Arthroscopic treatment of acute acromioclavicular joint dislocation with double flip button.

The ideal treatment for acute acromioclavicular joint dislocation is still controversial, both in terms of indications and surgical technique. The clinical and radiographic outcomes of 16 patients affected by acute AC joint dislocation (type III-V) and arthroscopically treated with a coracoclavicular double flip button are presented. Despite the excellent clinical results both in terms of Constant score (mean 97 points) and patient satisfaction, at a mean follow-up of 31 months the radiographs showed partial loss of reduction due to distal migration of the flip button within the upper third of the clavicle in one-fourth of the cases. The technique presented here proved to be safe and minimally invasive while delivering good aesthetic results and allowing for the treatment of associated lesions. Furthermore, the technique could benefit from more advanced retention devices, which ought to reduce or avoid migration of the flip buttons.

Interdependence of primary and Johari-Goldstein secondary relaxations in glass-forming systems.

We report evidence from broadband dielectric spectroscopy that the dynamics of the primary alpha- and secondary Johari-Goldstein (JG) beta-processes are strongly correlated in different glass-forming systems over a wide temperature T and pressure P range, in contrast with the widespread opinion of statistical independence of these processes. The alpha-beta mutual dependence is quantitatively confirmed by (a) the overall superposition of spectra measured at different T-P combinations but with an invariant alpha-relaxation time; (b) the contemporary scaling of the isothermal-pressure and isobaric-temperature dependences of the alpha-and beta-relaxation times as plotted versus the reduced variable Tg(P)/T where Tg is the glass transition temperature. These novel and model-independent evidences indicate the relevance of the JG relaxation phenomenon in glass transition, often overlooked by most current theories.

New experimental evidence about secondary processes in phenylphthalein-dimethylether and 1,1'-bis(p-methoxyphenyl)cyclohexane.

The slow secondary (beta) process of 1,1'-bis (4-methoxyphenyl) cyclohexane and phenolphthalein dimethylether has been investigated by dielectric spectroscopy. New experimental results about the pressure dependence of the two processes are reported, as well as new data about the dependence of the characteristic relaxation frequency on the cooling rate used to vitrify the system in isobaric conditions. Previous investigations on these systems suggested that the first one is not a true Johari-Goldstein relaxation and both processes should originate from the flip flop motion of the phenyl ring. The results herein reported evidence that the characteristic frequency of the beta process of phenolphthalein dimethylether is more sensitive to pressure variation and to the vitrification procedure than that of 1,1'-bis (4-methoxyphenyl) cyclohexane. Such results suggest an intermolecular origin for the secondary process in phenolphthalein dimethylether and an intramolecular origin for the other one, which do not completely agree with the previous interpretation. We evidence that the microscopic mechanism at the basis of these two processes is still an open question, which should be debated on the basis of new experimental investigations.

Two secondary modes in decahydroisoquinoline: which one is the true Johari Goldstein process?

Broadband dielectric measurements were carried out at isobaric and isothermal conditions up to 1.75 GPa for reconsidering the relaxation dynamics of decahydroisoquinoline, previously investigated by Richert et al. [R. Richert, K. Duvvuri, and L.-T. Duong, J. Chem. Phys. 118, 1828 (2003)] at atmospheric pressure. The relaxation time of the intense secondary relaxation tau(beta) seems to be insensitive to applied pressure, contrary to the alpha-relaxation times tau(alpha). Moreover, the separation of the alpha- and beta-relaxation times lacks correlation between shapes of the alpha-process and beta-relaxation times, predicted by the coupling model [see for example, K. L. Ngai, J. Phys.: Condens. Matter 15, S1107 (2003)], suggesting that the beta process is not a true Johari-Goldstein (JG) relaxation. From the other side, by performing measurements under favorable conditions, we are able to reveal a new secondary relaxation process, otherwise suppressed by the intense beta process, and to determine the temperature dependence of its relaxation times, which is in agreement with that of the JG relaxation.

Emergence of a new feature in the high pressure-high temperature relaxation spectrum of tri-propylene glycol.

We investigated dielectric relaxation of a tri-propylene glycol system under high compression. By increasing temperature and pressure we observed that a new relaxation process emerges from the low frequency tail of the structural peak. This new peak starts to be visible at about 0.5 GPa and becomes clearly evident at 1.7 GPa. However, this additional peak merges again with the structural one as the glass transition is approached, since it has a weaker temperature dependence. This finding enriches the relaxation scenario of molecular glass formers confirming that the application of very high hydrostatic pressure can favor the detection of new relaxation or otherwise unresolved processes in supercooled liquid systems.

Clinical and ultrasound results after arthroscopic repair of the rotator cuff.

The literature reports good functional results obtained with arthroscopic repair of the rotator cuff, but the incidence of anatomical healing has not been sufficiently studied. Ultrasound examination makes it possible to accurately document the healing process of the tendon at the bone, gathering information that may be useful in a comparison with clinical data. A total of 43 consecutive arthroscopic repairs of rotator cuff injuries were considered, that had made use of anchors and non-resorbable suturing. A total of 42 patients were willing to undergo clinical monitoring with an associated ultrasound examination after 3, 6 and 12 months. When ultrasound examination after 6 and 12 months was carried out, 36 patients presented with anatomical healing of the rotator cuff. The total percentage of repair failures was 14.3% and increased to 23% if we take into consideration the subscapular tendon alone. Constant score went from a preoperative mean of 51.25 to a mean of 78.21 after 12 months (p<0.001). Arthroscopic repair of the rotator cuff leads to anatomical healing of the tendons in a high percentage of cases, obtaining good functional results. The absence of healing is associated with lower values for recovery of strength at clinical follow-up. The advanced age of the patients (p<0.001) and the extensive injuries that involve several tendons (p=0.002) are negative prognostic factors.

Dynamics of supercooled and glassy dipropyleneglycol dibenzoate as functions of temperature and aging: Interpretation within the coupling model framework.

Dielectric relaxation measurements of a typical small molecular glassformer, dipropyleneglycol dibenzoate show the presence of two secondary relaxations. Their dynamic properties differ in the equilibrium liquid and glassy states, as well as the changes during structural recovery after rapid quenching the liquid to form a glass. These differences enable us to identify the slower secondary relaxation as the genuine Johari-Goldstein (JG) beta-relaxation, acting as the precursor of the primary alpha-relaxation. Agreement between the JG beta-relaxation time and the independent relaxation time of the coupling model leads to predicted quantitative relations between the JG beta-relaxation and the alpha-relaxation that are supported by the experimental data.

Relaxation processes in an epoxy resin studied by time-resolved optical Kerr effect.

The dynamics of the epoxy resin phenyl glycidyl ether, a fragile glass-forming liquid, is investigated in the liquid and supercooled phases by time-resolved optical Kerr effect experiment with an heterodyne detection technique. We tested the mode-coupling theory and found that the predicted dynamic scenario allows to reproduce properly the measured signal, for t>1 ps, in the whole temperature interval investigated. Furthermore, the values of T(c) and lambda, obtained from the analysis of three different and independent dynamic regimes (alpha regime, von Schweidler, beta regime), are in remarkable agreement. Moreover, relaxation times obtained from optical Kerr effect and dielectric spectroscopy measurements are compared. The two time scales differ only for a constant factor in the whole temperature interval investigated.

Effect of pressure on the dynamics of glass formers.

A description of the pressure dependence of the structural relaxation time has been derived from the Adam-Gibbs theory by writing the configurational entropy in terms of the excess heat capacity and the molar thermal expansion. This new equation was tested successfully on dielectric relaxation data for an epoxy compound over a wide range of temperature and pressure.

Pressure dependence of structural relaxation time in terms of the Adam-Gibbs model.

A new equation describing the behavior of the structural relaxation time, tau(T,P), as a function of both pressure and temperature, is discussed. This equation has been derived from the Adam-Gibbs theory by writing the configurational entropy, S(c), in terms of the excess thermal heat capacity and of the molar thermal expansion. Consequently, the parameters introduced in the expression are directly related to specific physical properties of the material, such as the thermal expansion coefficient alpha and the isothermal bulk modulus K0. At a fixed pressure, for low pressures, the found equation reduces to a Vogel-Fulcher-Tammann equation of tau versus temperature with the fragility parameter independent from pressure. The equation for tau(T,P) was successfully tested directly by fitting the dielectric relaxation time data for two isothermal and one isobaric measurements on diglycidyl ether of bisphenol-A, carried out in previous experiments. The parameters estimated by the best fit were in reasonable agreement with the values determined from the known physical properties of the material. Finally, the expression for the change versus pressure of the temperatures at which the same value of tau(max) is obtained (e.g., the change versus pressure of the glass transition temperature) agrees with several expressions previously proposed in the literature to provide a phenomenological description of the observed phenomena.

Light-scattering study of a supercooled epoxy resin.

The dynamics of the fragile glass-forming liquid diglycidyl ether of bisphenol-A was studied by depolarized Rayleigh-Brillouin light-scattering and photon correlation spectroscopy above the glass transition, in the temperature range from 261 to 473 K and in the frequency range from 1 Hz to 300 GHz. The structural (alpha-) relaxation process was revealed and no signature of the secondary relaxation previously evidenced by dielectric spectroscopy at about 0.1 GHz was observed. The characteristic time of the alpha process differs from that determined by dielectric spectroscopy of an amount, which increases with increasing temperature. The relaxation times were compared with viscosity data to test the predictions of the classic Stokes-Einstein-Debye model. The tau proportional, variant eta behavior was verified for dielectric data, while a fractional power law of viscosity tau proportional, variant eta(0.89) was obtained for light-scattering relaxation times, extending over more than seven decades in viscosity and time. This deviation of light scattering from viscosity data could be interpreted in terms of cooperative motion in the supercooled liquid with a characteristic length xi(a) proportional, variant(T-T0)(-v) where T(0)=229 K is the Vogel temperature and v is close to 2 / 3 which is consistent with the prediction of the fluctuation theory of glass transition.

Influence of temperature and pressure on dielectric relaxation in a supercooled epoxy resin.

Isothermal and isobaric dielectric measurements of a supercooled epoxy resin have been compared. A simple scaling relates isobaric and isothermal spectra corresponding to the same frequency of the main loss peak. Thus, the main and secondary processes retain a relative weight that is the same under isothermal and isobaric conditions. It is inferred that both pressure and temperature, equivalently, are able to take effect on the relaxation processes, without changing the relaxation mechanism itself. Careful analysis of the structural relaxation time behavior revealed that the traditional free volume equation, where only the macroscopic volume controls the pressure evolution of free volume, is not a suitable description of the data, as well as a Vogel-Fulcher (VF) type pressure dependent function. Based on a derivative method, a different function for describing the bidimensional surface tau(T,P) has been proposed, which accounts for the observed behavior through a nonlinear correction of the critical temperature T0 in the VF law. The function we propose predicts pressure dependencies of the glass transition temperature and fragility which are appealing in view of a comparison with experimental results in this and many other systems. Interesting hints for interpreting the phenomenological results can be obtained within the Adam-Gibbs theory.

Reversibility of the inhibitory effect of salmon calcitonin on bone resorption in rats.

Inhibition of osteoclastic bone resorption has been induced in growing rats with high doses of salmon calcitonin. This effect was evaluated by measuring the perichondrial ring height of the proximal tibial metaphysis. The aim was to assess whether osteoclastic activity resumed after a period of inhibition with high doses of calcitonin. 20 male Sprague-Dawley rats were treated for 21 days with 100 units/kg/day of salmon calcitonin subcutaneously and killed after 0-60 days, together with non-treated controls at 0 and 60 days. Arrest of metaphyseal modeling and increased height of the perichondrial ring at the end of the period of therapy (P 0.002 versus controls) were observed. Recovery of bone resorption was evident 20 and 40 days after withdrawal of calcitonin.

Loss of the deltoid after shoulder operations: An operative disaster.

A series of 36 patients who had a postoperative loss of the anterior or anterior lateral deltoid muscle after shoulder operations (i.e., acromioplasties, anterior shoulder reconstructions, or arthroplasty procedures) was referred to the senior author. Three patients last the function of their deltoid after an injury to the axillary nerve, and 33 patients lost deltoid function after loss of the origin of the deltoid from the clavicle and acromion. All patients were significantly disabled. All patients were dissatisfied with the result of the previous operation, and eight patients experienced painful anterior or anterior/superior dislocation of the glenohumeral joint. Treatment was nonspecific and supportive. The authors conclude that loss of anterior deltoid function secondary to denervation or detachment results in irrevocable pain and impairment of function. Careful attention to the surgical technique of deltoid reattachment and protection of the axillary nerve are essential to the prevention of dire consequences to shoulder function.

[The direct and computed radiographic assessment of vertebral locations in children with acute lymphatic leukemia]. / Valutazione radiografica diretta e computerizzata delle localizzazioni vertebrali nei bambini affetti da leucemia linfatica acuta.

The children affected with acute lymphoblastic leukemia (ALL) often exhibit secondary lesions of the spine. The diagnosis of spinal involvement is currently made by means of conventional radiography in postero-anterior and lateral views. The osteolytic lesions of the vertebral body present with collapse of the vertebral plates in a wide range of severity. Body evaluation is usually made by comparison with the adjacent vertebrae. Since leukemia is a systemic disease, several vertebrae are possibly involved in each case. In the attempt to develop a more sensitive method, which is less dependent on observers' evaluation, a quantitative and comparative analysis of vertebral bodies was performed. The radiographs in lateral view of the dorsal and lumbar spine of 14 children with ALL were analyzed: previous radiological reports suggested the lesion of one or more vertebral bodies. The area of each vertebral body was measured and digitalized by means of a backlighted graphic table and of a software developed to this purpose. The criteria to define the collapse of a vertebral body were the ratio between areas of adjacent vertebral bodies, in conformity to the anatomic and radiographic principle that, in the dorsal and lumbar spine, the body of a normal vertebra is equal to or bigger than that of the upper one. The data obtained by quantitative analysis were compared with conventional radiologic reports. A hundred and fifty-five vertebrae were analyzed by computerized analysis; 17 (10.9%) vertebrae, undetected at conventional analysis, were collapsed. This method allows a more precise diagnosis of collapsed vertebral lesions; its accuracy can be improved with further development of digital technology.

Treatment of slipped capital femoral epiphysis: evaluation of the results of extracapsular epiphysiodesis and open reduction-epiphysiodesis.

The authors review 26 patients who underwent either "in situ" extracapsular epiphysiodesis or intracapsular reduction followed by epiphysiodesis for slipped capital femoral epiphysis (SCFE). A total of 32 operations were performed. In the first group (chronic grade II SCFE), no complications occurred in the 16 operations and the results were excellent in all cases. In the second group (chronic grade II and III SCFE and acute-on-chronic SCFE), in 16 operations we observed four cases of avascular necrosis, two of which accompanied by chondrolysis. Three of these were in cases of acute-on-chronic SCFE. The results confirm that the cases of acute-on-chronic SCFE have the worst prognosis and a much higher risk of avascular necrosis and/or chondrolysis than purely chronic SCFE. Early diagnosis of ischemic complications make it possible to maintain the spherical shape of the femoral head and good joint function. The results are considerably better than in untreated cases.

[Stomatological problems related to pregnancy. A statistical study]. / Problematiche odontostomatologiche connesse alla gravidanza. Un'indagine statistica.

Pregnancy is related to particular dental issues, such as the increased incidence of diseases( gingivitis, caries, epulis), the fluoride supplementation, and the limits of diagnostics and therapy. Moreover, the mysterious halo surrounding pregnancy often makes the dentist uneasy. In order to objectively evaluate the implications of pregnancy in dentistry, we distributed a form to 100 pregnant women. The results of the form showed that 53 of them had gingival bleeding, 22 had toothache, 19 had caries but that just 12 of them had gone to the dentist because of dental troubles while 54 had not gone at all. Among the pluri-gravidae, all the women with dental diseases in their previous pregnancies had them again in their current pregnancy but nonetheless only some had undergone a dental check-up. The dentists did not show any uneasiness, as they performed tooth extractions in 5 women, endodontics in 2 women and fillings in 11 women. Just 4 out of 100 women had taken a fluoride supplementation. We deem advisable a stronger collaboration between physician, gynecologist and dentist in order to resolve specialist problems and to make pregnant women more aware of the need for dental follow-ups and fluoride supplementations.