Observation of a New Narrow Axial-Vector Meson a1(1420)

The COMPASS Collaboration at CERN has measured diffractive dissociation of 190  GeV/c pions into the π(-)π(-)π(+) final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins of 3π mass and four-momentum transfer using the isobar model and the so far largest PWA model consisting of 88 waves. A narrow peak is observed in the f0(980)π channel with spin, parity and C-parity quantum numbers J(PC)=1(++). We present a resonance-model study of a subset of the spin-density matrix selecting 3π states with J(PC)=2(++) and 4(++) decaying into ρ(770)π and with J(PC)=1(++) decaying into f0(980)π. We identify a new a1 meson with mass (1414(-13)(+15))  MeV/c2 and width (153(-23)(+8))  MeV/c2. Within the final states investigated in our analysis, we observe the new a1(1420) decaying only into f0(980)π, suggesting its exotic nature.

Measurement of the charged-pion polarizability

The COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, Q(2)<0.0015  (GeV/c)(2). From a sample of 63,000 events, the pion electric polarizability is determined to be α(π)=(2.0±0.6(stat)±0.7(syst))×10(-4)  fm(3) under the assumption α(π)=-β(π), which relates the electric and magnetic dipole polarizabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambiguously known, was performed for an independent estimate of the systematic uncertainty.

Liver resection in patients with eight or more colorectal liver metastases

BACKGROUND

Patients with large numbers of colorectal liver metastases (CRLMs) are potential candidates for resection, but the benefit from surgery is unclear.

METHODS

Patients undergoing resection for CRLMs between 1998 and 2012 in two high-volume liver surgery centres were categorized according to the number of CRLMs: between one and seven (group 1) and eight or more (group 2). Overall (OS) and recurrence-free (RFS) survival were compared between the groups. Multivariable analysis was performed to identify adverse prognostic factors.

RESULTS

A total of 849 patients were analysed: 743 in group 1 and 106 in group 2. The perioperative mortality rate (90 days) was 0.4 per cent (all group 1). Median follow-up was 37.4 months. Group 1 had higher 5-year OS (44.2 versus 20.1 per cent; P < 0.001) and RFS (28.7 versus 13.6 per cent; P < 0.001) rates. OS and RFS in group 2 were similar for patients with eight to ten, 11-15 or more than 15 metastases (48, 40 and 18 patients respectively). In group 2, multivariable analysis identified three preoperative adverse prognostic factors: extrahepatic disease (P = 0.010), no response to chemotherapy (P = 0.023) and primary rectal cancer (P = 0.039). Patients with two or more risk factors had very poor outcomes (median OS and RFS 16.9 and 2.5 months; 5-year OS zero); patients in group 2 with no risk factors had similar survival to those in group 1 (5-year OS rate 44 versus 44.2 per cent).

CONCLUSION

Liver resection is safe in selected patients with eight or more metastases, and offers reasonable 5-year survival independent of the number of metastases. However, eight or more metastases combined with at least two adverse prognostic factors is associated with very poor survival, and surgery may not be beneficial.

Global color estimation of special-effect coatings from measurements by commercially available portable multiangle spectrophotometers

Colors of special-effect coatings have strong dependence on illumination/viewing geometry and an appealing appearance. An open question is to ask about the minimum number of measurement geometries required to completely characterize their observed color shift. A recently published principal components analysis (PCA)-based procedure to estimate the color of special-effect coatings at any geometry from measurements at a reduced set of geometries was tested in this work by using the measurement geometries of commercial portable multiangle spectrophotometers X-Rite MA98, Datacolor FX10, and BYK-mac as reduced sets. The performance of the proposed PCA procedure for the color-shift estimation for these commercial geometries has been examined for 15 special-effect coatings. Our results suggest that for rendering the color appearance of 3D objects covered with special-effect coatings, the color accuracy obtained with this procedure may be sufficient. This is the case especially if geometries of X-Rite MA98 or Datacolor FX10 are used.

The impact of CBCT imaging when placing dental implants in the anterior edentulous mandible: a before-after study

OBJECTIVES

To evaluate the impact of CBCT imaging when placing dental implants in the anterior edentulous mandible, using a "before-after" study design.

METHODS

Eight dental practitioners, who regularly place dental implants in independent dental practice in the North West of England, were presented with realistic simulations of four edentulous cases. The practitioners were asked to assess case difficulty, select implants and then drill osteotomies in preparation for dental implants in the lower canine regions to support a complete overdenture. In the "before" part of the study, a panoramic and a trans-symphyseal view were available. In the "after" part of the study, a CBCT image was added. Perception of case difficulty, implant selection and the incidence of perforations or "near miss perforations" of the lingual cortical plate were recorded. Two cases were regarded as "regular" and two as "challenging".

RESULTS

In challenging cases, the availability of CBCT led practitioners to select narrower implants and to assess cases as more difficult. In the challenging cases only, there were fewer perforations of the lingual cortical plate after the availability of CBCT, but this difference was not statistically significant. There were no perforations in the regular cases either before or after the availability of CBCT.

CONCLUSIONS

Perception of case difficulty and implant selection are of importance only if they change the outcome for the patient. This study provided weak evidence that CBCT is helpful in avoiding perforations in challenging cases. The availability of CBCT had no impact in regular cases.

Impact of perioperative symbiotic therapy on infectious morbidity after Hpb Surgery in jaundiced patients: a randomized controlled trial

This study aimed at evaluating whether the administration of symbiotic therapy in jaundiced patients could reduce their postoperative infectious complications. The study was conducted between November 2008 and February 2011. Jaundiced patients scheduled for elective extrahepatic bile duct resection without liver cirrhosis, intestinal malabsorption or intolerance to symbiotic therapy were randomly assigned to receive [Group A] or not [Group B] symbiotics perioperatively. The primary endpoint was the infectious morbidity rate. Forty patients were included in the analysis (20 in each group). The patients in Group B presented a higher overall morbidity (70 vs 50%) and infectious morbidity rate (50 vs 25%), but the differences were not significant. Eleven patients in Group A (Group ndA) and 13 in Group B (Group ndB) did not receive preoperative biliary drainage. The results of the two groups were comparable. Infectious complications were higher in Group B [5 (34%) vs 0, p = 0.030], while the prevalence of natural killer (NK) cells was higher in Group ndA the day before surgery (17% ± 5.1 vs 10% ± 5.3, p < 0.01) and on post-operative day (POD) 7 (13.1% ± 4.1 vs 7.7% ± 3.4, p < 0.01). The rates of lymph node colonization were similar. The symbiotic therapy failed to reduce the rate of infectious morbidity in jaundiced patients. Further studies investigating the place of symbiotic in no-drainage patients are required.

Color representation and interpretation of special effect coatings

A representation of the color gamut of special effect coatings is proposed and shown for six different samples, whose colors were calculated from spectral bidirectional reflectance distribution function (BRDF) measurements at different geometries. The most important characteristic of the proposed representation is that it allows a straightforward understanding of the color shift to be done both in terms of conventional irradiation and viewing angles and in terms of flake-based parameters. A different line was proposed to assess the color shift of special effect coatings on a*,b*-diagrams: the absorption line. Similar to interference and aspecular lines (constant aspecular and irradiation angles, respectively), an absorption line is the locus of calculated color coordinates from measurement geometries with a fixed bistatic angle. The advantages of using the absorption lines to characterize the contributions to the spectral BRDF of the scattering at the absorption pigments and the reflection at interference pigments for different geometries are shown.

Locally advanced gallbladder cancer: which patients benefit from resection?

OBJECTIVES

Patients with T3-4 gallbladder cancers (GBCs) often require extended surgical procedures, and up to 30% of patients have N2 metastases. This study investigated which patients with T3-4 GBC benefit from resection.

METHODS

Consecutive patients (n = 78) with T3-4 GBC who underwent resection between 1990 and 2011 were analysed (38 before 2003, 40 in 2003-2011). Forty patients required common bile duct (CBD) resection, 10 pancreatoduodenectomy, 4 right colectomy and 2 gastric resection. Fifty-two (67%) patients had LN metastases, including 22 with N2 metastases.

RESULTS

The in-hospital mortality rate was 8%, 11% before 2003 vs. 5% in 2003-2011. The morbidity rate (47%) remained stable during the study. Undergoing liver and pancreatic resection did not increase severe morbidity (0%) or mortality (10%). Sixty-seven (86%) patients had R0 resection. The 5-year survival rate was 17% (median follow-up, 65 months). Survival improved after 2002 (26% vs. 9%, p = 0.04). R1 patients had poor 3-year survival (0% vs. 32%, p = 0.001). N+ patients also had low survival (5-year survival, 10% vs. 32% in N0, p = 0.019), but N1 and N2 patients had similar outcomes. CBD resection and major hepatectomy did not worsen prognosis. Patients requiring pancreatoduodenectomy, gastric or colonic resection had 0% 3-year survival (p = 0.036 in multivariate analysis).

CONCLUSIONS

Resection of T3-4 GBC is worthwhile only if R0 surgery is achievable. Outcomes improved in most recent years. N2 metastases should not preclude surgery. Good results are possible even with CBD resection or major hepatectomy, while benefits from surgery are doubtful if pancreatoduodenectomy or other organ resection is needed.

A single analytical model for sparkle and graininess patterns in texture of effect coatings

Flakes in effect coatings, which are responsible for its color shift, are not perfectly horizontally oriented, producing a non uniform texture when observed from a distance of around one meter or less. If the coating is illuminated by a diffuse source, a granular appearance is observed, called graininess. But when the coating is illuminated by unidirectional light, some luminous spots on a dark background appear, effect that is known as sparkle. The characterization of these two textures is getting more important for automotive industry because of the high percentage of cars with effect coatings and because improvements in imaging technology allows this effect to be measured by, for instance, commercial instruments as BYK-mac. A single analytical model to understand and radiometrically characterize both sparkle and graininess in effect coatings is presented and studied in this work. It allows both patterns to be explained and, despite its simplicity, includes variables related to the optical system (Point Spread Function (PSF) and size of the entrance pupil), its distance to the coating, the diffusion grade of the illumination, the illumination and observation directions, and coating parameters.

Metronomic chemotherapy may be active in heavily pre-treated patients with metastatic adreno-cortical carcinoma

OBJECTIVE

The potential benefit of further chemotherapy approaches in patients with adrenocortical carcinoma (ACC) showing progressive disease after 2 chemotherapy lines is actually unknown. This study provides explorative information on the activity of metronomic chemotherapy in heavily pre-treated ACC patients.

DESIGN AND METHODS

We tested the activity of cytotoxic treatments administered on a metronomic schedule in metastatic ACC patients showing disease progression after treatment with gemcitabine and capecitabine scheme.

RESULTS

Eight patients out of 28 consecutively enrolled in that trial were treated with several metronomic cytotoxic regimens. Six of them showed disease progression, but 2 patients obtained a clear benefit. The first patient was treated with oral etoposide (50 mg daily) as the 6th-line therapy and obtained a partial response lasting 24 months, while the second patient obtained a partial response lasting 10 months with metronomic oral cyclophosphamide (50 mg daily) as the 5th chemotherapy line. Both patients had sex hormone secreting tumors and were bearing a rather indolent ACC.

CONCLUSIONS

The administration of several chemotherapy lines in advanced ACC patients cannot be routinely recommended outside prospective clinical trials. Few patients with indolent tumors, however, may benefit from this approach. According to our experience, oral cyclophosphamide and oral etoposide may be used in this setting.

Comparison of laparoscopic and open intraoperative ultrasonography for staging liver tumours

BACKGROUND

Laparoscopic liver surgery must reproduce open surgical steps. Intraoperative ultrasonography (IOUS) is mandatory, but reliability of laparoscopic IOUS has been poorly evaluated. The aim of this study was to compare laparoscopic versus open IOUS in staging liver tumours.

METHODS

All patients scheduled for liver resection between September 2009 and March 2011 were considered. Inclusion criteria were primary and metastatic tumours. Exclusion criteria were: hilar/gallbladder cholangiocarcinoma, ten or more lesions, repeat resection, laparoscopic hepatectomy, adhesions and unresectability. Following percutaneous ultrasonography and thoracoabdominal computed tomography (CT), and on indication contrast-enhanced (CE) liver magnetic resonance imaging (MRI) and/or positron emission tomography (PET)-CT, patients were scheduled for laparoscopy, laparoscopic IOUS, then laparotomy, open IOUS and Partial hepatectomy. Data were collected prospectively. Reference standards were final pathology and 6-month follow-up results.

RESULTS

Sixty-five patients were included, who had a median of 3 preoperative imaging studies (ultrasonography/CT 100 per cent, CE-MRI 67 per cent, PET-CT 54 per cent). A total of 119 lesions were diagnosed. Laparoscopic IOUS detected 22 additional lesions (+18·5 per cent) in 14 patients. Open IOUS detected two additional lesions, but did not confirm four lesions; overall 20 additional lesions (+16·8 per cent) were detected in ten patients. Pathology confirmed 14 newly detected malignant nodules (+11·8 per cent) in eight patients. After 6 months ten new nodules were identified in six patients. The sensitivity of preoperative imaging, laparoscopic IOUS and open IOUS was 83·1, 92·3 and 93·0 per cent respectively; accuracy was 79, 82 and 88 per cent. In comparison with open IOUS, the sensitivity and accuracy of laparoscopic IOUS were 98·6 and 94 per cent.

CONCLUSION

Laparoscopic IOUS is a reliable tool for staging liver tumours with a performance similar to that of open IOUS in detecting new nodules.