Impact of Additive Manufacturing Materials on Thermal Performance of Silicon Reference Cells.

Additive manufacturing, or 3D printing, is quickly becoming a widespread manufacturing method offering timely and cost-effective build times for unique part geometries with an increasing range of material offerings. One unique use for additive manufacturing is constructing the housing for reference solar cells, which are crucial instruments for evaluating the electrical performance of photovoltaic solar cells and modules. These instruments, which require good thermal conduction, are costly to manufacture because they are usually machined from aluminum using precision milling machines. In this work, we set out to evaluate several presently available additive manufacturing materials for their thermal properties when used to house reference solar cells. We fabricated several types of reference cell instruments with a tabletop, filament-based 3D printer using polylactic acid (PLA) and composite PLA/metal materials with different infill percentages. Furthermore, we fabricated several all-metal 3D printed reference cells using a binder jet printed stainless steel-bronze material blend and compared the thermal properties of all 3D printed instruments against a standard aluminum housing reference cell. Measurements included temperature monitoring of an embedded thermocouple sensor on an isothermal plate under the ambient environment and when exposed to high irradiation under a solar simulator. Current vs voltage measurements were also taken under the solar simulator and the open circuit voltage results were used to verify the actual silicon cell temperature. Our findings indicate that the stainless steel-bronze option can function well as an alternative to traditional aluminum-based housings, while the lower-cost metal-PLA composite can only be used under indoor light spectra or when used in a flash-type solar simulator when the instrument is not exposed to excessive radiation and heat.

Ventilation in a Residential Building Brings Outdoor NOx Indoors with Limited Implications for VOC Oxidation from NO3 Radicals.

Energy-efficient residential building standards require the use of mechanical ventilation systems that replace indoor air with outdoor air. Transient outdoor pollution events can be transported indoors via the mechanical ventilation system and other outdoor air entry pathways and impact indoor air chemistry. In the spring of 2022, we observed elevated levels of NOx (NO + NO2) that originated outdoors, entering the National Institute of Standards and Technology (NIST) Net-Zero Energy Residential Test Facility through the mechanical ventilation system. Using measurements of NOx, ozone (O3), and volatile organic compounds (VOCs), we modeled the effect of the outdoor-to-indoor ventilation of NOx pollution on the production of nitrate radical (NO3), a potentially important indoor oxidant. We evaluated how VOC oxidation chemistry was affected by NO3 during NOx pollution events compared to background conditions. We found that nitric oxide (NO) pollution introduced indoors titrated O3 and inhibited the modeled production of NO3. NO ventilated indoors also likely ceased most gas-phase VOC oxidation chemistry during plume events. Only through the artificial introduction of O3 to the ventilation duct during a NOx pollution event (i.e., when O3 and NO2 concentrations were high relative to typical conditions) were we able to measure NO3-initiated VOC oxidation products, indicating that NO3 was impacting VOC oxidation chemistry.

Retraction: Ni/Co/Ti layered double hydroxide for highly efficient photocatalytic degradation of Rhodamine B and Acid Red G: a comparative study.

Retraction of 'Ni/Co/Ti layered double hydroxide for highly efficient photocatalytic degradation of Rhodamine B and Acid Red G: a comparative study' by Priyadarshi Roy Chowdhury and Krishna G. Bhattacharyya, Photochem. Photobiol. Sci., 2017, 16, 835-839.

Cutaneous Branch of the Obturator Nerve Extending to the Medial Ankle and Foot: A Report of Two Cadaveric Cases.

The area of skin supplied by the cutaneous branch of the obturator nerve (CBO) is highly variable. Although most introductory anatomy texts describe the CBO as innervating only a portion of the medial thigh, there are numerous reports in the literature of CBOs passing the knee to innervate the proximal, middle, or even distal leg. There are no previous reports of CBOs extending to the ankle and foot. Herein we describe 2 cases of CBOs extending at least to the medial foot. Both cases were discovered incidentally, during routine cadaver dissections by osteopathic and podiatric medical students in the anatomy laboratory of Western University of Health Sciences in California. In both instances, the anomalously long CBOs shared several characteristics: (1) they arose as direct branches of the anterior division of the obturator nerve, not from the subsartorial plexus; (2) they coursed immediately posterior to the great saphenous vein from the distal thigh to the distal leg, only deviating away from the saphenous vein just above the medial malleolus; and (3) they terminated in radiating fibers to the posterior half of the medial ankle and foot. In both cases, the saphenous branch of the femoral nerve was present but restricted to the area anterior to the great saphenous vein. It is likely that the variant CBOs carried fibers of the L4 spinal nerve and thus provided cutaneous innervation to the medial foot and ankle, a function most commonly reserved for the saphenous branch of the femoral nerve distal to the knee. Saphenous neuropathy is a common postoperative complication of saphenous cutdowns for coronary artery bypass grafts, so the potential involvement of a long CBO can add additional complexity to regional anesthetic blocks for foot and ankle surgery and procedures such as vein harvesting for coronary artery bypass grafts.

Nonlinearity measurements of solar cells with an LED-based combinatorial flux addition method.

We present a light emitting diode (LED)-based system utilizing a combinatorial flux addition method to investigate the nonlinear relationship in solar cells between the output current of the cell and the incident irradiance level. The magnitude of the light flux is controlled by the supplied currents to two LEDs (or two sets of them) in a combinatorial fashion. The signals measured from the cell are arranged within a related overdetermined linear system of equations derived from an appropriately chosen Nth degree polynomial representing the relationship between the measured signals and the incident fluxes. The flux values and the polynomial coefficients are then solved for by linear least squares to obtain the best fit. The technique can be applied to any solar cell, under either monochromatic or broadband spectrum. For the unscaled solution, no reference detectors or prior calibrations of the light flux are required. However, if at least one calibrated irradiance value is known, then the entire curve can be scaled to an appropriate spectral responsivity value. Using this technique, a large number of data points can be obtained in a relatively short time scale over a large signal range.

Large-area irradiance-mode spectral response measurements of solar cells by a light-emitting, diode-based integrating sphere source.

An irradiance-mode absolute differential spectral response (SR) measurement system based on a light emitting diode (LED) array is described. The LEDs are coupled to an integrating sphere whose output irradiance is uniform to better than 2% over an area of 160 mm by 160 mm. SR measurements of solar cells when subject to diffuse irradiation, as provided by the integrating sphere, are compared with collimated irradiance SR measurements. Issues originating from the differences in angular response of the reference versus the test cells are also investigated. The SR curves of large-area cells with dimensions of up to 155 mm are measured and then used to calculate the cell's short circuit current (I(sc)), if illuminated by a defined solar spectrum. The resulting values of I(sc) agree well with the values obtained from secondary measurements.

Ozone generation and chemistry from 222 nm germicidal ultraviolet light in a fragrant restroom.

Devices using 222 nm germicidal ultraviolet light (GUV222) have been marketed to reduce virus transmission indoors with low risk of occupant harm from direct UV exposure. GUV222 generates ozone, an indoor air pollutant and oxidant, under constrained laboratory conditions, but the chemistry byproducts of GUV222-generated ozone in real indoor spaces is uncharacterized. We deployed GUV222 in a public restroom, with an air change rate of 1 h-1 one weekend and 2 h-1 the next, to measure ozone formation and byproducts generated from ozone chemistry indoors. Ozone from GUV222 increased background concentrations by 5 ppb on average for both weekends and reacted rapidly (e.g., at rates of 3.7 h-1 for the first weekend and 2.0 h-1 for the second) with gas-phase precursors emitted by urinal screens and on surfaces. These ozone reactions generated volatile organic compound and aerosol byproducts (e.g., up to 2.6 µg m-3 of aerosol mass). We find that GUV222 is enhancing indoor chemistry by at least a factor of two for this restroom. The extent of this enhanced chemistry will likely be different for different indoor spaces and is dependent upon ventilation rates, species and concentrations of precursor VOCs, and surface reactivity. Informed by our measurements of ozone reactivity and background aerosol concentrations, we present a framework for predicting aerosol byproduct formation from GUV222 that can be extended to other indoor spaces. Further research is needed to understand how typical uses of GUV222 could impact air quality in chemically diverse indoor spaces and generate indoor air chemistry byproducts that can affect human health.

Ozone Generation from a Germicidal Ultraviolet Lamp with Peak Emission at 222 nm.

Recent interest in commercial devices containing germicidal ultraviolet lamps with a peak emission wavelength at 222 nm (GUV222) has focused on mitigating virus transmission indoors while posing minimum risk to human tissue. However, 222 nm light can produce ozone (O3) in air. O3 is an undesirable component of indoor air because of health impacts from acute to chronic exposure and its ability to degrade indoor air quality through oxidation chemistry. In seven four-hour experiments we measured O3 produced from a single filtered GUV222 lamp in a 31.5 m3 stainless steel chamber. Using an emission model, we determined an O3 generation rate of 19.4 ppbv h-1 ± 0.3 ppbv h-1 (equivalent to 1.22 mg h-1 ± 0.02 mg h-1). We estimated the fluence rate from the lamp using two methods: (1) chemical actinometry using tetrachloroethylene (actinometry) and (2) geometric projection of the irradiance field from radial and angular distribution measurements of the GUV222 lamp fluence (irradiance). Using the estimated lamp fluence rates of 2.2 µW cm-2 (actinometry) and 3.2 µW cm-2 (irradiance) we predicted O3 production in our chamber within 20 % of the average measured mixing ratio. Future studies should evaluate the indoor air quality impacts of GUV222 technologies.

Outcomes from IBD-associated and non-IBD-associated colorectal cancer: a Surveillance Epidemiology and End Results Medicare study.

BACKGROUND: There is controversy as to whether the clinicopathological features of colorectal cancer in the setting of IBD are distinct from sporadic colorectal cancer. OBJECTIVE: The aim of this study was to compare the characteristics and outcomes between IBD-associated and sporadic colorectal cancer. DESIGN: This retrospective population-based cohort study used the Surveillance, Epidemiology, and End Results Medicare-linked database. SETTINGS: This study was conducted in 6 US metropolitan areas enrolled in Surveillance, Epidemiology, and End Results. PATIENTS: Beneficiaries of Medicare parts A and B identified from the Surveillance, Epidemiology, and End Results database with a diagnosis of IBD-associated or sporadic colorectal cancer who underwent surgical resection were included in the study. MAIN OUTCOMES MEASURES: The main outcome was death. The adjusted risk ratio for death compared patients with IBD-associated colorectal cancer with patients who had sporadic colorectal cancer. RESULTS: Patients with IBD-associated colorectal cancer were more likely to present at an earlier stage, use immunosuppression, and have metachronous colorectal cancer. Although total proctocolectomy was more common among IBD patients with colorectal cancer, the majority (>75%) underwent a segmental resection. Cancer-specific survival was worse for IBD-associated colorectal cancer vs sporadic colorectal cancer (mean, 32.9 months vs 42.4 months). After adjusting for potential confounders, older age, male sex, higher stage, IBD, immunosuppression, neoadjuvant radiation, and metachronous tumor were associated with a higher risk of cancer-specific mortality. Among patients with IBD, there was no difference in cancer-specific survival for segmental colectomy vs proctocolectomy. LIMITATIONS: This is a retrospective cohort study utilizing insurance data dependent on the correct coding of patient claims. CONCLUSION: Older patients with IBD-associated colorectal cancer appear to have a slightly worse outcome than those with sporadic colorectal cancer. The cause of this is multifactorial, but it does not appear to be associated with a more limited surgical resection.

An evaluation of surgical site infections by wound classification system using the ACS-NSQIP.

BACKGROUND: Surgical wound classification has been the foundation for infectious risk assessment, perioperative protocol development, and surgical decision-making. The wound classification system categorizes all surgeries into: clean, clean/contaminated, contaminated, and dirty, with estimated postoperative rates of surgical site infection (SSI) being 1%-5%, 3%-11%, 10%-17%, and over 27%, respectively. The present study evaluates the associated rates of the SSI by wound classification using a large risk adjusted surgical patient database. METHODS: A cross-sectional study was performed using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) dataset between 2005 and 2008. All surgical cases that specified a wound class were included in our analysis. Patient demographics, hospital length of stay, preoperative risk factors, co-morbidities, and complication rates were compared across the different wound class categories. Surgical site infection rates for superficial, deep incisional, and organ/space infections were analyzed among the four wound classifications using multivariate logistic regression. RESULTS: A total of 634,426 cases were analyzed. From this sample, 49.7% were classified as clean, 35.0% clean/contaminated, 8.56% contaminated, and 6.7% dirty. When stratifying by wound classification, the clean, clean/contaminated, contaminated, and dirty wound classifications had superficial SSI rates of 1.76%, 3.94%, 4.75%, and 5.16%, respectively. The rates of deep incisional infections were 0.54%, 0.86%, 1.31%, and 2.1%. The rates for organ/space infection were 0.28%, 1.87%, 2.55%, and 4.54%. CONCLUSION: Using ACS-NSQIP data, the present study demonstrates substantially lower rates of surgical site infections in the contaminated and dirty wound classifications than previously reported in the literature.

Race and cognitive decline among community-dwelling elders with mild cognitive impairment: findings from the Memory and Medical Care Study.

OBJECTIVE: Previous studies have reported conflicting findings on the relationship between race and cognitive decline in elders with dementia. Few studies have examined the role of race in cognitive decline in mild cognitive impairment (MCI). We investigate the relationship between race and cognitive decline in participants with MCI in a community-based, longitudinal study of cognitively impaired elders. METHOD: Based on a validated method utilizing a neuropsychiatric battery, 133 subjects [mean age: 78.7 years (SD = 6.5); female: 112 (76.7%); black: 59 (44.4%)] out of 512 participants in the Memory and Medical Care Study were diagnosed with MCI. The main outcome measure was the Telephone Interview for Cognitive Status (TICS) score over three years. Other baseline subject characteristics (demographics, health-related variables, behavioral, and psychiatric symptoms) were included in the analysis. RESULTS: Overall, the three-year decline in mean TICS score was significantly higher among African Americans than non-African Americans [3.31 (SD: 7.5) versus 0.96 (SD: 3.0), t-value = 1.96, p-value = 0.05]. General estimating equation analyses revealed that African American race was associated with a faster rate of cognitive decline in all models. CONCLUSION: The rate of cognitive decline in MCI appears to be faster in African Americans than non-African Americans in the community. Diagnosis of MCI among African American elders could lead to early interventions to prevent or delay cognitive decline in the future.

Readmission rates and cost following colorectal surgery.

BACKGROUND: Hospital readmission is emerging as a quality indicator by the state, federal, and private payors with the goal of denying payment for select readmissions. OBJECTIVE: We designed a study to measure the rate, cost, and risk factors for hospital readmission after colorectal surgery. STUDY DESIGN/SETTING: We reviewed commercial health insurance records of 10,882 patients who underwent colorectal surgery over a 7-year period (2002-2008). PATIENTS: All patients undergoing colon and/or rectal resection ages 18 to 64 were included. MAIN OUTCOME MEASURE: The 30-day and 90-day readmission rates, the number of readmissions per patient, the median cost, length of stay, and risk factors for readmission were analyzed. RESULTS: Thirty-day readmission occurred in 11.4% (1239/10,882) of patients. Readmission between 31 and 90 days occurred in an additional 11.9% (1027/10,882) of patients for a total 90-day readmission rate of 23.3%. Two or more readmissions occurred in 1.4% (155) and 5.2% (570) of patients in the first 30 and 90 days. Mean readmission length of stay was 8 days, and the median cost per stay was $8885. Initial hospitalization risk factors for readmission were the diagnosis of a surgical site infection (OR 1.2), creation of a stoma (OR 1.2), discharge to nursing home (OR 1.2), index admission length of stay >7 days (OR 1.2), proctectomy (OR 1.1), and severity of illness score (severity of illness 3 = OR 1.1; severity of illness 4 = OR 1.3). CONCLUSIONS: Readmission after colorectal surgery occurs frequently and is associated with a cost of approximately $9000 per readmission. Nationwide these findings account for $300 million in readmission costs annually for colorectal surgery alone. Clinical and systems-based prevention strategies are needed to reduce readmission.

Cardiac surgery errors: results from the UK National Reporting and Learning System.

OBJECTIVE: To describe cardiac surgery-related incidents and compare the types and severity of incidents occurring in the operating room (OR) versus non-OR locations. We hypothesized that the type and severity of incidents in cardiac surgery would differ in the OR compared with non-OR locations. DESIGN: A retrospective cross-sectional study of all incidents categorized as cardiac surgery in the UK National Reporting and Learning System database between January 2003 and February 2007. Differences in proportions were evaluated by χ(2) or Fischer's exact test. The odds ratio of an event occurring in the OR compared with all non-OR settings was calculated using logistic regression. The harm susceptibility ratio ranked locations by the degree of harm. SETTING: All trusts performing cardiac surgery. PARTICIPANTS: None. INTERVENTION: None. MAIN OUTCOME MEASURES: Cardiac surgery incidents occurring in the OR versus non-OR. RESULTS: A total of 4828 (<1%) incidents from 55 trusts were designated as involving cardiac surgery patients during the study period; 21% occurred in the OR. Overall, 32% of incidents resulted in harm: 23% of OR and 34% of non-OR incidents. The distribution of incident type and harmful incidents differed in the OR compared with the non-OR setting (P < 0.05). CONCLUSIONS: Our findings offer unique insights into the types of incidents occurring during cardiac surgical care in the UK. In the OR, interventions should focus on reducing errors associated with medical devices/equipment, whereas outside the OR, they may focus on medication errors and patient accidents.

National study on the frequency, types, causes, and consequences of voluntarily reported emergency department medication errors.

BACKGROUND: Medication errors contribute to significant morbidity, mortality, and costs to the health system. Little is known about the characteristics of Emergency Department (ED) medication errors. STUDY OBJECTIVE: To examine the frequency, types, causes, and consequences of voluntarily reported ED medication errors in the United States. METHODS: A cross-sectional study of all ED errors reported to the MEDMARX system between 2000 and 2004. MEDMARX is an anonymous, confidential, de-identified, Internet-accessible medication error-reporting program designed to allow hospitals to report, track, and share error data in a standardized format. RESULTS: There were 13,932 medication errors from 496 EDs analyzed. The error rate was 78 reports per 100,000 visits. Physicians were responsible for 24% of errors, nurses for 54%. Errors most commonly occurred in the administration phase (36%). The most common type of error was improper dose/quantity (18%). Leading causes were not following procedure/protocol (17%), and poor communication (11%), whereas contributing factors were distractions (7.5%), emergency situations (4.1%), and workload increase (3.4%). Computerized provider order entry caused 2.5% of errors. Harm resulted in 3% of errors. Actions taken as a result of the error included informing the staff member who committed the error (26%), enhancing communication (26%), and providing additional training (12%). Patients or family members were notified about medication errors 2.7% of the time. CONCLUSION: ED medication errors may be a result of the acute, crowded, and fast-paced nature of care. Further research is needed to identify interventions to reduce these risks and evaluate the effectiveness of these interventions.

Refining the definition of perioperative mortality following hepatectomy using death within 90 days as the standard criterion.

OBJECTIVES: Defining perioperative mortality as death that occurs within 30 days of surgery may underestimate 'true' mortality among patients undergoing hepatic resection. To better define perioperative mortality, trends in the risk for death during the first 90 days after hepatectomy were assessed. METHODS: Surveillance, Epidemiology and End Results (SEER) Medicare data were used to identify 2597 patients who underwent hepatic resection during 1991-2006. Data on their clinicopathological characteristics, surgical management and perioperative mortality were collected and survival was assessed at 30, 60 and 90 days post-surgery. RESULTS: Overall, 5.7% of patients died within the first 30 days. Postoperative mortality at 60 and 90 days were 8.3% and 10.1%. In-hospital mortality after hepatic resection was greater among patients with hepatocellular carcinoma (HCC) than among those with colorectal liver metastases (CRLM) (8.9% and 3.8%, respectively; P < 0.001). In CRLM patients, mortality increased from 4.3% at 30 days to 8.4% at 90 days, whereas mortality in HCC patients increased from 9.7% at 30 days to 15.0% at 90 days (both P < 0.05). Patients with HCC were twice as likely as CRLM patients to die within 30 days [odds ratio (OR) 2.03], 60 days (OR = 1.74) and 90 days (OR = 1.71) (all P < 0.001). Differences in 30- and 90-day mortality were greatest among HCC patients undergoing major hepatic resection (P < 0.05). CONCLUSIONS: Reporting deaths that occur within a maximum of 30 days of surgery underestimates the mortality associated with hepatic resection. Traditional 30-day definitions of mortality are misleading and surgeons should report all perioperative outcomes that occur within 90 days of hepatic resection.

Indoor light energy harvesting for battery-powered sensors using small photovoltaic modules.

As interest in Internet-of-Things (IoT) devices like wireless sensors increases, research efforts have focused on finding ways for these sensors to self-harvest energy from the environment in which they are installed. Photovoltaic (PV) cells or mini-modules are an intuitive choice for harvesting indoor ambient light, even under low light conditions, and using it for battery charging and powering of these devices. Characterizations of battery charging, for small rechargeable batteries from low charge to full charge, have been investigated using PV mini-modules of equal area. We present battery charging results using three different PV technologies, monocrystalline silicon (c-Si), gallium-indium-phosphide (GaInP) and gallium-arsenide (GaAs) under a warm color temperature (3000 K) LED lighting at an illuminance of 1000 lx. Battery charging times are shortest for the more efficient GAInP and GaAs mini-modules whose spectral response are a better match to the LED test source, which contains mostly visible photons, and longest for the less efficient Si cells. As a demonstration, a wireless temperature sensor mote was attached to the charging circuit and operated to determine its power consumption in relation to the available charging power. The mote's maximum power draw was less than the charging power from the least efficient c-Si mini-module. Our findings affirm the feasibility of utilizing PV under typical indoor lighting conditions to power IoT devices.

Combinatorial transcription factor regulation of the cyclic AMP-response element on the Pgc-1alpha promoter in white 3T3-L1 and brown HIB-1B preadipocytes.

Cold stress in rodents increases the expression of UCP1 and PGC-1alpha in brown and white adipose tissue. We have previously reported that C/EBPbeta specifically binds to the CRE on the proximal Pgc-1alpha promoter and increases forskolin-sensitive Pgc-1alpha and Ucp1 expression in white 3T3-L1 preadipocytes. Here we show that in mice exposed to a cold environment for 24 h, Pgc-1alpha, Ucp1, and C/ebpbeta but not C/ebpalpha or C/ebpdelta expression were increased in BAT. Conversely, expression of the C/EBP dominant negative Chop10 was increased in WAT but not BAT during cold exposure. Reacclimatization of cold-exposed mice to a warm environment for 24 h completely reversed these changes in gene expression. In HIB-1B, brown preadipocytes, forskolin increased expression of Pgc-1alpha, Ucp1, and C/ebpbeta early in differentiation and inhibited Chop10 expression. Employing chromatin immunoprecipitation, we demonstrate that C/EBPbeta, CREB, ATF-2, and CHOP10 are bound to the Pgc-1alpha proximal CRE, but CHOP10 does not bind in HIB-1B cell lysates. Forskolin stimulation and C/EBPbeta overexpression in 3T3-L1 cells increased C/EBPbeta and CREB but displaced ATF-2 and CHOP10 binding to the Pgc-1alpha proximal CRE. Overexpression of ATF-2 and CHOP10 in 3T3-L1 cells decreased Pgc-1alpha transcription. Knockdown of Chop10 in 3T3-L1 cells using siRNA increased Pgc-1alpha transcription, whereas siRNA against C/ebpbeta in HIB-1B cells decreased Pgc-1alpha and Ucp1 expression. We conclude that the increased cAMP stimulation of Pgc-1alpha expression is regulated by the combinatorial effect of transcription factors acting at the CRE on the proximal Pgc-1alpha promoter.

The association of increasing body mass index and kidney stone disease.

PURPOSE: Previous epidemiological works have reported that obesity is a risk factor for kidney stone disease. However, the effect of increasing degrees of obesity on stone formation has yet to be defined. To address this question we examined how an increasing body mass index affects the risk of kidney stone disease. MATERIALS AND METHODS: We evaluated claims from a 5-year period (2002 to 2006) in a national private insurance database to identify subjects diagnosed with or treated for kidney stones. From a data set of 95,598 patients, subjects were identified by ICD-9 or CPT codes specific to kidney stone disease. Descriptive analyses were performed and odds ratios were calculated. RESULTS: Gender distribution of the 3,257 stone formers was 42.9% male and 57.1% female. Obesity (body mass index greater than 30 kg/m(2)) was associated with a significantly greater likelihood of being diagnosed with a kidney stone. However, when obese patients were stratified by body mass index there were no significant differences in the likelihood of a kidney stone diagnosis, suggesting a stabilization of risk once body mass index increased above 30 kg/m(2). The association of body mass index and a stone removal procedure was significant only for men and women with a body mass index between 30 and 45 kg/m(2) relative to a body mass index less than 25 kg/m(2) (p <0.001). CONCLUSIONS: An obese body mass index is associated with an increased risk of kidney stone disease. However, the magnitude of this risk appears to be stable in the morbidly obese population. Once body mass index is greater than 30 kg/m(2), further increases do not appear to significantly increase the risk of stone disease.

Living alone with dementia: lack of awareness adds to functional and cognitive vulnerabilities.

BACKGROUND: Approximately 25% of individuals with dementia live alone, yet little is known about the cognitive and functional factors that impact detection of impairment. METHODS: Subjects with dementia (n = 349) from a community study of dementia management were administered the Mini-mental State Examination (MMSE) and were asked to rate their cognitive status. Each participant's knowledgeable informant (KI) was interviewed to provide information about the subject's mental health and levels of cognitive and functional impairment. Subjects with dementia living alone (n = 97, 27.8%) were compared to subjects living with others (n = 252, 72.2%) regarding functional impairment, psychiatric symptoms, cognitive functioning, and dementia recognition. RESULTS: While subjects with dementia living alone had significantly fewer ADL impairments (p < 0.0001) and less cognitive impairment (p < 0.0001) than subjects with dementia who were living with others, nearly half of subjects living alone had two or more IADL impairments. Both knowledgeable informants (p < 0.001) and primary care physicians (p < 0.009) were less likely to detect dementia in subjects living alone, while 77.3% of subjects with dementia living alone rated their cognitive abilities as "good" or "a little worse". Subjects with dementia living alone and those living with others had similar rates of psychosis (p = 0.2792) and depressive symptoms (p = 0.2076). CONCLUSIONS: Lack of awareness of cognitive impairment by individuals with dementia living alone as well as their knowledgeable informants and physicians, combined with frequent functional impairment and psychiatric symptoms, heightens risk for adverse outcomes. These findings underscore the need for increased targeted screening for dementia and functional impairment among older persons living alone.

Retraction: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag2S quantum dots emitting in the second near-infrared biological window.

Retraction of 'A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag2S quantum dots emitting in the second near-infrared biological window' by Rijun Gui et al., Dalton Trans., 2014, 43, 16690-16697, DOI: 10.1039/C4DT00699B.