Urethral dysfunction is a common complication of diabetes mellitus, spinal cord injury, vaginal childbirth, and pelvic trauma. Stress urinary incontinence (SUI) is the involuntary loss of urine due to the inability of the urethral sphincter to maintain a tight seal during the storage phase and is a condition that physically and emotionally affects 25 million American women annually [1]. There are currently several treatments for SUI including surgery, Kegel exercises, and electrical stimulation, each accompanied by limited effectiveness and/or complications [2–3]. We believe that regenerative medicine techniques, applied to the native urethra, may aid in improving the function and support of the diseased urethra. Thus, we have begun the development of a tissue engineered urethral wrap (TEUW) for placement as a cuff around the native urethra and integration with the host tissue. The goal of this work was to explore structural and mechanical effects following implantation of a TEUW.

Urethral dysfunction is a common complication of diabetes mellitus, spinal cord injury, vaginal childbirth, and pelvic trauma. Stress urinary incontinence (SUI) is the involuntary loss of urine due to the inability of the urethral sphincter to maintain a tight seal during the storage phase, and is a disease that physically and emotionally affects 25 million American women annually [1]. There are currently several treatments for SUI including surgery, Kegel exercises, and electrical stimulation, each accompanied by limited effectiveness and/or complications [2–3]. We believe that regenerative medicine techniques applied to the native urethra may aid in improving the function and support of the diseased urethra. Thus, we have begun the development of a tissue engineered urethral wrap (TEUW) for placement as a cuff around the native urethra and integration with the host tissue. The goal of this work was to determine optimized culture conditions for TEUWs and to determine if their use in vivo improves urethral function.

Pelvic organ prolapse (POP) is a multifactorial disorder characterized by the descent of the pelvic organs into the vaginal canal. This disorder is associated with decreased quality of life, and even depression, yet 50% of women over the age of fifty are living with POP. The cost associated with the repair of POP exceeds one billion dollars annually, in the United States alone. This rather exorbitant figure includes the cost of surgery performed for symptom management, but does not include strategies which address the underlying cause of the disorder for which there are none. Because failure rates of native tissue repairs are as high as 30%, vaginal mesh is increasingly used in the surgical repair of POP. The procedure aims to reinforce the fibromuscular layer of the vagina and the paravaginal attachments, thus providing structural integrity to the weakened native tissues. However, the use of mesh is limited by mesh-related complications including exposure, erosion, pain contraction and infection.

A fixed tubesheet type heat exchanger with semi-ellipsoidal heads which is dealt with in this paper has been adopted for refrigerant heat exchange process in LNG Plant. Since the conventional design standards, e.g. ASME Sec VIII Div.1 and TEMA, are not meant to be used for such a special type of heat exchanger, FEA should be performed to determine minimum required thickness of the tubesheet. The elastic design procedure uses a stress classification methodology to guard against failure due to gross plastic deformation. According to the design standards, mechanical stresses in the tubesheet due to tube-side and/or shell-side pressure are defined as the primary membrane and bending stress and are evaluated by comparing with allowable values of the primary stress. For the special type of heat exchanger, however, stresses in the tubesheet obtained by FEA are actually complex combination of primary and secondary stresses. Application of this conventional design approach to the FEA-calculated stresses in tubesheet may lead to over-conservative design. In helping to establish reliable and economical design of the tubesheet for such a special type of heat exchanger, authors conducted FEA investigation employing axisymmetric analysis model. Considering the geometric parameters, such as thickness of a tubesheet, heads type and shell dimension, the characteristics of tubesheet stresses was investigated and an appropriate stress classification was proposed.

Pelvic organ prolapse (POP) is a multifactorial disorder, characterized by the descent of the pelvic organs into the vaginal canal. POP is associated with decreased quality of life, and even depression, yet 50% of women over the age of fifty are living with this disorder. The estimated direct cost for POP surgeries is over one billion dollars annually, in the United States alone. This rather exorbitant figure includes the cost of surgery performed for symptom management, but does not include strategies which address the underlying cause of the disorder. It is not surprising then, that within a few years over 10% of repairs will require a second procedure. Thus, more studies are needed to understand the pathophysiology of POP.