Quantifying the ossification of the carpus in skeletal age estimation: Radiographic standards for Australian subadults.

An evaluation of the development of a child's skeleton and estimation of bone age provides an insight into a child's overall maturation. This study aimed to introduce a contemporary method for assessing bone age of Australian children using formulae incorporating carpal areal measurements. The standards introduced in this study can be used to assess the developmental status of Australian children who may be affected by growth-related illnesses. Additionally, in situations where the living age of a subadult is unknown, methodologies to accurately estimate age are required, particularly in the Western world where knowledge of the age of an individual is necessary for legal reasons. The sample consisted of retrospective hand and wrist radiographs acquired from 541 children (females: 246, males: 295) aged from birth to 20 years. Using the DICOM viewer Weasis, the carpal area ratio (B.Ar/T.Ar) was calculated for each individual radiograph by measuring the carpal bone area (B.Ar) and total tissue area of the carpus (T.Ar). A changepoint regression model demonstrated that the model constructed in this study was the most accurate in the younger age groups and was able to accurately determine whether a child was under 12 years if female and 13 years if male. A rapid acceleration of growth was observed at approximately 12-13 years in our sample, which may represent the onset of the pubertal growth spurt; this resulted in a high data variance and low model prediction accuracy in female and male children older than 12 and 13 years, respectively.

Large Metasurface Aperture for Millimeter Wave Computational Imaging at the Human-Scale.

We demonstrate a low-profile holographic imaging system at millimeter wavelengths based on an aperture composed of frequency-diverse metasurfaces. Utilizing measurements of spatially-diverse field patterns, diffraction-limited images of human-sized subjects are reconstructed. The system is driven by a single microwave source swept over a band of frequencies (17.5-26.5 GHz) and switched between a collection of transmit and receive metasurface panels. High fidelity image reconstruction requires a precise model for each field pattern generated by the aperture, as well as the manner in which the field scatters from objects in the scene. This constraint makes scaling of computational imaging systems inherently challenging for electrically large, coherent apertures. To meet the demanding requirements, we introduce computational methods and calibration approaches that enable rapid and accurate imaging performance.

Indomethacin for prevention of neonatal intraventricular hemorrhage.

Up to 50 percent of premature infants develop an intracerebral hemorrhage. Intracerebral hemorrhage in neonates occurs most frequently in the periventricular or intraventricular areas. Intravascular, vascular, and extravascular factors influence the development of hemorrhage. Pharmacologic therapies, such as phenobarbital, vitamin K, pancuronium bromide, vitamin E, and indomethacin, have been used in an attempt to prevent intraventricular hemorrhage (IH). Indomethacin inhibits prostaglandin production, which results in cerebral vasoconstriction and reduced cerebral blood flow. Several clinical studies have evaluated the role of indomethacin for the prevention of IH in premature infants. No definitive recommendations can be made regarding indomethacin use for this purpose. However, the two largest studies conducted to date have shown indomethacin to be effective in preventing or limiting the progression of IH. The drug appears to be most effective in reducing low-grade IH. More extensive research is needed to determine the most effective dose, duration, and serum concentration of indomethacin.

Use of surfactant in the prevention and treatment of neonatal respiratory distress syndrome.

The rationale for surfactant therapy in premature infants is presented, along with a discussion of the characteristics of surfactant and a review of clinical trials of surfactant for the prevention and treatment of neonatal respiratory distress syndrome (RDS). RDS is a major complication of prematurity, affecting up to 40,000 infants in the United States and Canada annually. Poor lung compliance due to a functional or quantitative deficiency of surfactant causes progressive collapse of the lungs. Surfactant, a mixture of phospholipids, neutral lipids, and proteins synthesized by pneumocytes during gestation, reduces surface tension and stabilizes alveoli, which increases lung compliance and decreases the work of breathing. Mammalian, human, and artificial surfactants are being investigated for use in premature infants. Several controlled trials of exogenous surfactant therapy have demonstrated reductions in mortality and pulmonary air-leak phenomena and improved gas exchange, but these results are not seen consistently, and no significant reductions in bronchopulmonary dysplasia have been observed. Surfactant has no appreciable toxicity, although the potential for immunogenicity exists. Typical doses range from 60 mg to 200 mg/kg administered endotracheally either before the first breath or after development of RDS. Surfactant is a safe investigational agent that appears promising for the prevention and treatment of neonatal RDS, although additional clinical trials with long-term follow-up are needed to determine its true efficacy.

Mupirocin: a new topical therapy for impetigo.

Mupirocin is a new, topical antibiotic effective for the treatment of impetigo. It has a unique structure, mechanism of action, and water-miscible formulation. When it is applied to an infected area three times daily, clinical improvement should be seen in 85% to 100% of patients within 3 to 5 days. It is associated with a low incidence of adverse effects and cross-resistance. Further studies are necessary to define the exact role of mupirocin in treating other primary and secondary cutaneous infections.