Hall drift in the crust of neutron stars - necessary for radio pulsar activity?

The radio pulsar models based on the existence of an inner accelerating gap located above the polar cap rely on the existence of a small scale, strong surface magnetic field $B_s$. This field exceeds the dipolar field $B_d$, responsible for the braking of the pulsar rotation, by at least one order of magnitude. Neither magnetospheric currents nor small scale field components generated during neutron star's birth can provide such field structures in old pulsars. While the former are too weak to create $B_s \gtrsim 5\times 10^{13}$G$\;\gg B_d$, the ohmic decay time of the latter is much shorter than $10^6$ years. We suggest that a large amount of magnetic energy is stored in a toroidal field component that is confined in deeper layers of the crust, where the ohmic decay time exceeds $10^7$ years. This toroidal field may be created by various processes acting early in a neutron star's life. The Hall drift is a non-linear mechanism that, due to the coupling between different components and scales, may be able to create the demanded strong, small scale, magnetic spots. Taking into account both realistic crustal microphysics and a minimal cooling scenario, we show that, in axial symmetry, these field structures are created on a Hall time scale of $10^3$-$10^4$ years. These magnetic spots can be long-lived, thereby fulfilling the pre-conditions for the appearance of the radio pulsar activity. Such magnetic structures created by the Hall drift are not static, and dynamical variations on the Hall time scale are expected in the polar cap region.Comment: 4 pages, 5 figures, contribution to the ERPM conferences, Zielona Gora, April 201

Cancer and HIV-1 Infection: Patterns of Chronic Antigen Exposure.

The main role of the human immune system is to eliminate cells presenting foreign antigens and abnormal patterns, while maintaining self-tolerance. However, when facing highly variable pathogens or antigens very similar to self-antigens, this system can fail in completely eliminating the anomalies, leading to the establishment of chronic pathologies. Prototypical examples of immune system defeat are cancer and Human Immunodeficiency Virus-1 (HIV-1) infection. In both conditions, the immune system is persistently exposed to antigens leading to systemic inflammation, lack of generation of long-term memory and exhaustion of effector cells. This triggers a negative feedback loop where effector cells are unable to resolve the pathology and cannot be replaced due to the lack of a pool of undifferentiated, self-renewing memory T cells. In addition, in an attempt to reduce tissue damage due to chronic inflammation, antigen presenting cells and myeloid components of the immune system activate systemic regulatory and tolerogenic programs. Beside these homologies shared between cancer and HIV-1 infection, the immune system can be shaped differently depending on the type and distribution of the eliciting antigens with ultimate consequences at the phenotypic and functional level of immune exhaustion. T cell differentiation, functionality, cytotoxic potential and proliferation reserve, immune-cell polarization, upregulation of negative regulators (immune checkpoint molecules) are indeed directly linked to the quantitative and qualitative differences in priming and recalling conditions. Better understanding of distinct mechanisms and functional consequences underlying disease-specific immune cell dysfunction will contribute to further improve and personalize immunotherapy. In the present review, we describe relevant players of immune cell exhaustion in cancer and HIV-1 infection, and enumerate the best-defined hallmarks of T cell dysfunction. Moreover, we highlight shared and divergent aspects of T cell exhaustion and T cell activation to the best of current knowledge

Short-term effects of focal muscle vibration on motor recovery after acute stroke: a pilot randomized sham-controlled study

Repetitive focal muscle vibration (rMV) is known to promote neural plasticity and long-lasting motor recovery in chronic stroke patients. Those structural and functional changes within the motor network underlying motor recovery occur in the very first hours after stroke. Nonetheless, to our knowledge, no rMV-based studies have been carried out in acute stroke patients so far, and the clinical benefit of rMV in this phase of stroke is yet to be determined. The aim of this randomized double-blind sham-controlled study is to investigate the short-term effect of rMV on motor recovery in acute stroke patients. Out of 22 acute stroke patients, 10 were treated with the rMV (vibration group–VG), while 12 underwent the sham treatment (control group–CG). Both treatments were carried out for 3 consecutive days, starting within 72 h of stroke onset; each daily session consisted of three 10-min treatments (for each treated limb), interspersed with a 1-min interval. rMV was delivered using a specific device (Cro®System, NEMOCO srl, Italy). The transducer was applied perpendicular to the target muscle's belly, near its distal tendon insertion, generating a 0.2–0.5 mm peak-to-peak sinusoidal displacement at a frequency of 100 Hz. All participants also underwent a daily standard rehabilitation program. The study protocol underwent local ethics committee approval (ClinicalTrial.gov NCT03697525) and written informed consent was obtained from all of the participants. With regard to the different pre-treatment clinical statuses, VG patients showed significant clinical improvement with respect to CG-treated patients among the NIHSS (p < 0.001), Fugl-Meyer (p = 0.001), and Motricity Index (p < 0.001) scores. In addition, when the upper and lower limb scales scores were compared between the two groups, VG patients were found to have a better clinical improvement at all the clinical end points. This study provides the first evidence that rMV is able to improve the motor outcome in a cohort of acute stroke patients, regardless of the pretreatment clinical status. Being a safe and well-tolerated intervention, which is easy to perform at the bedside, rMV may represent a valid complementary non-pharmacological therapy to promote motor recovery in acute stroke patients

Evaluation of the weight loss of raw beef cuts vacuum-packaged with two different techniques

In the present study, 25 cuts of shank form adult cattle coming from the same slaughtering batch, were withdrawn just after manual sectioning/deboning, and each divided into two pieces (Prox and Dist) of approximately the same weight, that were vacuum packaged by using two different packaging systems: vacuum chamber machine with a bag material and a thermo-forming packaging machine with top and bottom webs named BAG and THF respectively. The packed cuts were stored at 2-3\ub0C for 20 days. The drip loss was calculated at the end of the storage as the difference between drained weight and net. Internal muscle pH and pH of the exudate present in the package and microbiological analyses (by pooling the samples) were performed at T0 and at the end of the storage. The drip loss, was significantly lower with BAG packaging: this difference was evident after 20 days of storage (average \ub1 STD BAG vs THF = 1.04\ub10.36% vs 1.71\ub10.42%; P<0.01). The values were, in general, low for both the packaging systems, never above 2%. Moreover, shrink bag packages are characterized by better overall pack appearance and less plastic weight per pack. Forming step reduce the thickness of ther-moforming material lowering the mechanical resistance and the barrier to oxygen, on the contrary after shrinking bag materials are thickened. The pH of muscles was stable, although a slight increase was evidenced after 20 (average \ub1 STD BAG vs THF= 5.73\ub10.05 vs 5.78\ub10.09; P<0.01), due to the ageing of meat. The pH of the exudate was equal at T20 (average \ub1 STD BAG vs THF = 5.34\ub10.20 vs 5.33\ub10.17). The drip loss didn\u2019t influence the development of all the microflora; in particular LAB, that represented the main microbial population, showed a gradual increase from T0 (2.20\ub10.41 Log CFU/g) to T20 (average \ub1 STD BAG vs THF= 4.76\ub10.29 Log CFU/g vs 4.75\ub10.0.15 Log CFU/g). No Enterobacteriaceae showed an increase, if compared to the initial counts, due to the prolonged storage and the gradual growth of ephemeral microorganisms, without differences among the two series (Enterobacteriaceae: T0=<1.7 Log CFU/g to T20 average \ub1 STD BAG vs THF = 2.83\ub10.77 Log CFU/g vs 3.09\ub10.0.70 Log CFU/g). In conclusion, the use of the BAG system demonstrated to have an effect in reducing the drip loss of beef cuts during the refrigerated storage, with only slight influence on the other characteristics of raw meat

The X-ray outburst of the Galactic Center magnetar over six years of Chandra observations

The magnetar SGR J1745-2900 discovered at parsecs distance from the Milky Way central black hole, Sagittarius A*, represents the closest pulsar to a supermassive black hole ever detected. Furthermore, its intriguing radio emission has been used to study the environment of the black hole, as well as to derive a precise position and proper motion for this object. The discovery of SGR J1745-2900 has opened interesting debates about the number, age and nature of pulsars expected in the Galactic center region. In this work, we present extensive X-ray monitoring of the outburst of SGR J1745-2900 using the Chandra X-ray Observatory, the only instrument with the spatial resolution to distinguish the magnetar from the supermassive black hole (2.4" angular distance). It was monitored from its outburst onset in April 2013 until August 2019, collecting more than fifty Chandra observations for a total of more than 2.3 Ms of data. Soon after the outburst onset, the magnetar emission settled onto a purely thermal emission state that cooled from a temperature of about 0.9 to 0.6 keV over 6 years. The pulsar timing properties showed at least two changes in the period derivative, increasing by a factor of about 4 during the outburst decay. We find that the long-term properties of this outburst challenge current models for the magnetar outbursts.Comment: 11 pages, 6 figures. Accepted by Ap

The effect of left fronto-parietal resections on hand selection: a lesion-tractography study

Strong right-hand preference on the population level is a uniquely human feature, although the neural basis for this is still not clearly defined. Recent behavioural and neuroimaging literature suggests that hand preference may be related to the orchestrated function and size of fronto-parietal white matter tracts bilaterally. Lesions to these tracts induced during tumour resection may provide an opportunity to test this hypothesis. In the present study, a cohort of seventeen neurosurgical patients with left hemisphere brain tumours were recruited to investigate whether resection of certain white matter tracts affects the choice of hand selected for the execution of a goal-directed task (assembly of jigsaw puzzles). Patients performed the puzzles, but also tests for basic motor ability, selective attention and visuo-constructional ability, preoperatively and one month after surgery. Diffusion tractography of fronto-parietal tracts (the superior longitudinal fasciculus) and the corticospinal tract were performed, to evaluate whether resection of tracts was significantly associated with changes in hand selection. A complementary atlas-based disconnectome analysis was also conducted. Results showed a shift in hand selection despite the absence of any motor or cognitive deficits, which was significantly associated with patients with frontal and parietal resections, compared with those with resections in other lobes. In particular, this effect was significantly associated with the resection of dorsal fronto-parietal white matter connections, but not with the ventral fronto-parietal tract. Dorsal white matter pathways contribute bilaterally, with specific lateralised competencies, to control of goaldirected hand movements. We show that unilateral lesions, by unbalancing the cooperation of the two hemispheres, can alter the choice of hand selected to accomplish movements

A strongly magnetized pulsar within grasp of the Milky Way's supermassive black hole

The center of our Galaxy hosts a supermassive black hole, Sagittarius (Sgr) A*. Young, massive stars within 0.5 pc of SgrA* are evidence of an episode of intense star formation near the black hole a few Myr ago, which might have left behind a young neutron star traveling deep into SgrA*'s gravitational potential. On 2013 April 25, a short X-ray burst was observed from the direction of the Galactic center. Thanks to a series of observations with the Chandra and the Swift satellites, we pinpoint the associated magnetar at an angular distance of 2.4+/-0.3 arcsec from SgrA*, and refine the source spin period and its derivative (P=3.7635537(2) s and \dot{P} = 6.61(4)x10^{-12} s/s), confirmed by quasi simultaneous radio observations performed with the Green Bank (GBT) and Parkes antennas, which also constrain a Dispersion Measure of DM=1750+/-50 pc cm^{-3}, the highest ever observed for a radio pulsar. We have found that this X-ray source is a young magnetar at ~0.07-2 pc from SgrA*. Simulations of its possible motion around SgrA* show that it is likely (~90% probability) in a bound orbit around the black hole. The radiation front produced by the past activity from the magnetar passing through the molecular clouds surrounding the Galactic center region, might be responsible for a large fraction of the light echoes observed in the Fe fluorescence features.Comment: ApJ Letters in pres

Autologous Microfragmented Adipose Tissue Reduces the Catabolic and Fibrosis Response in an in Vitro Model of Tendon Cell Inflammation

Background. Mesenchymal stem cells (MSCs) emerged as a promising therapy for tendon pathologies. Microfragmented adipose tissue (\u3bcFAT) represents a convenient autologous product for the application of MSC-based therapies in the clinical setting. In the present study, the ability of \u3bcFAT to counteract inflammatory processes induced by IL-1\u3b2 on human tendon cells (TCs) was evaluated. Methods. Cell viability and proliferation were evaluated after 48 hours of transwell coculture of TCs and autologous \u3bcFAT in the presence or absence of IL-1\u3b2. Gene expression of scleraxis, collagen type I and type III, metalloproteinases-1 and -3, and cyclooxygenase-2 was evaluated by real-time RT-PCR. The content of VEGF, IL-1Ra, TNF\u3b1, and IL-6 was evaluated by ELISA. Results. IL-1\u3b2-treated TCs showed augmented collagen type III, metalloproteases, and cyclooxygenase-2 expression. \u3bcFAT was able to reduce the expression of collagen type III and metalloproteases-1 in a significant manner, and at the same time, it enhanced the production of VEGF, IL-1Ra, and IL-6. Conclusions. In this in vitro model of tendon cell inflammation, the paracrine action of \u3bcFAT, exerted by anti-inflammatory molecules and growth factors, was able to inhibit the expression of fibrosis and catabolic markers. Then, these results suggest that the application of \u3bcFAT may represent an effective conservative or adjuvant therapy for the treatment of tendon disorders

SARS-COV-2 comorbidity network and outcome in hospitalized patients in Crema, Italy

We report onset, course, correlations with comorbidities, and diagnostic accuracy of nasopharyngeal swab in 539 individuals suspected to carry SARS-COV-2 admitted to the hospital of Crema, Italy. All individuals underwent clinical and laboratory exams, SARS-COV-2 reverse transcriptase-polymerase chain reaction on nasopharyngeal swab, and chest X-ray and/or computed tomography (CT). Data on onset, course, comorbidities, number of drugs including angiotensin converting enzyme (ACE) inhibitors and angiotensin-II-receptor antagonists (sartans), follow-up swab, pharmacological treatments, non-invasive respiratory support, ICU admission, and deaths were recorded. Among 411 SARS-COV-2 patients (67.7% males) median age was 70.8 years (range 5-99). Chest CT was performed in 317 (77.2%) and showed interstitial pneumonia in 304 (96%). Fatality rate was 17.5% (74% males), with 6.6% in 60-69 years old, 21.1% in 70-79 years old, 38.8% in 80-89 years old, and 83.3% above 90 years. No death occurred below 60 years. Non-invasive respiratory support rate was 27.2% and ICU admission 6.8%. Charlson comorbidity index and high Creactive protein at admission were significantly associated with death. Use of ACE inhibitors or sartans was not associated with outcomes. Among 128 swab negative patients at admission (63.3% males) median age was 67.7 years (range 1-98). Chest CT was performed in 87 (68%) and showed interstitial pneumonia in 76 (87.3%). Follow-up swab turned positive in 13 of 32 patients. Using chest CT at admission as gold standard on the entire study population of 539 patients, nasopharyngeal swab had 80% accuracy. Comorbidity network analysis revealed a more homogenous distribution 60-40 aged SARS-COV-2 patients across diseases and a crucial different interplay of diseases in the networks of deceased and survived patients. SARS-CoV-2 caused high mortality among patients older than 60 years and correlated with pre-existing multiorgan impairment. Copyright