Artificial dielectric stepped-refractive-index lens for the terahertz region.

In this paper we theoretically and experimentally demonstrate a stepped-refractive-index convergent lens made of a parallel stack of metallic plates for terahertz frequencies based on artificial dielectrics. The lens consist of a non-uniformly spaced stack of metallic plates, forming a mirror-symmetric array of parallel-plate waveguides (PPWGs). The operation of the device is based on the TE1 mode of the PPWG. The effective refractive index of the TE1 mode is a function of the frequency of operation and the spacing between the plates of the PPWG. By varying the spacing between the plates, we can modify the local refractive index of the structure in every individual PPWG that constitutes the lens producing a stepped refractive index profile across the multi stack structure. The theoretical and experimental results show that this structure is capable of focusing a 1 cm diameter beam to a line focus of less than 4 mm for the design frequency of 0.18 THz. This structure shows that this artificial-dielectric concept is an important technology for the fabrication of next generation terahertz devices.

Modifying the polarization state of terahertz radiation using anisotropic twin-domains in LaAlO3.

Polarization-resolved terahertz (THz) time-domain spectroscopy was utilized to examine the complex refractive index of lanthanum aluminate (LaAlO3), a rhombohedrally distorted perovskite that exhibits crystallographic twin domains. The uniaxial anisotropy of the refractive index was quantified. The ellipticity of THz radiation pulses after transmission through single domains indicated that LaAlO3 can be used as a quarter- or half-wave plate. The effective anisotropy of [001]-oriented LaAlO3 was found to be reduced when the material exhibited multiple, narrow twin domains.

Quality control of leather by terahertz time-domain spectroscopy.

We use terahertz time-domain spectroscopy, combined with effective-medium theory, to measure the moisture content and thickness of leather simultaneously. These results demonstrate that this method could become a standard quality control test for the industrial tanning process.

Beating the wavelength limit: three-dimensional imaging of buried subwavelength fractures in sculpture and construction materials by terahertz time-domain reflection spectroscopy.

We use reflection terahertz spectroscopy to locate and produce three-dimensional images of air gaps between stones that resemble fractures, even of subwavelength thicknesses. This technique is found to be promising tool for sculpture and building damage evaluation as well as structural quality control in other dielectric materials.

Lunate biomechanics: application to Kienböck's disease and its treatment.

Kienböck's disease was initially considered as lunate osteomalacia due to lesions of its nutrient arteries during carpal ligament tears. It has also been suggested following primary fractures, or because of repeated microtrauma. It is only in the past 20 or 30 years that it has appeared as aseptic necrosis. Based on Hultén's hypothesis that a negative radioulnar index was the cause of Kienböck's disease, equalization osteotomies (shortening of the radius or lengthening of the ulna) were developed. The observation of Kienböck's disease in subjects with a positive index and the risk of ulnar abutment after osteotomy led to the introduction of new osteotomies to get around these difficulties, still in the hope of treating the cause of Kienböck's disease. While it has been confirmed that a negative radioulnar index promotes lunate fracture, it clearly does not induce the pathology in the form of necrosis. In this scenario, perilunar osteotomies produce durable decompression, limiting the risk of lunate fracture in case of necrosis by removing the compressive constraints. After comparing the different osteotomies used to treat Kienböck's disease, it seems that the Camembert osteotomy for radius shortening, combined with selective shortening of the ulnar head as described by Sennwald, decompresses the lunate maximally, and protects it long enough for potential natural revascularization to occur.

Ulna shortening osteotomy versus arthroscopic wafer procedure in the treatment of ulnocarpal impingement syndrome.

Post-traumatic or constitutional ulnar impaction syndrome can be treated by shortening the ulna. This can be achieved by diaphyseal or metaphyseal osteotomy, or by arthroscopic epiphyseal resection. The objective of this study was to compare the results of the diaphyseal shortening osteotomy (USO) and arthroscopic wafer procedure (AWP) of the ulna in this indication. This was a retrospective case series of 33 patients operated for ulnar impaction syndrome by the same surgeon between 1997 and 2017. The diagnosis was made based on pain on the ulnar edge of the wrist with positive provocative tests. Radiographs were made and CT arthrography or MRI were used to confirm the diagnosis. Per-and post-operative assessments were functional (DASH and PRWE scores), clinical (pain, range of motion and grip strength) and radiographic. Diaphyseal ulnar shortening osteotomy (USO) was performed in 9 patients using a volar plate and a cutting guide. Twenty-four patients underwent an arthroscopic wafer procedure. Mean follow-up was 103 ± 8 months in the USO group versus 55 ± 4 months in the AWP group. There was no significant difference between groups in pain levels (1.2/10 in the USO group versus 0.9/10 in the AWP group, p = 0.88), grip strength (39 Kg in the USO group versus 34 Kg in the AWP group, p = 0.27) and PRWE score (5,8/100 in the USO group versus 11,2 in the AWP group, p = 0.34), and DASH score (25/100 in the USO group versus 28 in the AWP group, p = 0.63). The time away from work was long in the USO group than in the AWP group (7.86 months versus 3.75 months) (p = 0.002). Seven patients were reoperated in the USO group (5 plate removal, 1 nonunion and 1 delayed union) versus 3 in the AWP group (1 ECU stabilization, 1 ablation for painful ulnar styloid due to nonunion and 1 wrist denervation) (p = 0.0004). The study found no clinical differences between these two techniques except the return to work time. In our series, diaphyseal USO was associated with a greater number of reoperations than the AWP.

Repurposing CPAP machines as stripped-down ventilators.

The worldwide shortage of medical-grade ventilators is a well-known issue, that has become one of the central topics during the COVID-19 pandemic. Given that these machines are expensive and have long lead times, one approach is to vacate them for patients in critical conditions while patients with mild to moderate symptoms are treated with stripped-down ventilators. We propose a mass-producible solution that can create such ventilators with minimum effort. The central part is a module that can be attached to CPAP machines and repurpose them as low-pressure ventilators. Here, we describe the concept and first measurements which underline the potential of our solution. Our approach may serve as a starting point for open-access ventilator technologies.

Arthroscopic-assisted 6U approach for foveal reattachment of triangular fibrocartilage complex with an anchor: Clinical and radiographic outcomes at 4 years' mean follow-up.

The main objective of this study was to evaluate the long-term clinical and radiological outcomes of arthroscopic-assisted foveal repair of proximal triangular fibrocartilage complex (TFCC) tears with an anchor. The secondary objective was to look for ligament damage associated with TFCC tears. Twenty-four patients who underwent foveal repair of the TFCC were evaluated retrospectively: 16 stage 2 and 8 stage 3 in the Atzei-EWAS classification. The TFCC was repaired with an anchor using an expanded 6U approach. Systematic testing of intrinsic and extrinsic ligaments was performed. The assessment criteria were pain on a visual analog scale (VAS), wrist joint range of motion, grip strength and pronation-supination strength, and the QuickDASH and PRWE outcome scores. X-rays were also taken to assess anchor position and to look for distal radioulnar (DRU) joint damage. The average follow-up was 44 months. After the surgical repair, pain was reduced (7.36±1.3 preoperatively vs. 0.69±1.3 postoperatively; P<0.001), the QuickDASH score improved (52.1±16 vs. 21.7±7; P<0.001), the PRWE score improved (83.7±35 vs. 9.3±12; P<0.001) as did strength (35 vs. 43kg; P<0.001). The DRU joint stability was also significantly improved. The time away from work was 2.6 months. During the arthroscopy exploration, 25% of patients had an ulnotriquetral ligament lesion and 8% had an ulnolunar ligament lesion in combination with their TFCC tear. Fifteen anchors were positioned in the anatomical fovea (62%). No DRU joint damage was noted. Six patients had neurapraxia of the dorsal branch of the ulnar nerve, although it recovered spontaneously. One patient still had hypoesthesia of the ulnar side of the fifth finger at 48 months. Arthroscopic-assisted foveal repair of the TFCC yields good results in terms of pain, strength and DRU joint stability. In one-quarter of cases, TFCC foveal tears are associated with lesions of the ulnotriquetral ligament. There is no long-term degeneration of the DRU joint.

An ion-implanted InP receiver for polarization resolved terahertz spectroscopy.

We report on the construction, optical alignment and performance of a receiver which is capable of recording the full polarization state of coherent terahertz radiation. The photoconductive detector was fabricated on InP which had been implanted with Fe(+) ions. The device operated successfully when it was gated with near infrared femtosecond pulses from either a Ti:sapphire laser oscillator or a 1 kHz regenerative laser amplifier. When illuminated with terahertz radiation from a typical photoconductive source, the optimized device had a signal to noise figure of 100:1 with a usable spectral bandwidth of up to 4 THz. The device was shown to be very sensitive to terahertz polarization, being able to resolve changes in polarization of 0.34 degrees. Additionally, we have demonstrated the usefulness of this device for (i) polarization sensitive terahertz spectroscopy, by measuring the birefringence of quartz and (ii) terahertz emission experiments, by measuring the polarization dependence of radiation generated by optical rectification in (110)-ZnTe.

Terahertz imaging for early screening of diabetic foot syndrome: A proof of concept.

Most people with diabetes suffer some deterioration of the feet. Diabetic foot syndrome causes ulceration in about 15% of cases and such deterioration leads to amputation in about 2.5% of diabetic patients, diminishing their quality of life and generating extraordinary costs for patients and public health systems. Currently, there is no objective method for the detection of diabetic foot syndrome in its early stages. We propose terahertz imaging as a method for the evaluation of such deterioration. This screening method could aid the prevention and medical treatment of this condition in the future.

Terahertz meets sculptural and architectural art: Evaluation and conservation of stone objects with T-ray technology.

Conservation of cultural heritage is an area where novel scientific techniques are having enormous impact. Given the value and uniqueness of art pieces, non-invasive diagnostic methods are highly appreciated by conservators. Terahertz radiation has shown enormous potential as non-contact probe that can be used for the three-dimensional reconstruction of internal structure of stone-made objects. In this article we report the evaluation of the internal damage state of two art pieces, a medallion from the Castle of Celle and a window sill from the St. Peter of Trier Cathedral. We also used terahertz radiation to follow and assess the restoration process of the window sill. We found that terahertz spectroscopy is an excellent non-destructive evaluation method for stone artwork that shows enormous potential as a tool for conservation.

An automatic method for bone histomorphometry: assessment with reference to usual static and dynamic parameters.

To perform a fast and reproducible analysis in bone histomorphometry, we developed an automatic method for calculating static and dynamic parameters. A color automatic image analyzer (SAMBA 200) was used to obtain the usual parameters of bone histomorphometry: bone volume (Cn-BV%TV), osteoid volume (Cn-OV%BV), and osteoid surface (Cn-OS%BS). A specialized algorithm was designed for calculation of the mineral apposition rate (MAR). Eroded surface (Cn-ES%BS) was read in a semiautomatic mode using a cursor. To validate this program, we input 30 samples from patients with bone disease (20 osteoporosis, 6 renal osteodystrophy, 2 osteomalacia, and 2 hyperparathyroidism) using manual and automatic modes. The results obtained showed a highly significant correlation with the usual manual method for all parameters: OS/BS, r = 0.93; OV/BV, r = 0.98; MAR, r = 0.90. With the automatic method, larger values were found for osteoid parameters and MAR and lower values for BV/TV. There were no statistical differences for OV/BV and MAR when compared to the reference manual method. This study establishes that automatic measurements of osteoid parameters and MAR can be performed by a fast analyzer with as good reproducibility and accuracy as the manual method.

Alternative splicing in the human interleukin enhancer binding factor 3 (ILF3) gene.

The Interleukin Enhancer Binding Factor 3 (ILF3) gene has been mapped to chromosome 19 in humans and to chromosome 9 in mice. Several reported double-stranded RNA binding proteins including NF90, ILF3, MPP4 and DRBP76 have been suggested to be isoforms of the ILF3 gene but this has not been clearly established. We isolated several ilf3 transcripts from a melanoma cDNA library and two corresponding genomic fragments, and report alternative splicing and polyadenylation site selection in the human ILF3 gene. We show the existence of an alternative splice site responsible for the sequence divergence in the 3' part of the transcripts. Another alternative splicing event at a site between the two double-stranded RNA binding motifs leads to the additional presence in some cases of a four amino acids NVKQ peptide. We also describe the utilization of three distinct polyadenylation signals and the generation of an ilf3 transcript with a long extended 3' UTR. The expression of the different transcripts was evaluated. We used a GenBank sequence for the part of chromosome 19 corresponding to the ILF3 gene to determine the exon-intron organization of the entire gene which spans 38 kb and is divided into 21 exons.

The role of Amblyomma variegatum in the transmission of heartwater with special reference to Guadeloupe.

Heartwater has been diagnosed in Guadeloupe, Marie-Galante, and Antigua; it induces important losses among goats and European or cross-bred cattle when local zebu creole are highly resistant to infection. Amblyomma variegatum is the vector of the disease in the Caribbean. The tick strain of Martinique, occurring in that island that has apparently been disease-free since 1948, has not lost its ability to experimentally transmit the disease. In Guadeloupe 97% of nymphs and nearly 100% of adults feed on cattle and goats. Some immature ticks (4.5%) feed on wildlife, including birds that may be involved in the spread of infected ticks. Only 1 to 4% of adult ticks are infected and only a proportion of infected ticks are really infective: 53%, 9%, and 50% of nymphs, males, and females, respectively. Nymphs play the major role in the transmission: they are more numerous than adults and engorge faster. Infected ticks have the same maximum longevity as noninfected ticks, that is, 18 months for nymphs and nearly 23 months for adults. Cowdria is not transmitted immediately after tick fixation but after a delay of 2-3 days for nymphs and 4 days for adults. The disease is more often fatal when transmitted by tick biting rather than by needle transmission. The daily infection rate that summarizes all the parameters is very low (0.14% and 0.20% for goats and cattle, respectively), resulting in an unstable epidemiological situation. The transmission of Cowdria by A. variegatum in Guadeloupe shows significant differences compared with the transmission by A. hebraeum in Africa.

A perspective on animal protein production in sub-Saharan Africa.

A large survey of animal protein production in sub-Saharan Africa was performed. The objective was to identify specific production needed to ensure sustainable development. Starting from data collection and analysis to gain control of this information, the study proposes possible paths of evolution for supply and demand for animal production. Africa will be the continent where the demand will grow the most (together with Asia), because of demography and urbanization. Urbanization will represent an extraordinary opportunity for the development of animal production. In 2020, the global demand will be 20 million tons per year (7.3 in 1994) for meat, 45 million tons for milk (18.6 in 1994) and 2.9 million tons for eggs (1.1 in 1994). Red meat, which now provides 55.6% of present meat consumption will satisfy only 36.5% in 2020. This underlines the immense effort needed to intensify ruminant production and/or to develop monogastric production. Consequently, there is a need in tropical animal health and research for better knowledge and control of monogastric diseases and particularly those linked to intensification. The development of peri-urban milk production will require particular attention to hemoparasitic diseases. Globally, there is an urgent need to set up projects for the development of animal production.

Serological survey of leptospirosis in livestock animals in the Lesser Antilles.

A serological survey was performed of 1788 cattle, goats and sheep on 13 islands in the Lesser Antilles. Sera were tested by microscopic agglutination (MAT) using a panel of 22 live antigens. Evidence of past exposure, at a titer of > or = 100, was found in 101 animals (5.6%). Antibodies were more common in cattle and goats (7.2% in each) than in sheep (1.7%). Seroprevalence was highest in cattle in Martinique (20%) and in goats in St. Vincent (23%). The predominant serogroups were Sejroe (largely confined to cattle in Martinique), Autumnalis, Icterohaemorrhagiae, Grippotyphosa, and Cynopteri. Eleven cattle from Martinique and 2 sheep with titers of > or = 800 showed evidence of recent infection.

Genetic resistance of Creole goats to cowdriosis in Guadeloupe. Status in 1995.

A genetic predisposition to resistance (R)/susceptibility (S) has been demonstrated for cowdriosis in certain goal lines. In order to identify genetic markers of R/S and to follow their transmission to the offspring, 4 groups of sires and dams were crossbred in 1991, 1992, and 1993: Rr, RS, SR, and SS. The offspring were challenged at the age of six months with subsequent challenge of the S parent. From 28 presumed S dams, 7 turned out R and from 2 presumed S sires, 1 was R and the other undefinable. The resistance rate was 76% for 21 RR kids and 45% for 20 RS kids. The R character seems to be better transmitted by dams than the S one. No difference was observed between R and S goats in terms of incubation period and body temperature level after challenge. There was no statistical effect found of sex, litter size, or birth mass on the R/S character; only a slight effect on daily mass gain was observed. Sperm has been collected from 4 S sires (died after challenge) and 5 R sires, and stored in liquid nitrogen in order to conceive additional SR and SS progeny. Several caprine leucocyte antigens seem to be genetic markers of R (Be 1, CLY) and of S (Be 9, Be 22, Be 23). Further powerful tools like microsatellites and probes defining other interesting loci possibly involved in disease pathogenesis are now at hand and will be included in future experiments.

Tropical bont tick eradication campaign in the French Antilles. Current status.

The Amblyomma variegatum eradication campaign was officially started in April 1994 in Martinique and in Guadeloupe, including its dependencies of Marie Galante, Desirade and St Martin. A budget of $10.5 and $5.9 million for Guadeloupe and Martinique, respectively, was initially (1991) calculated and considered necessary to achieve the program. However, EEC, the most important donor, estimated that 75% only of this proposal was acceptable, on which it agrees to support a maximum of 50%. The balance had to be provided by French government, local political institutions, and animal owners. The current budget actualized in 1995 by veterinary authorities of Martinique and Guadeloupe is $7,200,000 and $9,900,000 respectively. The program will take 5 years: preparation (1 year), acaricide application (3 years), surveillance (1 year). During this first year, a pilot committee was established, and a project leader was designated for each island. Efforts were essentially oriented to organize the program in the field and to obtain funds from French and local counterparts. Funds allowed the recruitment and training of 19 new agents in Guadeloupe and 9 in Martinique, in addition to personnel already involved in the tick control program. Census of animal owners and identification of cattle started or were developed. Tenders were invited to provide vehicles and acaricides. For the latter, choices were made considering the prices and efficacy as well as funds available. Due to a limited budget and cost of pour-on formulations, pour-on acaricides will be used on a maximum of 30% of animals only. In order to investigate animal owners' reticences and the most appropriate media channels to establish a communication and a training program, a survey was conducted in Guadeloupe on a sample of 301 animal owners. The results are presented. In order to strengthen the chances of success of the campaign in the French islands, it is expected that a similar program will take place soon in infested neighboring islands.

Validation and comparison of three enzyme-linked immunosorbent assays for the detection of antibodies to Cowdria ruminantium infection.

Serological tests for Cowdria ruminantium infection have been hampered by low specificity. Here, an indirect ELISA based on purified antigen, a competitive ELISA using a recombinant major antigenic protein (MAP-1) and an indirect ELISA based on the MAP-1B region of the recombinant MAP-1 were compared. The tests were validated using 3000 sera of ruminants from 14 islands of the Lesser Antilles as well as sequential serum samples from 10 cattle, 17 goats and 10 sheep vaccinated with inactivated C. ruminantium in ISA 50 adjuvant and from 14 goats infected with a virulent culture supernatant. All tests detected significantly higher percentages of positives on Antigua, Guadeloupe and Marie-Galante, where C. ruminantium had been isolated before. Overall specificity calculated with sera from the other 11 heartwater-free islands was 98.1%, 98.5%, and 99.4% for the ELISA based on crude antigen, recombinant MAP-1 and MAP-1B, respectively. Sensitivities observed with sequential serum samples were similar for all tests. Tests based on recombinant antigens, especially the MAP-1B, showed improved specificity, suggesting their use for epidemiological studies in regions where the distribution of cowdriosis is unknown. In addition, the competitive ELISA is useful for studies in wildlife for which species-specific conjugates do not exist.