White hard clam (Meretrix lyrata) shells as novel filter media to augment the phosphorus removal from wastewater.

It is well recognized that filter media play a crucial role in constructed wetlands (CWs) for decontamination of phosphorus (P)-rich wastewater. This study investigates the suitability of raw white hard clam shells (WHC) and white hard clam shells thermally modified at 800 °C (WHC-M800) as potential media to enhance P treatment performance in CWs. The results indicated that both WHC and WHC-M800 displayed appropriate physicochemical properties, such as high porosity, excellent hydraulic conductivity, and rich Ca content. WHC-M800 exhibited a superior P adsorption capacity (38.7 mg/g) to WHC (12.8 mg/g). However, the practical utilization of WHC-M800 as filter media in CWs may be compromised, due to certain limitations, for example: extremely high pH values in the post-adsorption solutions; high weight losses during calcination and adsorption processes; low mechanical strength; and intensive energy consumption. In contrast, the WHC demonstrated significant advantages of reasonably high P adsorption capacity, locally abundant availability, low cost, and marginal side effects. The fractionation of inorganic P of WHC and WHC-M800 revealed that Ca-bounded P was the most dominant binding form, followed by loosely bound P, Fe-P, occluded P, and Al-P. The present study demonstrates that recycling of WHC shells as a potential substrate in CWs provides a feasible method for upgrading P removal in CWs. Additionally, it helps to reduce waste WHC shells in a simple, cheap, and eco-friendly way, thus can double environmental benefits.

Results of wrist hemiarthroplasty for comminuted distal radius fractures in independent elderly people: A retrospective study on eleven patients.

The comminuted distal radius fractures among elderly people are usually linked to osteoporosis, and repairing them in this context is a therapeutical challenge. Several teams have reported good results of radius resurfacing. The goal of our study was to evaluate the usability of the wrist in a new series of patients after surgery. We performed a monocentric retrospective study on the data of the medical files. All the included patients were older than 65 years and received a wrist hemiarthroplasty according to the criteria that have been established by the in charge medical team. Eleven patients have been included, their average age was 80.4 years old, and the average follow-up was 18.3 months. The average QuickDASH Score was 59 (27-95). The Visual Analogue Scale for pain was in average 3.8/10 and the average mobility was: flexion 36° (12-50), extension 27° (12-50), radial deviation 15° (12-15), ulnar deviation 26° (12-40), pronation-supination range of motion 164° (150-170). The average measured strength was 44% (16-72%) of the strength of the unaffected hand. Our results are rather modest, probably because of insufficient follow-up and very severe fractures. Furthermore, the implant that has been used does not take into account the distal radioulnar joint. Another bound of this treatment is the complexity of surgical revision in case of bad result. So far, hemiarthroplasty cannot be considered as the standard treatment for complex fractures of the distal radius.

[Is there pisotriquetral instability after carpal tunnel release? Retrospective study of 55 cases]. / Existe-il une instabilité piso-triquétrale après une neurolyse du nerf médian au poignet ? Étude rétrospective à propos de 55 cas.

The aim of this study was to determine if pisotriquetral instability is present after neurolysis of the median nerve in the wrist. Fifty-five patients who underwent carpal tunnel release between December 2005 and March 2009 were included in this retrospective study. The surgical procedure consisted of cutting the transverse carpal ligament under local anesthesia through an anterior approach. Instability was evaluated clinically and radiologically by measuring the pisometacarpal angle. The mean patient age was 61years and the mean follow-up 42months. Only 9% of patients complained of pain on the ulnar side of wrist. The pisometacarpal angle in all the operated wrists was the same as in the non-operated wrists. Our findings suggest there is no pisotriquetral instability after median nerve neurolysis.

[Long fingers articular fractures treatment by glued traction]. / Traitement des fractures articulaires des doigts longs par « traction collée décoaptante ¼ (TCD).

Comminuted articular fractures of the fingers are a real surgical challenge. Many surgical treatments are proposed, but despite their complexity, their results are often unsatisfactory. We describe a simple and functional treatment intended to ensure these articular fractures heal in the right position. The material used in this technique is inexpensive and easily available.

Scattered radiation emission imaging: principles and applications.

Imaging processes built on the Compton scattering effect have been under continuing investigation since it was first suggested in the 50s. However, despite many innovative contributions, there are still formidable theoretical and technical challenges to overcome. In this paper, we review the state-of-the-art principles of the so-called scattered radiation emission imaging. Basically, it consists of using the cleverly collected scattered radiation from a radiating object to reconstruct its inner structure. Image formation is based on the mathematical concept of compounded conical projection. It entails a Radon transform defined on circular cone surfaces in order to express the scattered radiation flux density on a detecting pixel. We discuss in particular invertible cases of such conical Radon transforms which form a mathematical basis for image reconstruction methods. Numerical simulations performed in two and three space dimensions speak in favor of the viability of this imaging principle and its potential applications in various fields.

Compton scattered imaging based on the V-line radon transform and its medical imaging applications.

The Radon transform (RT) on straight lines deals as mathematical foundation for many tomographic modalities (e.g. Xray scanner, Positron Emission Tomography), using only primary radiation. In this paper, we consider a new RT defined on a pair of half-lines forming a letter V, arising from the modeling a two-dimensional emission imaging process by Compton scattered gamma rays. We establish its analytic inverse, which is shown to support the feasibility of the reconstruction of a two-dimensional image from scattered radiation collected on a one-dimensional collimated camera. Moreover, a filtered back-projection inversion method is also constructed. Its main advantages are algorithmic efficiency and computational rapidity. We present numerical simulations to illustrate the working. To sum up, the V-line RT leads not only to a new imaging principle, but also to a new concept of detector with high energetic resolution capable to collect the scattered radiation.

On the v-line radon transform and its imaging applications.

Radon transforms defined on smooth curves are well known and extensively studied in the literature. In this paper, we consider a Radon transform defined on a discontinuous curve formed by a pair of half-lines forming the vertical letter V. If the classical two-dimensional Radon transform has served as a work horse for tomographic transmission and/or emission imaging, we show that this V-line Radon transform is the backbone of scattered radiation imaging in two dimensions. We establish its analytic inverse formula as well as a corresponding filtered back projection reconstruction procedure. These theoretical results allow the reconstruction of two-dimensional images from Compton scattered radiation collected on a one-dimensional collimated camera. We illustrate the working principles of this imaging modality by presenting numerical simulation results.

Bacillus subtilis isolated from the human gastrointestinal tract.

As part of an ongoing study to determine the true habitat of Bacillus species, we report here the isolation and characterisation of Bacillus subtilis from the human gastrointestinal tract (GIT). Strains were obtained from ileum biopsies as well as from faecal samples and their biotypes defined. 16S rRNA analysis revealed that most isolates of B. subtilis were highly conserved, in contrast to RAPD-PCR fingerprinting that showed greater diversity with 23 distinct RAPD types. The majority of B. subtilis strains examined possessed features that could be advantageous to survival within the GIT. This included the ability to form biofilms, to sporulate anaerobically and secretion of antimicrobials. At least one isolate was shown to form spores that carried an exosporium, a loosely attached outer layer to the mature endospore, this being the first report of B. subtilis spores carrying an exosporium. This study reinforces a growing view that B. subtilis and probably other species have adapted to life within the GIT and should be considered gut commensals rather than solely soil microorganisms.

On high sensitivity emission imaging by scattered gamma radiation.

A new concept of gamma emission imaging based on the use of scattered radiation with a non collimated gamma camera is put forward. A few years ago, scattered radiation by Compton effect is shown to be capable to reconstruct a three dimensional object using a standard collimated gamma camera. To increase drastically in sensitivity, we propose now that data acquisition should be performed without collimation. We present this new image formation by scattered radiation via the properties of its Point Spread Functions (PSF). Comparison with the PSF in the presence of a collimator exhibits a striking image enhancement. We also present numerical simulations on image formation and reconstruction to support the attractiveness of this modality.

Novel approach to stationary transmission scanning using Compton scattered radiation.

Transmission scanning-based estimation of the attenuation map plays a crucial role in quantitative radionuclide imaging. X-ray computed tomography (CT) reconstructs directly the attenuation coefficients map from data transmitted through the object. This paper proposes an alternative route for reconstructing the object attenuation map by exploiting Compton scatter of transmitted radiation from an externally placed radionuclide source. In contrast to conventional procedures, data acquisition is realized as a series of images parameterized by the Compton scattering angle and registered on a stationary gamma camera operating without spatial displacement. Numerical simulation results using realistic voxel-based phantoms are presented to illustrate the efficiency of this new transmission scanning approach for attenuation map reconstruction. The encouraging results presented in this paper may suggest the possibility of proposing a new concept for emission/transmission imaging using scattered radiation, which has many advantages compared to conventional technologies.

The Mathematical Foundations of 3D Compton Scatter Emission Imaging.

The mathematical principles of tomographic imaging using detected (unscattered) X- or gamma-rays are based on the two-dimensional Radon transform and many of its variants. In this paper, we show that two new generalizations, called conical Radon transforms, are related to three-dimensional imaging processes based on detected Compton scattered radiation. The first class of conical Radon transform has been introduced recently to support imaging principles of collimated detector systems. The second class is new and is closely related to the Compton camera imaging principles and invertible under special conditions. As they are poised to play a major role in future designs of biomedical imaging systems, we present an account of their most important properties which may be relevant for active researchers in the field.

Bayesian approach with the maximum entropy principle in image reconstruction from microwave scattered field data.

Microwave imaging is of great interest in medical applications owing to its high sensitivity with respect to dielectric properties. It allows detection of very small inhomogeneities. The image reconstruction employing the microwave inverse scattering consists of reconstructing the image of an object from the scattered field measured behind the object. This reconstruction runs up against the nonuniqueness of the solution of the inverse scattering problem. The authors propose to solve the ill-posed inverse problem by a statistical regularization method based on the Bayesian maximum a posteriori estimation where the principle of maximum entropy is used for assigning the a priori laws. The results obtained demonstrate the power and potential of this method in image reconstruction.