ACS Publications最新文献

ConspectusDuring the past few years, the interest among organic synthesis practitioners in the use of sulfonium salts has exponentially growth. This can arguably be attributed to a series of specific factors: (a) The recent development of more direct and efficient protocols for the synthesis of these species, which make sulfonium reagents of a wide structural variety easily available in multigram scale. (b) The recognition that the reactivity of these salts resembles that of hypervalent iodine compounds, and therefore, they can be used as effective replacement of such species in most of their applications. (c) Their intrinsic thermal stability and tolerance to air and moisture, which clearly surpass that of I(III)-reagents of analogue reactivity, and facilitate their purification, isolation as well-defined species, storage, and safely handling on larger scale. (d) Finally, the possibility to further functionalize sulfonium salts once the sulfur-containing platform has been incorporated. Specifically, this last synthetic approach is not trivial when working with hypervalent I(III)-species and facilitates the access to sulfonium salts with no counterpart in the I(III) realm.This renewed interest in sulfonium salts has led to the improvement of already existing transformations as well as to the discovery of unprecedented ones; in particular, by the development of protocols that incorporate sulfonium salts as partners in traditional cross-coupling and C-H activation steps or combine them with more modern technologies such as photocatalysis or electrosynthesis. In this Account, the reactivity of a series of sulfonium salts originally prepared in our laboratory will be outlined and compared to their I(III)-counterparts. Some of these reagents are now commercially available, and their use has started to spread widely across the synthetic chemistry community, helping to speed the process of identification of potentially bioactive products or new functionaliced materials. However, challenges still remain. The development of sulfonium reagents characterized by an optimal balance between reactivity and site-selectivity, or showing broader compatibility toward sensitive functional groups is still a need. In addition, the intrinsic stability of sulfonium salts often makes necessary the use of (sophisticated) catalysts that activate the latent reactivity hidden in their structures. Although a priori one can see this fact as a disadvantage, it might actually be decisive to harvest the full synthetic potential of sulfonium salts because their thermal stability will surely facilitate the preparation of operational reagents with no counterpart in the context of I(III)-chemistry. If this becomes true, sulfonium salts may contribute to the expediting of retrosynthetic disconnections that, to date, are impossible.

Abnormal amyloid beta (Aβ) aggregation in the form of plaques and its deposition across the human nerve cells are a major hallmark of Alzheimer's disease. Aβ aggregation dynamics and, more importantly, various drugs' effects, either to inhibit the fibril aggregation or to degrade the mature fibrils, have been an area of active research. Large molecule (peptide-based) inhibitors, such as decapeptide (RYYAAFFARR) and pentapeptide (LPFFD), show inhibition/degradation effects on amyloid beta fibrils. Herein, a mathematical model has been proposed. The model simulates Aβ aggregation and inhibitory/degradative action of peptide inhibitors on Aβ fibrillation. Model parameters are tuned by curve fitting the experimental data. The tuned model is used to predict experimental data at different initial dose/fibril concentrations. Model predicted results are observed to be in good agreement with the reported experimental data, demonstrating model's applicability at the molecular level. Sensitivity analyses of the model parameters on the fibril concentration further establish the robustness of the proposed model.

Previous research has established that juveniles who experience negative parental influence are more likely to engage in problem and offending behavior. Less attention has been given to the possibility that criminal thinking styles might partially explain this relationship. This study examined the negative parental influences and criminal thinking styles of 1,354 juvenile offenders to establish that both negative parental influences and criminal thinking are significantly associated with juvenile problem and offending behavior. Further, the analysis showed that juvenile criminal thinking (proactive, reactive, and general) might mediate the relationship between negative parental influences and problem behavior. Implications for such findings are discussed.

Background: Spinal dysraphism is characterized by failure of fusion at dorsal midline structures through the embryonic developmental stages. A terminal myelocystocele consists of a skin-covered lumbosacral spina bifida and meningocele that directly continuous with the spinal subarachnoid space.

Observation: A 43-year-old woman who was diagnosed at birth with myelocystocele in the lower segments of the lumbar spine. She was not operated in the early stages of life. At the 43th years of her old, during 9-months, the sac began to progressively increase in size. In our initial examination before surgery, an extremely large skin-covered myelocystocele sac was observed in the thoracolumbar with a diameter of approximately 60 * 70 * 40 cm. patient operated and sac repaired. More than 20 liter of cerebrospinal fluid drainaged from cyst during surgery.

Lessons: The mechanism of cyst enlargement is not well understood. Progressive and severe increase in size of unrepaired myelocystocele sac is possible in old ages even without cerebral hydrocephalus.

Most pituitary adenoma/neuroendocrine tumours (PitNET) are histologically benign and grow slowly; however, a subset of these tumours exhibit a more aggressive clinical course characterized by local invasiveness and early recurrence. These high-risk PitNETs often require multiple surgeries and radiation over several years and may eventually acquire carcinomatous characteristics, such as metastasis in some cases. Herein, we report a rare case of PitNET causing oculomotor paresis with extremely rapid recurrence only 3 months after initial surgery, followed by lethal liver metastasis. Preoperative magnetic resonance imaging and intraoperative findings were consistent with typical PitNETs, other than moderate invasion of the cavernous sinus. Pathological examination of the specimen obtained from the initial transsphenoidal surgery revealed increased mitosis and elevated rates of cells positive for Ki-67 and p53. Based on the immunohistochemical assessment for transcription factors and pituitary hormones, the diagnosis was determined to be a silent sparsely granulated corticotroph PitNET with focal malignant transformation. Aggressive features represented by Ki-67 and p53 positivity were more robust in recurrent and metastatic specimens, but hormone immunostaining was decreased. Epigenetic analysis revealed methylation of the telomerase reverse transcriptase (TERT) promoter in the tumour, resulting in TERT upregulation. Despite extensive research, markers for distinguishing extremely aggressive PitNETs have not been determined. Although further analysis is needed, our case demonstrates the possible usefulness of assessing TERT promoter methylation status in the stratification of recurrence risk in extremely high-risk variants of PitNET.

Background: Dropped head syndrome (DHS) is a recently recognised cause of cervical spinal deformity and disability. The combination of Parkinson's disease (PD) and inflammatory myopathy in the genesis of DHS has not been previously reported. Furthermore, the optimal surgical treatment of progressive DHS remains undefined.

Case description: We report the case of a 64-year-old patient with severe DHS and coronal plane deformity secondary to underlying PD, precipitated by a focal paraspinal myositis, successfully corrected using asymmetric sternocleidomastoid (SCM) release and circumferential cervical fusion. The nuances of decision-making in this challenging patient population are highlighted, including the benefits of intraoperative traction, anterior column reconstruction and bicortical screw fixation. Postoperatively, significant reductions in pain and disability were achieved, along with restoration of cervical lordosis (CL), C2-7 sagittal vertical axis (CSVA) and chin-brow vertical angle (CBVA).

Conclusions: Circumferential cervical fusion with concomitant SCM release is a useful option in the treatment of recalcitrant DHS with biplanar deformity, addressing the unique biomechanical and endocrinological challenges posed by patients with underlying PD.

While anterior lumbar interbody fusion (ALIF) is known as an established and safe procedure for treatment of degenerative disc disease, albeit rare, the development of postoperative intra-abdominal or retroperitoneal collection of lymph warrants timely diagnosis and management. This study presents the case of a 62-year-old male who underwent L4-L5 and L5-S1 ALIF and developed a persistent left-sided fluid collection, resulting in a symptomatic retroperitoneal lymphocele confirmed by computed tomography (CT). After percutaneous drainage by interventional radiology (IR), output remained high at 1 liter (L) per day, necessitating sclerotherapy with doxycycline and ethanol. In the absence of improvement, a lymphangiogram demonstrating a persistent lymph leak and glue embolization was performed. Due to refractory symptoms, retroperitoneal exploration with methylene blue dye was utilized for lymphatic mapping, and a lymphatic capillary leak in proximity to the left iliac artery was identified and successfully ligated with resolution of symptoms. With suspected fluid collections following ALIF, confirmation with CT or ultrasound (US) imaging followed by percutaneous drainage and testing of fluid is necessary. In mild cases, drainage alone or nonsurgical chemical sclerotherapy may suffice. In symptomatic refractory cases, localization of the site with lymphangiogram or US-guided injection of methylene blue dye allows for easier identification and definitive management with either transabdominal laparoscopic fenestration or retroperitoneal surgical exploration and ligation.

We present a general framework for causal mediation analysis using nonparametric Bayesian methods in the potential outcomes framework. Our model, which we refer to as the Bayesian causal mediation forests model, combines recent advances in Bayesian machine learning using decision tree ensembles, Bayesian nonparametric causal inference, and a Bayesian implementation of the g-formula for computing causal effects. Because of its strong performance on simulated data and because it greatly reduces researcher degrees of freedom, we argue that Bayesian causal mediation forests are highly attractive as a default approach. Of independent interest, we also introduce a new sensitivity analysis technique for mediation analysis with continuous outcomes that is widely applicable. We demonstrate our approach on both simulated and real data sets, and show that our approach obtains low mean squared error and close to nominal coverage of 95% interval estimates, even in highly nonlinear problems on which other methods fail. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

The current guidelines for estimating reliability recommend using two omega combinations in multidimensional data. One omega is for factor analysis (FA) reliability estimators, and the other omega is for omega hierarchical estimators (i.e., ω_h). This study challenges these guidelines. Specifically, the following three questions are asked: (a) Do FA reliability estimators outperform non-FA reliability estimators? (b) Is it always desirable to estimate ω_h? (c) What are the best reliability and ω_h estimators? This study addresses these issues through a Monte Carlo simulation of reliability and ω_h estimators. The conclusions are given as follows. First, the performance differences among most reliability estimators are small, and the performance of FA estimators is comparable to that of non-FA estimators. However, the current, most-recommended estimators, that is, estimators based on the bifactor model and exploratory factor analysis, tend to overestimate reliability. Second, the accuracy of ω_h estimators is much lower than that of reliability estimators, so we should perform ω_h estimation selectively only on data that meet several requirements. Third, exploratory bifactor analysis is more accurate than confirmatory bifactor analysis only in the presence of cross-loading; otherwise, exploratory bifactor analysis is less accurate than confirmatory bifactor analysis. Fourth, techniques known to improve the Schmid-Leiman (SL) transformation are not superior to SL transformation but have different advantages. This study provides an R Shiny app that allows users to obtain multidimensional reliability and ω_h estimates with a few mouse clicks. (PsycInfo Database Record (c) 2025 APA, all rights reserved).