Search for serendipitous TNO occultation in X-rays

To study the population properties of small, remote objects beyond Neptune's orbit in the outer solar system, of kilometer size or smaller, serendipitous occultation search is so far the only way. For hectometer-sized Trans-Neptunian Objects (TNOs), optical shadows actually disappear because of diffraction. Observations at shorter wave lengths are needed. Here we report the effort of TNO occultation search in X-rays using RXTE/PCA data of Sco X-1 taken from June 2007 to October 2011. No definite TNO occultation events were found in the 334 ks data. We investigate the detection efficiency dependence on the TNO size to better define the sensible size range of our approach and suggest upper limits to the TNO size distribution in the size range from 30 m to 300 m. A list of X-ray sources suitable for future larger facilities to observe is proposed.Comment: Accepted to publish in MNRA

Segmented Compression Molding for Composite Manufacture

In the present study a new technique of vacuum assisted resin transfer molding (VARTM), called segmented compression molding (SCM), is proposed to improve filling process. In the method, a double-bag is placed between the upper mold and the cavity, and each bag is controlled individually. Through the vacuum pulling the double-bag upward, resin is easily infused into the loose preform. After the completion of resin infusion, the resin inlet is closed. The vacuum on the bags are sequentially released to atmospheric pressure, the inflated bags squeeze the surplus resin from the wetted preform toward dry loose preform and the filling process is thus reduced. This study is to introduce the SCM, model the filling process and explore the surface quality of the SCM parts. Results show that the SCM filling process is decreased by using a high initial cavity thickness. As compared with transfer resin transfer molding (RTM) and typical VARTM, SCM can reduce the filling process in the work. The surface roughness of SCM part approximates that of VARTM, but it is much inferior to that of RTM

Spinal column shortening versus revision detethering for recurrent adult tethered cord syndrome: a preliminary comparison of perioperative and clinical outcomes.

OBJECTIVE:Recurrent tethered cord syndrome (TCS), believed to result from tension on the distal portion of the spinal cord, causes a constellation of neurological symptoms. Detethering surgery has been the traditional treatment for TCS. However, in cases of recurrent TCS, there is a risk of new neurological deficits developing, and subsequent retethering is difficult to prevent. Spinal column shortening has been proposed as an alternative technique to reduce the tension on the spinal cord without incurring the morbidity of revision surgery on the spinal cord. The authors compared the perioperative outcomes and morbidity of patients who were treated with one or the other procedure. METHODS:The medical records of 16 adult patients with recurrent TCS who were treated between 2005 and 2018 were reviewed. Eight patients underwent spinal column shortening, and 8 patients underwent revision detethering surgery. Patient demographics, clinical outcomes, and perioperative factors were analyzed. The authors include a video to illustrate their technique of spinal column shortening. RESULTS:Within the spinal column shortening group, no patients experienced any complications, and all 8 patients either improved or stabilized with regard to lower-extremity and bowel and bladder function. Within the revision detethering group, 2 patients had worsening of lower-extremity strength, 3 patients had worsening of bowel and bladder function, and 1 patient had improvement in bladder function. Also, 3 patients had wound-related complications. The median estimated blood loss was 731 ml in the shortening group and 163 ml in the revision detethering group. The median operative time was 358 minutes in the shortening group and 226 minutes in the revision detethering group. CONCLUSIONS:Clinical outcomes were comparable between the groups, but none of the spinal column shortening patients experienced worsening, whereas 3 of the revision detethering patients did and also had wound-related complications. Although the operative times and blood loss were higher in the spinal column shortening group, this procedure may be an alternative to revision detethering in extremely scarred or complex wound revision cases

Haemophilus Aphrophilus Associated Spleen Abscess: An Unusual Presentation of Subacute Endocarditis

The HACEK group of bacteria (Haemophilus spp., Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella spp.), is uncommon pathogens of infective endocarditis, but can cause life-threatening events such as heart failure or formation of lethal emboli. Here we report a 58-year-old Asian man with a past history of congenital valvular heart disease who presented with sudden onset of left flank pain followed by fever with chills for 2 weeks. Abdominal computed tomography (CT) indicated a 1.6 cm abscess in the spleen. Culturing indicated the presence of Haemophilus aphrophilus. We diagnosed the patient with subacute endocarditis complicated with spleen abscess. The patient recovered fully after two weeks antibiotic (Ceftriaxone) treatment. Clinicians should give further attention to infective endocarditis caused by bacteria in the HACEK group in patients with metastatic infection such as spleen abscess with suspected valvular heart disease

Experimental Study of Progressive Compression Method of Resin Delivery in Liquid Composite Molding

A new technique of resin delivery, which we refer to as the progressive compression method (PCM), has been invented to reduce filling time associated with the vacuum assisted resin transfer molding (VARTM) process. In the method, the bag is divided into several segments. During infusion, all segmented bags are pulled away from the preform by the vacuum. Hence, resin is easily infused into the loose preform. Once enough volume of resin is infused, the vacuum within the segmented bags is released in a step-wise manner. The atmospheric pressure of the heated air is progressively applied on the segmented bag that is inflated to compact the wetted preform and drive the resin through the remaining dry preform. The resin flow is enhanced since the dry preform remains loose during the filling process. The research aims to investigate the effect of seven process parameters on the PCM complete filling process by applying Taguchi’s method. All chosen factors are designed with two levels. Experimental results show that the predicted optimum settings are higher vacuum pressure, more compression segment, later initiation of the next compression segment, higher air temperature, later introduction of the heated air, lower initial height of the cavity and less excess infused resin for reducing the filling time. Compared with typical VARTM without flow enhancement, PCM at the optimum settings reduces the filling time by 72.85%