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From the material analyzed in this study it appears that, if a hundred patients with inerniated nucleus pulposus are subjected to disc excision, one may expect sixty of them to obtain long-term results which are satisfactory. If the same hundred patients should have spine fusions in addition to the disc excisions, the results will be satisfactory in seventy of them. Sixty of these patients would not have needed the fusion operation, and of the forty whose results are unsatisfactory only ten could have expected sufficient improvement to make them satisfactory. Furthermore, the fusion procedure is an added operation, and we have no reason to believe that its effectiveness is greater if it is done at the time of the disc excision than if it is performed at a later date as a second-stage operation. We are therefore led to the conclusion that, when surgical intervention is necessary for simple cases of herniated nucleus pulposus, the operation of choice is disc excision only. Spine fusion can be performed at a later elate in those patients whose poor results warrant additional surgery. Recognition is given to the fact that technical improvements in the operative procedures may be expected. Such improvements may lead to results which differ from those found in this study and will justify a re-evaluation after a lapse of years.

Finely ground alunite (hydrated potassium aluminium sulphate) can be dissolved in hot 72.5% perchloric acid. Determinations of silica and R 2 O 3 in samples of alunite so dissolved agree closely with similar determinations following a sodium carbonate fusion procedure.

Duplex perception is the simultaneous perception of a speech syllable and of a nonspeech “chirp” and occurs when a single formant transition and the remainder (the “base”) of a synthetic syllable are presented to different ears. The current study found a slight but nonsignificant advantage for correct labeling of the fused syllable when the chirp was presented to the left ear. This advantage was amplified in the performance of a “split-brain” subject. A subject with a left pontine lesion performed at chance level when the chirp was presented to her left ear. These findings suggest that some, if not complete, ipsilateral suppression does occur in the dichotic fusion procedure, and that identification of the fused syllable is maximal when the left hemisphere fully processes the linguistic characteristics of the base (through contralateral presentation), and at least minimally processes the frequency transition information of the chirp (through ipsilateral presentation).

This retrospective study of 24 patients with adolescent idiopathic scoliosis who underwent L-rod instrumentation, posterior thoracoplasty, and rib-bone grafting analyzed the correlation between the quality of rib regeneration and the host response to the rib-bone grafts. A planimetric technique was used to quantitate the coronal plane area of the resected ribs and of an L1-L2 concave fusion area immediately after surgery and at the end of the first postsurgical year. Using computerized regression analysis, these and other variables such as age, Cobb angle, and grafting technique were studied. Rib regeneration correlated with spinal fusion but not with age or Cobb angle. A better host response with strip vs. morseled graft was suggested, but not statistically proven. The data strongly support the belief that systemic biologic factors are a major variable affecting the quality of the fusion procedure.

The syndrome produced by lytic spondylolisthesis depends on the level at which it occurs. Above the lumbosacral level the incidence of neurologic signs and spinal stenosis increases, and further forward slip in adult life is not uncommon. Twenty-seven patients with lesions above the fifth lumbar vertebra and symptoms severe enough to warrant surgery were studied. Some radiologic observations are made. The patients were divided into two groups for assessment of the results of surgery. Patients with no neurologic signs obtained satisfactory results after a fusion procedure alole. Patients with a neurologic deficit fared less well after surgery, and the importance of decompression in this group is stressed.

Viable hybrids of Saccharomyces cerevisiae were obtained by transfer of isolated diploid nuclei into haploid protoplasts using a polyethylene glycol (PEG) fusion procedure.

Polyethylene glycol (PEG) has been used extensively to induce protoplast fusion (1). However, protoplasts of many plant species do not tolerate the inevitable osmotic transitions during PEG treatment. This toxicity may firstly be due to acidic impurities found in some commercial PEG preparations (2), or secondly may relate to the dehydrating capacity of PEG, thus making protoplasts irreversibly leaky (3). Protoplast aggregates often result from an inadequate rehydration during the elution of PEG which renders the protoplasts less amenable to flow cytometry.

5,6-Dimethyl-1-(β-D-ribofuranosyl)imidazo[4,5-b]pyrazine (12) has been synthesised by three different routes: (a) glycosylation of thetrimethylsilyl derivative (5) of 5,6-dimethylimidazo[4,5-b]pyrazine, (b) the fusion procedure, and (c) ring closure of an imidazole nucleoside. The assignment of the site of ribosylation and of the anomeric configuration of compound (12) and the imidazo[4,5-b]pyrazine nucleosides -(10) and (11) is discussed.

We construct exact eigenvectors and eigenvalues for $U_q(\mathfrak{sp}_{2n})$- and $U_q(\mathfrak{so}_{2n})$-symmetric closed spin chains by means of a nested algebraic Bethe ansatz method. We use a fusion procedure to construct higher-dimensional Lax operators. Our approach generalises and extends the results obtained by Reshetikhin and De Vega-Karowski. We also present a generalisation of Tarasov-Varchenko trace formula for nested Bethe vectors., 22 pages, v2: final version

We aimed to evaluate the importance of modulations of within-tree carbon (C) allocation by water and low-temperature stress for the prediction of annual forest growth with a process-based model. A new C allocation scheme was implemented in the CASTANEA model that accounts for lagged and direct environmental controls of C allocation. Different approaches (static vs dynamic) to modelling C allocation were then compared in a model–data fusion procedure, using satellite-derived leaf production estimates and biometric measurements at c. 104 sites. The modelling of the environmental control of C allocation significantly improved the ability of CASTANEA to predict the spatial and year-to-year variability of aboveground forest growth along regional gradients. A significant effect of the previous year's water stress on the C allocation to leaves and wood was reported. Our results also are consistent with a prominent role of the environmental modulation of sink demand in the wood growth of the studied species. Data available at large scales can inform forest models about the processes driving annual and seasonal C allocation. Our results call for a greater consideration of C allocation drivers, especially sink–demand fluctuations, for the simulations of current and future forest productivity with process-based models.

A peculiar form of C1-2 block vertebra (anterior arch of the atlas with the axis) is described. The progressive ossification is followed up in a child from the age of 9 to 15. The author also reviews the data of his five previously reported cases.

The synthesis of 1-(4-thio-beta-D-ribofuranosyl)-1,2,4-triazole-3-carboxamide (3) is described. The acid-catalyzed fusion procedure with 3-cyano-1,2,4-triazole and 1,2,3,5-tetra-O-acetyl-4-thio-D-ribofuranose provided 3-cyano-1-(2,3,5-tri-O-acetyl-4-thio-beta-D-ribofuranosyl-1,2,4-triazole (2) which was converted with NH4OH to 3. In contrast to 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (1), the 4'-thio nucleoside 3 did not exhibt significant antiviral activity in vitro.