Quantum simulation of thermodynamics in an integrated quantum photonic processor.

One of the core questions of quantum physics is how to reconcile the unitary evolution of quantum states, which is information-preserving and time-reversible, with evolution following the second law of thermodynamics, which, in general, is neither. The resolution to this paradox is to recognize that global unitary evolution of a multi-partite quantum state causes the state of local subsystems to evolve towards maximum-entropy states. In this work, we experimentally demonstrate this effect in linear quantum optics by simultaneously showing the convergence of local quantum states to a generalized Gibbs ensemble constituting a maximum-entropy state under precisely controlled conditions, while introducing an efficient certification method to demonstrate that the state retains global purity. Our quantum states are manipulated by a programmable integrated quantum photonic processor, which simulates arbitrary non-interacting Hamiltonians, demonstrating the universality of this phenomenon. Our results show the potential of photonic devices for quantum simulations involving non-Gaussian states.

Mode-splitting in a microring resonator for self-referenced biosensing.

Self-referenced biosensing based on mode-splitting on a microring resonator is experimentally demonstrated. A Bragg grating integrated on the surface of the ring provides coupling between the clockwise and counterclockwise travelling modes of the pristine ring resonator lifting their degeneracy. The amount of mode-splitting is directly related to the reflectivity of the grating and it is only affected by structurally modifying the grating. Environmental perturbations to the surroundings of the gratings, such as temperature and bulk refractive index variations, have a minor effect on the amount of mode-splitting. This principle allows the realization of a self-referenced sensing scheme based on the detection of variations of the mode-splitting induced by structural changes to the grating. In this work, a polymethyl methacrylate (PMMA) Bragg grating is integrated onto a ring resonator in Al2O3. It is shown both theoretically and experimentally that the amount of splitting of a resonance varies minimally under temperature or bulk refractive index perturbations. However, the structural change of attaching a layer of biomolecules inside the grating does affect its reflectivity and the amount of mode splitting present. This result represents the first proof-of-concept demonstration of an integrated mode-splitting biosensor insensitive to temperature and refractive index variations of the liquid matrix where the molecules to be detected are embedded. The reported results pave the road towards the realization of truly self-referenced biosensors.

Al2O3 microring resonators for the detection of a cancer biomarker in undiluted urine.

Concentrations down to 3 nM of the rhS100A4 protein, associated with human tumor development, have been detected in undiluted urine using an integrated sensor based on microring resonators in the emerging Al2O3 photonic platform. The fabricated microrings were designed for operation in the C-band (λ = 1565 nm) and exhibited a high-quality factor in air of 3.2 × 105. The bulk refractive index sensitivity of the devices was ~100 nm/RIU (for TM polarization) with a limit of detection of ~10-6 RIU. A surface functionalization protocol was developed to allow for the selective binding of the monoclonal antibodies designed to capture the target biomarker to the surface of the Al2O3 microrings. The detection of rhS100A4 proteins at clinically relevant concentrations in urine is a big milestone towards the use of biosensors for the screening and early diagnosis of different cancers. Biosensors based on this microring technology can lead to portable, multiplexed and easy-to-use point of care devices.

Perioperative outcomes and costs of laparoscopic versus open inguinal hernia repair.

PURPOSE: Studies comparing laparoscopic (LIHR) vs. open inguinal hernia repair (OIHR) have shown similar recurrence rates but have disagreed on perioperative outcomes and costs. The aim of this study is to compare laparoscopic vs. open outcomes and costs. METHODS: The National Surgical Quality Improvement Program (NSQIP) was used to compare durations of surgery, anesthesia time, and length of stay (LOS). The University HealthSystem Consortium (UHC) was used to review the cost and complications between approaches. Patients were matched on demographics, year of procedure and surgical approach between datasets for statistical analysis. RESULTS: A sample of 5468 patients undergoing OIHR (N = 4,693) or LIHR (N = 775) was selected from UHC from 2008-2011. An identical number of patients from NSQIP were matched to those from UHC resulting in a total of 10,936 records. LIHR patients had shorter duration of wait from admission to operation (p < 0.05). Conversely, LIHR patients had longer operating time (p < 0.05), duration of anesthesia (p < 0.05), and time in the operating room (p < 0.05).Overall complication rate was higher in open (3.1 vs. 1.8 %, p < 0.05). Cost favored open over LIHR ($4360 vs $5105). The cost discrepancy mainly stemmed from LIHR supplies ($1448 vs. $340; p < 0.05) and OR services ($1380 vs. $1080; p < 0.05). CONCLUSION: This study demonstrates the LOS and perioperative outcomes were superior in the LIHR group; however, the overall cost was higher due to the supplies. Advancement in technology, surgeons' skill level and preference of supplies are all factors in decreasing the overall cost of LIHR.

Not all biologics are equal!

BACKGROUND: Although the efficacy of various biologic meshes in the abdominal reconstruction of complex ventral hernia has been shown, the performance profile of various biologic mesh scaffolds in terms of hernia-specific outcomes such as recurrence, mesh explantation, and mesh infections has not been examined. AIM: To evaluate the clinical outcomes of patients who underwent complex ventral hernia repair with bioprosthetic material. METHODS: This study is a retrospective analysis of the use of bioprosthetic material in complex ventral hernia at an academic institution from January 2002 to December 2007. RESULTS: A total of 58 patients with a mean age of 57.2 years and mean body mass index (BMI) of 33.8 who underwent reconstruction of ventral abdominal defects with a bioprosthetic from January 2002 to February 2009 were included in the study. The study patients had about 4.8 previous surgeries and 43.1% of patients had reconstruction in a setting of enterocutaneous fistula, while 46.6% had a previous mesh infection. Complex ventral hernia was seen in 50 patients, while eight patients had ventral and parastomal hernia. The type of biologic used for reconstruction was human-derived (AlloDerm, 29), porcine cross-linked (CollaMend, 3; Permacol, 2), and non-cross-linked porcine (Surgisis, 16; Strattice, 8). At least one complication was seen in 72.4% of patients. Major complications noted were surgical wound infections (19.0%), seroma (8.6%), and abscess formation (5.2%). The one-year hernia recurrence rate was 27.9% and mesh explantation was needed in 17.2% of patients. AlloDerm was less likely to be explanted (13.8%) or become infected (37.9%) but more likely to recur (28.6%) compared to porcine cross-linked bioprosthesis. Porcine cross-linked biologics were more likely to become infected (60%) and explanted (40%) but less likely to recur (20%) compared to AlloDerm. Non-cross-linked porcine biologics were less likely to be explanted (16.7%) but had higher recurrence (29.4%) compared to cross-linked porcine biologics and a higher infection rate (54.2%) compared to AlloDerm. CONCLUSIONS: The results from this study underscore the difficulty of repairing complex abdominal wall defects in contaminated fields. Cross-linked porcine biologics showed relatively higher infection and explantation rates. Equivalent recurrence and explantation rates were observed for the non-cross-linked porcine biologics and AlloDerm. These data indicate that there is currently no ideal biologic for complex ventral hernia repair.

The Draw-A-Person Test: an indicator of children's cognitive and socioemotional adaptation?

The authors examined aspects of reliability and validity of the Goodenough-Harris Draw-A-Person Test (DAP; D. B. Harris, 1963). The participants were 115 seven- to nine-year-old students attending regular or special education schools. Three judges, with a modest degree of training similar to that found among practicing clinicians, rated the students' human figure drawings on developmental and personality variables. The authors found that counting details and determining developmental level in the DAP test could be carried out reliably by judges with limited experience. However, the reliability of judgments of children's social and emotional development and personality was insufficient. Older students and students attending regular schools received significantly higher scores than did younger students or students attending special education schools. The authors found that the success of the DAP test as an indicator of cognitive level, socioemotional development, and personality is limited when global judgments are used. The authors concluded that more specific, reliable, valid, and useful scoring systems are needed for the DAP test.

Family problems and youth unemployment.

This study attempted to determine the extent to which family and personal characteristics relate to the employment situation of adolescents. Data were drawn from the Utrecht Study of Adolescent Development (USAD), which investigated, longitudinally, a national sample of Dutch youths aged 12 to 24 years in 1991. Specifically, two waves of a sample of 955 non-school-going respondents between 18 and 27 years old were analyzed. Parental divorce, parental unemployment (only for males), low parental affective involvement, and adolescent relationship problems were related to youth unemployment, but educational career and work commitment were not. For males, parental unemployment demonstrated the strongest correlation with youth unemployment. For females, only variables in the relational domain played a role in explaining unemployment; relationship variables were also important predictors of male unemployment. The results suggest that the family factors included in this study are better predictors of youth unemployment than are the classic individual (personal) variables.

How do vocational and relationship stressors and identity formation affect adolescent mental health?

PURPOSE: This article examines the effects of stressors in both the vocational and relationship career of youngsters in the formation of their identity; the effects of identity formation on adolescent mental health; the influence of career stressors on mental health, directly or via identity, and differences in these effects on boys and girls. METHODS: Data were used from the Dutch national panel study, Utrecht Study of Adolescent Development, a study of developmental processes as they occur in the life course of young people during the 1990s. Using LISREL, we tested hypotheses on two waves of a sample of 1222 respondents between 15 and 24 years of age in Wave 1 (1991). RESULTS: The correlation between relationship stressors and relationship identity can be neglected, while vocational stressors lead to a less achieved vocational identity, particularly in boys. Occupational and relationship identity have similar effects on mental health (i.e., the more achieved the identity, the better the person's mental health). Vocational and especially relationship stressors lead to poorer mental health, but did not affect the mental health of boys and girls differently. The same goes for the influence of relationship and vocational identity formation on mental health. CONCLUSIONS: Career stressors, especially stressors in the relationship domain, appear to have significant long-term effects on adolescent mental health. Vocational and relationship identity formation are also significant predictors for adolescent mental health.

Transitions in family structure and adolescent well-being.

This article examines the effects of transitions in family structure on physical health, thoughts of suicide, mental health, relational well-being, and employment situation of adolescents from four family structures: stable intact families, conflict intact families, single-parent families, and stepfamilies. Data were used from the Utrecht Study of Adolescent Development (USAD), a study of developments in the life course of young people during the 1990s. Results are presented from over 2,500 respondents between 15 and 24 years of age. Their parents were also interviewed on a number of topics. Transition in family structure after marital problems, divorce, and remarriage does appear to have significant long-term effects on a number of adolescent well-being variables. Young people from single-parent families have the lowest scores on the different indicators; they are more likely to have relational problems and experience unemployment as compared with youngsters from stable intact families. Adolescents from conflict intact families and stepfamilies have moderate scores. These effects remain after controlling for family income, gender, age, and educational level.

Effects of parental divorce and youth unemployment on adolescent health.

The aim of this study is to gain more insight into the effects of two important events on adolescent health in the life course of youngsters, namely parental divorce and being unemployed. We made use of the dataset of the Utrecht Study of Adolescent Development, a longitudinal panel study, based on a representative sample of young people in the Netherlands (12-24 years old). We used the data of non-school-going youngsters who are at least 18 years old. Parental divorce does indeed have negative effects on adolescent health: however, this applies only for girls. Being unemployed or having been unemployed has negative effects on psychological health, especially for boys. But this experience does not have negative effects on physical health, either for boys or girls. Any conclusions on the consequences of parental divorce and youth unemployment for adolescent health have to be specified, at least for sex.

An analysis of the elements essential in the development of a customized TBI program.

Bone marrow transplant, once a procedure carried out at a relatively small number of large medical centers, is being employed at an increasing number of non-academic hospitals. The use of total body photon irradiation for the purpose of marrow ablation and immunosuppression can be expected to accompany the outward growth of bone marrow transplantation at these same hospitals. An analysis of the fundamental physical factors associated with total body photon irradiation (TBI) should be of value to facilities considering the incorporation of a total body irradiation program into an existing radiation oncology department. By examining the existing resources of a radiotherapy center and the clinical objectives of the treatment, a facility considering TBI may determine whether or not their center already fulfills the necessary criteria, in addition to the avoidance of potential pitfalls in project implementation.

Estimation of the mean effective organ doses for total body irradiation from Rando phantom measurements.

For the total body irradiation (TBI) procedure, it is necessary to compare the mean dose obtained from the tissue or organs and the estimated dose equivalent value from the computer program. Due to the easy-access of the Rando phantom and repeatability of TLDs and its output, the results from the experiment are quite encouraging for the verification of the dose distributions from total body irradiation at the given prescribed monitor units. The estimation of effective dose equivalent particularly across the lung sections was studied by combinations of using arms as the scatter volume to compensate for the inhomogeneity across the breast portion, as well as using the spoiler for skin-sparing purposes. The results were based upon various beam quality such as 4 MV, 6 MV, and 10 MV X rays. One series of experiments performed for this survey to ascertain the dose equivalent of the tissues was conducted. This paper describes the method and procedure for comparison between the measured data and computed data as a reference in the dosimetry of total body irradiation. Comparison of the measured and computed data for the largest collimated field shows that the calculated dose rates do not differ by more than 2% from the measured data. Because uncertainty is inherent in non-patient-like phantoms, the calculated data may be served as a reference for the dosimetry. For the total body irradiation setup, considering the radiation field size and treatment distances commonly employed, we conclude that the best combination of the patient setup will be (1) laying both arms down as compensation for lung inhomogeneity, and (2) the spoiler, which is made of acrylic about 8 mm thick and functions like a bolus, is needed to reduce the skin sparing effects and contribute the uniform dose distribution. The beam spoiler with the frame stands near the patient during the treatment.

Comparison of energy expenditure measurement techniques in severely burned patients.

The degree of accuracy of existing formulas for calculating energy expenditure can be determined by comparing them to the measured energy expenditure via indirect calorimetry. As a result, one can modify traditional predicted recommendations for nutrition alimentation of the burn patient with real-time data. In this study, 21 sequential adult admissions with second- and third-degree total body surface area (TBSA) burn wounds (range 21%-81% TBSA) underwent serial assessments of energy expenditure by indirect calorimetry. On admission, maximum, and discharge, measured energy expenditure (MEE) was compared with the calculations for predicted energy expenditure by the Curreri (CEE) and modified Harris-Benedict (MBEE) equations. The mean energy expenditure calculated from the Curreri equation on admission (CEEA) overestimated the mean MEE on admission (MEEA) by 25% (P less than 0.001) and on discharge (MEED) by 36% (P less than 0.0005). The mean modified Harris-Benedict equation overestimated the mean MEEA by 32% (P less than 0.0005) and the mean MEED by 39% (P less than 0.0005). No significant difference was noted between the mean MEE at maximum (MEEM) and the mean CEEA or the mean MBEEA. This indicates excessive overfeeding of the burn patient from admission to discharge by both standard formulas. Actual measured data provide a better indicator of varying nutritional needs throughout the hospital course than the standard formulas, and their use would result in significant savings in the expenses of enteral/parenteral nutritional supplements.

Corrections to megavoltage depth-dose values due to reduced backscatter thickness.

Multiplicative corrections for percent depth-dose values were measured for situations with nonmaximal backscatter because of reduced thickness of the irradiated phantom. Data were obtained for common clinical field sizes for a 60Co beam as well as beams from a 2.5-MV and a 4.0 MV generator. Functional forms, which summarize the results and include field size effects, depth, and thickness of the backscatter medium as variables, were obtained by regression analysis.

Central axis depth dose for a 2.5 MV Van de Graaff generator.

Central axis percentage depth dose values and isodose curves for the bremsstrahlung beam from a 2.5 MV Van de Graaff generator were measured with a water phantom at 100 cm target-to-surface distance. Tissue-air ratios were calculated from the central axis depth dose data. Use of the 2.5 MV percentage depth dose values are necessary for treatment planning since they are substantially larger than the values given in compilations for 2.0 MV beams.