Preload Loss in a Spacecraft Fastener via Vibration-Induced Unwinding

Sound engineering practice requires that fasteners and bolted joints maintain preload in service. NASA recently concluded a series of vibration tests of a multicomponent structure intended to simulate an upper stage section of a launch vehicle. The stacked components were joined through six circumferentially placed bolted cup-cone-style pyrotechnic joint mechanisms designed to share spacecraft structural loads and then enable separation during ascent. Over the course of the vibration test campaign, all six bolted cup-cone mechanisms experienced some degree of preload loss with two mechanisms losing half of their original bolt preload. A subsequent forensic anomaly investigation concluded that vibration-induced unwinding of the preload nut-and-bolt assemblies occurred despite the use of safety wire and high levels of thread friction. A series of experiments were done to better understand how large, heavily preloaded fasteners could unwind. Additionally, thread friction torque was measured and the fastener locking capability of safety wire was evaluated. The friction coefficient between the clamped cup-cone components was characterized and finally a highly instrumented mechanism-level vibration test was done to reproduce the unwinding phenomenon to better understand the mechanism's behavior. The conclusion drawn was that vibration and structural forces led to relative motion (sliding) of the clamped components, resulting in self-loosening and unwinding effects on the nut-and-bolt assembly. To counter this phenomenon, more effective fastener locking methodologies were recommended and a follow-on effort was initiated to quantify the relationship between preload, component motion, and resulting unwinding forces. It is hoped that elucidation of these effects can be used to design more effective fastener locking features

Women in radiology: gender diversity is not a metric-it is a tool for excellence.

Women in Focus: Be Inspired was a unique programme held at the 2019 European Congress of Radiology that was structured to address a range of topics related to gender and healthcare, including leadership, mentoring and the generational progression of women in medicine. In most countries, women constitute substantially fewer than half of radiologists in academia or private practice despite frequently accounting for at least half of medical school enrolees. Furthermore, the proportion of women decreases at higher academic ranks and levels of leadership, a phenomenon which has been referred to as a "leaky pipeline". Gender diversity in the radiologic workplace, including in academic and leadership positions, is important for the present and future success of the field. It is a tool for excellence that helps to optimize patient care and research; moreover, it is essential to overcome the current shortage of radiologists. This article reviews the current state of gender diversity in academic and leadership positions in radiology internationally and explores a wide range of potential reasons for gender disparities, including the lack of role models and mentorship, unconscious bias and generational changes in attitudes about the desirability of leadership positions. Strategies for both individuals and institutions to proactively increase the representation of women in academic and leadership positions are suggested. KEY POINTS: • Gender-diverse teams perform better. Thus, gender diversity throughout the radiologic workplace, including in leadership positions, is important for the current and future success of the field. • Though women now make up roughly half of medical students, they remain underrepresented among radiology trainees, faculty and leaders. • Factors leading to the gender gap in academia and leadership positions in Radiology include a lack of role models and mentors, unconscious biases, other societal barriers and generational changes

Evaluation of legumes for fermentability and protein fractions using in vitro rumen fermentation

Diversifying feed with non-traditional options could minimize the dependency on traditional sources, maintain the feed supply throughout the year, and potentially reduce the cost of raising animals. A total of eight forage legumes including Peltophorum pterocarpum, Neptunia monosperma, Vachellia sutherlandii (Corkwood), Gliricidia sepium, Bauhinia hookeri and three Desmanthus species (JCU4, JCU5 and JCU9) were collected to assess their in vitro fermentability, degradable and undegradable protein fractions using in vitro gas production method. Soybean meal and lucerne hay were used as control. The total gas production ranged from 12.8 mL/g in P. pterocarpum to 127.3 mL/g in soybean meal. The total volatile fatty acid (VFA) concentration from G. sepium (117.7 mM/L) and V. sutherlandii (111.3 mM/L) were larger than other legumes except for soybean meal (157.1 mM/L) and lucerne hay (130.4 mM/L), P < 0.001. The methane gas produced from B. hookeri and P. pterocarpum (0.39 and 0.32 mL/g) was lower than other feeds, P < 0.001. The V. sutherlandii (720 g/kg crude protein (CP)) and G. sepium (745 g/kg CP) had the greatest effective CP degradation (EPD) than other legume species examined, P < 0.001, which was approaching that measured in the control samples. The amount of protein fraction ‘a’ (rapidly degradable) was larger in JCU9 (551 g/kg CP), and G. sepium (472 g/kg CP), and lower in B. hookeri (10.9 g/kg CP) and P. pterocarpum (14.8 g/kg CP), P < 0.001. The V. sutherlandii (386 g/kg CP) and G. sepium (272 g/kg CP) exceeded other legumes in the proportion of fraction ‘b’ (slowly degradable), P < 0.001, but not the controls. The undegradable fraction increased with increasing phenolic content and reached more than 940 g/kg CP for both B. hookeri and P. pterocarpum. The Desmanthus cultivars showed intermediate values among the tested legumes in fermentation characteristics and shows potential to provide slowly degradable protein while reducing methane. The findings indicate the possibility of using V. sutherlandii and G. sepium to substitute other forages for their greater slowly degradable protein content. Moreover, B. hookeri and P. pterocarpum plants emerged as candidates to assist protein protection in the rumen and reduce methane emissions. However, these legumes need to be evaluated in vivo before promoting for further use to confirm the variability reported here

Towards the “Baby Connectome”: Mapping the Structural Connectivity of the Newborn Brain

Defining the structural and functional connectivity of the human brain (the human “connectome”) is a basic challenge in neuroscience. Recently, techniques for noninvasively characterizing structural connectivity networks in the adult brain have been developed using diffusion and high-resolution anatomic MRI. The purpose of this study was to establish a framework for assessing structural connectivity in the newborn brain at any stage of development and to show how network properties can be derived in a clinical cohort of six-month old infants sustaining perinatal hypoxic ischemic encephalopathy (HIE). Two different anatomically unconstrained parcellation schemes were proposed and the resulting network metrics were correlated with neurological outcome at 6 months. Elimination and correction of unreliable data, automated parcellation of the cortical surface, and assembling the large-scale baby connectome allowed an unbiased study of the network properties of the newborn brain using graph theoretic analysis. In the application to infants with HIE, a trend to declining brain network integration and segregation was observed with increasing neuromotor deficit scores

MRI safety and devices: An update and expert consensus

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154533/1/jmri26909_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154533/2/jmri26909.pd

Identification and characterization of a spontaneous ovarian carcinoma in Lewis rats

<p>Abstract</p> <p>Background</p> <p>Ovarian carcinoma is the fourth most common cause of death from cancer in women. Limited progress has been made toward improving the survival rate of patients with this disease in part because of the lack of a good animal model. We present here a model of spontaneous ovarian carcinoma arising in a normal Lewis rat.</p> <p>Methods</p> <p>A spontaneously occurring tumor of the left ovary was found in a normal Lewis rat during necropsy, which was sectioned for histological examination and placed into single cell suspension. Tumor cells were passaged <it>in vivo </it>by intraperitoneal injection into immunocompetent Lewis rats, and <it>in vitro </it>culture resulted in generation of a cell line. Tumor cells were examined by flow cytometry for expression of estrogen receptor α, progesterone receptor, androgen receptor, her-2/neu, epithelial cell adhesion molecule, and CA125. β-catenin expression and cellular localization was assessed by immunocytochemistry. RNA was harvested for gene expression profiling and studying the expression of cytokines.</p> <p>Results</p> <p>The tumor, designated FNAR, could be serially transplanted into Lewis rats and propagated as a cell line <it>in vitro</it>, maintaining the properties of the original tumor. The FNAR cells displayed striking morphologic similarities to human ovarian carcinoma, resembling the endometrioid carcinoma subtype of surface epithelial neoplasms. The cells expressed estrogen receptor α, progesterone receptor, androgen receptor, her-2/neu, epithelial cell adhesion molecule, CA125, and nuclear β-catenin. A gene expression profile showed upregulation of a number of genes that are also upregulated in human ovarian carcinoma.</p> <p>Conclusion</p> <p>This reliable model of ovarian carcinoma should be helpful in better understanding the biology of the disease as well as the development of novel treatment strategies.</p

Neurodevelopmental abnormalities in children with PHACE syndrome.

Prior case reports have identified neurodevelopmental abnormalities in children with PHACE syndrome, a neurocutaneous disorder first characterized in 1996. In this multicenter, retrospective study of a previously identified cohort of 93 children diagnosed with PHACE syndrome from 1999 to 2010, 29 children had neurologic evaluations at ≥ 1 year of age (median age: 4 years, 2 months). In all, 44% had language delay, 36% gross motor delay, and 8% fine motor delay; 52% had an abnormal neurological exam, with speech abnormalities as the most common finding. Overall, 20 of 29 (69%) had neurodevelopmental abnormalities. Cerebral, but not posterior fossa, structural abnormalities were identified more often in children with abnormal versus normal neurodevelopmental outcomes (35% vs. 0%, P = .04). Neurodevelopmental abnormalities in young children with PHACE syndrome referred to neurologists include language and gross motor delay, while fine motor delay is less frequent. Prospective studies are needed to understand long-term neurodevelopmental outcomes

Women in radiology: gender diversity is not a metric—it is a tool for excellence

Abstract: Women in Focus: Be Inspired was a unique programme held at the 2019 European Congress of Radiology that was structured to address a range of topics related to gender and healthcare, including leadership, mentoring and the generational progression of women in medicine. In most countries, women constitute substantially fewer than half of radiologists in academia or private practice despite frequently accounting for at least half of medical school enrolees. Furthermore, the proportion of women decreases at higher academic ranks and levels of leadership, a phenomenon which has been referred to as a “leaky pipeline”. Gender diversity in the radiologic workplace, including in academic and leadership positions, is important for the present and future success of the field. It is a tool for excellence that helps to optimize patient care and research; moreover, it is essential to overcome the current shortage of radiologists. This article reviews the current state of gender diversity in academic and leadership positions in radiology internationally and explores a wide range of potential reasons for gender disparities, including the lack of role models and mentorship, unconscious bias and generational changes in attitudes about the desirability of leadership positions. Strategies for both individuals and institutions to proactively increase the representation of women in academic and leadership positions are suggested. Key Points: • Gender-diverse teams perform better. Thus, gender diversity throughout the radiologic workplace, including in leadership positions, is important for the current and future success of the field. • Though women now make up roughly half of medical students, they remain underrepresented among radiology trainees, faculty and leaders. • Factors leading to the gender gap in academia and leadership positions in Radiology include a lack of role models and mentors, unconscious biases, other societal barriers and generational changes