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Objective We present a series of 20 cases of a sleeve-type injury of the distal tibia characterized by traumatic periosteal stripping caused by a high ankle sprain. We characterize the magnetic resonance imaging findings associated with this injury and highlight its association with distal tibial osteonecrosis. Materials and methods We collected 20 cases of high ankle sprains with periosteal stripping of the distal tibia through teaching files and a search through our PACS database. We recorded the presence and pattern of syndesmotic ligamentous injury and the presence or absence of syndesmotic widening in patients with periosteal stripping. The presence or absence of associated fractures and osteonecrosis was noted and characterized by location. Results The most commonly torn ligament was the anterior inferior tibiofibular ligament. 25% (5/20) of the patients in our series developed osteonecrosis. Osteonecrosis developed as early as 3–4 weeks following the initial injury. Of the patients with osteonecrosis, 40% (2/5) had fractures of the posterior malleolus. All patients with osteonecrosis had widening of the syndesmosis. Two of the five patients with osteonecrosis were in the pediatric age group. Conclusion In contrast to conventional syndesmotic and interosseous ligamentous tearing, high ankle injuries with tibial periosteal stripping may result in avulsion of the extra-osseous vasculature supplied by the periosteum, leading to osteonecrosis. This pattern of injury has not been emphasized in the literature. Our findings underscore the importance of the integrity of the periosteum for maintaining adequate vascularity of the distal tibia.

A promising route for the development of opto-elelctronic technology is to use terahertz radiation to modulate the optical properties of semiconductors. Here we demonstrate the dynamical control of photoluminescence (PL) emission in few-layer InSe using picosecond terahertz pulses. We observe a strong PL quenching (up to 50%) after the arrival of the terahertz pulse followed by a reversible recovery of the emission on the time scale of 50ps at T =10K. Microscopic calculations reveal that the origin of the photoluminescence quenching is the terahertz absorption by photo-excited carriers: this leads to a heating of the carriers and a broadening of their distribution, which reduces the probability of bimolecular electron-hole recombination and, therefore, the luminescence. By numerically evaluating the Boltzmann equation, we are able to clarify the individual roles of optical and acoustic phonons in the subsequent cooling process. The same PL quenchingmechanismis expected in other van derWaals semiconductors and the effectwill be particularly strong for materials with low carrier masses and long carrier relaxation time, which is the case for InSe. This work gives a solid background for the development of opto-electronic applications based on InSe, such as THz detectors and optical modulators., Comment: The following article has been accepted by Applied Physics Letters. After it is published, it will be found at https://publishing.aip.org/resources/librarians/products/journals/

Inversion-symmetry breaking for second-harmonic generation in centrosymmetric Si and Ge is artificially realized with a pair of asymmetric-coupled SiGe quantum wells. Laser spectroscopy experiments demonstrate a nonlinear susceptibility four orders of magnitude larger than that of natural nonlinear materials in the visible range.

The objective of this study was to assess the clinical significance of increased fluorine-18-fluorodeoxyglucose (F-FDG) uptake on PET/CT in joints for evaluation of symptomatic osteoarthritis (OA) and prediction of progression.In this prospective study, shoulder, hip, and knee joints were imaged in 65 patients undergoing routine F-FDG PET/CT imaging. Patients completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire to assess joint pain, stiffness, and physical function. Standardized uptake values (SUVs) were measured in hip, knee, acromioclavicular (AC), and glenohumeral (GH) joints. Scout PET/CT images were evaluated for OA using the Kellgren and Lawrence (K/L) system. Patients were followed-up for 5 years to determine the progression of OA on the basis of follow-up imaging or surgical intervention.SUV of knee (r=0.309, P=0.0003), hip (r=0.260, P=0.0027), AC (r=0.186, P=0.0313), and GH (r=0.191, P=0.0271) joints correlated with WOMAC overall scores. Furthermore, SUV of knee (r=0.410, P0.0001), hip (r=0.203, P=0.0199), and AC (r=0.364, P0.0001) joints correlated with K/L scores. The area under the receiver operating characteristic curves for SUV were 0.734 (knee), 0.678 (hip), 0.661 (AC), and 0.544 (GH) for symptomatic OA detection based on WOMAC overall z-score greater or equal to 2. Compared with K/L score [hazard ratio (HR)=0.798, P=0.5324], age (HR=0.992, P=0.8978), and WOMAC overall score (HR=1.089, P=0.1265), only SUV (HR=5.653, P=0.0229) was an independent predictor of OA progression in the knees.F-FDG PET/CT may be helpful with localization of painful abnormalities in the inflamed regions of the joints, which could potentially be used to direct individualized treatment in moderate and severe OA. Furthermore, SUV measurement on F-FDG PET/CT could serve as an inflammation activity index in the knees that may be predictive of outcomes and progression rate of OA.

SrRuO3 (SRO) is a perovskite increasingly used in oxide-based electronics both for its intrinsic metallicity, which remains unaltered in thin films and for the ease of deposition on dielectric perovskites like SrTiO3, (STO) to implement SRO/STO microcapacitors and other devices. In order to test the reliability of SRO/STO also as high-current on-chip conductor, when the SRO dimensions are pushed to the nanoscale, here we have measured the electrodynamic properties of arrays of nanoribbons, fabricated by lithography starting from an ultrathin film of SRO deposited on a STO substrate. The nanoribbons are 6 or 4 nm thick, 400, 200 and 100 nm wide and 5 mm long. The measurements have been performed by infrared spectroscopy, a non-contact weakly perturbing technique which also allows one to separately determine the carrier density and their scattering rate or mobility. Far-infrared reflectivity spectra have been analyzed by Rigorous Coupled-Wave Analysis (RCWA) and by an Effective Medium Theory, obtaining consistent results. With the radiation polarized along the nanoribbons, we obtain a carrier density similar to that of a flat film used as reference, which in turn is similar to that of bulk SRO. Moreover, in the nanoribbons the carrier scattering rate is even smaller than in the unpatterned film by about a factor of 2. This shows that the transport properties of SRO deposited on STO remain at least unaltered down to nanometric dimensions, with interesting perspectives for implementing on-chip nano-interconnects in an oxide-based electronics. When excited in the perpendicular direction, the nanoribbons appear instead virtually transparent to the radiation field, as predicted by RCWA.

We report on an orbital and temperature dependent study of the onset of coherent quasiparticles in V

7043 Background: Pathologic downstaging following induction chemotherapy in patients with stage III-N2 NSCLC is a well-known positive prognostic indicator. However, the predictive factors for locoregional recurrence (LRR) in these patients are largely unknown. Methods: Between 1998-2008, 153 patients with clinically or pathologically-staged III-N2 NSCLC from two cancer centers in the United States were treated with induction chemotherapy and surgery. All patients had pathologic N0-1 disease, and no one received postoperative radiotherapy. LRR were defined as disease recurrence at the surgical site, lymph nodes (levels 1-14 including supraclavicular) or both. Overall survival (OS) was calculated using the Kaplan and Meier method and comparisons were made using the log-rank test. Univariate and multivariate Cox proportional hazards model were used to assess the association of LRR and risk factors. Results: The median follow up time for survivors was 39.3 months. Baseline pretreatment N2 nodal involvement was staged by either pathologic confirmation (18.2%) or PET/CT (81.8%). Overall, the 5 year LRR rate was 30.8% (n=38), with LRR being the first site of failure in 51% (22 of 43). The 5 year OS for patients with LRR compared to those without was 21% versus 60.1%, respectively (p

Hypocalcemia is a common complication following thyroidectomy. However, the incidence of postoperative hypocalcemia varies widely in the literature, and factors associated with hypocalcemia after thyroid surgery are not well established. We aimed to identify incidence trends and independent risk factors of postoperative hypocalcemia using the nationwide inpatient sample (NIS) database from 1998 to 2008. Overall, 6,605 (5.5%) of 119,567 patients who underwent thyroidectomy developed hypocalcemia. Total thyroidectomy resulted in a significantly higher increased incidence (9.0%) of hypocalcemia when compared with unilateral thyroid lobectomy (1.9%; 𝑃 . 0 0 1 ). Thyroidectomy with bilateral neck dissection, the strongest independent risk factor of postoperative hypocalcemia (odds ratio, 9.42; 𝑃 . 0 0 1 ), resulted in an incidence of 23.4%. Patients aged 45 years to 84 years were less likely to have postoperative hypocalcemia compared with their younger and older counterparts ( 𝑃 . 0 0 1 ). Hispanic ( 𝑃 = . 0 0 3 ) and Asian ( 𝑃 = . 0 2 7 ) patients were more likely, and black patients were less likely ( 𝑃 = . 0 0 3 ) than white patients to develop hypocalcemia. Additional factors independently associated with postoperative hypocalcemia included female gender, nonteaching hospitals, and malignant neoplasms of thyroid gland. Hypocalcemia following thyroidectomy resulted in 1.47 days of extended hospital stay (3.33 versus 1.85 days 𝑃 . 0 0 1 ).

Municipal sewage and WWTP effluents are considered to be a major source of pollution, regarding the occurrence of endocrine disrupting compounds (EDCs) in the environment. Although removal potential of many EDCs by conventional WWTPs is recognised, literature data are not easily comparable. Besides, in order to reach very low concentrations, a further treatment might be sometimes required. Positive results can be achieved by tertiary chemical oxidation; nevertheless, technical-economic suitability is still to be fully demonstrated. In this work, two estrogen-like susbstances were considered: nonylphenol (NP) (and its parent compounds) and bisphenol A (BPA). The experimental work was conducted at Verona (Northern Italy) WWTP (370,000 p.e.): after a 15 days sampling campaign, which was carried out in order to calculate mass balance of target compounds, chemical oxidation tests were performed on effluent by means of UV/H2O2 process and ozonation. Technical-economic feasibility of these solutions is discussed.

Neurogenic tumors account for approximately 10–12% of all benign soft tissue tumors and 7–8% of all malignant soft tissue tumors. These can be divided into neoplastic and pseudotumors. Neoplastic tumors include those derived from the Schwann cell (collectively referred to as “peripheral nerve sheath tumors” or PNSTs), such as neurilemoma, neurofibroma, and rare malignant counterparts. Another neurogenic tumor is the neural fibrolipoma. This is likely to be congenital in origin and presents as fibrofatty infiltration of the nerve, usually the median nerve at the wrist. Following trauma or surgery a neuroma may develop at the site of injury. Tumors may also develop from peripheral autonomic nerves; an example of this is the glomus tumor, commonly seen beneath the fingernail in women.

Objectives The aims of this study were to determine the incidence of placental sonolucencies on first-trimester screening sonograms in a general obstetric population and assess whether these findings are associated with adverse obstetric outcomes. Methods A retrospective cohort analysis of 201 pregnant patients screened at a high-risk prenatal diagnostic center was conducted with first-trimester cine clips reviewed by 2 radiologists. Placental sonolucencies were defined as intraplacental anechoic or heterogeneous areas 0.7 cm or greater. Obstetric and neonatal outcomes were collected by chart review. Results Placental sonolucencies 0.7 cm or greater were seen in 45 (22.4%) of first-trimester ultrasound examinations. The ultrasonographic presence of a placenta previa, marginal sinus, and subchorionic hemorrhage was not more common in those with placental sonolucencies 0.7 cm or greater (P > 0.05). Sonolucencies were not associated with prior cesarean deliveries (P > 0.05). Both the groups with and without sonolucencies 0.7 cm or greater had similar rates of antepartum hemorrhage, preeclampsia, preterm delivery, cesarean delivery, postpartum hemorrhage, and delivery of small-for-gestational-age infants. One placenta accreta and no fetal demises occurred in the study population. Conclusions Placental sonolucencies detected on first-trimester screening sonograms in the general obstetric population are not predictive of poor obstetric outcomes.

The band structure and the optical transitions of symmetric ultra-short period (GaAs)m/(AlAs)n superlattices (n=m is the number of monolayers) have been studied using different spectroscopic techniques, namely photoacoustic spectroscopy, reflectivity and luminescence, photoluminescence excitation and high excitation intensity time-resolved luminescence. Direct observation of the transition from type I to type II energy band alignment is reported for superlattices whose configuration consists of more than 12 monolayers (i.e. m=n>12). The radiative recombination processes associated with the real space indirect transitions have been investigated as a function of the density of photogenerated electron-hole pairs, revealing an unusual density-dependent behaviour. A tentative interpretation in terms of a condensed electron-hole state at the indirect gap is given, which accounts for the long decay time of the type II luminescence at high excitation rate.

Twenty-five novel HLA-B alleles are described in this paper: B*0729, B*1309, B*1814, B*1815, B*2724, B*2725, B*3539, B*3926, B*4037, B*4040, B*4042, B*4043, B*4044, B*4204, B*440203, B*4428, B*4429, B*4430, B*4505, B*5308, B*5309, B*5510, B*5511, B*570102, and B*5709. Most of the variants are single nucleotide substitutions. Two involve variants at the Bw4/Bw6 epitope. Two alleles carry substitutions of conserved amino acids.

This paper describes 17 novel HLA-A alleles: A*0244, A*0251, A*0254, A*0309, A*1111, A*2432, A*2434, A*2504, A*2618, A*2905, A*2906, A*3106, A*3107, A*3207, A*6820, A*7407, and A*7408. Most substitutions are found in other alleles.

Rotating stall is a key problem in centrifugal compressors especially for high-pressure applications. Among the several solutions proposed to prevent this problem, low solidity vaned diffusers (LSDs) have been successfully applied. The aim of this research is to find an optimized LSD configuration in terms of stall inception and performance for the tested compressor. The influence of the vane leading and trailing edge radii, maintaining the same solidity and null deflection were investigated. The geometrical parameters of tested configurations were methodically chosen in order to achieve a design of experiment (DOE) analysis. In view of the above, a series of tests on five low solidity vaned diffuser configurations were carried out. Tests allowed determination of 2 different LSDs that showed the best behavior in terms of working range and performance. These LSDs were then compared with the standard and the reduced-width vaneless diffuser to better understand the best solution to the stall problem.Copyright © 2003 by ASME

Vaneless diffuser rotating stall is a major problem for centrifugal compressors since it is a limit to their working range. In particular the last stage seems to be the most critical. In the literature some good correlations for predicting stall inception can be found but they do not adequately cover the case of the last stage configuration, especially for very low blade-outlet-width-to-impeller-radius-ratio impellers typically used in high-pressure applications. Extensive research has been performed to define diffuser stall limits for this family of stages: three impellers characterized by different blade-outlet-width-to-impeller-radius-ratios are tested with different diffuser configurations (different pinch shapes, diffuser widths and diffusion ratios). Part I and II report the results of these geometry modifications on diffuser stability for the first impeller. Part III, those for the second impeller. In this part the comparison of these results in terms of impeller influence on diffuser stability is reported.

This paper describes two novel HLA-B locus alleles. B*0713 appears to have resulted from an interlocus recombinational event which inserted a sequence from an HLA-C allele into B*0702. This event altered a significant portion of the alpha-1 domain alpha helix. B*6702 shares much of its exon 2 sequence with B*0713 but is identical in exon 3 to several HLA-B locus alleles including B*67012.

Extensive research on centrifugal compressors has been planned to define diffuser stall limits for a group of stages characterized by low blade-outlet-width-to-impeller-radius-ratio. Very little data is available on this centrifugal compressor family, especially for the last stage configuration. In addition, the most important stall diffuser prediction criteria barely cover this machine type. Many experimental tests have been planned to investigate several geometry variations. A simulated stage with a backward channel upstream, a 2D impeller with a vaneless diffuser and a constant cross section volute downstream constitute the basic geometry. Several diffuser geometries with different widths, pinch shapes, diffusion ratios were tested. Test results and conclusions are shown in the paper in terms of critical diffuser inlet flow angles, flow coefficients at stall inception and stage working ranges. The main task of the present work is to increase the knowledge and the amount of available data to characterize rotating stall phenomena, in particular for very narrow stages.

A preliminary definition of light absorption spectra of brain neoplasm represents a correct approach to the laser therapy of cerebral tumours. The goal should be the identification of those oncotypes more sensive to the laser energy, allowing consequently a dosage of the energy proportional to the light absorption coefficient, reducing any side effects. With this purpose the coefficients of light-absorption of 63 different brain tumours have been analyzed and defined by means of photocoustic spectrometry. The study has been focused at wavelength of the Ar+ laser (4,600-6,000 A). The results show a close relationship between histology, degree of vascularization and/or pigmentation and light absorption: the more immature and/or pigmented oncotypes show the highest coefficients of optical absorption. In the laser therapy of these neoplasms it will be sufficient to use low powers and short exposure time.

The choice of imaging modality for suspected scaphoid fracture depends on factors such as age, patient activity, cost, and availability of services

Space charge limited current measurements in ZnIn2S4 and some ZnIn2S4In2S3 alloys are made. A continuous trap distribution which can be quite accurately described by an exponential model is a distinctive characteristic of all experimental data. The “energy decay constant” of the distribution is about 50 meV, which agrees with the conclusion obtainable by other types of measurements. Raumladungsbegrenzte Strome wurden in ZnIn2S4 und in einigen ZnIn2S4In2S3 Legierungen gemessen. Eine stetige, von einem Exponentialmodell genau beschriebene „Trap”- Verteilung ist fur die experimentellen Ergebnisse kennzeichnend. Die „Abfallkonstante” der Exponentialverteilung betragt ungefahr 50 meV, was mit den Ergebnissen anderer Mesverfahren ubereinstimmt.

The Photoacoustic (PA) spectra in several layered compounds such as HfSe2, ZrS2, HfS2, WSe2, MoSe2 and MoS2 have been measured at energies above the fundamental absorption edge. In this optical region the PA signal is regarded to be independent of the optical absorption coefficient and the dips in the PA spectra may be ascribed to optical reflection effects inherent the band structure. Generally, our experimental data prove that the information on the band structure of the layered semiconductors is in good agreement with that obtainable by means of conventional spectroscopic techniques, and moreover it is comparable with the data which are usually obtained by means of modulatory spectroscopy.

SCLC measurements in single crystals of the layered semiconductor n -type InSe are reported. The measurements were carried out at various temperatures and on samples grown with indium added in excess (from 5 to 10%). The experimental results suggest that the trapping levels location and the charge transport are dependent on the indium excess. Only the samples grown with an indium excess of about 5% show the features typical of intrinsic semiconductors. The anomalous behaviour of samples grown with indium excess between 6 and 10 is explained by means of scattering mechanisms between charge carriers and ionized impurity centers.

Photoacoustic spectroscopy measurements reveal that HeNe low-power irradiation causes changes in mitochondrial optical properties. However, it has been found that this process damages neither the membrane of the mitochondria nor some of their enzymatic activities. The HeNe laser irradiation effect was investigated both with regard to the redox state change of intramitochondrial pyridine nucleotides, induced by addition to the mitochondria of oxaloacetate, oxoglutarate plus ammonia and cis-aconitate, and to the permeability of rat liver mitochondria to the same substrates. It was found that laser irradiation modifies some NADH-linked dehydrogenase reactions of the mitochondria.

A systematic investigation of photoconductive (ΔG) and photoelectromagnetic (PEM) properties of lead iodide is reported. The samples show different polytypic modifications or different stoichiometry. The results, compared with different theoretical models, show that the phototransport properties are not affected by the polytypism but depend on doping; furthermore the sublinear dependences of the measured effects on incident light intensity suggest the occurrence of trapping effects. The application of a new phototransport model accounts for these experimental results and allows the evaluation of the lifetimes. Die Ergebnisse einer systematischen Untersuchung der Photoleitungs (ΔG)- und photoelektromagnetischen (PEM) Eigenschaften von Bleijodid werden mitgeteilt. Die Proben besitzen verschiedene Polytypenmodifikationen oder unterschiedliche Stochiometrie. Die mit verschiedenen theoretischen Modellen verglichenen Ergebnisse zeigen, das die Phototransporteigenschaften durch den Polytypismus nicht beeinflust werden, jedoch von der Dotierung abhangen; daruberhinaus weisen die sublinearen Abhangigkeiten der gemessenen Effekte von der Intensitat des einfallenden Lichtes auf das Auftreten von Anhafteffekten hin. Die Anwendung eines neuen Phototransportmodells erklart diese experimentellen Ergebnisse und gestattet die Berechnung der Lebensdauren.

Photoacoustic saturation spectra in some semiconductors as HfSe2, ZrS2 and HfS2 have been measured at energies above the fundamental absorption edge, where the photoacoustic signal is independent of the optical coefficient and the dips detected in the photoacoustic spectra may be ascribed to optical reflection effects inherent to the band structure. The comparison between our experimental data and those obtained by means of conventional and modulatory spectroscopic techniques proves that such method is a useful tool in order to determine the electronic structure of photoacoustically active semiconductors.

We report the direct observation of the transition from type I to type II in (GaAs${)}_{\mathrm{m}}$/(AlAs${)}_{\mathrm{n}}$ ultra-short-period superlattices with m=n by means of photoacoustic spectroscopy and high-excitation-intensity photoluminescence. The transition is found to occur when the constituent superlattice layers have a critical thickness of about 12 monolayers (m=n=12). Different temperature dependences of the type-I and type-II recombinations are observed, which are tentatively ascribed to the thermal transfer of the carriers between quantized subbands, in different critical points of the superlattice.

Saturation photoacoustic spectra in some group IV-A transition metal dichalcogenides like TiTe 2 , TiS 2 and TiSe 2 have been measured at energies above the fundamental absorption edge. In this optical region the photoacoustic signal is independent of the optical absorption coefficient and the dips detected in the photoacoustic spectra may be ascribed to optical reflection effects inherent to the band structure. Our experimental data implement information about interband transitions of these layered compounds and, furthermore, prove that saturation photoacoustic spectroscopy is a useful alternative tool to other reflectivity measurements.

Combined measurements of the photoelectromagnetic effect and photoconductivity in three different geometries can be used to determine the anisotropy factors (μn∥/μn⊥, μp∥/μp∥) and the mobility ratios (μn∥/μp∥, μn⊥/μp⊥) in anisotropic semiconductors. In the present work this method has been applied to mercuric iodide; previous data on electron mobilities are confirmed, whereas the hole mobility is nearly isotropic.

Photoacoustic spectra in thin samples of CdI 2 layered semiconductor have been measured in the region of energies near the fundamental energy gap. By means of this technique it was possible to obtain the spectrum of the low values of the absorption coefficient in the range between 3.12 and 3.26 eV, where the absorption coefficient varied from 5 to 100 cm -1 . The experimental results are sound with respect to the indirect nature of the optical gap of the CdI 2 .

The photoacoustic spectra in GaSe, GaTe and InSe semiconductors have been measured in the region of energy greater than the fundamental absorption edge. In this range the photoacoustic signal magnitude can be regarded as independent of the absorption coefficient, i.e. photoacoustic spectroscopy in saturation region, and the dips in the spectra are ascribed to the optical reflection effect inherent in semiconductors interband transitions. The photoacoustic signal phase spectra have been also measured; they are shown to be a useful check of the structures observed in the magnitude saturation spectra. The experimental results are in good agreement with the allowed interband transition energies as observed in thermo-reflectance, electroreflectance and normal reflectivity experiments.

The electro-optic coefficient of CdS 0.75 Se 0.25 is measured at the frequency of the He-Ne laser light and the application of this crystal in light modulators is discussed. The figure of merit is found to be | 3 o r c | = 7 × 10 -9 cm/V at room temperature. The voltage required to achieve one half wave retardation is 9 kV.

Taking as starging point three patients who unsuccessfully underwent both medical treatment and different neurosurgical interventions, the Authors discuss the problem of the dystonia musculorum deformans nosographic arrangement and its present therapeutical possibilities. They believe that the dystonia musculorum deformans must be considered, rather than as a syndrome, as a real disease, to be distinguished in particular from the various infantile dystonic syndromes and from spasmodic torticollis. In fact in these last morbid forms, at least from a neurosurgical standpoint, the therapeutical possiblities are not so uncertain as those of the dystonia musculorum deformans.

The surgical use of CO2 c.w. laser as a knife and of Nd:YAG laser as photocoagulator is generally explained in terms of the different absorption coefficients of the water contained in high amount in the living tissues at the operating wavelengths of the two sources (alphaCO2 congruent to 10(2) cm(-1), alpha Nd congruent to 1cm(-1)). This approach can be shown to be incorrect once spectrophotometric measurements carried out on a mucous membrane and blood give the values gammaCO2 = 200 cm(-1) and gamma Nd = 10 cm(-1) for the effective absorption coefficient (the effective coefficient is gamma = alpha + beta where beta is the internal light scattering coefficient). It is worth noting that gammaCO2 congruent to alpha CO2 but gammaNd congruent to 10alphaNd. Then we have calculated the temperature distribution on tissues irradiated either by Co2 or by Nd laser. In the Co2 irradiation two energy transfer mechanisms are present: the surface optical absorption and the thermal diffusion in the bulk of the tissue. Under Nd irradiation the optical absorption of internally scattered radiation must also be taken into account. The calculation model is based on the classical heat equation, but assuming a "source" given by the expression S (r,z; t) = alpha [IB (r,z; t)+IS (r,z;t)], where IB and IS are respectively the direct and scattered components of a beam propagating along a z direction perpendicular to the tissue surface. The general expression of the temperature increases deltaT (r,z;t) have been obtained for both laser sources. The calculation show that even a few watts CO2 laser can induce a surface temperature rise of about 60 degrees C with negligible bulk effects, depending only on the thermal conductivity and on the irradiation time (knife effect). On the contrary a 40 w Nd:YAG laser induces a 50 degrees C temperature rise in the whole thickness of the tissue becoming in this way unable to "cut" even though it coagulates a region much larger than the beam dimensions.

The temperature increases in biological tissues irradiated by a C.W. CO2 laser beam have been calculated through the classical heat equation. The temperature behaviours, as a function either of the spatial coordinates or of the irradiation time, are obtained and they are confirmed by preliminary experimental results. The energy penetration into the biological medium, due to the thermal diffusivity, is pointed out and a simple relationship between the superficial and the depth coordinates, relatively to the same isotherm, has been found.© (1980) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Over the last thirteen years we have accumulated a vast experience5 in all the most important methods proposed by various authors for the treatment of spastic disorders of infantile cerebral palsy, such as stereotactic dentatolysis or pulvinolysis, C1–C4 posterior cervical rhizotomies or cronic paleocerebellar stimulation4.

Immediate and late results of a series of 44 patients suffering from spastic syndromes, operated on from January 1973 to December 1976 by selective posterior rootlet section, have been analyzed and reported. The operation consisted of a selective section of the dorsomedial part of the rootlets constituting each posterior root and was performed usually from L1 to S1 bilaterally. Thirty patients improved markedly after the operation and there were no immediate or late complications. The procedure caused no sensory disorders. The indications and contraindications to the operation are discussed.