15 ps −1 and a bath temperature of 298 K were used to propagate the equations of motion within the Langevin approach. Periodic boundary conditions were applied to simulate a continuous medium." should instead appear as "A friction coefficient of 10 ps −1 and a bath temperature of 298 K were used to propagate the equations of motion within the Langevin approach. No boundary conditions were imposed; the system freely evolved in vacuum."These errors do not affect the conclusions of the article.

IMPORTANCE Failure of bone fracture healing occurs in 5% to 10% of all patients. Nonunion risk is associated with the severity of injury and with the surgical treatment technique, yet progression to nonunion is not fully explained by these risk factors.OBJECTIVE To test a hypothesis that fracture characteristics and patient-related risk factors assessable by the clinician at patient presentation can indicate the probability of fracture nonunion.DESIGN, SETTING, AND PARTICIPANTS An inception cohort study in a large payer database of patients with fracture in the United States was conducted using patient-level health claims for medical and drug expenses compiled for approximately 90.1 million patients in calendar year 2011. The final database collated demographic descriptors, treatment procedures as per Current Procedural Terminology codes; comorbidities as per International Classification of Diseases, Ninth Revision codes; and drug prescriptions as per National Drug Code Directory codes. Logistic regression was used to calculate odds ratios (ORs) for variables associated with nonunion. Data analysis was performed from January 1, 2011, to December 31, 2012, EXPOSURES Continuous enrollment in the database was required for 12 months after fracture to allow sufficient time to capture a nonunion diagnosis. RESULTSThe final analysis of 309 330 fractures in 18 bones included 178 952 women (57.9%); mean (SD) age was 44.48 (13.68) years. The nonunion rate was 4.9%. Elevated nonunion risk was associated with severe fracture (eg, open fracture, multiple fractures), high body mass index, smoking, and alcoholism. Women experienced more fractures, but men were more prone to nonunion. The nonunion rate also varied with fracture location: scaphoid, tibia plus fibula, and femur were most likely to be nonunion. The ORs for nonunion fractures were significantly increased for risk factors, including number of fractures (OR, 2.65; 95% CI, 2.34-2.99), use of nonsteroidal anti-inflammatory drugs plus opioids (OR, 1.84; 95% CI, 1.73-1.95), operative treatment (OR, 1.78; 95% CI, 1.69-1.86), open fracture (OR, 1.66; 95% CI, 1.55-1.77), anticoagulant use (OR, 1.58; 95% CI, 1.51-1.66), osteoarthritis with rheumatoid arthritis (OR, 1.58; 95% CI, 1.38-1.82), anticonvulsant use with benzodiazepines (OR, 1.49; 95% CI, 1.36-1.62), opioid use (OR, 1.43; 95% CI, 1.34-1.52), diabetes (OR, 1.40; 95% CI, 1.21-1.61), high-energy injury (OR, 1.38; 95% CI, 1.27-1.49), anticonvulsant use (OR, 1.37; 95% CI, 1.31-1.43), osteoporosis (OR, 1.24; 95% CI, 1.14-1.34), male gender (OR, 1.21; 95% CI, 1.16-1.25), insulin use (OR, 1.21; 95% CI, 1.10-1.31), smoking (OR, 1.20; 95% CI, 1.14-1.26), benzodiazepine use (OR, 1.20; 95% CI, 1.10-1.31), obesity (OR, 1.19; 95% CI, 1.12-1.25), antibiotic use (OR, 1.17; 95% CI, 1.13-1.21), osteoporosis medication use (OR, 1.17; 95% CI, 1.08-1.26), vitamin D deficiency (OR, 1.14; 95% CI, 1.05-1.22), diuretic use (OR, 1.13; 95% CI, 1.07-1.18), and renal insufficiency (OR, 1.11; 95% CI, 1.04-1.17) (multivariate P < .001 for all).C...

Levels of misconduct appear to be higher than in the past. This may reflect either a real increase in the incidence of fraud or a greater effort on the part of journals to police the literature. However, research bias is rarely cited as a reason for retraction.

Average volumetric changes are close to the limit of detection by MRI methods. It remains to be determined whether schizophrenia is a neurodegenerative process that begins at about the time of symptom onset, or whether it is better characterised as a neurodevelopmental process that produces abnormal brain volumes at an early age.

A systematic review of the literature identified 64 published English-language papers that used proton ( 1 H) magnetic resonance spectroscopy to measure N-acetylaspartate (NAA) concurrently in healthy controls and in patients with a diagnosis of schizophrenia (SZ). A total of 1209 controls and 1256 patients have been evaluated, with 88% of studies carried out at 1.5 T field strength, and 77% of studies focused on patients with chronic SZ. There is consistent evidence that NAA is reduced in a broad range of tissues in the SZ brain. Broad consensus (X10 studies) is emerging that NAA levels are reduced X5% in hippocampus and in both cortical gray matter (GM) and white matter (WM) of the frontal lobe. There is no evidence to support a hypothesis that relative NAA levels are reduced to a different degree in frontal lobe GM and WM, nor is there robust evidence of a difference in NAA levels between patients with firstepisode and chronic SZ. Study reliability may be a problem, as most studies appear to be underpowered. With simple assumptions about the inherent difference in NAA levels between patients and controls, it can be calculated that a minimum sample size of approximately 39 patients and 39 controls is required for acceptable statistical power. Only three of 64 studies included enough subjects to have 80% power to detect a 10% NAA reduction in patients, and no studies were adequately powered to detect a 5% NAA reduction with 80% power.