Negative ion production and beam extraction processes in a large ion source (invited)

Recent research results on negative-ion-rich plasmas in a large negative ion source have been reviewed. Spatial density and flow distributions of negative hydrogen ions (H(-)) and positive hydrogen ions together with those of electrons are investigated with a 4-pin probe and a photodetachment (PD) signal of a Langmuir probe. The PD signal is converted to local H(-) density from signal calibration to a scanning cavity ring down PD measurement. Introduction of Cs changes the slope of plasma potential local distribution depending upon the plasma grid bias. A higher electron density H2 plasma locally shields the bias potential and behaves like a metallic free electron gas. On the other hand, the bias and extraction electric fields penetrate in a Cs-seeded electronegative plasma even when the electron density is similar. Electrons are transported by the penetrated electric fields from the driver region along and across the filter and electron deflection magnetic fields. Plasma ions exhibited a completely different response against the penetration of electric fields.

Numerical simulations of the first operational conditions of the negative ion test facility SPIDER

In view of the realization of the negative ion beam injectors for ITER, a test facility, named SPIDER, is under construction in Padova (Italy) to study and optimize production and extraction of negative ions. The present paper is devoted to the analysis of the expected first operations of SPIDER in terms of single-beamlet and multiple-beamlet simulations of the hydrogen beam optics in various operational conditions. The effectiveness of the methods adopted to compensate for the magnetic deflection of the particles is also assessed. Indications for a sequence of the experimental activities are obtained.

Simulation of diatomic gas-wall interaction and accommodation coefficients for negative ion sources and accelerators

Particle-wall interactions determine in different ways the operating conditions of plasma sources, ion accelerators, and beams operating in vacuum. For instance, a contribution to gas heating is given by ion neutralization at walls; beam losses and stray particle production-detrimental for high current negative ion systems such as beam sources for fusion-are caused by collisional processes with residual gas, with the gas density profile that is determined by the scattering of neutral particles at the walls. This paper shows that Molecular Dynamics (MD) studies at the nano-scale can provide accommodation parameters for gas-wall interactions, such as the momentum accommodation coefficient and energy accommodation coefficient: in non-isothermal flows (such as the neutral gas in the accelerator, coming from the plasma source), these affect the gas density gradients and influence efficiency and losses in particular of negative ion accelerators. For ideal surfaces, the computation also provides the angular distribution of scattered particles. Classical MD method has been applied to the case of diatomic hydrogen molecules. Single collision events, against a frozen wall or a fully thermal lattice, have been simulated by using probe molecules. Different modelling approximations are compared.

Isoform-specific interactions of the von Hippel-Lindau tumor suppressor protein

Deregulation of the von Hippel-Lindau tumor suppressor protein (pVHL) is considered one of the main causes for malignant renal clear-cell carcinoma (ccRCC) insurgence. In human, pVHL exists in two isoforms, pVHL19 and pVHL30 respectively, displaying comparable tumor suppressor abilities. Mutations of the p53 tumor suppressor gene have been also correlated with ccRCC insurgence and ineffectiveness of treatment. A recent proteomic analysis linked full length pVHL30 with p53 pathway regulation through complex formation with the p14ARF oncosuppressor. The alternatively spliced pVHL19, missing the first 53 residues, lacks this interaction and suggests an asymmetric function of the two pVHL isoforms. Here, we present an integrative bioinformatics and experimental characterization of the pVHL oncosuppressor isoforms. Predictions of the pVHL30 N-terminus three-dimensional structure suggest that it may exist as an ensemble of structured and disordered forms. The results were used to guide Yeast two hybrid experiments to highlight isoform-specific binding properties. We observed that the physical pVHL/p14ARF interaction is specifically mediated by the 53 residue long pVHL30 N-terminal region, suggesting that this N-terminus acts as a further pVHL interaction interface. Of note, we also observed that the shorter pVHL19 isoform shows an unexpected high tendency to form homodimers, suggesting an additional isoform-specific binding specialization.

Functional Interaction Between the ESCRT-I Component TSG101 and the HSV-1 Tegument Ubiquitin Specific Protease

Similar to phosphorylation, transient conjugation of ubiquitin to target proteins (ubiquitination) mediated by the concerted action of ubiquitin ligases and de-ubiquitinating enzymes (DUBs) can affect substrate function. As obligate intracellular parasites, viruses rely on different cellular pathways for their own replication and the well conserved ubiquitin conjugating/de-conjugating system is not an exception. Viruses not only usurp the host proteins involved in the ubiquitination/de-ubiquitination process, but they also encode their own ubiquitin ligases and DUBs. Here we report that an N-terminal variant of the herpes simplex virus (HSV) type-1 large tegument protein VP1/2 (VP1/2(1-767)), encompassing an active DUB domain (herpesvirus tegument ubiquitin specific protease, htUSP), and TSG101, a component of the endosomal sorting complex required for transport (ESCRT)-I, functionally interact. In particular, VP1/2(1-767) modulates TSG101 ubiquitination and influences its intracellular distribution. Given the role played by the ESCRT machinery in crucial steps of both cellular pathways and viral life cycle, the identification of TSG101 as a cellular target for the HSV-1 specific de-ubiquitinating enzyme contributes to the clarification of the still under debate function of viral encoded DUBs highly conserved throughout the Herpesviridae family.

Clear cell endometrial cancer: a CTF multicentre Italian study

Endometrial clear cell carcinoma (CCC) is a rare entity and only accounts for 1-6% of all endometrial cancers. CCC is considered an aggressive subtype of endometrial cancer with worse prognosis compared with type I cancer and more frequent relapses at distant and extrapelvic sites. These characteristics require specific treatment modalities, but rarity of the disease does not allow to identify evidence based indications for therapies. Objective of the present study is to analyse a series of cases treated in a multicentre Italian setting.

MATERIALS AND METHODS

Sixty-five endometrial CCC were treated in the period 1990-2010 in the participating institutions. Slides of the pathological specimens were reviewed by a single pathologist of each institution and debatable cases were collegially reviewed. Clinical records were collected by a common database. Demographic, surgical pathological, and follow-up data were registered. Results: All patients received primary surgery. Stage of disease according FIGO 2009 was as follow: l a: 16.9%, lb: 35.4%, 2: 9.2%, 3a: 9.2%, 3b: 3.1%, 3c: 16.9%, 4a: 3.1%, and 4b: 6.1%. Adjuvant post-operative treatment was adopted in 53.8% of cases. A relapse was detected in 29.2% of cases with a majority of extrapelvic sites (68.4%). Five-year survival rate was significantly related to stage of disease with an excellent prognosis for Stage Ia e lb disease with a complete staging. In these cases adjuvant treatment does not show significant improvement of survival. Relapsed cases show a response rate to treatment in 26% of cases (predominantly chemotherapy).

CONCLUSION

CCC requires extensive surgical staging. Stage I disease completely staged does not require adjuvant therapy. More advanced stages require adjuvant chemotherapy.

Comparative study of beam losses and heat loads reduction methods in MITICA beam source

In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

Non-ideal operating conditions of the ion source prototype for the ITER neutral beam injector due to thermal deformation of the support structure

The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.

Physics design of the injector source for ITER neutral beam injector (invited)

Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R&D physics program aimed to the development of the injector source are presented.

Survival and toxicity of radical radiotherapy (with or without brachytherapy) for FIGO stage I and II cervical cancer: a mono-institutional analysis

PURPOSE OF INVESTIGATION

To add to the existing outcome data regarding radical radiotherapy (RT) for FIGO Stage I and II cervical cancer in a mono-institutional series and to evaluate the cost-benefit ratio of the addition of brachytherapy (BRA) to external-beam radiotherapy (EBRT).

MATERIALS AND METHODS

The authors report on 240 patients (pts) with FIGO Stage I and II cervical cancer, consecutively treated with radical RT from 1990 through 2009 at the Istituto del Radio "O. Alberti" (EBRT alone, 32, EBRT and BRA, 189, BRA alone, 19). BRA was delivered with low dose rate (LDR, 133.64%) until 2003 and then with high dose rate (HDR, 75.36%). RT was associated with concomitant chemotherapy (CHT), mainly weekly cisplatin 40 mg/m2, in 87 pts, mostly after 2000. The Chi-square test was used to compare the different variables, the Log-Rank test to compare the actuarial survival values, and the Cox-model for the multivariate analysis.

RESULTS

Five-year actuarial overall survival (OS) equalled 65%, disease specific survival (DSS) 77%. Regardless of disease stage, better DSS was evident in pts treated with EBRT and BRA compared with those treated with EBRT alone (82% and 58% respectively, p = 0.005); pts treated with concomitant CHT (dose intensity > or = 50%) and higher RT doses (RT cumulative EQD2 > or = 75 Gy) obtained better DSS. Complete response (CR) rate approached 88.4% (206/233 evaluable pts) and more than half of the subsequent failures (21/36) were in distant sites. Older patients and those given BRA had better OS and DSS, while BRA dose rate did not result related with these outcomes. Chronic G3/G4 toxicity involved more frequently the intestinal/rectal tract than other organs at risk. Rectal and vaginal serious chronic sequelae developed mainly in pts treated with EBRT and BRA and suggest the need for more advanced treatment techniques.

CONCLUSIONS

the present mono-institutional analysis confirms the efficacy of radical RT for the treatment of cervical cancer and provides support to the role of BRA to obtain better outcomes. An effort to reduce long-term toxicity of the treatment is needed.

Is there a role for postoperative treatment in patients with stage Ib2-IIb cervical cancer treated with neo-adjuvant chemotherapy and radical surgery? An Italian multicenter retrospective study

PURPOSE

Neoadjuvant chemotherapy [NACT] followed by radical hysterectomy is an alternative therapeutic option to concurrent chemotherapy-radiotherapy for locally advanced cervical cancer. However there are very few data about the effectiveness of any post-operative treatment in this clinical setting. The purpose of this study was to correlate the patterns of recurrence and the clinical outcomes of cervical cancer patients who received NACT, with postoperative adjuvant treatment.

PATIENTS AND METHODS

This retrospective multicenter study included 333 patients with FIGO stage Ib2-IIb cervical cancer who underwent platinum-based NACT followed by radical surgery. Pathological responses were retrospectively assessed as complete; optimal partial; and suboptimal response. Overall optimal response rate was the sum of complete and optimal partial response rates.

RESULTS

On the whole series, recurrence-free survival was significantly longer in patients who achieved an overall optimal response than in those who did not (p<0.0001), and in patients who received adjuvant chemotherapy compared to those who did not (p=0.0001). On multivariate analysis, consolidation therapy (p=0.0012) was the only independent prognostic variable for recurrence-free survival; whereas FIGO stage (p=0.0169) and consolidation therapy (p=0.0016) were independent prognostic variables for overall survival.

CONCLUSION

Optimal responders after chemo-surgical treatment for FIGO stage Ib2-IIb cervical cancer do not need any further treatment. Additional cycles of chemotherapy could be of benefit for patients with suboptimal response and intra-cervical residual disease. Both adjuvant chemotherapy and adjuvant radiation treatments do not seem to improve the clinical outcome of patients with extra-cervical residual disease compared to no further treatment.

Pathological response on surgical samples is an independent prognostic variable for patients with Stage Ib2-IIb cervical cancer treated with neoadjuvant chemotherapy and radical hysterectomy: an Italian multicenter retrospective study (CTF Study)

OBJECTIVES

The purpose of this retrospective multicenter study was to correlate patterns of recurrences and clinical outcome of cervical cancer patients who underwent neoadjuvant chemotherapy [NACT] to surgery.

METHODS

This study was conducted on 333 patients with FIGO stage Ib2-IIb cervical cancer who underwent NACT to surgery with pelvic lymphadenectomy. The median follow-up was 66.5 months (range, 8-212 months). Overall optimal response rate was the sum of complete and optimal partial response rates.

RESULTS

An overall optimal response was obtained in 64 patients (19.2%). As for the 220 sub-optimal responders (66.1%), 127 patients had negative nodes and negative parametria and/or surgical margins, 75 patients had positive nodes with positive or negative parametria and/or surgical margins, and 18 patients had positive parametria and/or surgical margins with negative nodes. At the time of the present analysis, 79 (23.7%) of the 333 patients had a recurrence after a median time of 14.9 months (range, 4.5-123 months). Recurrent disease was pelvic in 50 (63.3%), extra-pelvic in 22 (27.9%), and both in 7 (8.8%). On multivariate analysis, pathological response to NACT was an independent prognostic variable for recurrence-free and overall survival. Patients who did not achieve an overall optimal response had a 2.757-fold higher risk of recurrence and a 5.413-fold higher risk of death than those who obtained an overall optimal response.

CONCLUSIONS

Results appear to suggest that the chemo-surgical approach is an effective therapeutic option for patients with stage Ib2-IIb cervical cancer and that pathological response to NACT is the strongest prognostic factor for the outcome.

Photolysis of endoperoxides in the presence of nitroxides: a laser flash photolysis study with optical and ESR detection

Time-resolved electron paramagnetic resonance spectroscopy, transient absorption, and phosphorescence spectroscopy were used to investigate the spin polarization of a nitroxide free radical induced by interaction with singlet oxygen ((1)O2). The latter was generated by photolysis of endoperoxides of two anthracene derivatives. Although both anthracene endoperoxides are structurally similar, opposite spin polarization of the nitroxide was observed. Photolysis of one endoperoxide leads to absorptive nitroxide spin polarization due to interaction with the generated (1)O2. Photolysis of the other endoperoxide generated emissive nitroxide spin polarization, probably due to interaction of the endoperoxide triplet states with nitroxides.

Analysis of failures and clinical outcome of advanced epithelial ovarian cancer in patients with microscopic residual disease at second-look reassessment following primary cytoreductive surgery and first-line platinum-based chemotherapy

AIM

To assess the pattern of failure and survival of advanced ovarian cancer patients with microscopic residual disease at second-look following cytoreductive surgery and platinum-based chemotherapy.

MATERIALS AND METHODS

Nine-five women were retrospectively analyzed. Residual disease after initial surgery was > one cm in 58 (61.1%) patients, first-line chemotherapy was paclitaxel/platinum-based in 70 (73.7%) patients, second-look findings showed no macroscopic residuum but positive random peritoneal biopsies and/or positive washing ("true" microscopic residual disease) in 79 (83.2%) patients, and a macroscopic residuum which was completely resected (converted complete response) in 16(16.8%) patients.

RESULTS

Eight-one (85.2%) patients developed recurrent disease after a median time of 14 months (range four to 51). The abdomen (29.6%) and the pelvis (28.4%) were the most common sites of failure. Two- and five-year survival after second-look were 78.1% and 31.0%, respectively. The clinical and pathological features with prognostic relevance at presentation (age, histotype, and tumor grade), as well as type of first-line chemotherapy and treatment after second-look were not related to the clinical outcome. There was a trend for a better survival in patients with optimal primary cytoreduction compared with those with suboptimal primary cytoreduction (five-year survival = 42.7% vs 23.4%). There was no significant difference in survival between the converted complete responders and the patients with "true" microscopic residual disease.

CONCLUSIONS

These data confirm the unsatisfactory clinical outcome of patients with microscopic residual disease after first-line chemotherapy and the limited benefit of second-look reassessment.

Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator

The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

Energy metabolism and re-establishment of intercellularadhesion complexes of gel entrapped hepatocytes

We studied the effect of continuous medium flow on the viabilityand structural organization of hepatocytes high density entrapped inalginate gel beads in the first few hours after isolation.The metabolic energy status of the entrapped cells, monitored invivo by (31)P NMR spectroscopy, was stable during theexperimental time and a physiological redox ratio was reachedafter the first three hours of culture. The morphologicalanalysis revealed that the entrapped hepatocytes placed in a fixed-bed bioreactor under continuous flow showed a polyhedricalshape with numerous microvilli on cell surface and reconstitutedtight junctions as well as bile canalicular structures, closelyresembling those present in the liver.These results suggest that continuous flow allows the culture ofhepatocytes at very high cell density within a matrix withoutloss of viability and accelerates cellular tissue reconstructionat very short times after isolation. This type of culture couldrepresent a very useful model for physiological andtoxicological studies as well as a promising approach toward thedevelopment of a bioartificial hybrid support device in acuteliver failure.

Natalizumab and drug holiday in clinical practice: an observational study in very active relapsing remitting multiple sclerosis patients

BACKGROUND

In order to reduce the risk of progressive multifocal leucoencephalopathy when using natalizumab for more than 12 months, a 6-month drug holiday has been discussed. However, the consequences on short term disease activity have been poorly assessed.

OBJECTIVE

The aim of this study was to assess clinical and radiological disease activity within 6 months after stopping natalizumab in very active relapsing remitting Multiple Sclerosis (RRMS) patients.

METHODS

In 8 hospitals from Western France, we retrospectively collected clinical and MRI data from consecutive RRMS patients treated with natalizumab for at least 6 months, and who stopped the drug for various reasons except therapeutic failure. Patients didn't receive any other disease modifying treatment after discontinuing natalizumab.

RESULTS

A total of 27 patients with very active RRMS before natalizumab start (mean annualized relapse rate of 2.3, MRI activity in 21 of 27 patients) were studied. Within 6 months after discontinuing natalizumab, 18 patients (67%) experienced clinical relapse and 3 additional patients had radiological activity, without clinical relapse. Four patients (15%) experienced a rebound activity, with severe relapse and 20 or more gadolinium enhancing lesions on MRI.

CONCLUSION

Such observational data didn't support the concept of drug holiday when using natalizumab in very active RRMS.

Herpes simplex virus type 2 infection increases human immunodeficiency virus type 1 entry into human primary macrophages

Epidemiological and clinical data indicate that genital ulcer disease (GUD) pathogens are associated with an increased risk of human immunodeficiency virus type 1 (HIV-1) acquisition and/or transmission. Among them, genital herpes simplex virus type 2 (HSV-2) seems to play a relevant role. Indeed, the ability of HSV-2 to induce massive infiltration at the genital level of cells which are potential targets for HIV-1 infection may represent one of the mechanisms involved in this process. Here we show that infection of human primary macrophages (MDMs) by HSV-2 results in an increase of CCR5 expression levels on cell surface and allows higher efficiency of MDMs to support entry of R5 HIV-1 strains. This finding could strengthen, at the molecular level, the evidence linking HSV-2 infection to an increased susceptibility to HIV-1 acquisition.

Cancer in pregnancy: maternal and fetal implications on decision-making

BACKGROUND

Cancer complicates one out of 1,000 pregnancies. No standardized therapeutic interventions have been reported for these patients.

METHODS

Fifteen patients with cancer during pregnancy were diagnosed between 6.5 and 36 weeks of gestational age between January 1991 and December 2007.

RESULTS

Among the 15 cases one patient with early diagnosis (11 weeks) asked for interruption of pregnancy, two patients rejected chemotherapy in order to avoid fetal effects, seven patients underwent surgery during the first or second trimester, and two patients agreed to start the treatment only after delivery. Standard platinum-based chemotherapy (cisDDP) was postponed in six patients to the second trimester (administered after surgery in 2 cases). Chemotherapy was started between 18.3 and 29.6 weeks (median 22.3 weeks). One patient had pPROM (22.3 weeks) after chemotherapy with cisDDP. Ten patients were delivered by elective cesarean section and three by vaginal delivery. Mean gestational age at delivery was 33.5 weeks (range 32.1-40.0); mean weight at birth was 2,550 g (range 1,250-3,450). None of the newborns showed congenital malformations, and all had normal Apgar scores. Anemia occurred in two newborns. At a median follow-up of 56 months (range 2-198 months) all children were well and healthy. Eleven out of 15 mothers are alive and well, and one is alive with disease. An advanced neoplasm was diagnosed in three patients who died.

CONCLUSION

When platinum-based chemotherapy is administered during the 2nd-3rd trimester, adverse effects in newborns are comparable to those in the general population. Deliberate treatment delay to achieve fetal viability or to improve fetal outcome may be reasonable for patients with early-stage cancer.

Nef and cell signaling transduction: a possible involvement in the pathogenesis of human immunodeficiency virus-associated dementia

Although the introduction of highly active antiretroviral therapy (HAART) has resulted in a significant decrease of acquired immunodeficiency syndrome (AIDS) morbidity and mortality, the prevalence of human immunodeficiency virus (HIV)-associated dementia (HAD) has actually risen, due to the increasing life expectancy of the infected subjects. To date, several aspects of the HAD pathogenesis remain to be dissected. In particular, the viral-cellular protein interplay is still under investigation. Given their specific features, two viral proteins, Tat and Nef, have been mainly hypothesized to play a role in HIV neuropathology. Here we show that HIV-1 Nef has an effect on the transcriptional levels of a cellular protein, anaplastic lymphoma kinase (ALK), that is preferentially expressed in the central and peripheral nervous system at late embryonic stages. By its overexpression along with Nef, the authors demonstrate ALK ability to influence, at least in the U87MG astrocytic glioma cells, the mytogen-activated protein kinase (MAP-K)-dependent pathway. Moreover, although in the absence of a physical direct interaction, Nef and ALK activate matrix metalloproteinases (MMPs), which are likely to contribute to blood-brain barrier (BBB) damage in HAD. Finally, in the in vitro model of glioblastoma cells adopted, Nef and ALK show similar effects by increasing different cytochines/chemokines that may be relevant for HAD pathogenesis. If confirmed in vivo, these data may indicate that, thanks to its ability to interfere with specific cellular pathways involved in BBB damage and in central nervous system (CNS) integrity, Nef, along with specific cellular counterparts, could be one of the viral players implicated in HAD development.

The spin chemistry and magnetic resonance of H2@C60. From the Pauli principle to trapping a long lived nuclear excited spin state inside a buckyball

One of the early triumphs of quantum mechanics was Heisenberg's prediction, based on the Pauli principle and wave function symmetry arguments, that the simplest molecule, H(2), should exist as two distinct species-allotropes of elemental hydrogen. One allotrope, termed para-H(2) (pH(2)), was predicted to be a lower energy species that could be visualized as rotating like a sphere and possessing antiparallel ( upward arrow downward arrow) nuclear spins; the other allotrope, termed ortho-H(2) (oH(2)), was predicted to be a higher energy state that could be visualized as rotating like a cartwheel and possessing parallel ( upward arrow upward arrow) nuclear spins. This remarkable prediction was confirmed by the early 1930s, and pH(2) and oH(2) were not only separated and characterized but were also found to be stable almost indefinitely in the absence of paramagnetic "spin catalysts", such as molecular oxygen, or traces of paramagnetic impurities, such as metal ions. The two allotropes of elemental hydrogen, pH(2) and oH(2), may be quantitatively incarcerated in C(60) to form endofullerene guest@host complexes, symbolized as pH(2)@C(60) and oH(2)@C(60), respectively. How does the subtle difference in nuclear spin manifest itself when hydrogen allotropes are incarcerated in a buckyball? Can the incarcerated "guests" communicate with the outside world and vice versa? Can a paramagnetic spin catalyst in the outside world cause the interconversion of the allotropes and thereby effect a chemical transformation inside a buckyball? How close are the measurable properties of H(2)@C(60) to those computed for the "quantum particle in a spherical box"? Are there any potential practical applications of this fascinating marriage of the simplest molecule, H(2), with one of the most beautiful of all molecules, C(60)? How can one address such questions theoretically and experimentally? A goal of our studies is to produce an understanding of how the H(2) guest molecules incarcerated in the host C(60) can "communicate" with the chemical world surrounding it. This world includes both the "walls" of the incarcerating host (the carbon atom "bricks" that compose the wall) and the "outside" world beyond the atoms of the host walls, namely, the solvent molecules and selected paramagnetic molecules added to the solvent that will have special spin interactions with the H(2) inside the complex. In this Account, we describe the temperature dependence of the equilibrium of the interconversion of oH(2)@C(60) and pH(2)@C(60) and show how elemental dioxygen, O(2), a ground-state triplet, is an excellent paramagnetic spin catalyst for this interconversion. We then describe an exploration of the spin spectroscopy and spin chemistry of H(2)@C(60). We find that H(2)@C(60) and its isotopic analogs, HD@C(60) and D(2)@C(60), provide a rich and fascinating platform on which to investigate spin spectroscopy and spin chemistry. Finally, we consider the potential extension of spin chemistry to another molecule with spin isomers, H(2)O, and the potential applications of the use of pH(2)@C(60) as a source of latent massive nuclear polarization.

Possible role of palliative surgery for bowel obstruction in advanced ovarian cancer patients

OBJECTIVES

Bowel obstruction is a relatively common event (30-40%) in advanced or recurrent ovarian cancer patients. No definitive data are available on the optimal management of this serious complication and treatment is generally limited to adoption of palliative measures. These modalities include both surgical and medical procedures. The aim of this study was to define selection criteria for subjects who would benefit from palliative surgery.

STUDY DESIGN

Out of 270 epithelial ovarian cancer patients treated in the period 1984-2005, 75 (28%) developed bowel obstruction related to progression/recurrence of the disease. Palliative treatment - both medical and surgical - was applied on an individual basis. A new score developed by these authors was retrospectivelly applied to this group of patients with the aim of defining a subgroup that could benefit from surgical treatment.

RESULTS

Fifty cases (66.7%) were medically treated whereas 25 patients (33.3%) underwent surgery. Mean and median survival rates were 34 and 28 weeks in the surgical group versus 12 and four weeks in the medical group. Distribution according to score showed 53 cases (71%) in the low score group (< 14) and 22 (29%) in the high score group (> 14). A significantly better survival was observed in the low-score group (p < 0.0001) and in the surgically treated patients (p < 0.001). According to the risk score variables patients treated surgically for obstruction with low scores had a longer survival (p < 0.005) compared to medical treatment but this difference was not found in the high-risk group (p < 0.05).

CONCLUSIONS

The prognosis of patients with bowel obstruction in relation to advanced ovarian cancer is best determined by comprehensive assessment of all prognostic parameters to define a subgroup of patients in a low-risk group that may benefit from surgical treatment.