Lateral mass screw fixation in the cervical spine

pre-printTo The Editor: We read with interest the article by Kawabata et al.15 (Kawabata S, Watanabe K, Hosogane N, et al: Surgical correction of severe cervical kyphosis in patients with neurofibromatosis Type 1. Report of 3 cases. J Neurosurg Spine 18:274-279, March 2013). Reconstructive spinal surgery has undergone a tremendous transformation in the last several decades, with improvements in imaging, biologics, and implant technologies. Not uncommonly, the spine surgical community may abandon an older technique when it becomes evident that a new approach or technology is clearly safer or superior. Comparative clinical trials of older versus newer techniques are often limited to a small number of cases published over a short period of time and are typically not performed under the rigors of randomized controlled study sufficient to meet the standards set by governmental agencies to gain regulatory approval. Lateral mass screw fixation (LMSF) of the cervical spine, which has generally supplanted older wiring and hook cervical fixation methods, is one such technique

Pathophysiology-based treatment of idiopathic calcium kidney stones

Idiopathic calcium oxalate (CaOx) stone-formers (ICSFs) differ from patients who make idiopathic calcium phosphate (CaP) stones (IPSFs). ICSFs, but not IPSFs, form their stones as overgrowths on interstitial apatite plaque; the amount of plaque covering papillary surface is positively correlated with urine calcium excretion and inversely with urine volume. The amount of plaque predicts the number of recurrent stones. The initial crystal overgrowth on plaque is CaP, although the stone is mainly composed of CaOx, meaning that lowering supersaturation (SS) for CaOx and CaP is important for CaOx stone prevention. IPSFs, unlike ICSFs, have apatite crystal deposits in inner medullary collecting ducts, which are associated with interstitial scarring. ICSFs and IPSFs have idiopathic hypercalciuria, which is due to decreased tubule calcium reabsorption, but sites of abnormal reabsorption may differ. Decreased reabsorption in proximal tubules (PTs) delivers more calcium to the thick ascending limb (TAL), where increased calcium reabsorption can load the interstitium, leading to plaque formation. The site of abnormal reabsorption in IPSFs may be the TAL, where an associated defect in bicarbonate reabsorption could produce the higher urine pH characteristic of IPSFs. Preventive treatment with fluid intake, protein and sodium restriction, and thiazide will be effective in ICSFs and IPSFs by decreasing urine calcium concentration and CaOx and CaP SS and may also decrease plaque formation by increased PT calcium reabsorption. Citrate may be detrimental for IPSFs if urine pH rises greatly, increasing CaP SS. Future trials should examine the question of appropriate treatment for IPSFs

Economic Origins of War and Peace

Why do wars happen, and what do societies fight over? Why are international relations sometimes fearful and aggressive and other times harmonious? I show that these questions can be fruitfully explored by importing some basic economic theory into the existing bargaining theory of war. A separate essay analyzes the interactions between the United States and countries that may be pursuing nuclear weapons. "Costly Peace: A New Rationalist Explanation for War" posits a new explanation for war: sometimes peace is more costly (in the sense of leaving both sides worse off in expectation) than war. This means that some wars improve overall welfare relative to peace. I develop models for three common sources of costly peace tailored to particular wars and analyze them to expose the common underlying logic for war. The costs of: arming explain the Iraq War; imposition explain the civil conflicts within Iraq after the earlier Gulf War; and predation explain the American War of Independence. "The Modern Economic Peace" develops a theory of the origins of international disputes, in which the economic conflict of interests between two states is determined by the benefits and costs of transferring wealth from one state's economy to the other's. Whether such a transfer happens depends on the military situation between the two states and also the characteristics of their economies and governments. Nations with sensitive, integrated ("modern") economies of comparable size and representative governments have little to fight over. This might explain not only the puzzling comity of the West, but also long-run global patterns in organized violence, economic liberalization, and democratization. "A Model of Arms Proliferation and Prevention" is co-authored with Muhammet Bas. We develop a formal model of bargaining between two states, where one can invest in developing nuclear weapons and the other imperfectly observes its efforts and progress over time, and use it to analyze the occurrence of proliferation and war, the viability of non-proliferation agreements, and the role of intelligence-gathering and estimates. The model explains some of the complex phenomena that occur in these interactions, such as mistaken wars, cyclical crises, and the failure of non-proliferation deals.Governmen

JRC QSAR Model Database: EURL ECVAM DataBase service on ALternative Methods to animal experimentation: Guideline for Authors and Editors

EURL ECVAM DataBase service on ALternative Methods to animal experimentation In the regulatory assessment of chemicals, Quantitative Structure-Activity Relationship (QSAR) models are playing an increasingly important role in predicting properties needed for hazard and risk assessment. The JRC QSAR Model Database provides information on the validity of QSAR models that have been submitted to the JRC. The database is intended to help to identify valid QSARs, e.g. for the registration and authorisation purposes of chemical substances within the context of REACH Registration, Evaluation, Authorisation and Restriction of Chemicals (EC 1907/2006), a European Union regulation dated 18 December 2006. The QSAR Model Reporting Format (QMRF) is a harmonised template for summarising and reporting key information on QSAR models, including the results of any validation studies. The information is structured according to the OECD principles for the validation of QSAR models.JRC.F.3-Chemicals Safety and Alternative Method

JRC QSAR Model Database: EURL ECVAM DataBase service on ALternative Methods to animal experimentation: To promote the development and uptake of alternative and advanced methods in toxicology and biomedical sciences: SDF - STRUCTURE DATA FORMAT: How to create from SMILES

EURL ECVAM DataBase service on ALternative Methods to animal experimentation To promote the development and uptake of alternative and advanced methods in toxicology and biomedical sciences. This publication is a Tutorial by the Joint Research Centre (JRC), the European Commission’s science and knowledge service. It aims to provide user support. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.JRC.F.3-Chemicals Safety and Alternative Method

Idiopathic hypercalciuria and formation of calcium renal stones

The most common presentation of nephrolithiasis is idiopathic calcium stones in patients without systemic disease. Most stones are primarily composed of calcium oxalate and form on a base of interstitial apatite deposits, known as Randall’s plaque. By contrast some stones are composed largely of calcium phosphate, as either hydroxyapatite or brushite (calcium monohydrogen phosphate), and are usually accompanied by deposits of calcium phosphate in the Bellini ducts. These deposits result in local tissue damage and might serve as a site of mineral overgrowth. Stone formation is driven by supersaturation of urine with calcium oxalate and brushite. The level of supersaturation is related to fluid intake as well as to the levels of urinary citrate and calcium. Risk of stone formation is increased when urine citrate excretion is 200 mg per day also increase stone risk and often result in negative calcium balance. Reduced renal calcium reabsorption has a role in idiopathic hypercalciuria. Low sodium diets and thiazide-type diuretics lower urine calcium levels and potentially reduce the risk of stone recurrence and bone disea

Mechanisms of human kidney stone formation

The precise mechanisms of kidney stone formation and growth are not completely known, even though human stone disease appears to be one of the oldest diseases known to medicine. With the advent of the new digital endoscope and detailed renal physiological studies performed on well phenotyped stone formers, substantial advances have been made in our knowledge of the pathogenesis of the most common type of stone former, the idiopathic calcium oxalate stone former as well as nine other stone forming groups. The observations from our group on human stone formers and those of others on model systems have suggested four entirely different pathways for kidney stone formation. Calcium oxalate stone growth over sites of Randall's plaque appear to be the primary mode of stone formation for those patients with hypercalciuria. Overgrowths off the ends of Bellini duct plugs have been noted in most stone phenotypes, do they result in a clinical stone? Micro-lith formation does occur within the lumens of dilated inner medullary collecting ducts of cystinuric stone formers and appear to be confined to this space. Lastly, cystinuric stone formers also have numerous small, oval, smooth yellow appearing calyceal stones suggestive of formation in free solution. The scientific basis for each of these four modes of stone formation are reviewed and used to explore novel research opportunities

Stand structure in eastside old-growth ponderosa pine forests of Oregon and northern California."

Abstract Quantitative metrics of horizontal and vertical structural attributes in eastside old-growth ponderosa pine (Pinus ponderosa P. and C. Lawson var. ponderosa) forests were measured to guide the design of restoration prescriptions. The age, size structure, and the spatial patterns were investigated in old-growth ponderosa pine forests at three protected study areas east of the crest of the Cascade Range: Metolius Research Natural Area and Pringle Butte Research Natural Area in central Oregon and Blacks Mountain Experimental Forest in northern California. The three study areas represented sites characterized by deep accumulations of pumice from Cascade volcanism. All stems !15 cm in height (minimum height of an established seedling) were mapped and measured on a total of 27 1-ha plots. The distribution of trees within each individual plot was investigated by second-order spatial analysis with Ripley's K(d) function, and then evaluated across each study area with functional data analysis. Coarse woody debris was sampled by using the strip-plot method to determine log density, mean log size, volume, and cover. The oldest trees were 618 years at Metolius, 613 years at Pringle Butte, and 330 years at Blacks Mountain. Stands were multi-aged, with as many as 16 cohorts at Metolius and 22 cohorts at Pringle Butte. Density of live old-growth ponderosa pine in the upper canopy ranged from 34 to 94 trees ha À1 at Metolius, 35 to 79 trees ha À1 at Pringle Butte, and 15 to 73 trees ha À1 at Blacks Mountain; the differences between study areas were not significant, resulting in an overall mean density of 50 AE 3.5 live old-growth trees ha À1 . Mean diameters of these oldgrowth trees did not differ among the three study areas; the overall mean was 60.0 AE 1.55 cm dbh. Large dead ponderosa pines (overall mean diameter 61.7 AE 4.33 cm) were a common feature at all three study areas; the overall mean density was 9.0 AE 0.97 trees ha À1 . Ripley's K(d) analysis of spatial point patterns using upper canopy trees revealed significant departure from randomness in 24 of the 27 plots. Functional data analysis of the spatial relationship of all sample plots by study area revealed two strong patterns. At scales of 1.2 d 2.6 m at Metolius and 1.6 d 8.4 m at Blacks Mountain, the deviation from random was not significant, suggesting the distribution of old-growth trees was random. More important, significant positive deviation from complete spatial randomness at larger scales at Metolius and Blacks Mountain suggested a clumped distribution. Maximum radii of the clumps were about 22.5 m in diameter at Metolius and about 24 m in diameter at Blacks Mountain. In contrast, old-growth trees at Pringle Butte were randomly distributed. Density of logs at Metolius and Pringle Butte was 47.0 AE 5.28 logs ha À1 , their mean large-end diameter was 37.6 AE 2.41 cm, the mean length of each log was 4.2 AE 0.09 m, the cumulative length of all logs averaged 512.9 AE 78.12 m, the total volume averaged 62.3 AE 6.30 m 3 ha À1 , and the cover averaged 1.7 AE 0.08%. A majority of the logs were in an advanced stage of decomposition, suggesting that they were in place for considerable time. These results are discussed i

Black carbon physical and optical properties across northern India during pre-monsoon and monsoon seasons

Black carbon (BC) is known to have major impacts on both climate and human health and is therefore of global importance, particularly in regions close to large populations that have strong sources. The size-resolved mixing state of BC-containing particles was characterised using a single-particle soot photometer (SP2). The study focusses on the Indo-Gangetic Plain (IGP) during the pre-monsoon and monsoon seasons. Data presented are from the UK Facility for Airborne Atmospheric Measurements BAe-146 research aircraft that performed flights during the pre-monsoon (11 and 12 June) and monsoon (30 June to 11 July) seasons of 2016. Over the IGP, BC mass concentrations were greater (1.95 µg m−3) compared to north-west India (1.50 µg m−3) and north-east India (0.70 µg m−3) during the pre-monsoon season. Across northern India, two distinct BC modes were recorded; a mode of small BC particles (core diameter <0.16 µm and coating thickness <50 nm) and a mode of moderately coated BC (core diameter <0.22 µm and coating thickness of 50–200 nm). The IGP and north-east India locations exhibited moderately coated black carbon particles with enhanced coating thicknesses, core sizes, mass absorption cross sections, and scattering enhancement values compared to much lower values present in the north-west. The coating thickness and mass absorption cross section increased with altitude (13 %) compared to those in the boundary layer. As the monsoon arrived across the region, mass concentration of BC decreased over the central IGP and north-east locations (38 % and 28 % respectively), whereas for the north-west location BC properties remained relatively consistent. Post-monsoon onset, the coating thickness, core size, mass absorption cross section, and scattering enhancement values were all greatest over the central IGP much like the pre-monsoon season but were considerably reduced over both north-east and north-west India. Increases in mass absorption cross section through the atmospheric column were still present during the monsoon for the north-west and central IGP locations, but less so over the north-east due to lack of long-range transport aerosol aloft. Across the Indo-Gangetic Plain and north-east India during the pre-monsoon and monsoon seasons, solid-fuel (wood burning) emissions form the greatest proportion of BC with moderately coated particles. However, as the monsoon develops in the north-east there was a switch to small uncoated BC particles indicative of traffic emissions, but the solid-fuel emissions remained in the IGP into the monsoon. For both seasons in the north-west, traffic emissions form the greatest proportion of BC particles. Our findings will prove important for greater understanding of the BC physical and optical properties, with important consequences for the atmospheric radiative forcing of BC-containing particles. The findings will also help constrain the regional aerosol models for a variety of applications such as space-based remote sensing, chemistry transport modelling, air quality, and BC source and emission inventories