Balances for analytical purposes

Weighing is a key activity in every quality control laboratory as it is one of the first steps in the preparation of samples and reagents for most analytical procedures. It is also critical because weighing errors will add up and propagate throughout the whole analysis, affecting the accuracy and precision of the reported results. A new general chapter, Balances for analytical purposes (2.1.7), has recently been published in the European Pharmacopoeia (Ph. Eur.). This new text sets out clear requirements for an instrument that is essential to every analytical procedure described within the pages of the Ph. Eur. This article explains in detail these requirements and generally reviews the other quantity-related requirements present in Ph. Eur. texts.

Predictors and Outcomes of Digital Weighing and Activity Tracking Lapses Among Young Adults During Weight Gain Prevention

OBJECTIVES

Self-monitoring is critical for weight management, but little is known about lapses in the use of digital self-monitoring. The objectives of this study were to examine whether lapses in self-weighing and wearing activity trackers are associated with weight and activity outcomes and to identify objective predictors of lapses.

METHODS

Participants (N = 160, BMI = 25.5 ± 3.3 kg/m2 , 33.1 ± 4.6 years old) were drawn from a sample of young adults in the Study of Novel Approaches to Prevention-Extension (SNAP-E) weight gain prevention trial. Analyses evaluated associations between weighing and tracker lapses and changes in weight and steps/day during the first 90 days after receiving a smart scale and activity tracker.

RESULTS

On average, participants self-weighed 49.6% of days and wore activity trackers 75.2% of days. Every 1-day increase in a weighing lapse was associated with a 0.06-lb gain. Lapses in tracker wear were not associated with changes in steps/day or weight between wear days. Weight gain predicted a higher likelihood of starting a lapse in weighing and tracker wear, whereas lower steps predicted a higher likelihood of a tracker lapse.

CONCLUSIONS

Weight gain may discourage adherence to self-monitoring. Future research could examine just-in-time supports to anticipate and reduce the frequency or length of self-monitoring lapses.

Examining Self-Weighing Behaviors and Associated Features and Treatment Outcomes in Patients with Binge-Eating Disorder and Obesity with and without Food Addiction

Food addiction (FA) has been linked to clinical features in binge-eating disorder (BED) and obesity. A feature of behavioral weight loss (BWL) treatment involves frequent weighing. However, little is known regarding how frequency of self-weighing and related perceptions are associated with BWL outcomes among individuals with BED and obesity stratified by FA status. Participants (n = 186) were assessed with the Eating Disorder Examination before and after BWL treatment. Mixed effects models examined FA (presence/absence) before and after (post-treatment and 6- and 12-month follow-up) treatment and associations with frequency of weighing and related perceptions (reactions to weighing, sensitivity to weight gain and shape/weight acceptance). Participants with FA reported more negative reactions to weighing and less acceptance of shape/weight throughout treatment and follow-ups, and both variables were associated with greater disordered eating at follow-ups among participants with FA. Sensitivity to weight gain decreased over time independent of FA status. Frequency of weighing was associated with a greater likelihood of achieving 5% weight loss only among those without FA. Reactions to weighing and sensitivity to weight gain are associated with FA and poorer treatment outcomes in individuals with BED and obesity. Targeting these features may improve BWL outcomes among individuals with BED, obesity and FA.

Apical extrusion of debris after canal shaping with three single-file systems

Objectives

The aim of this study was to evaluate the quantity of apically extruded debris after canal shaping with three single-file systems.

Materials and Methods

Sixty mesiobuccal canals of mandibular molars were divided into three experimental groups according to the used file systems-WaveOne Gold, RECIPROC Blue, and HyFlex EDM One file. Debris extruded during canal shaping were collected in preweighed vials. Each canal was irrigated with 5 mL of distilled water via a 30 G side-vented needle. The amount of the debris extruded from each canal was calculated by subtracting the preinstrumentation from postinstrumentation measurement. The preparation times were recorded. Data were analyzed using analysis of variance (ANOVA) and posthoc Tukey tests with α = 0.05.

Results

WaveOne Gold extruded the least amount of debris. Results between WaveOne Gold and HyFlex EDM were significantly different. No significant differences in canal shaping time were detected among the three groups (P > 0.05).

Conclusion

WaveOne Gold showed the best results regarding apical debris extrusion. Difference between WaveOne Gold and HyFlex EDM suggests that file design and motion kinematics affect the quantity of debris extrusion.

Effectiveness of a behavioural intervention involving regular weighing and feedback by community midwives within routine antenatal care to prevent excessive gestational weight gain: POPS2 randomised controlled trial

OBJECTIVES

To assess the effectiveness of a brief behavioural intervention based on routine antenatal weighing to prevent excessive gestational weight gain (defined by US Institute of Medicine).

DESIGN

Randomised controlled trial.

SETTING

Antenatal clinic in England.

PARTICIPANTS

Women between 10⁺⁰ and 14⁺⁶ weeks gestation, not requiring specialist obstetric care.

INTERVENTIONS

Participants were randomised to usual antenatal care or usual care (UC) plus the intervention. The intervention involved community midwives weighing women at antenatal appointments, setting maximum weight gain limits between appointments and providing brief feedback. Women were encouraged to monitor and record their own weight weekly to assess their progress against the maximum limits set by their midwife. The comparator was usual maternity care.

PRIMARY AND SECONDARY OUTCOME MEASURES

Excessive gestational weight gain, depression, anxiety and physical activity.

RESULTS

Six hundred and fifty-six women from four maternity centres were recruited: 329 women were randomised to the intervention group and 327 to UC. We found no evidence that the intervention decreased excessive gestational weight gain. At 38 weeks gestation, the proportions gaining excessive gestational weight were 27.6% (81/305) versus 28.9% (90/311) (adjusted OR 0.84, 95% CI: 0.53 to 1.33) in the intervention and UC group, respectively. There were no significant difference between the groups in anxiety or depression scores (anxiety: adjusted mean -0.58, 95% CI:-1.25 to -0.8; depression: adjusted mean -0.60, 95% CI:-1.24 to -0.05). There were no significant differences in physical activity scores between the groups.

CONCLUSIONS

A behavioural intervention delivered by community midwives involving routine weighing throughout pregnancy, setting maximum weight gain targets and encouraging women to weigh themselves each week to check progress did not prevent excessive gestational weight gain. There was no evidence of psychological harm.

TRIAL REGISTRATION NUMBER

ISRCTN67427351.

Clinician and patient characteristics and cognitions that influence weighing practice in cognitive-behavioral therapy for eating disorders

OBJECTIVE

Clinicians commonly fail to weigh patients appropriately in cognitive-behavioral therapy for eating disorders (CBT-ED), despite guidelines stressing the need to do so. This study considered the possible patient- and clinician-based reasons why this element of treatment is omitted.

METHOD

Seventy-four CBT-ED clinicians were presented with vignettes that varied in patient diagnosis and distress levels, to determine whether those characteristics influenced different clinician weighing practices. Clinicians' own attitudes to weighing and their anxiety levels were also assessed to determine whether they were related to weighing intentions.

RESULTS

Clinicians were more likely to weigh patients with anorexia nervosa than patients with bulimia nervosa, probably due to focusing on physical risk. However, they were less likely to weigh patients who were distressed at the prospect, despite that course of action being particularly clinically indicated. Clinicians were more likely to weigh patients if they had positive beliefs about the value of doing so, and if they were not prone to making unsupported exceptions in delivering this technique.

DISCUSSION

This study provides evidence that clinicians use weighing differently according to the patient's presentation and their own beliefs, rather than working within guidelines. Education, training, and supervision are suggested to help clinicians address this failure to weigh patients in the most therapeutic way.

Self-weighing behavior in individuals with eating disorders

OBJECTIVE

To describe the frequency of self-weighing and reactions to prescribed weekly weighing among individuals with eating disorder (ED) diagnoses, and to compare individuals weighing more or less frequently on mass index (BMI) and the Eating Disorder Examination (EDE) subscales.

METHOD

Baseline EDE and demographics from five studies (N = 758).

RESULTS

Self-weighing was most frequent among individuals with anorexia nervosa (AN), followed by those with bulimia nervosa (BN) and binge eating disorder (BED). On average, participants reacted moderately negative to prescribed weekly weighing. No relationship between weighing frequency and BMI was evident in any sample. There was indication of greater pathology (i.e., restraint, shape concern, weight concern, global) in AN with more frequent weighing. In BN, mixed evidence emerged to support a relationship between more frequent weighing and higher shape concern, weight concern, and global score. In BED, higher restraint was found in those who weighed versus those who did not.

DISCUSSION

Weighing frequency in each eating disorder (ED) sample was to some extent associated with greater ED severity, but not BMI. Future research should examine relationships between self-weighing, reactions to changing weighing frequency, and ED symptomatology in both ED and non-ED groups to understand the impact of self-weighing in heterogeneous populations. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:817-821).

Weight loss methods and changes in eating habits among successful weight losers

BACKGROUND

Changes in several lifestyle related factors are required for successful long-term weight loss. Identification of these factors is of major importance from a public health point of view.

METHODS/SUBJECTS

This study was based upon findings from the Finnish Weight Control Registry (FWCR), a web-based registry. In total, 316 people were recruited and 184 met the study inclusion criteria. The aims of this study were to assess means and typical changes in eating habits associated with successful long-term weight loss.

RESULTS

Half of the participants (48%) reported that they lost weight slowly primarily with dietary changes. Self-weighing frequency was high, 92% was weighing themselves at least once a week during the weight loss phase, and 75% during the maintenance phase. Dietary aspects associated with successful weight loss and weight maintenance included an increase in intake of vegetables, a reduction in frequency of eating candies and fast food, regular meal frequency and application of the Plate model.

CONCLUSIONS

Both slow and fast weight loss may lead to successful long-term results and weight maintenance. A decrease in energy intake was achieved by reducing intake of energy-dense food, applying the Plate model and by regular meal frequency. Key messages Successful long-term weight loss is associated with a reduction in intake of energy-dense food. A more regular meal frequency and a high frequency of self-weighing seem to be helpful.

A perfect storm: examining the synergistic effects of negative and positive emotional instability on promoting weight loss activities in anorexia nervosa

Growing evidence indicates that both positive and negative emotion potentially influence the development and maintenance of anorexia nervosa, through both positive and negative reinforcement of weight loss activities. Such reactive emotional experience may be characterized by frequent and intense fluctuations in emotion, a construct known as "emotional instability." The purpose of this study was to investigate the association between positive emotional instability and weight loss activities in anorexia nervosa, and to investigate the synergistic effects of positive and negative emotional instability on promoting weight loss activities. Using ecological momentary assessment methods, 118 participants with anorexia nervosa reported their emotional experiences and behaviors at least six times daily over 2 weeks using a portable digital device. Using generalized linear modeling, results indicated that high levels of both positive and negative emotional instability, and the interaction between the two, were associated with more frequent weight-loss activities, beyond anorexia subtype and mean levels of emotional intensity. These findings indicate that when women with anorexia exhibit both high levels of both positive and negative emotional instability they are more prone to a variety of weight loss activities. The importance of addressing the role of both positive and negative emotion in anorexia treatment is discussed.

Nothing Tastes as Good as Thin Feels: Low Positive Emotion Differentiation and Weight Loss Activities in Anorexia Nervosa

Positive emotion (PE) has not been well studied in anorexia nervosa. Low positive emotion differentiation (PED), which involves a diminished ability to distinguish between discrete positive emotions, may contribute to positive emotion dysregulation in anorexia. Specifically, low PED may interact with elevated PE intensity to both motivate and reinforce weight loss and evaluation behaviors. Using ecological momentary assessment, we examined PE and weight loss behaviors reported over two weeks. As hypothesized, low PED predicted more vomiting, laxative-use, exercising, weighing, checking for fat, and restricting. Furthermore, those with low PED who experienced elevated average PE intensity reported even more frequent behaviors. Within-person analyses indicated that, for those with low PED, more weight loss behaviors at one recording predicted elevated PE at the subsequent recording. Similarly, for those with low PED higher momentary PE predicted more subsequent weight loss behaviors. Thus, low PED in anorexia may reinforce and motivate weight loss behavior.

Effectiveness of female community health volunteers in the detection and management of low-birth-weight in Nepal

INTRODCTION

Low birth weight (LBW) is a major risk factor for neonatal death. However, most neonates in low-income countries are not weighed at birth. This results in many LBW infants being overlooked. Female community health volunteers (FCHVs) in Nepal are non-health professionals who are living in local communities and have already worked in a field of reproductive and child health under the government of Nepal for more than 20 years. The effectiveness of involving FCHVs to detect LBW infants and to initiate prompt action for their care was studied in rural areas of Nepal.

METHODS

FCHVs were tasked with weighing all neonates born in selected areas using color-coded spring scales. Supervisors repeated each weighing using electronic scales as the gold standard comparator. Data on the relative birth sizes of the infants, as assessed by their mothers, were also collected and compared with the measured weights. Each of the 205 FCHVs involved in the study was asked about the steps that she would take when she came across a LBW infant, and knowledge of zeroing a spring scale was also assessed through individual interviews. The effect of the background social characteristics of the FCHVs on their performance was examined by logistic regression. This study was nested within a community-based neonatal sepsis-management intervention surveillance system, which facilitated an assessment of the performance of the FCHVs in weighing neonates, coverage of FCHVs' visits, and weighing of babies through maternal interviews.

RESULTS

A total of 462 babies were weighed, using both spring scales and electronic scales, within 72 hours of birth. The prevalence of LBW, as assessed by the gold standard method, was 28%. The sensitivity of detection of LBW by FCHVs was 89%, whereas the sensitivity of the mothers' perception of size at birth was only 40%. Of the 205 FCHVs participating in the study, 70% of FCHVs understood what they should do when they identified LBW and very low birth weight (VLBW) infants. Ninety-six per cent could describe how to zero a scale and approximately 50% could do it correctly. Seventy-seven per cent of FCHVs weighed infants at least once during the study period, and 19 of them (12%) miscategorized infant weights. Differences were not detected between the background social characteristics of FCHVs who miscategorized infants and those who did not. On the basis of maternal reporting, 67% of FCHVs who visited infants had weighed them.

CONCLUSIONS

FCHVs are able to correctly identify LBW and VLBW infants using spring scales and describe the correct steps to take after identification of these infants. Use of FCHVs as newborn care providers allows for utilization of their logistical, geographical, and cultural strengths, particularly a high level of access to neonates, that can complement the Nepalese healthcare system. Providing additional training to and increasing supervision of local FCHVs regarding birth weight measurement will increase the identification of high-risk neonates in resource-limited settings.

A high-sensitivity hydraulic load cell for small kitchen appliances

In this paper we present a hydraulic load cell made from hydroformed metallic bellows. The load cell was designed for a small kitchen appliance with the weighing function integrated into the composite control and protection of the appliance. It is a simple, low-cost solution with small dimensions and represents an alternative to the existing hydraulic load cells in industrial use. A good non-linearity and a small hysteresis were achieved. The influence of temperature leads to an error of 7.5%, which can be compensated for by software to meet the requirements of the target application.

A 30 kg Capacity High Precision Load Cell Mass Comparator

Described here are simple means to fabricate a 30 kg mass comparator based on an ordinary direct reading load cell. The mass comparator performs with a precision of 1 ppm.

A Simple Gravimetric Method to Determine Barometer Corrections

Presented here is a gravimetric method to calibrate barometers. The difference in forces exerted on the pan of a balance is observed for two well characterized artifacts of nearly equal masses but different volumes. During the weighing, air temperature and relative humidity are measured; the ambient pressure is then calculated from an air density equation. A barometer correction is derived and then compared to an independent value based on a standard barometer. The data indicate that pressure can be calculated with an uncertainty (1 S.D.) of not more than 400 ppm at one atmosphere.

A High Precision Load Cell Mass Comparator

Described here is a simple mechanical method used to fabricate a high precision mass comparator using a bonded strain gage load cell. Results indicate that a standard deviation of less than 0.0003% is readily attainable, and the device works well for objects normally considered too unwieldy for large high-precision balances.