Temporal and Spatial Comparison of Mercury Bioaccumulation in the Lower Trophic Levels of a Post-glacial Lake Food Web.

Total mercury (Hg) concentrations and carbon (δ13C) and nitrogen (δ15N) stable isotopes were quantified among aquatic invertebrate and sediment samples collected from Keuka Lake in New York's Finger Lakes region to evaluate temporal and spatial variability in Hg bioaccumulation and trophic ecology among these lower trophic levels. Hg concentrations ranged from 6.3 to 158.8 ng/g (dry wt) across dreissenid mussel, zooplankton, and juvenile (< 10 mm) and adult (≥ 10 mm) mysid shrimp (Mysis diluviana) samples. Hg concentrations were higher in samples collected from the western basin in 2015 relative to those for samples collected from this basin in 2022 (p < 0.001). While no specific mechanisms could be identified to explain this difference, higher δ15N values for zooplankton collected in 2015 support conclusions regarding the role of zooplankton trophic status on Hg concentrations in these populations. Spatial patterns in Hg concentrations were of generally low variability among samples collected from the lake's east, west and south basins in 2022. Trophic positions as inferred by δ15N were represented by adult mysids > juvenile mysids > large zooplankton (≥ 500 µm) > dreissenid mussels ≥ small zooplankton (64-500 µm). Differences were evident among the regression slopes describing the relationships between sample Hg concentrations and δ15N values across the lake's three basins (p = 0.028). However, this was primarily attributed to high δ15N values measured in dreissenid mussels collected from the south basin in 2022. Biota sediment accumulation factors ranged from 0.2 to 2.3 and were highest for adult M. diluviana but mysid δ13C values generally supported a pelagic pathway of Hg exposure relative to benthic sediments. Overall, these results provide additional support regarding the contributions of lower trophic levels to Hg biomagnification in aquatic food-webs.

Trifluoromethylated Phenanthroline Ligands Reduce Excited-State Distortion in Homoleptic Copper(I) Complexes.

We report the synthesis and excited-state dynamics for a series of homoleptic copper(I) trifluoromethylated phenanthroline complexes with two, three, and four trifluoromethyl functional groups. Our analysis of the steady-state absorbance and emission, transient-absorption spectroscopy, and electronic-structure-theory calculations results enable in-depth analysis of the pseudo-Jahn-Teller distortion inhibition from increased steric hindrance of the trifluoromethyl functional group relative to the prototypical dimethyl phenanthroline complex. Surprisingly, our results demonstrate that the greatest degree of pseudo-Jahn-Teller distortion inhibition is achieved with trifluoromethylation of only the 2 and 9 positions by an unusual combination of steric hindrance and stabilization of a nondistorted 1MLCT manifold observed by transient kinetic lifetimes and optimized excited-state structures. The intersystem-crossing (ISC) lifetime for the 2,9-bis(trifluoromethyl)-1,10-phenanthroline Cu(I) complex is 69 ps, while the triplet excited-state lifetime and emission quantum yield are 106 ns and 4 × 10-3, respectively. Further trifluoromethylation of the phenanthroline yields a greater σ bond inductive withdrawing force on the phenanthroline nitrogens, ultimately resulting in weaker coordination to the copper. Last, the surprising success of the 2,9-bis(trifluoromethyl)-1,10-phenanthroline Cu(I) complex by adjusting both ligand sterics and electronic properties outlines a new strategy for developing long-lived Cu(I) charge-transfer complexes.

Immune functional assay for immunosuppressive management in post-transplant malignancy.

Immunosuppression management in post-transplant malignancy is challenging because of a lack of objective immunologic assessment tools. The ImmuKnow assay measures the ATP level from CD4 T cells, quantifying cell-mediated immunity and providing an insight into the immune status of transplant recipients. Its potential use in patients with post-transplant de novo malignancy was evaluated. Thirteen adult transplant patients with de novo malignancy were divided into survivors (n = 9) and non-survivors (n = 4) after malignancy treatment. Tacrolimus and the ImmuKnow levels were monitored before, during, and after malignancy treatment. The ImmuKnow level in non-survivors group was significantly lower before and after malignancy treatment compared to survivors group (p = 0.013 and 0.0014 respectively). In survivor group, the ImmuKnow level was significantly decreased during malignancy treatment (p = 0.019) but recovered to the initial level after the treatment. However, in non-survivor group, the ImmuKnow level remained suppressed throughout the observed period despite a reduction in immunosuppressive drug levels. The ImmuKnow assay can be an objective means evaluating immune status of patients with de novo malignancy. The ImmuKnow assay can express the degree of immune suppression induced by chemotherapeutic or radiation therapy and may be a useful tool in optimizing the timing of re-introduction of immunosuppression after malignancy treatment.

Interplay between personality and antisocial peer affiliation as prospective predictors of marijuana use and academic achievement in the transition into and out of college.

Marijuana use has increased in recent cohorts and is associated with several negative outcomes, including poorer academic achievement. Less is known about how personality and peer factors in the first two years of college work together to predict problematic marijuana use and potentially co-occurring academic problems three years later. The longitudinal College Experiences Study (N = 209) was used to address this (N = 209, ~90% white, ~40% male); this study collected data from students in their first year of college, as well as ~1 year later (retention = 85%), and again ~4 years after the initial data collection (retention = 80%). Longitudinal data were analyzed via the traditional cross-lagged panel (CLPM) and the random-intercept CLPM approach. Results were consistent in that there was strong stability in problematic marijuana use, constraint, and antisocial peer affiliation across time, which were predominately influenced by stable, trait-like influences. These factors were also highly correlated but there was less evidence that one predicted the other over time. Nonetheless, greater constraint at Wave 1 was associated with significantly greater cumulative GPA in the transition out of college (ßs = 0.43-0.44). Results support the importance of early prevention and intervention of problematic marijuana use, as well as the possibility of using personality-targeted approaches in the first year of college to promote growth in behaviors related to constraint (e.g., staying organized, risk avoidant) in an effort to improve academic success and correlated substance use outcomes by the transition out of college.

Outcomes of transplantation of single pediatric renal allografts equal to or more than 6 cm in length.

BACKGROUND: Because of the donor organ shortage, kidneys from smaller pediatric donors are being increasingly used. However, it is unclear whether small pediatric deceased donor kidneys should be used as single grafts or en bloc. We reviewed our outcomes of single kidney transplants from small pediatric donors into adult recipients. METHODS: Kidneys equal to or more than 6 cm in length were transplanted as a single kidney in seven adult recipients weighing less than 80 kg. Creatinine clearance, kidney graft size, and glomerular size were followed up at 1, 3, 6, and 12 months after transplantation. RESULTS: All patients and grafts, with the exception of one patient, are currently alive with functional grafts. Two kidneys were procured after cardiac death of the donors, but no delayed graft function was observed. A total of 57% (four of seven) patients developed BK viremia, and 29% (two of seven) patients developed BK virus nephropathy. The graft size significantly increased during follow-up by ultrasonography (P=0.02). The renal allograft function by calculated creatinine clearance also significantly improved at 40.6+/-6.9 mL/min, 52.7+/-10.2 mL/min, and 66.2+/-9.7 mL/min at 1, 3, and 12 month after transplantation, respectively (P=0.01). The size of glomeruli significantly increased from 122+/-8.4 mum at 1 to 2 months to 169+/-22.5 mum at 3 to 12 months after transplantation (P<0.01). CONCLUSIONS: Kidneys equal to or more than 6 cm from small pediatric donors can be successfully transplanted as a single kidney. Single pediatric kidney transplantation can provide adequate renal function with a speedy increase in allograft size.

Modeling of sound transmission from ear canal to cochlea.

A 3-D finite element (FE) model of the human ear consisting of the external ear canal, middle ear, and cochlea is reported in this paper. The acoustic-structure-fluid coupled FE analysis was conducted on the model which included the air in the ear canal and middle ear cavity, the fluid in the cochlea, and the middle ear and cochlea structures (i.e., bones and soft tissues). The middle ear transfer function such as the movements of tympanic membrane, stapes footplate, and round window, the sound pressure gain across the middle ear, and the cochlear input impedance in response to sound stimulus applied in the ear canal were derived and compared with the published experimental measurements in human temporal bones. The frequency sensitivity of the basilar membrane motion and intracochlear pressure induced by sound pressure in the ear canal was predicted along the length of the basilar membrane from the basal turn to the apex. The satisfactory agreements between the model and experimental data in the literature indicate that the middle ear function was well simulated by the model and the simplified cochlea was able to correlate sound stimulus in the ear canal with vibration of the basilar membrane and pressure variation of the cochlear fluid. This study is the first step toward the development of a comprehensive FE model of the entire human ear for acoustic-mechanical analysis.

Pigmented villonodular synovitis: a disease in evolution.

Pigmented villonodular synovitis (PVNS) is a rare, benign, proliferative disease of the synovial membrane of joints, tendon sheaths, and bursas. Joint aspiration typically yields hemorrhagic or xanthochromic/serosanguinous (brown, murky) fluid. We describe a case of PVNS that presented as an acute, painless, nontraumatic right knee effusion with clear synovial fluid on arthrocentesis. Initial magnetic resonance imaging of the knee revealed no evidence for hemosiderin. A diagnostic arthroscopy and surgical arthrotomy revealed a unique case of PVNS evolving from local to diffuse involvement of the synovium.