers, multiplatform software tools were used and tested: central test node (CTN) release 2.8 [3], VAT [6], NV-3.3 [7], and IDI (UCL homemade multiplatform teleradiology tool for interactive visualization and processing of DICOM images). During the telediagnosis session, lead by radiologists in both hospitals, each site submitted neuroradiological clinical cases to the other for remote consultation. The connection, available for a period of two weeks, at 2-Mbit/s bandwidth, allowed the transmission of MR images (256 x 256 x 12 bit) and simultaneous multimedia interactive discussion of the cases. Both off-line transmission and review of the images, using the CTN DICOM transfer routines, and on-line interactive image discussion, using the IDI telediagnosis software, were tested successfully from the technical and medical point of view.

Anemia and growth retardation in totally gastrectomized swine

The effects of total gastrectomy in six young swine were followed and described during an experimental period up to 18 months. Two of the gastrectomized pigs (Nos. 1 and 2) were medicated with cycobemin every second week. Two other gastrectomized pigs (Nos. 11 and 14) were medicated with iron-dextran twice a week. Three non-gastrectomized swine receiving the same feed as the gastrectomized animals were observed as controls for up to eight months.

One of the gastrectomized non-medicated pigs (No. 4) did not gain weight, while the other gastrectomized animals had a normal appearance and gained weight but less than the controls. The non-medicated as well as the cycobemin-medicated gastrectomized animals developed a microcytic hypochrome anemia corresponding to the anemia in iron deficiency. Histochemically loss of iron in the depots (liver, spleen, bone marrow and intestine) was demonstrated in the gastrectomized animals except those treated with iron-dextran. Histological and histochemical examinations of the nervous system did not show any abnormalities.

The composition of gallstones from geriatric patients. Methods for the determination of cholesterol and of black substances in gallstones

78 female and 31 male Danish gallstone cases found by autopsy were studied. The mass of the gallstone(s) from each patient was recorded and the stones were ground. The content of cholesterol in the mixed material from each patient was determined, using the Liebermann-Burchard reaction. The ratio Gallstone(s) ash-mass/Gallstone(s)-mass was determined, and where this ratio exceeded 0.10, calcium and phosphate determinations were carried out. Subjective description of the stones as 'mixed stones' or 'pigment stones' was substituted by visual comparison of the ground gallstones with a 'grey scale' (black was given the highest value). The values of this quantity and the ash values generally increased with a decreasing content of cholesterol. The content of cholesterol in the gallstones increased with increasing stone mass. The chemical composition of gallstones found by surgery seems to differ from that of gallstones found by autopsy.

Vitamin B12 in the blood and in the liver of normal and of totally gastrectomized pigs

The concentration of vitamin R₁₂ in the blood was studied in five totally gastrectomized pigs followed for 10–18 months, and in four controls followed for 5¼–8 months. The concentration of vitamin B12 in the liver was investigated in three pigs of each group. The content of vitamin B₁₂ in the blood was of the same magnitude in both groups. Thus, removal of the stomach does not compromise the normal presence of this vitamin in the blood. The B₁₂ content in the liver was also unaffected by the operation, whereas it was increased after simultaneous administration of vitamin B₆.