A portable miniaturized laser heterodyne radiometer (mini­LHR) for remote measurements of column CH4 and CO2.

We present the design of a portable version of our miniaturized laser heterodyne radiometer (mini-LHR) that simultaneously measures methane (CH4) and carbon dioxide (CO2) in the atmospheric column. The mini-LHR fits on a backpack frame, operates autonomously, and requires no infrastructure because it is powered by batteries charged by a folding 30 W solar panel. Similar to our earlier instruments, the mini-LHR is a passive laser heterodyne radiometer that operates by collecting sunlight that has undergone absorption by CH4 and CO2. Within the mini-LHR, sunlight is mixed with light from a distributive feedback (DFB) laser centered at approximately 1.64 µm where both gases have absorption features. The laser scans across these absorption features roughly every minute and the resulting beat signal is collected in the radio frequency (RF). Scans are averaged into half hour and hour data products and analyzed using the Planetary Spectrum Generator (PSG) retrieval to extract column mole fractions. Instrument performance is demonstrated through two deployments at significantly different sites in interior Alaska and Hawaii. The resolving power (λ/∆λ) is greater than 500,000 at 1.64 µm with precisions of better than 20 ppb and 1 ppm for CH4 and CO2, respectively. Because mini-LHR instruments are portable and can be co-located, they can be used to characterize bias between larger, stationary, column observing instruments. In addition, mini-LHRs can be deployed quickly to respond to transient events such as methane leaks or can be used for field studies targeting geographical regions.

Contribution of minimally invasive bone augmentation to primary stabilization of the osteosynthesis of Schatzker type II tibial plateau fractures: Balloon vs bone tamp.

BACKGROUND: Schatzker type II tibial plateau fractures necessitate the least invasive treatment possible. Arthroscopic reduction by bone tamp followed by osteosynthesis is the current gold standard for this type of tibial plateau fracture. The objective of this study was to compare this technique to anterior approach tuberoplasty with balloon reduction. The comparison criteria were residual articular step off, metaphyseal cavity volume formed during reduction, and mechanical strength to separation and to depression displacement. METHODS: Fractures were created on 12 human cadaveric tibiae and reduced by a minimally invasive approach in six specimens by a balloon, and by bone tamp in the six others. Articular step off and metaphyseal-epiphyseal cavity volume were measured by TDM. Mechanical tests were performed up to assembly failure to characterize structural strength. Secondary displacements, fracture depression displacement and separation were measured by optical methods. FINDINGS: There was no significant difference in step off measurement after balloon reduction or bone tamp (0.29 cm vs 0.37 cm; p = 0.06). The cavity volume formed by balloon reduction was significantly smaller than the volume created by bone tamp reduction (0.45 cm3 vs 5.12 cm; p = 0.002). The compressive load required for assembly failure was significantly greater in the balloon group than in the bone tamp group (1210.17 N vs 624.50 N; p = 0.015). INTERPRETATION: There exists a correlation between load to failure of the assembly frame and the metaphyseal volume required for bone fracture reduction. The minimally invasive balloon technique has fewer negative effects on the osseous stock, thereby enabling better primary structural strength of the fracture.

Role for cementoplasty in intra-articular distal radius fractures: Cadaver study and application to arthroscopy.

BACKGROUND: Die-punch intra-articular fractures of the distal radius raise surgical challenges. The residual articular step-off must be less than 1mm to prevent the development of radio-carpal osteoarthritis. The objectives of this cadaver study were to evaluate whether cementoplasty was effective in reducing die-punch fractures and to determine whether this technique was feasible as an arthroscopic procedure. HYPOTHESIS: Cementoplasty performed as an arthroscopic procedure is effective in treating die-punch fractures. MATERIAL AND METHODS: Eleven cadaver forearms collected at a laboratory were studied. In each, a depressed fracture of the lunate fossa of the radial articular surface was created using a Tinius Olsen H25K-S compression test machine. A Kyphon XPander® balloon (Medtronic) was used to lift the depressed area, and calcium-phosphate cement was then injected to stabilise the reduction. Cementoplasty under arthroscopic guidance was performed on an additional forearm. RESULTS: Computed tomography of the wrists after fracture induction showed a mean depression of 4.66mm (range, 4.01-5.25mm). Arthroscopic cementoplasty proved feasible with the arthroscope inserted through the 3-4 radio-carpal portal. Positioning the balloon under the depressed area ensured satisfactory reduction and allowed the injection of cement. DISCUSSION: Cementoplasty may be useful for the treatment of die-punch fractures. Additional indications may be other types of distal radius fractures with articular surface depression. LEVEL OF EVIDENCE: IV, cadaver study.

Distinctive distribution of HPV genotypes in cervical cancers in multi-ethnic Suriname: implications for prevention and vaccination.

Suriname is ranked as high-risk country for cervical cancer, but recent national data of HPV prevalence and distribution in cervical cancer is scarce. In a retrospective cross-sectional study, cervical cancer incidence, HPV prevalence and HPV-type-specific distribution were investigated in all cervical cancer cases (n = 111), diagnosed in two consecutive years. HPV presence and type-specific prevalence were determined in paraffin-embedded biopsies utilizing master-nested multiplex PCR assays, targeting 14 HPV types. The age-standardized incidence rate of cervical cancer was 22·4/100 000 women, justifying revision of the current international ranking of Suriname. Eleven HPV types were detected, with the most common types in descending order of frequency: 16, 18, 45, 66, 58/52/35. HPV16 was predominant, although with markedly low presence (25%). HPV16 or 18 infections were detected in 43% of the cases, while 28% were untyped, implicating a divergent HPV-type distribution in Suriname with significant variation in the prevalence of less common high-risk virus types and/or presence of HPV16 variants. HPV-type distribution differed between ethnic groups. A vaccination efficacy of just 28-30% was anticipated, next to an uneven vaccination impact in different ethnic groups, cautioning Suriname and other multi-ethnic countries to tailor the information presented to different ethnic communities.