No-go theorem for the composition of quantum systems.

Building on the Pusey-Barrett-Rudolph theorem, we derive a no-go theorem for a vast class of deterministic hidden-variables theories, including those consistent on their targeted domain. The strength of this result throws doubt on seemingly natural assumptions (like the "preparation independence" of the Pusey-Barrett-Rudolph theorem) about how "real states" of subsystems compose for joint systems in nonentangled states. This points to constraints in modeling tensor-product states, similar to constraints demonstrated for more complex states by the Bell and Bell-Kochen-Specker theorems.

A Simplified Basis for Bell-Kochen-Specker Theorems.

We show that a reduced form of the structural requirements for deterministic hidden variables used in Bell-Kochen-Specker theorems is already sufficient for the no-go results. Those requirements are captured by the following principle: an observable takes a spectral value x if and only if the spectral projector associated with x takes the value 1. We show that the "only if" part of this condition suffices. The proof identifies an important structural feature behind the no-go results; namely, if at least one projector is assigned the value 1 in any resolution of the identity, then at most one is.

Implications of the Pusey-Barrett-Rudolph quantum no-go theorem.

Pusey, Barrett, and Rudolph introduce a new no-go theorem for hidden-variables models of quantum theory. We make precise the class of models targeted and construct equivalent models that evade the theorem. The theorem requires assumptions for models of composite systems, which we examine, determining compactness as the weakest assumption needed. On that basis, we demonstrate results of the Bell-Kochen-Specker theorem. Given compactness and the relevant class of models, the theorem can be seen as showing that some measurements on composite systems must have built-in inefficiencies, complicating its testing.

Laparoscopic repair of inguinal hernia with biomimetic matrix.

BACKGROUND AND OBJECTIVES: Materials utilized for the repair of hernias fall into 2 broad categories, synthetics and biologics. Each has its merits and drawbacks. The synthetics have a permanent, inherent strength but are associated with some incidence of chronic pain. The biologics rely on variable tissue regeneration to give strength to the repair, limiting their use to specific situations. However, thanks to their transient presence and tissue ingrowth, the biologics do not result in a significant incidence of chronic pain. We studied the use of a biomimetic (REVIVE, Biomerix Corporation, Fremont, CA) in this setting in an attempt to obviate the disadvantages of each material. METHODS: Fourteen patients underwent laparoscopic repair by totally extraperitoneal and transabdominal preperitoneal techniques of 16 inguinal hernias. Follow-up was as long as 19 mo, and 8 patients were followed for > 12 mo. There were no recurrences and a 5% incidence of functionally insignificant discomfort. RESULTS: REVIVE is shown in histology and in vivo to demonstrate regeneration and tissue ingrowth into the polycarbonate/polyuria matrix similar to that in the biologics rather than scarring or encapsulation. There were no recurrences, indicating its strength and resilience as a permanent repair similar to that in the synthetics. CONCLUSION: This is proof of the concept that a biomimetic may bridge the gap between the biologics and synthetics and may be able to be utilized on a regular basis with the benefits of both materials and without their drawbacks.

Laparoscopic repair of inguinal hernia using Surgisis mesh and fibrin sealant.

OBJECTIVE: We tested the hypothesis that laparoscopic inguinal herniorrhaphy using Surgisis mesh secured with fibrin sealant is an effective long-term treatment for repair of inguinal hernia. This case series involved 38 adult patients with 51 inguinal hernias treated in a primary care center. METHODS: Between December 2002 and May 2005, 38 patients with 45 primary and 6 recurrent inguinal hernias were treated with laparoscopic repair by the total extraperitoneal mesh placement (TEP) technique using Surgisis mesh secured into place with fibrin sealant. Postoperative complications, incidence of pain, and recurrence were recorded, as evaluated at 2 weeks, 6 weeks, 1 year, and with a follow-up questionnaire and telephone interview conducted in May and June 2005. RESULTS: The operations were successfully performed on all patients with no complications or revisions to an open procedure. Average follow-up was 13 months (range, 1 to 30). One hernia recurred (second recurrence of unilateral direct hernia), indicating a 2% recurrence rate. CONCLUSIONS: Laparoscopic repair of inguinal hernia using Surgisis mesh secured with fibrin sealant can be effectively used to treat primary, recurrent, direct, indirect, and bilateral inguinal hernias in adults without complications and minimal recurrence within 1-year of follow-up.

Minimally invasive surgery may result in lower peak levels of circulating vascular endothelial growth factor.

BACKGROUND: Angiogenesis is felt to be a factor in the establishment and progression of cancer and cancer metastasis. Vascular endothelial growth factor (VEGF) is one of the most powerful stimulants of tumor angiogenesis identified. VEGF levels can be affected by physiologic stimuli and measured systemically. METHODS: Circulating VEGF levels were measured immediately before and after laparoscopic colon surgery in 10 unselected sequential patients with a diagnosis requiring surgical intervention for colon pathology. RESULTS: Preoperative VEGF ranged from 31.3 pcg/cc to 187 pcg/cc. Postoperative VEGF ranged from 45 pcg/cc to 2228 pcg/cc. Factors of age, weight, diagnosis, length of cumulative skin incisions, and the receipt of preoperative blood products were considered. Data were compared by t test and regression analysis. Although several patients showed variability, some pronounced, in their pre- and postoperative levels, no 1 factor reached statistical significance as the cause of this variability. Utilizing regression analysis, however, considering only those patients in whom a diagnosis of cancer existed and who received blood products, the length of the incision alone accounted for an R2 change of 0.471. That is, in this subset of patients, incision size alone accounted for almost half of the variability in VEGF. CONCLUSION: The data suggest a possible link between incision size in colon surgery and levels of VEGF. The sample size was insufficient for statistical significance. The study also does not answer whether a systemic release of VEGF at the time of surgery adversely affects the clinical outcome in cases of colon cancer. The data do warrant further investigation with a larger sample size and clinical follow-up.