Radiation attenuation by single-crystal diamond windows

As artificial diamond becomes more cost effective it is likely to see increasing use as a window for sample environment equipment used in diffraction experiments. Such windows are particularly useful as they exhibit exceptional mechanical properties in addition to being highly transparent to both X-ray and neutron radiation. A key application is in high-pressure studies, where diamond anvil cells (DACs) are used to access extreme sample conditions. However, despite their utility, an important consideration when using single-crystal diamond windows is their interaction with the incident beam. In particular, the Bragg condition will be satisfied for specific angles and wavelengths, leading to the appearance of diamond Bragg spots on the diffraction detectors but also, unavoidably, to loss of transmitted intensity of the beam that interacts with the sample. This effect can be particularly significant for energy-dispersive measurements, for example, in time-of-flight neutron diffraction work using DACs. This article presents a semi-empirical approach that can be used to correct for this effect, which is a prerequisite for the accurate determination of diffraction intensities.

Screening for inborn errors of metabolism among newborns with metabolic disturbance and/or neurological manifestations without determined cause

CONTEXT

Inborn Errors of Metabolism are hereditary affections resulting from incompetence in enzymatic reactions of intermediary metabolism. At present, several hundred hereditary metabolic disturbances are known, many of which correspond to severe life-threatening disorders.

OBJECTIVE

The early detection of carriers has motivated the screening for these disturbances among newborns at the Neonatal Unit of Hospital São Paulo, in an attempt to initiate support treatment, when available, before clinical manifestations become evident.

DESIGN

Prospective study of risk patients.

SETTING

Laboratory for Inborn Errors of Metabolism at the Center for Medical Genetics of the Departments of Pediatrics and Morphology of Universidade Federal de São Paulo/Escola Paulista de Medicina. Newborn care unit at a tertiary care hospital.

PARTICIPANTS

101 children admitted into the Neonatal Unit were included in this study by presenting hypoglycemia, metabolic acidosis, jaundice, difficulty in gaining weight, diarrhea, vomiting, hepato- and/or splenomegaly, cataracts, apnea, convulsions, hypo- or hypertonia.

DIAGNOSTIC TESTS

Tests routinely utilized, performed for qualitative research of abnormal substances excreted in the urine in situations of metabolic disorder.

RESULTS

Children were included in the study mainly because of presenting hypoglycemia, jaundice and metabolic acidosis. Sixty-four newborns presented at least one positive test result. Most of the positivity was due to transitory metabolic alterations of the newborn, such as the case of Transitory Neonatal Tyrosinemia, presented by 29 patients. Nine infants were referred to the Center for Medical Genetics of Universidade Federal de São Paulo for continuation of the diagnostic investigation. For three of them, the tests applied permitted us to formulate a diagnostic hypothesis of mucopolysaccharidosis, tyrosinemia type I and non-ketotic hyperglycinemia, respectively.

CONCLUSIONS

The high positivity observed in the tests reflects the newborn's own metabolic immaturity. The selection of 9% of the studied cases for outpatient follow-up confirms that Inborn Errors of Metabolism must be suspected whenever a patient presents metabolic disturbances or neurological manifestations without a determined cause. They should be researched in parallel with the other diagnostic possibilities and not just taken to be exceptional diagnoses.

[Educational program for HIV/AIDS prevention]

The objective of this study is the evaluation of an educative program intended to bring scientific knowledge to common sense persons about HIV/AIDS prevention. A participative study was carried out with clients of a health center. To the development of the program, an educative game was used. It had 30 cards with verbal and non-verbal messages about the topic. The discussion about those messages were observed and recorded. The analysis of the data made possible the elaboration of themes categories: "men, women and preservative", "beliefs, attitudes, feelings and behavior", "pursuing meaning of life", "media and HIV/IDS". The evaluation of the program by the participants shows attainment to its objectives. The game was considered excellent to start the discussion about the topic and a good educational tool, in which knowledge raises freely from the encounter of scientific and common sense perspectives.

Validity of behavioral and physiologic parameters for acute pain assessment of term newborn infants

CONTEXT

The subjectivity of pain causes enormous difficulties in evaluating neonatal pain with a single, practical and easy-to-apply tool. Pain evaluation in the neonatal period should be performed by valid, safe, useful and feasible methods.

OBJECTIVE

To evaluate the validity of the Neonatal Facial Coding System (NFCS), Neonatal Infant Pain Scale (NIPS), heart rate (HR) and O2 saturation (O2 sat) for neonatal pain assessment.

DESIGN

Prospective, double-blind randomized trial.

SETTING

A secondary level maternity hospital.

PARTICIPANTS

70 healthy neonates requiring bilirubin dosage were randomly assigned to receive a venous puncture (P: n = 33, BW 3.2 kg, SD 0.6; GA 39 wk, SD 1; 59 h of life, SD 25) or an alcohol swab friction (F: n = 37; BW 3.1 kg, SD 0.5; GA 39 wk, SD 1; 52 h of life, SD 17).

INTERVENTION

All measurements were taken prior to (PRE), during (TO), and 1 (T1), 3(T3), 5(T5) and 10(T10) minutes after the procedure.

MEASUREMENTS

A neonatologist evaluated NFCS, NIPS, HR and O2 sat by pulse oxymetry.

RESULTS

Median NFCS and NIPS results at T0, T1 and T3 were higher in P group, compared to F. More P neonates presented NFCS > 2 and/or NIPS > 3 at T0, T1 and T3. HR was lower in P group at T1. Average O2 sat was above 90% during the whole study period in both groups.

CONCLUSION

NFCS and NIPS are suitable instruments for neonatal pain evaluation. Heart rate and O2 saturation can be used only as auxiliary methods.

[Behavioral pain scales assessment in neonates]

OBJECTIVE

To establish the sensitivity and specificity of two behavioral pain scales in different gestational ages (GA).

METHODS

133 clinically stable neonates, <72 h of life, without diseases, analgesic/sedative use or Apgar<7 at 5' were randomly assigned to receive capillary puncture--P or alcohol swab friction--F. Patients were divided according to GA (28-33 wk=A; 34-37 wk=B; 38-41 wk=C ) and procedure: Group A-P (n=17, BW 1.5 +/- .4 kg); A-F (n=18, BW 1.5 +/- .4 kg); B-P (n=25, BW 2.5 +/- .5 kg); B-F (n=25, BW 2.4 +/- 0.6 kg); C-P (n=23, BW 3.3 kg +/- 0.5 kg); C-F (n=25; BW 3.3 +/- 0.4 kg). A neonatologist, blind to P or F, evaluated the Neonatal Facial Action Coding System (NFCS 0-8 pts, pain>3) and the Neonatal Infant Pain Scale (NIPS 0-7 pts, pain>3). All evaluations were performed prior to P or F, without (pr) and with foot heating (h), during (0), 1' and 3' after P or F. Reliability was assessed in 20% of the sample. Agreement rate was NFCS-97% and NIPS-95%.

RESULTS

During the procedure, median NFCS and NIPS P score were greater than F (M. Whitney), p< or =0.0001) for A, B and C groups. At 1', NCFS and NIPS P scores were greater than F (MW, p< or =0.04) for A and C groups. For P patients, NFCS and NIPS scores were similar among the 3 GA groups at all study periods (K. Wallis). For F patients only at 0; NIPS scores were different (K. Wallis, p<0.03). During the procedure, NFCS>3 had sensitivity of 88-91% and specificity of 80-84%, NIPS>3 presented sensitivity of 77-87% and specificity of 68-83%.

CONCLUSION

Both behavioral scales are sensitive tools for pain assessment in premature infants, although NFCS seems superior to NIPS.

[Positive serology for syphilis in neonatal period: prevalence in secondary level maternity. Association with maternal risk factors and with positive serology for HIV-1]

To study neonatal Syphilis seropositivity incidence, its association with HIV-1 seropositivity and the impact of Congenital Syphilis CDC case definition, cord blood VDRL and Indirect Hemagglutination (IHA) for Syphilis were performed in 3,664 newborns from Dec/91-July/92. A positive group was formed by those with positive VDRL and IHA or just positive IHA. The control group consisted of 200 VDRL and IHA negative neonates. Among the 3,664 neonates 5.6% were seropositive for Syphilis. A significant association was noted (p < or = 0.05) between neonatal seropositivity for Syphilis and mothers older than 20 years, single, with sexual promiscuity, drug use, no pre-natal care, multiparity and previous still-births. All positive neonates fitted in the Presumptive Congenital Syphilis CDC definition. In 50 seropositive for Syphilis neonates ELISA for HIV-1 was performed and 6/50 were positive. Congenital Syphilis is of concern, specially in neonates of mothers with risk factors for Syphilis acquisition. HIV-1 should be considered in seropositive for Syphilis neonates. Adoption of Congenital Syphilis new CDC case definition is advised, particularly in countries where prenatal care is deficient.

Day- and shiftworkers' leisure time

Cross-sectional studies of working and living conditions were conducted in two Brazilian petrochemical plants between 1988-1989. This paper presents analyses of reported activities undertaken during day- and shiftworkers' leisure time. One hundred and sixteen workers (67 continuous shiftworkers) daily logged standard protocols of all leisure activities, for three consecutive weeks. Workers logged 11,957 instances grouped in 27 different activities. The 14 most commonly mentioned leisure activities were analysed. Those most reported were meals with the family (breakfast, lunch, and dinner) and home TV viewing. Using chi 2 statistics, the results showed that the two factors studied--activities and work schedules (day and shift)--were not related. Analysing estimated coefficients of a second order log linear model, only a very few of the 14 activities most mentioned, did not differ in their frequencies between day and shiftworkers of the same plant. The same happened with the 12 activities most-mentioned of both plants: shiftworkers and dayworkers showed significant differences (p < 0.0001) on almost all frequencies of those activities mentioned. Hypotheses are made to explain some of the results. Home placement, and types of shiftwork schedules (weekly or swiftly rotating shifts) can be responsible for some of the activities performed during the workers' leisure time. Further investigation of those activities which are disturbed or cannot be performed due to work schedules is suggested.