A Compact Neutron Generator for the Niort® Treatment of Severe Solid Cancers

In the last four years, TheranostiCentre S.r.l , Berkion Technology LLC and ENEA have patented and fabricated a first prototype of a Compact Neutron Generator (CNG) currently under testing in the ENEA laboratories. Besides the usual applications in the field of materials irradiation, this CNG - producing neutrons of 2.45 MeV energy through the deuterium-deuterium (DD) fusion reaction - was conceived for the neutron irradiation of the solid cancer’s tumour bed by means of the Intra-Operative Radiotherapy (IORT) technique, the so-called neutron-IORT (nIORT®). The DD-CNG is self-shielded and light-weight (~120 kg) making possible its remote handling by a robotic arm. Accurate Monte Carlo simulations, modelling the CNG and the “open wound” biological tissues near its irradiation window, demonstrated that the apparatus operated at 100 kV-10 mA supplies a neutron flux ~108 cm-2 s-1 and can deliver equivalent dose rates ~2 Gy (RBE)/min. Hence, it can administer very high dose levels in limited treatment times. This article briefly summarizes the main findings of this collaborative research study, the clinical rationales underpinning the nIORT® idea and the potential performances of the DD-CNG for the treatment of solid cancer pathologies. Indeed, the CNG can be installed in an operating room dedicated to nIORT® treatments, without posing any environmental and safety issues. Monte Carlo simulations have been carried out by envisioning the CNG equipped with an IORT applicator, that is an applicator pipe with a tuneable diameter to be inserted in the surgical cavity. By foreseeing the clinical endpoints of the standard IORT protocols, the irradiation performances for potential nIORT® treatments - obtained with an applicator pipe of 6 cm diameter - are here reported for different regimes: from 10 up to 75 Gy (RBE), that can be administered in a single session of about 4 to 30 minutes. Besides the dose peak in the centre of the tumour bed, the almost isotropic neutrons emission allows to irradiate its surroundings side-walls – usually filled by potential quiescent cancer cells – and therefore reducing the chances of local recurrences by improving the local control of the tumour. The rapid decrease in tissues depth of the dose profile (in few centimetres) will spare the neighbouring organs at risk from harmful radiations. Thus, the DD-CNG apparatus developed for nIORT® applications can potentially improve the resectability rate of a given neoadjuvant cancer treatment and, generally, could satisfy all five R’s criteria of radiotherapy. Furthermore, in comparing with the current IORT techniques with electrons or low-keV Xrays, the nIORT® exploiting a high-flux neutrons beam of 2.45 MeV energy could lead to some significant clinical advantages due to its high linear energy transfer (~ 40 keV/mm as average) and significantly higher relative biological effectiveness (@16) than all other forms of ionizing radiation

Can job turnover improve technical efficiency? : a study of state-owned enterprises in Shanghai

This paper studies the relationship between job turnover and technical efficiency of state-owned enterprise (SOEs) in Shanghai\u27s manufacturing sector during the period of 1989-1992. Data Envelopment Analysis (DEA) is used to compute measure of technical efficiency for each enterprise. Our findings indicate that, for non-expanding SOEs, the relationship between job turnover (i.e., downsizing) and technical efficiency is a U-shaped one such that efficiency declines at low levels of turnover,but after a certain level, it starts to increase. In addition, we show that small non-expanding SOEs (i.e., with employment size less than 100) start to increase their efficiency at a lower level of turnover than other medium and large SOEs. We also find that for medium and large expanding SOEs, the turnover-efficiency relationship is a positive and linear one

Ion source for neutral beam injection meant for plasma and magnetic field diagnostics

At the Lawrence Berkeley National Laboratory (LBNL) a diagnostic neutral beam injection system for measuring plasma parameters, flow velocity, and local magnetic field is being developed. The systems is designed to have a 90 % proton fraction and small divergence with beam current at 5-6 A and a pulse length of {approx}1 s occurring once every 1-2 min. The ion source needs to generate uniform plasma over a large (8 cm x 5 cm) extraction area. For this application, we have compared RF driven multicusp ion sources operating with either an external or an internal antenna in similar ion source geometry. The ion beam will be made of an array of six sheet-shaped beamlets. The design is optimized using computer simulation programs

Highly Compact Accelerator-Driven Subcritical Assembly for Medical and Industrial Applications

Highly Compact Accelerator-Driven Subcritical Assembly for Medical and Industrial Application

Dynamic association between energy transition technologies, renewable energy production, trade openness, green investment, carbon tax, and carbon neutrality: empirical evidences from China

The existing millennium documents the most adverse consequences of global warming which in contrast to pre-industrial era are more devastating. Thus, these prevailing consequences raise numerous concerns regarding the well-being of future and current generation. Scholars, in this regard, are putting efforts punctiliously towards methods that could halt the surging emissions. This paper also attempts to contributes to existing literature by reporting the empirical evidences regarding the role of energy transition technologies, renewable energy production (REP), trade openness, green investment, and carbon taxes in carbon neutrality in Chinse economy covering the time span of 1980–2020. By employing Dynamic Auto-regressive Distributed Lags (DARDL) model to check the association, findings exposed that electricity production from water sources, electricity production from solar sources, REP, trade openness, green investment, and carbon taxes are negatively correlated with CO2 emissions. Study offers policymakers a help in formulating policies related to achieve carbon neutrality using renewable sources of energy production, carbon taxes, and green investmen

Consumption patterns of entrepreneurs in the People\u27s Republic of China

Since the implementation of economic reforms in 1978 in the People\u27s Republic of China, entrepreneurs have emerged as a new consumer group. With rising income and high consumption power, entrepreneurs have become major consumers for expensive goods and services. However, little research has been carried out to understand their consumption decisions. In this paper, we study the consumption patterns of small business .owners, getihu, in China by using a set of large-scale, nation-wide survey data. Their consumption is postulated to be affected by (1) risk factors which include failure risk and financial (leverage) risk, (2) household variables such as the household size, financial and labor resources in the family, (3) the future plans of their business, and (4) home ownership. The effects of these factors on consumption patterns are evaluated. Our empirical results, based on regression and Tobit analysis, showed that all these factors are important in the consumption decisions of the entrepreneurs\u27 households. In particular, risk and household factors are statistically significant in accounting for the variations in their consumption patterns. The marketing implications are also discussed

Job turnover in China : a case study of Shanghai\u27s manufacturing enterprises

This paper studies the job turnover among manufacturing enterprises in Shanghai during the period from 1989 to 1992. Various indicators of job turnover, including job expansion rate, job contraction rate, net job growth rate, gross job reallocation rate, and excess job reallocation rate are calculated. The empirical results demonstrate that types of ownership and firm size are significant factors in accounting for the changes in job generation and job reallocation. Among various types of enterprise, international joint ventures and small firms (i.e., those that employ less than 100 workers) are more able to create jobs and to generate job reallocation

Characteristics of a RF-Driven Ion Source for a Neutron Generator Used For Associated Particle Imaging

We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium (2D(3T,n)4 alpha) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 108 n/s for a 50 muA D/T ion beam current accelerated to 80 kV. The generator utilizes a RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively-coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80percent can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results, such as the current density, atomic ion fraction, electron temperature, and electron density, from ion source testing will be discussed

Measurement of actinide neutron cross sections

The maintenance of strong scientific expertise is criticalto the U.S. nuclear attribution community. It is particularly importantto train students in actinide chemistry and physics. Neutroncross-section data are vital components to strategies for detectingexplosives and fissile materials, and these measurements requireexpertise in chemical separations, actinide target preparation, nuclearspectroscopy, and analytical chemistry. At the University of California,Berkeley and the Lawrence Berkeley National Laboratory we have trainedstudents in actinide chemistry for many years. LBNL is a leader innuclear data and has published the Table of Isotopes for over 60 years.Recently, LBNL led an international collaboration to measure thermalneutron capture radiative cross sections and prepared the EvaluatedGamma-ray Activation File (EGAF) in collaboration with the IAEA. Thisfile of 35,000 prompt and delayed gamma ray cross-sections for allelements from Z=1-92 is essential for the neutron interrogation ofnuclear materials. LBNL has also developed new, high flux neutrongenerators and recently opened a 1010 n/s D+D neutron generatorexperimental facility

Protein trafficking through the endosomal system prepares intracellular parasites for a home invasion

Toxoplasma (toxoplasmosis) and Plasmodium (malaria) use unique secretory organelles for migration, cell invasion, manipulation of host cell functions, and cell egress. In particular, the apical secretory micronemes and rhoptries of apicomplexan parasites are essential for successful host infection. New findings reveal that the contents of these organelles, which are transported through the endoplasmic reticulum (ER) and Golgi, also require the parasite endosome-like system to access their respective organelles. In this review, we discuss recent findings that demonstrate that these parasites reduced their endosomal system and modified classical regulators of this pathway for the biogenesis of apical organelles