Combustion Stability Verification for the Thrust Chamber Assembly of J-2X Developmental Engines 10001, 10002, and 10003

The J-2X engine, a liquid oxygen/liquid hydrogen propellant rocket engine available for future use on the upper stage of the Space Launch System vehicle, has completed testing of three developmental engines at NASA Stennis Space Center. Twenty-one tests of engine E10001 were conducted from June 2011 through September 2012, thirteen tests of the engine E10002 were conducted from February 2013 through September 2013, and twelve tests of engine E10003 were conducted from November 2013 to April 2014. Verification of combustion stability of the thrust chamber assembly was conducted by perturbing each of the three developmental engines. The primary mechanism for combustion stability verification was examining the response caused by an artificial perturbation (bomb) in the main combustion chamber, i.e., dynamic combustion stability rating. No dynamic instabilities were observed in the TCA, although a few conditions were not bombed. Additional requirements, included to guard against spontaneous instability or rough combustion, were also investigated. Under certain conditions, discrete responses were observed in the dynamic pressure data. The discrete responses were of low amplitude and posed minimal risk to safe engine operability. Rough combustion analyses showed that all three engines met requirements for broad-banded frequency oscillations. Start and shutdown transient chug oscillations were also examined to assess the overall stability characteristics, with no major issues observed

Contemporary management of primary parapharyngeal space tumors

The parapharyngeal space is a complex anatomical area. Primary parapharyngeal tumors are rare tumors and 80% of them are benign. A variety of tumor types can develop in this location; most common are salivary gland neoplasm and neurogenic tumors. The management of these tumors has improved greatly owing to the developments in imaging techniques, surgery, and radiotherapy. Most tumors can be removed with a low rate of complications and recurrence. The transcervical approach is the most frequently used. In some cases, minimally invasive approaches may be used alone or in combination with a limited transcervical route, allowing large tumors to be removed by reducing morbidity of expanded approaches. An adequate knowledge of the anatomy and a careful surgical plan is essential to tailor management according to the patient and the tumor. The purpose of the present review was to update current aspects of knowledge related to this more challenging area of tumor occurrence.Peer reviewe

The impact of childhood trauma on change in depressive symptoms, eating pathology, and weight after Roux-en-Y gastric bypass

Background: History of childhood trauma is associated with increased risk of mental disorders, eating pathology, and obesity. Objective: To examine associations between childhood trauma and changes in depressive symptoms, eating pathology, and weight after Roux-en-Y Gastric Bypass (RYGB). Setting: Three U.S. academic medical centers. Method: Adults undergoing bariatric surgery (2007-2011) were enrolled in a cohort study. Participants (96 of 114; 86%) completed the Beck Depression Inventory-1 (BDI-1) to assess depressive symptomology, the interviewer-administered Eating Disorder Examination (EDE) to assess subthreshold eating pathology, weight assessment before and 6 months and annually after RYGB for ?7 years, and the Childhood Trauma Questionnaire (CTQ) once post-RYGB. Results: Presurgery, median age was 46 years, and median body mass index was 47 kg/m2; 79% were female. Data completeness across 7-year follow-up was 78% to 90%, 66% to 91%, and 93% to 100% for the BDI-1, EDE, and weight, respectively. Using mixed models, presence/severity of childhood emotional abuse, emotional neglect, and physical neglect, but not sexual abuse or physical abuse, were significantly associated (P \u3c.05) with change (i.e., less improvement/worsening) in the BDI-1 and EDE global scores, as were higher total CTQ score and more types of moderate-intensity trauma. All CTQ measures were associated (P \u3c.05) with less improvement or worsening in the EDE eating concern and shape concern scores. CTQ measures were not significantly related to weight loss or regain. Conclusions: Although childhood trauma did not affect weight outcomes after RYGB, those who experienced childhood trauma had less improvement in depressive symptomology and eating pathology and therefore might benefit from clinical intervention

Mental disorders and weight change in a prospective study of bariatric surgery patients: 7 years of follow-up

Background: Long-term, longitudinal data are limited on mental disorders after bariatric surgery. Objective: To report mental disorders through 7 years postsurgery and examine their relationship with changes in weight and health-related quality of life. Setting: Three U.S. academic medical centers. Method: As a substudy of the Longitudinal Assessment of Bariatric Surgery Consortium, 199 adults completed the structured clinical interview for Diagnostic and Statistical Manual of Mental Disorders, 4th Edition prior to Roux-en-Y gastric bypass (RYGB) or laparoscopic adjustable gastric band. Participants who completed ?1 follow-up through 7 years postsurgery are included (n = 173; 86.9%). Mixed models were used to examine mental disorders over time, and among the RYGB subgroup (n = 104), their relationship with long-term (?4 yr) pre- to postsurgery changes in weight and health-related quality of life, measured with the Short Form-36 Health Survey, and with weight regain from nadir. Results: Compared with presurgery (34.7%), the prevalence of having any mental disorder was significantly lower 4 years (21.3%; P \u3c .01) and 5 years (19.2%; P = .01), but not 7 years (29.1%; P = .27) after RYGB. The most common disorders were not related to long-term weight loss postRYGB. However, independent of weight change, mood and anxiety disorders, both pre- and postRYGB, were significantly related to less improvement in mental (but not physical) health-related quality of life. Having a concurrent mood disorder appeared to be associated with greater weight regain (6.4% of maximum weight lost, 95% confidence interval, ?.3 to 13.1), but this was not statistically significant (P = .06). Conclusions: Bariatric surgery does not result in consistent long-term reductions in mental disorders. Mood disorders may impact long-term outcomes of bariatric surgery

Examining emotion-, personality-, and reward-related dispositional tendencies in relation to eating pathology and weight change over seven years in the Longitudinal Assessment of Bariatric Surgery (LABS) study

This study examined dispositional emotion-, personality/temperament-, and reward-related variables in relation to post-surgery eating pathology and weight-change among 107 adults who underwent Roux-en-Y gastric bypass (RYGB) or laparoscopic adjustable gastric banding (LAGB). As part of a prospective cohort study, annual post-surgical assessments were conducted to evaluate eating pathology, using the Eating Disorder Examination-Bariatric Surgery Version, and percent weight change from pre-surgery. Dispositional measures were administered at the 6- or 7-year assessment and included the Affect Intensity Measure, Difficulties in Emotion Regulation Scale, UPPS-P Impulsive Behavior Scale, Adult Temperament Questionnaire-Effortful Control Scale, and Sensitivity to Punishment/Sensitivity to Reward Questionnaire. Results from a series of linear mixed models revealed significant associations of emotion dysregulation, affect intensity, positive and negative urgency, effortful control, and reward sensitivity with eating pathology severity across 7 years; additionally, all but two of the subscales comprising the total scores were also significantly associated. Fewer statistically significant results were found in relation to weight change; emotion dysregulation and affect intensity (along with several subscales) were significantly associated with lower percent weight change (i.e., less weight loss), but of the reward-related and personality/temperament variables, only total effortful control emerged as significant. However, the associations of the other variables with both outcomes were consistently in the expected direction. Associations also appeared consistent across surgical procedures. Taken together, findings suggest that certain dispositional tendencies may relate to less optimal long-term outcomes following bariatric surgery and thus may be useful to assess in pre-surgical or early post-surgical evaluations to inform targeted recommendations