Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 ¹/₂ years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

In Vitro and in Vivo Assessment of Bone-Implant Interface: A Comparative Study

The present in vitro and in vivo comparison of three bioactive (HA, AP40, RKKP) and three bioinert (Ti6-Al4-V, Al2O3, ZrO2) materials was undertaken to identify which of them provide(s) the most suitable coating for prostheses implanted in patients with altered metabolic status.

The experimental design included in vitro tests with human osteoblasts and morphological observations by scanning electron microscopy. For the in vivo evaluation, the materials were implanted in the femoral condyle of ovariectomised and intact female rats, and two months after surgery an X-ray microanalytical study was performed.

The in vitro study showed good biocompatibility with all materials. Microanalysis evidenced a similar behaviour with all materials except the two biological glasses. The differences in Ca and P content observed between intact and ovariectomised rats can be explained by the intrinsic capability of biological glasses to undergo surface modifications in the presence of alterations of the bone metabolism. Thus, their use seems to be indicated in recipients with osteoporotic pathologies.

Biomaterials for Orthopedic Surgery in Osteoporotic Bone: A Comparative Study in Osteopenic Rats

To evaluate orthopedic devices in pathological bone, an experimental study was performed by implanting Titanium (Ti) and Hydroxyapatite (HA) rods in normal and osteopenic bone. Twenty-four rats were used: 12 were left intact (Control: C) while the other 12 were ovariectomized (OVX). After 4 months all the animals were submitted to the implant of Ti or HA in the left femoral condyle (Ti-C, HA-C, Ti-OVX, HA-OVX). Two months later the animals were sacrificed for histomorphometric, ultrastructural and microanalytic studies. Our results show a significant difference between the Affinity Index (A.I.) of HA-C and Ti-C (77.0 ± 7.4 vs 61.2 ± 9.7) (p < 0.05). No significant differences were observed between the osteointegration of Ti-C and Ti-OVX (61.2 ± 9.7 vs 48.2 ± 6.7). Significant differences also exist between the osteointegration of HA-C and HA-OVX (77.0 ± 7.4 vs 57.6 ± 11.5) (p < 0.01). Microanalysis shows some modifications in Sulphur (S) concentration at the bone/biomaterial interface of the Ti-OVX group. Therefore our results confirmed the importance of biomaterials characteristics and of bone quality in osteointegration processes.

The effect of osteopenia on the osteointegration of different biomaterials: histomorphometric study in rats

The osteointegration of Hydroxyapatite (HA), Titanium (Ti-6Al-4V: Ti), Zirconia (ZrO2), Alumina (Al2O3) and 2 biological glasses (AP40 and RKKP) was comparatively investigated in normal and osteopenic rats by means of histomorphometry. Thirty-six Sprague Dawley female rats were left intact (Group C) while 36 were ovariectomized (Group OVX). Group C and OVX were further divided into 6 subgroups. After 16 weeks all animals were submitted to the femoral implant of nails made of the above-mentioned materials. Eight weeks after implantation the animals were euthanized, the femurs were harvested for histomorphometric analysis. The data showed that: (1) all the tested materials were biocompatible in vitro; (2) no significant differences existed in Affinity Index (AI) of Group C; and (3) results from paired comparison applied to the AI showed significant differences among the Groups C and OVX. The AI did not significantly change among intact groups, while it significantly decreased when some materials were implanted in OVX subgroups (AP40, ZrO2 and Ti-6Al-4V: p < 0.0005, p < 0.05 and p < 0.01). It is confirmed that bone mineral density is a strong predictor of the osteointegration of an orthopedic implant and that the use of pathological animal models is necessary to completely characterize biomaterials.

Bioactivity of chitosan in dentistry. Preliminary data on chitosan-based cements

BACKGROUND

The chemical association of chitosan with inorganic salts, such as calcium phosphate, finds a promising application in dentistry as room-temperature self-hardening cement. We present the physical, chemical and crystallographic characterization of newly-developed cements made of 1) calcium-phosphate and a chitosan gel obtained by acetic acid treatment, and 2) calcium phosphate and a chitosan gel obtained by ascorbic acid treatment. Both cements are self-hardening at room temperature.

METHODS

The cements were characterized by X-ray diffractography, scanning electron microscopy and fluorine-selective electrode analysis.

RESULTS

The chitosan-hydroxyapatite cements had hardness comparable to spongy bone and above that of PMMA.

CONCLUSIONS

The cements are promising for application in endodontics and restorative dentistry.

In vitro and in vivo assessment of bone-implant interface: a comparative study

The present in vitro and in vivo comparison of three bioactive (HA, AP40, RKKP) and three bioinert (Ti6-Al4-V, Al2O3, ZrO2) materials was undertaken to identify which of them provide(s) the most suitable coating for prostheses implanted in patients with altered metabolic status. The experimental design included in vitro tests with human osteoblasts and morphological observations by scanning electron microscopy. For the in vivo evaluation, the materials were implanted in the femoral condyle of ovariectomised and intact female rats, and two months after surgery an X-ray microanalytical study was performed. The in vitro study showed good biocompatibility with all materials. Microanalysis evidenced a similar behaviour with all materials except the two biological glasses. The differences in Ca and P content observed between intact and ovariectomised rats can be explained by the intrinsic capability of biological glasses to undergo surface modifications in the presence of alterations of the bone metabolism. Thus, their use seems to be indicated in recipients with osteoporotic pathologies.

Osteoblast behaviour in the presence of bisphosphonates: ultrastructural and biochemical in vitro studies

OBJECTIVE

A positive balance in bone remodelling is an important goal of bone metabolism both in the presence of the osteoporotic processes characteristic of ageing and, especially, of prosthetic implants. The aim of the present work was to obtain new information about the initial steps of osteoblastic growth in an in vitro osteoblastic model in the presence of two bisphosphonates.

METHODS

Experiments were performed with Alendronate and Neridronate, two molecules used in the therapy of osteoporosis. Since differentiating features into osteoblastic cells are known to parallel the presence in the cytoplasm of alkaline phosphatase and osteocalcin, we also carried out immunohistochemical typing.

RESULTS

Good differentiation and osteoblastic activity were generally observed in the cells in contact with these compounds, except for 10(-4) Neridronate, where biochemical data clearly indicated its toxic effect on the cells.

CONCLUSION

The detection of osteoblastic markers associated with an ultrastructural picture of correct organellar morphology in our cultures further supports the hypothesis of a metabolically positive action of these molecules on osteoblasts.

N,N-dicarboxymethyl chitosan as delivery agent for bone morphogenetic protein in the repair of articular cartilage

Bone morphogenetic protein (BMP), associated with N,N-dicarboxymethyl chitosan, is used to induce or facilitate the repair of articular cartilage lesions. This association is intended for the synergistic potentiation of the respective biological effects. Data show that BMP-7 enhances the in vivo proliferation of cells with chondrocytes phenotype in the articular environment, leading to partial healing of the articular surface of the lesions. N,N-dicarboxymethyl chitosan is found to be useful as a molecular carrier or drug delivery agent.

Bioactivity modulation of bioactive materials in view of their application in osteoporotic patients

The application of bioactive ceramic coatings to prostheses confers strength to a material (ceramic or biological glass) that exerts beneficial effects on bone-tissue growth but that itself lacks the toughness and stability required of an implant device. The rate of bioactivity is related to the chemical reactivity of the material and causes interface dissolution, precipitation and ion-exchange reactions. Ceramics may differ in sintering temperature and thus exhibit differences in their in vitro dissolution features and in vivo performance. To test these effects, in vitro and in vivo studies were carried out on two biocompatible biological glasses and a ceramic of proven bioactivity in view of their potential utilization as covering materials. In addition, a modified chitosan was adsorbed on the surface of a series of hydroxyapatite (HA) samples. Human fibroblasts and/or osteoblasts were used for the in vitro tests, and normal (INT) and osteoporotic (OVX) rats, normal rabbits and sheep for the in vivo studies. Similar chemical changes were observed in both glasses, suggesting that these materials underwent modifications directly dependent on their biological environment. The in vivo tests point to the possibility of improving the bioactivity of ceramic substrates with chitosan. However, the different behaviour of the materials in vitro and in vivo suggests that these tests should be conducted in parallel.

Study of the interface reactions between cells and a biocompatible ceramic

Preliminary results on the modifications induced by the growth of a Chinese Hamster Ovary (CHO) cell line on the surface of a CORD 1014 ceramic cordierite are reported. Results proved that cells strongly modify the crystallography and the chemical composition of the surface and near surface regions of the cordierite.

Biomaterials for orthopedic surgery in osteoporotic bone: a comparative study in osteopenic rats

To evaluate orthopedic devices in pathological bone, an experimental study was performed by implanting Titanium (Ti) and Hydroxyapatite (HA) rods in normal and osteopenic bone. Twenty-four rats were used: 12 were left intact (

CONTROL

C) while the other 12 were ovariectomized (OVX). After 4 months all the animals were submitted to the implant of Ti or HA in the left femoral condyle (Ti-C, HA-C, Ti-OVX, HA-OVX). Two months later the animals were sacrificed for histomorphometric, ultrastructural and microanalytic studies. Our results show a significant difference between the Affinity Index (A.I.) of HA-C and Ti-C (77.0 +/- 7.4 vs 61.2 +/- 9.7) (p < 0.05). No significant differences were observed between the osteointegration of Ti-C and Ti-OVX (61.2 +/- 9.7 vs 48.2 +/- 6.7). Significant differences also exist between the osteointegration of HA-C and HA-OVX (77.0 +/- 7.4 vs 57.6 +/- 11.5) (p < 0.01). Microanalysis shows some modifications in Sulphur (S) concentration at the bone/biomaterial interface of the Ti-OVX group. Therefore our results confirmed the importance of biomaterials characteristics and of bone quality in osteointegration processes.

[Human subcutaneous dirofilariasis: 8 more cases in Italy]

Eight new cases of Human Subcutaneous Dirofilariasis due to Dirofilaria repens in subjects aged 14 to 83 years, 5 men and 3 women, are recorded. The patients were living in Piedmont (5 cases), Tuscany (1), Friuli-Venetia Julia (1) and Apulia (1). The nematodes were immature in 6 cases (2 males and 4 females) and adults in 2 (both females). Microfilariae in the uterus of one of them were detected.

[Changes in carnitine metabolism. A case report about probable partial deficiency of muscle carnitine palmitoyltransferase]

The main alterations of carnitine metabolism are mentioned synthetically in order to point up the heterogeneity of clinical, biohumoral, instrumental and enzymatic pictures deriving from the deficiency of carnitine-palmitoyl-transferase. We describe a case with a slight deficiency of CPT, showing a typical symptomatology, but with some peculiarities, such as the absence of myoglobinuria and, in particular way, the presence of haemolysis caused by a long fasting, that doesn't find an easy interpretation. On the basis of some experimental dates described in literature, we may suppose that the red blood cells might be somewhat affected by the consequence of the metabolical deficiency (change). The case is mentioned also in order to focus the attention on the possibility of diagnosing this disease since childhood, before the symptoms deriving as a consequence from the enzymatic deficiency are completely clear. And this in order to allow an early dietetic and therapeutic treatment.