A long-period radio transient active for three decades.

Several long-period radio transients have recently been discovered, with strongly polarized coherent radio pulses appearing on timescales between tens to thousands of seconds1,2. In some cases, the radio pulses have been interpreted as coming from rotating neutron stars with extremely strong magnetic fields, known as magnetars; the origin of other, occasionally periodic and less-well-sampled radio transients is still debated3. Coherent periodic radio emission is usually explained by rotating dipolar magnetic fields and pair-production mechanisms, but such models do not easily predict radio emission from such slowly rotating neutron stars and maintain it for extended times. On the other hand, highly magnetic isolated white dwarfs would be expected to have long spin periodicities, but periodic coherent radio emission has not yet been directly detected from these sources. Here we report observations of a long-period (21 min) radio transient, which we have labelled GPM J1839-10. The pulses vary in brightness by two orders of magnitude, last between 30 and 300 s and have quasiperiodic substructure. The observations prompted a search of radio archives and we found that the source has been repeating since at least 1988. The archival data enabled constraint of the period derivative to <3.6 × 10-13 s s-1, which is at the very limit of any classical theoretical model that predicts dipolar radio emission from an isolated neutron star.

Localized thermonuclear bursts from accreting magnetic white dwarfs.

Nova explosions are caused by global thermonuclear runaways triggered in the surface layers of accreting white dwarfs1-3. It has been predicted4-6 that localized thermonuclear bursts on white dwarfs can also take place, similar to type-I X-ray bursts observed in accreting neutron stars. Unexplained rapid bursts from the binary system TV Columbae, in which mass is accreted onto a moderately strong magnetized white dwarf from a low-mass companion, have been observed on several occasions in the past 40 years7-11. During these bursts, the optical/ultraviolet luminosity increases by a factor of more than three in less than an hour and fades in around ten hours. Fast outflows have been observed in ultraviolet spectral lines7, with velocities of more than 3,500 kilometres per second, comparable to the escape velocity from the white dwarf surface. Here we report on optical bursts observed in TV Columbae and in two additional accreting systems, EI Ursae Majoris and ASASSN-19bh. The bursts have a total energy of approximately 10-6  times than those of classical nova explosions (micronovae) and bear a strong resemblance to type-I X-ray bursts12-14. We exclude accretion or stellar magnetic reconnection events as their origin and suggest thermonuclear runaway events in magnetically confined accretion columns as a viable explanation.

Genome-scale estimate of the metabolic turnover of E. coli from the energy balance analysis.

In this article the notion of metabolic turnover is revisited in the light of recent results of out-of-equilibrium thermodynamics. By means of Monte Carlo methods we perform an exact sampling of the enzymatic fluxes in a genome scale metabolic network of E. coli in stationary growth conditions from which we infer the metabolites turnover times. However the latter are inferred from net fluxes, and we argue that this approximation is not valid for enzymes working nearby thermodynamic equilibrium. We recalculate turnover times from total fluxes by performing an energy balance analysis of the network and recurring to the fluctuation theorem. We find in many cases values one of order of magnitude lower, implying a faster picture of intermediate metabolism.

[Our experience on surgical treatment of papillary thyroid microcarcinoma]. / Nostra esperienza sul trattamento chirurgico del microcarcinoma papillifero della tiroide (PTMC).

The papillary thyroid microcarcinoma (PTMC) is a subtype of the papillary thyroid carcinoma (PTC) 1 cm or less in diameter, bilateral and multifocal in a percentage of 15-20%. We describe our experience on the surgical treatment of 217 patient treated between 2005 and 2008. Our therapeutic algorithm for PTMC includes always total thyroidectomy with surgical exploration of the median cervical compartment and recurrent laryngeal nerve lymph node dissection, reserving the median lymph node dissection only to the cases with pathological lymph nodes and the lateral compartment lymphectomy to the cases that show suspect nodes with or without positive cytology. We usually perform total thyroidectomy rather than partial one, in relation to the high rate of multifocality of papillary microcarcinoma, to reduce rate of recurrencies and to better utilize I131 with diagnostic and curative aims. Complete central compartment dissection is mandatory when pathological nodes are present at surgical exploration. It prevents nodal recurrencies and decrease number of re-operations, that have a greater number of complications or morbidity, including hypoparathyroidism and inferior laryngeal nerve lesions. The rate of nodal metastases is not affected by the site of primitive tumor, but the tumor size does. The rate of nodal metastases varies from 55.7% for tumors 5 mm or less in diameter, to 73.7% for tumors sized from 5 to 10 mm, and is affected from the capsular infiltration, the presence of multiple foci, and the histological type, i.e. sclerosing type. All patients presenting papillary microcarcinoma with invasion of the capsule and extension to the perithyroid tissues, sclerosing histological type, multifocal and/or metastatic to the regional nodes, were treated with radiometabolic therapy and suppressing l-tiroxin administration, according to the guidelines of the Multidisciplinary Group for the Thyroid Cancer of our Institution.

[Cancer of the rectum in elderly patients over the age of seventy-five years. Results of the surgical treatment]. / Le cancer du rectum chez les sujets âgés de plus de soixante-quinze ans. Résultats du traitement chirurgical.

The authors reviewed 122 rectal cancers observed over a period of 14 years in patients over the age of 75 years. Sixty-eight patients underwent extensive rectal resection, 17 were treated by local excision, and 28 only underwent a colostomy. Eight patients were excluded for surgery. The analysis of all of these groups showed that perioperative mortality was greater for large resections than for local resections, but with a lower recurrence rate and a higher survival at 3 years. Survival at 5 years after large resections was very close to the natural life expectancy for people of the same age. Moreover, survival was the quality of more comfortable than after local excision, and operative mortality was generally due to organ failure rather than to age itself. Radical surgery does not have to be systematically refused for very old patients, but he discussed in terms of the patients general status.

[The elective use of protective colostomy in rectal resection surgery]. / Impiego in elezione della colostomia di protezione nella chirurgia resettiva del retto.

To clarify the indications and clinical value of "protective colostomy" in cases of low colorectal anastomoses, some recent series are analyzed and compared to the experience of the authors, which includes 65 low anterior resections of the rectum for cancer, with colorectal anastomosis at less than 10 cm from the anus. "Protective colostomy" seems not to prevent the onset of anastomotic fistulae, but appears effective in reducing its clinical effects. "Protective colostomy" seems convenient when there is an increased risk of fistulization, as indicated by a series of factors defined by the authors. In doubtful cases "protective colostomy" may be performed but not opened. So the patient will be given the maximum safety, and not submitted to the uneasiness of an open colostomy unless needed.

[Biodegradable compression ring in intestinal anastomosis]. / L'anello bioframmentabile a compressione nelle anastomosi intestinali.

The Authors report their experience with the use of biofragmentable anastomosis ring ("Bowel Anastomosis Ring" B.A.R.--Valtrac): 34 patients underwent colic resection and bowel anastomosis by B.A.R. No complications related to the anastomosis were recorded. The ring was always discharged in the third postoperative week and the endoscopic follow up showed no late complications. It is concluded that B.A.R. is a safe technique and represents a good alternative to hand or mechanical anastomosis with a favorable cost/benefit ratio.

Shear- and vibration-induced order-disorder transitions in granular media.

By molecular dynamics simulations we investigate the order-disorder transitions induced in granular media by an applied drive combining vibrations and shear. As the steady state is attained, the pack is found in disordered configurations for comparatively high intensities of the drive; conversely, ordering and packing fractions exceeding the random close packing are found when vibrations and shear are weak. As forcing amplitudes get smaller, we find diverging time scales in the dynamics, as the system enters a jamming region. Under this perspective, our picture supports the intuition that externally applied forcing has, in driven granular media, a role similar to temperature in thermal systems.

DNA damage induced by some bile acids, evaluated with alkaline elution technique.

Bile acids are promoting agents in colon carcinogenesis. In this work we have tried to characterize the DNA alteration induced by bile acids in Sprague-Dawley male rats. Confirming previous findings, a clear increase in elution rate was observed at alkaline pH. No effect could be observed when the nuclei were washed before the elution, in condition totally unsuitable for the repair of the type of DNA damage induced by typical genotoxic agents. We advanced the hypothesis that the increased alkaline elution rate observed with bile acids could be independent of DNA fragmentation and related to changes in chromatin structure.