Dynamic nuclear polarization and ESR hole burning in As doped silicon.

We present an experimental study of the Dynamic Nuclear Polarization (DNP) of 29Si nuclei in silicon crystals of natural abundance doped with As in the temperature range 0.1-1 K and in a strong magnetic field of 4.6 T. This ensures a very high degree of electron spin polarization, extremely slow nuclear relaxation and optimal conditions for realization of Overhauser and resolved solid effects. We found that the solid effect DNP leads to the appearance of a pattern of holes and peaks in the ESR line, separated by the super-hyperfine interaction between the donor electron and 29Si nuclei closest to the donor. On the contrary, the Overhauser effect DNP mainly affects the remote 29Si nuclei having the weakest interaction with the donor electron. This leads to the appearance of a very narrow (≈3 mG wide) hole in the ESR line. We studied relaxation of the holes after burning, which is caused by the nuclear spin diffusion. Analyzing the dynamics of the hole in the spectrum with a simple one-dimensional diffusion model leads to a value of the diffusion coefficient D = 8(3) × 10-9 G2 s-1. Our data indicate that the spin diffusion is not completely prevented even in the frozen core near the donors. The emergence of the narrow hole after the Overhauser DNP may be explained by a partial "softening" of the frozen core caused by decoupling of the donor electron and remote 29Si nuclei.

Patient injuries in operative rhinology during a ten-year period: Review of national patient insurance charts.

OBJECTIVES: To assess factors contributing to patient injuries in operative rhinology. DESIGN: Data of the accepted patient injury claims involving operative rhinology, between the years 2001 and 2011, were obtained from the Finnish Patient Insurance Centre registry. Two senior otolaryngologists analysed and evaluated the injury mechanisms. MAIN OUTCOME MEASURES: Analysis and classification of factors contributing to patient injuries. RESULTS: During the ten-year study period, there were 67 patient injuries in operative rhinology, comprising 36% of all patient injuries in otorhinolaryngologic surgery. The majority (78%) of patients were treated in university or central hospitals and almost all (90%) by fully trained otolaryngology specialists. The factors contributing to the injuries were errors in surgical technique, like lesions to the orbit, skull base and meninges, and adjacent nerves, as well as mistakes with removable packings left in situ. Nearly half of the patients had undergone endoscopic sinus surgery. One patient died because of bleeding from the intracranial artery. Fourteen patients (21%) needed a re-operation due to the injury. CONCLUSIONS: Patient injuries in rhinology were caused by typical complications of common operations performed by otorhinolaryngology specialists. The increased volume of endoscopic sinus surgery was evident also in patient injuries.

ESR study of atomic hydrogen and tritium in solid T2 and T2:H2 matrices below 1 K.

We report on the first ESR study of atomic hydrogen and tritium stabilized in solid T2 and T2:H2 matrices down to 70 mK. The concentrations of T atoms in pure T2 approached 2 × 1020 cm-3 (0.60%) and record-high concentrations of H atoms ∼1 × 1020 cm-3 (0.33%) were reached in T2:H2 solid mixtures where a fraction of T atoms became converted into H due to the isotopic exchange reaction T + H2 → TH + H. The maximum concentrations of unpaired T and H atoms were limited by their recombination which becomes enhanced by efficient atomic diffusion due to the presence of a large number of vacancies and phonons generated in the matrices by ß-particles. Recombination also appeared in an explosive manner, both being stimulated and spontaneously in thick films where sample cooling was insufficient. We suggest that the main mechanism for H and T migration is physical diffusion related to tunneling or hopping to vacant sites in contrast to tunneling chemical exchange reactions which govern diffusion of H and D atoms created in H2 and D2 matrices by other methods.

Tunneling chemical exchange reaction D + HD → D2 + H in solid HD and D2 at temperatures below 1 K.

We report on a study of the exchange tunneling reaction D + HD → D2 + H in a pure solid HD matrix and in a D2 matrix with a 0.23% HD admixture at temperatures between 130 mK and 1.5 K. We found that the exchange reaction rates, kexHD ∼ 3 × 10-27 cm3 s-1 in the pure HD matrix, and kexD2 = 9(4) × 10-28 cm3 s-1 in the D2 matrix, are nearly independent of temperature within this range. This confirms the quantum tunnelling nature of these reactions, and their ability to proceed at temperatures down to absolute zero. Based on these observations we concluded that exchange tunneling reaction H + H2 → H2 + H should also proceed in a H2 matrix at the lowest temperatures. On the other hand, the recombination of H atoms in solid H2 and D atoms in solid D2 is substantially suppressed at the lowest temperatures as a result of a decreased probability of resonant tunneling of atoms when they approach each other.

Bose-Einstein condensation of magnons in atomic hydrogen gas.

We report on experimental observation of Bose-Einstein condensation (BEC)-like behavior of quantized electron spin waves (magnons) in a dense gas of spin-polarized atomic hydrogen. The magnons are trapped and controlled with inhomogeneous magnetic fields and described by a Schrödinger-like wave equation, in analogy to the BEC experiments with neutral atoms. We have observed the appearance of a sharp feature in the ESR spectrum displaced from the normal spin wave spectrum. We believe that this observation corresponds to a sudden growth of the ground-state population of the magnons and emergence of their spontaneous coherence for hydrogen gas densities exceeding a critical value, dependent on the trapping potential. We interpret the results as a BEC of nonequilibrium magnons which were formed by applying the rf power.

Dynamic nuclear polarization of high-density atomic hydrogen in solid mixtures of molecular hydrogen isotopes.

We report on magnetic resonance studies of high-density atomic hydrogen and deuterium in solid hydrogen matrices at temperatures below 1 K. Average concentrations of H atoms ≈3×10(19) cm(-3) are obtained in chemical tunneling reactions of isotope exchange with D atoms. The products of these reactions are closely located pairs of H atoms near D2 molecules with strong exchange interactions. We discovered a dynamic nuclear polarization effect on H atoms created by pumping the center of the H electron spin resonance spectrum, similar to the Overhauser effect in metals. Our results indicate that H atoms may be arranged inside molecular matrices at separations equivalent to local concentrations of 2.6×10(21) cm(-3). This opens up a way to build a metallic state of atomic hydrogen at zero pressure.

Radiation safety of dentomaxillofacial radiology in Finland: Reported abnormal irradiation-related incidents during 2012-2022.

INTRODUCTION: This study evaluates adverse events (AEs) in dentomaxillofacial radiology (DMFR) in Finland, including their quantity, nature, and outcomes. It also compares reporting activity between public and private healthcare organizations, as they share same legal obligations to report AEs. Two-thirds of dental images are taken in public, the rest in private healthcare. METHODS: In Finland, radiation-related AEs are reported to the Radiation and Nuclear Safety Authority (STUK). We categorized DMFR-related AEs by nature, outcome, and imaging modality. We also submitted a questionnaire to STUK to gather information on their observations and remarks made during inspections of establishments providing dental imaging services. RESULTS: During 2012-2022, STUK received reports of 1343 DMFR-related AEs, mostly causing patient harm (92.9%) leading almost always to excessive radiation doses (99.7%). Private healthcare reported most AEs (65.2%), with municipal institutions reporting the remainder (34.8%). Intraoral-related AEs (20.0%) slightly outnumbered panoramic-related ones (18.7%), but the majority (56.7%) didn't specify the imaging modality. CBCT-related incidents were least reported (4.5%). During STUK's inspections, remarks mostly concerned deficiencies in practical quality assurance (31.3%) or technical quality assurance (32.9%). CONCLUSION: DMFR-related AEs may be underreported despite legal obligations, with most stemming from human error, highlighting the need to enhance patient safety culture. There's a notable reporting gap between private and public healthcare providers relative to the number of dental radiographs conducted. Organizational deficiencies in practical and technical quality assurance underscore the importance of ongoing education, as well as monitoring by STUK. IMPLICATIONS FOR PRACTICE: Enhancing patient safety culture in dentistry, including dentomaxillofacial radiology, demands customized multiprofessional development, as unaltered patient safety procedures from medicine and secondary care may not align with dentistry's requirements.

Aerosol generation during coughing: an observational study.

OBJECTIVE: Coronavirus disease 2019 has highlighted the lack of knowledge on aerosol exposure during respiratory activity and aerosol-generating procedures. This study sought to determine the aerosol concentrations generated by coughing to better understand, and to set a standard for studying, aerosols generated in medical procedures. METHODS: Aerosol exposure during coughing was measured in 37 healthy volunteers in the operating theatre with an optical particle sizer, from 40 cm, 70 cm and 100 cm distances. RESULTS: Altogether, 306 volitional and 15 involuntary coughs were measured. No differences between groups were observed. CONCLUSION: Many medical procedures are expected to generate aerosols; it is unclear whether they are higher risk than normal respiratory activity. The measured aerosol exposure can be used to determine the risk for significant aerosol generation during medical procedures. Considerable variation of aerosol generation during cough was observed between individuals, but whether cough was volitional or involuntary made no difference to aerosol production.

Effect of antenatal growth and prematurity on brain white matter: diffusion tensor study.

BACKGROUND: White matter maturation is characterised by increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD). Contradictory results have been published on the effect of premature birth on white matter maturation at term-equivalent age. OBJECTIVE: To assess the association of gestational age and low birth-weight-for-gestational-age (z-score) with white matter maturation. MATERIALS AND METHODS: Infants (n = 76, 53 males) born at different gestational ages were imaged at term-equivalent age. Gestational age and birth weight z-score were used as continuous variables and the effect on diffusion parameters was assessed. Brain maturation was studied using regions-of-interest analysis in several white matter areas. RESULTS: Gestational age showed no significant effect on white matter maturation at term-equivalent age. Children with low birth weight z-score had lower FA in the genu and splenium of the corpus callosum (regression, P = 0.012 and P = 0.032; correlation, P = 0.009 and P = 0.006, respectively), and higher MD in the splenium of the corpus callosum (regression, P = 0.002; correlation, P = 0.0004) compared to children whose birth weight was appropriate for gestational age. CONCLUSION: Children with low birth weight relative to gestational age show delay and/or anomaly in white matter maturation at term-equivalent age.

Abnormal antenatal Doppler velocimetry and cognitive outcome in very-low-birth-weight infants at 2 years of age.

OBJECTIVE: To study neurodevelopmental outcome at 2 years of corrected age in very-low-birth-weight (VLBW) (< or = 1500 g) preterm infants with abnormal fetoplacental flow. METHODS: A total of 258 VLBW infants were born at Turku University Hospital between 2001 and 2006. Of these, 99 had undergone, within 1 week of delivery, antenatal Doppler assessment of blood flow in the umbilical artery (UA), fetal middle cerebral artery (MCA), descending aorta (DAo), aortic isthmus and ductus venosus and were eligible for inclusion in the study. Postnatally brain pathology was assessed by serial ultrasound and magnetic resonance imaging in 86 of the neonates and brain volume was measured in 80. Cognitive development was evaluated at 2 years of corrected age in 83 infants using the Bayley Scales of Infant Development-II. Motor development was assessed using the Hammersmith Infant Neurological Examination. RESULTS: On univariate analysis, abnormal pulsatility index (PI) in the UA and an abnormal UA-PI/MCA-PI ratio (P = 0.04 and P = 0.003, respectively) as well as increases in both the DAo-PI and in the DAo-PI/MCA-PI ratio (P = 0.03 and P = 0.02, respectively), were associated with adverse cognitive outcome at 2 years of age. However, when controlling for cerebral volume using multivariate analysis, the association between abnormal antenatal Doppler characteristics and cognitive outcome became statistically non-significant, which indicated the determinant role of the volume reduction. Motor development was not associated with antenatal Doppler indices. CONCLUSION: Abnormal antenatal Doppler indices are associated with adverse cognitive outcome at 2 years in VLBW infants. Our findings suggest that this association may be mediated through brain volume.

Incidence of necrotizing enterocolitis in very-low-birth-weight infants related to the use of Lactobacillus GG.

BACKGROUND: One of the five level III neonatal intensive care units (NICU) in Finland has used prophylactic Lactobacillus GG (LGG) for very-low-birth-weight (VLBW) infants since 1997. AIM: To examine retrospectively the incidence of necrotizing enterocolitis (NEC) in all five university hospital NICUs in Finland in relation to the use of LGG during the years each unit has belonged to the Vermont Oxford Network (VON). METHODS: The incidence of NEC was analysed from the national database and from the VON databases separately in all five level III NICUs and additionally in three groups according to the probiotic practice in the hospitals: prophylactic LGG group, probiotics 'on demand' group and no probiotics group. RESULTS: The incidence of NEC was 4.6% vs. 3.3% vs. 1.8% in the prophylactic LGG group, the no probiotics group and the probiotics 'on demand' group [corrected] respectively; p = 0.0090, chi-square. LGG had no influence on the clinical course of NEC. CONCLUSIONS: The results of this retrospective report failed to show that LGG prophylaxis protects VLBW infants from the occurrence of NEC, in contrast to previously published results. Our results call for more research regarding effective ways to administer probiotics, including data on appropriate bacteria, strain, dose and timing of administration to achieve clinically robust effects.

Cognitive outcome at 2 years of age in Finnish infants with very low birth weight born between 2001 and 2006.

AIM: To study cognitive outcome of premature, very low birth weight (VLBW) infants in relation to parental education and neonatal data. METHODS: A regional cohort of 182 VLBW infants born between 2001 and 2006 was followed up. Brain ultrasounds (US) were examined serially until term age and brain magnetic resonance imaging at term age. Neurological status was examined systematically. Cognitive development was assessed using the Mental Developmental Index (MDI) of Bayley Scales at 2 years of corrected age. A total of 192 healthy full-term (FT) controls were assessed with the MDI at 2 years of age. RESULTS: The mean MDI in VLBW infants was 101.7 (SD 15.4), which was lower compared with FT controls (109.8, SD 11.7, p < 0.001). In regression analysis of the demographic and medical data of VLBW infants, postnatal corticosteroids (p = 0.04), intestinal perforation (p = 0.03) and major brain pathology (p = 0.02) were negatively associated with the MDI. In VLBW infants, the prevalence of neurodevelopmental impairment was 9.9% (3.3% MDI below 70, 7.1% cerebral palsy, 2.2% hearing aid, no blind infants). CONCLUSION: Cognitive development of VLBW infants seemed to have improved in comparison with earlier publications, but it differed from the FT controls. Neonatal factors affected cognitive development. Therefore, updated regional follow-up data are important for clinicians.

Five-year follow-up of prematurely born children with postnatally developing caudothalamic cysts.

AIM: To assess the long-term developmental outcome of very low birth weight children with postnatally developing caudothalamic cysts. METHODS: Five very low birth weight children with postnatal caudothalamic cysts were examined using cranial ultrasound and brain Magnetic Resonance Imaging as neonates, the Bayley Scales of Infant Development, 2nd edition, and the Hammersmith Infant Neurological Examination at 2 years of corrected age, and with the Wechsler Preschool and Primary Scale of Intelligence-Revised and the standardization version of NEPSY II at 5 years of age. The Magnetic Resonance Imaging of the brain was repeated at 5 years of age. The developmental outcome at 5 years of age was compared with that of 23 very low birth weight children with normal brain structure. RESULTS: A cognitive level below normal and/or neuropsychological impairments was seen in all the children with caudothalamic cysts as well as in those with normal brain structure. CONCLUSION: Very low birth weight children with postnatally developing caudothalamic cysts had cognitive and neuropsychological impairments similar to very low birth weight children without such cysts.

Health and the use of health care services in 5-year-old very-low-birth-weight infants.

AIM: We aimed to study the effect of prematurity, time of birth and level of birth hospital on morbidity and the use of health care services at age 5. METHODS: This national study included all very-low-birth-weight infants (VLBWI, <32 gestational weeks or birth weight < or =1500 g) born in Finnish level II or III hospitals in 2001-2002 (n = 918), and full-term controls (n = 381). Parental questionnaires and register data were used to compare morbidity, and the use of health care services between VLBWI and full-term controls, and within VLBWI according to the time of birth and birth hospital level. RESULTS: Cerebral palsy, retinopathy of prematurity, other ophthalmic problems, respiratory infections, asthma or chronic lung disease, and inguinal hernia were overrepresented in VLBWI compared with the controls. VLBWI had more outpatient and inpatient days than the controls. The time of birth and birth hospital level were not associated with the use of services or with prematurity-related morbidity. CONCLUSION: Although morbidity and the use of health care services were increased in the surviving VLBWI, the average use of services was relatively small at age 5. In surviving VLBWI, the time of birth and the birth hospital level did not affect morbidity or the use of services.

Promoting shorter duration of ventilator treatment decreases the number of painful procedures in preterm infants.

AIM: To investigate whether promoting shorter ventilator treatment decreases the number of painful procedures and the use of analgesics in preterm infants. METHODS: Retrospective patient chart review of all preterm infants in one Neonatal Intensive Care Unit (NICU) was carried out in 2000 (n = 240) and 2005 (n = 206). Between these cohorts, early nasal continuous positive airway pressure (nCPAP) application and early extubation policy were introduced. RESULTS: Fewer infants were intubated (22 vs. 32%, p = 0.03), the duration of ventilator treatment decreased (6.7 SD 11.3 vs. 9.0 SD 11.1 days, p < 0.001) and nCPAP treatment became more common (41 vs. 25%, p < 0.001) in 2005 than in 2000. Similarly, the infants' exposure to painful procedures did not decrease significantly (61.9 SD 98.5 vs. 67.1 SD 104.3 procedures, p = 0.32) but the procedures related to respiratory support were fewer (45.2 SD 79.5 vs. 68.9 SD 91.1 procedures, p < 0.001) in 2005 than in 2000. In addition, the amount of pain medication used was significantly lower in 2005 than in 2000. One day on a ventilator included more painful procedures than a day on nCPAP (11.2 95% CI: 11.0-11.5 vs. 4.2 95% CI: 4.1-4.4 procedures, p < 0.001) during both study years. CONCLUSION: Early nCPAP and early extubation policies were successfully implemented in an NICU resulting in less invasive respiratory support. This was associated with fewer painful procedures and less pain medication in the preterm infants who required respiratory support. Despite this positive effect, the number of painful procedures in all preterm infants stayed at the same level. Our results provide further support for the use of nCPAP in preterm infants.

Perinatal health services organization for preterm births: a multinational comparison.

OBJECTIVE: To explore population characteristics, organization of health services and comparability of available information for very low birth weight or very preterm neonates born before 32 weeks' gestation in 11 high-income countries contributing data to the International Network for Evaluating Outcomes of Neonates (iNeo). STUDY DESIGN: We obtained population characteristics from public domain sources, conducted a survey of organization of maternal and neonatal health services and evaluated the comparability of data contributed to the iNeo collaboration from Australia, Canada, Finland, Israel, Italy, Japan, New Zealand, Spain, Sweden, Switzerland and UK. RESULTS: All countries have nationally funded maternal/neonatal health care with >90% of women receiving prenatal care. Preterm birth rate, maternal age, and neonatal and infant mortality rates were relatively similar across countries. Most (50 to >95%) between-hospital transports of neonates born at non-tertiary units were conducted by designated transport teams; 72% (8/11 countries) had designated transfer and 63% (7/11 countries) mandate the presence of a physician. The capacity of 'step-down' units varied between countries, with capacity for respiratory care available in <10% to >75% of units. Heterogeneity in data collection processes for benchmarking and quality improvement activities were identified. CONCLUSIONS: Comparability of healthcare outcomes for very preterm low birth weight neonates between countries requires an evaluation of differences in population coverage, healthcare services and meta-data.

Do the early development of gestures and receptive and expressive language predict language skills at 5;0 in prematurely born very-low-birth-weight children?

UNLABELLED: It is unclear what the predictive value of very early development of gestures and language is on later language ability in prematurely born very-low-birth-weight (VLBW; birth weight ≤1500g) children. The aim of the present study was to analyse the predictive value of early gestures and a receptive lexicon measured between the ages of 0;9 and 1;3, as well as the predictive value of receptive and expressive language ability at 2;0 for language skills at 5;0 in VLBW children. The subjects were 29 VLBW children and 28 full-term children whose language development has been followed intensively between the ages of 0;9 and 2;0 using the Finnish version of the MacArthur Developmental Inventory and the Reynell Developmental Language Scales (RDLS III). At 5;0, five selected verbal subtests of the Nepsy II test and the Boston Naming Test (BNT) were used to assess children's language skills. For the first time in VLBW children, the development of gestures measured between the ages of 0;9 and 1;3 was shown to correlate significantly and positively with language skills at 5;0. In addition, both receptive and expressive language ability measured at 2;0 correlated significantly and positively with later language skills in both groups. Moreover, according to the hierarchical regression analysis, the receptive language score of the RDLS III at 2;0 was a clear and significant predictor for language skills at 5;0 in both groups. The findings particularly underline the role of early receptive language as a significant predictor for later language ability in VLBW children. The results provide evidence for a continuity between early language development and later language skills. LEARNING OUTCOMES: After reading this article, readers will understand the associations between the very early (≤2 years of age) development of gestures and language (i.e. early receptive lexicon, expressive lexicon at 2;0, receptive and expressive language ability at 2;0) and the language skills at 5;0 in prematurely born very-low-birth-weight (VLBW) children. In addition, readers will understand the heterogeneity of the group of VLBW children. The information presented in this article is informative for those who work in a clinical context and who want to be able to identify those VLBW children who need support for their language development at an early age.

Hemodynamic and neurohumoral effects of continuous infusion of levosimendan in patients with congestive heart failure.

OBJECTIVES: We sought to define the therapeutic dose range of levosimendan in patients with New York Heart Association class II-IV heart failure of ischemic origin. BACKGROUND: Levosimendan is a calcium sensitizer for treatment of acute decompensated heart failure. METHODS: A double-blind, placebo-controlled, randomized, multicenter, parallel-group study included 151 adult patients. Levosimendan was given as a 10-min intravenous bolus of 3, 6, 12, 24 or 36 microg/kg, followed by a 24-h infusion of 0.05, 0.1, 0.2, 0.4 or 0.6 microg/kg/min, respectively. Dobutamine, for comparative purposes, was given as an open-label infusion (6 microg/kg/min). The primary efficacy variable was the proportion of patients achieving in each treatment group at least one of the following: 1) a > or =15% increase in stroke volume (SV) at 23 h to 24 h; 2) a > or =25% decrease in pulmonary capillary wedge pressure (PCWP) (and > or =4 mm Hg) at 23 h to 24 h; 3) a > or =40% increase in cardiac output (CO) (with change in heart rate [HR] <20%); 4) a > or =50% decrease in PCWP during two consecutive measurements. RESULTS: The response rate to levosimendan ranged from 50% at the lowest dose to 88% at the highest dose (compared with placebo 14%, dobutamine 70%). A dose-response relationship was demonstrated for levosimendan on increases in CO and SV, and reductions in PCWP during the infusion (for all, p< or =0.001). Headache (9%), nausea (5%) and hypotension (5%) were the most frequently reported adverse events at higher dosages. CONCLUSIONS: Dosing of levosimendan with a 10-min bolus of 6 to 24 microg/kg followed by an infusion of 0.05 to 0.2 microg/kg/min is well tolerated and leads to favorable hemodynamic effects.