Field-induced Bose-Einstein condensation in zigzag spin chain KGaCu(PO4)2

Single crystals of GaKCu(PO4)2were synthesized using the hydrothermal method, and subsequent measurements of specific heat, magnetic susceptibility, and high-field magnetization were performed. A broad peak is observed in the magnetic susceptibility and specific heat curves, with the maximum values appearing at about 11.5 K and 5.29 K, respectively. The highest maximum peak value of susceptibility is observed when the magnetic field is applied along thec-axis, followed by thea-axis,b-axis, and polycrystalline samples. These indicate that the system exhibits one-dimensional magnetism and the magnetic easy axis is thecaxis. The magnetization at 2 K reveals the occurrence of a field-induced Bose-Einstein condensation (BEC) phase within the magnetic field range of approximately 8-12 T. High-field magnetization up to 40 T indicates that the compound reaches magnetization saturation as the field exceedsHs= 12 T. Through systematic measurements, a field-temperature (H-T) phase diagram was constructed, and dome-like phase boundaries were observed. The findings suggest that GaKCu(PO4)2is a spin gap system and a promising candidate for studying BEC of magnons due to its phase transition boundary occurring at low magnetic fields.

[Clinical effect of modified vertical rectus abdominis myocutaneous flap in repairing skin and soft tissue defects after abdominoperineal resection for rectal cancer]

Objective: To investigate the clinical effect of the modified vertical rectus abdominis myocutaneous flap in repairing the skin and soft tissue defect after abdominoperineal resection for rectal cancer. Methods: This study was a retrospective observational study. From June 2019 to July 2022, five male patients with low rectal cancer who were conformed to the inclusion criteria were admitted to the Department of Basic Surgery of Xiangya Hospital of Central South University, with ages ranging from 65 to 70 years and the sizes of the perianal skin ulcers ranging from 5 cm×4 cm to 11 cm×9 cm, and all of them underwent abdominoperineal resection. The secondary skin and soft tissue defects in the perineum with an area of 8 cm×6 cm-14 cm×12 cm (with the depth of pelvic floor dead space being 10-15 cm) were repaired intraoperatively with transplantation of modified vertical rectus abdominis myocutaneous flaps with the skin area being 9 cm×7 cm-16 cm×12 cm, the volume of the muscle being 18 cm×10 cm×5 cm-20 cm×12 cm×5 cm, and the vessel pedicle being 18-20 cm in length. During the operation, most of the anterior sheath of the rectus abdominis muscle was retained, the flap was transferred to the recipient area through the abdominal cavity, the remaining anterior sheaths of the rectus abdominis muscle on both sides of the donor area were repeatedly folded and sutured, the free edge of the transverse fascia of the abdomen was sutured with the anterior sheath of the rectus abdominis muscle, and the donor area skin was directly sutured. After the operation, the survival of the transplanted myocutaneous flap was observed. The occurrence of complications in the perineal recipient area was recorded within 2 weeks after the operation. The recovery of the perineal recipient area and the abdominal donor area was observed during follow-up, and the occurrence of complications in the donor area of the abdomen as well as the recurrence of tumors and metastasis were recorded. Results: All transplanted myocutaneous flaps in 5 patients survived after surgery. One patient had dehiscence of the incision in the perineal recipient area 2 days after surgery, which healed after 7 d with intermittent dressing changes and routine vacuum sealing drainage treatment. In the other 4 patients, no complications such as incisional rupture, incisional infection, or fat liquefaction occurred in the perineal recipient area within 2 weeks after surgery. Follow-up for 6-12 months after discharge showed that the skin of the perineal recipient area had good color, texture, and elasticity, and was not bloated in appearance; linear scars were left in the perineal recipient area and the abdominal donor area without obvious scar hyperplasia or hyperpigmentation; no complications such as incisional rupture, incisional infection, intestinal adhesion, intestinal obstruction, or weakening of the abdominal wall strength occurred in the abdominal donor area, and the abdominal appearance was good with no localized bulge or formation of abdominal hernia; there was no local recurrence of tumor or metastasis in any patient. Conclusions: The surgical approach of using the modified vertical rectus abdominis myocutaneous flap to repair the skin and soft tissue defects after abdominoperineal resection for rectal cancer is relatively simple in operation, can achieve good postoperative appearances of the donor and recipient areas with few complications, and is worthy of clinical promotion.

Energetic Electron Precipitation Driven by Electromagnetic Ion Cyclotron Waves from ELFIN's Low Altitude Perspective

We review comprehensive observations of electromagnetic ion cyclotron (EMIC) wave-driven energetic electron precipitation using data collected by the energetic electron detector on the Electron Losses and Fields InvestigatioN (ELFIN) mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000 keV electrons with good pitch-angle and energy resolution. EMIC wave-driven precipitation exhibits a distinct signature in energy-spectrograms of the precipitating-to-trapped flux ratio: peaks at >0.5 MeV which are abrupt (bursty) (lasting ∼17 s, or Δ L ∼ 0.56 ) with significant substructure (occasionally down to sub-second timescale). We attribute the bursty nature of the precipitation to the spatial extent and structuredness of the wave field at the equator. Multiple ELFIN passes over the same MLT sector allow us to study the spatial and temporal evolution of the EMIC wave - electron interaction region. Case studies employing conjugate ground-based or equatorial observations of the EMIC waves reveal that the energy of moderate and strong precipitation at ELFIN approximately agrees with theoretical expectations for cyclotron resonant interactions in a cold plasma. Using multiple years of ELFIN data uniformly distributed in local time, we assemble a statistical database of ∼50 events of strong EMIC wave-driven precipitation. Most reside at L ∼ 5 - 7 at dusk, while a smaller subset exists at L ∼ 8 - 12 at post-midnight. The energies of the peak-precipitation ratio and of the half-peak precipitation ratio (our proxy for the minimum resonance energy) exhibit an L -shell dependence in good agreement with theoretical estimates based on prior statistical observations of EMIC wave power spectra. The precipitation ratio's spectral shape for the most intense events has an exponential falloff away from the peak (i.e., on either side of ∼ 1.45 MeV). It too agrees well with quasi-linear diffusion theory based on prior statistics of wave spectra. It should be noted though that this diffusive treatment likely includes effects from nonlinear resonant interactions (especially at high energies) and nonresonant effects from sharp wave packet edges (at low energies). Sub-MeV electron precipitation observed concurrently with strong EMIC wave-driven >1 MeV precipitation has a spectral shape that is consistent with efficient pitch-angle scattering down to ∼ 200-300 keV by much less intense higher frequency EMIC waves at dusk (where such waves are most frequent). At ∼100 keV, whistler-mode chorus may be implicated in concurrent precipitation. These results confirm the critical role of EMIC waves in driving relativistic electron losses. Nonlinear effects may abound and require further investigation.

High-field magnetization and electronic spin resonance study in the twisted honeycomb latticeα-Mn2V2O7

We report the single-crystal growth of Mn₂V₂O₇and the results of magnetic susceptibility, high-field magnetization up to 55 T and high-frequency electric spin resonance (ESR) measurements for its low-temperatureαphase. Two antiferromagnetic (AFM) ordering at 17.5 K and 3 K and obvious magnetic anisotropy are observed inα-Mn₂V₂O₇upon cooling. In pulsed high magnetic fields, the compound reaches the saturation magnetic moment of ∼10.5μ_Bfor each molecular formula at around 45 T after two undergoing AFM phase transitions atH_c1≈ 16 T,H_c2≈ 34.5 T forH//[11-0] andH_sf1= 2.5 T,H_sf2= 7 T forH//[001]. In these two directions, two and seven resonance modes are detected by ESR spectroscopy, respectively. Theω₁andω₂modes ofH//[11-0] can be well described by two-sublattice AFM resonance mode with two zero-field gaps at 94.51 GHz and 169.28 GHz, indicating a hard-axis feature. The seven modes forH//[001] are partially separated by the critical fields ofH_sf1andH_sf2, displaying the two signs of spin-flop transition. The fittings ofω_c1andω_c2modes yield zero-field gaps at 69.50 GHz and 84.73 GHz forH//[001], confirming the axis-type anisotropy. The saturated moment and gyromagnetic ratio indicate the Mn²⁺ion inα-Mn₂V₂O₇is in a high spin state with orbital moment completely quenched. A quasi-one-dimensional magnetism with a zig-zag-chain spin configuration is suggested inα-Mn₂V₂O₇, due to the special neighbor interactions caused by a distorted network structure with honeycomb layer.

Origin of the Ligand Ring-Size Effect on the Catalytic Activity of Cationic Calcium Hydride Dimers in the Hydrogenation of Unactivated 1-Alkenes

Recently, it was shown that the double Ca-H-Ca-bridged calcium hydride cation dimer [LCaH₂ CaL]²⁺ when stabilized by a larger macrocyclic N,N',N'',N''',N''''-pentadentate ligand showed evidently higher activity than when stabilized by a smaller N,N',N'',N'''-tetradentate ligand in the catalytic hydrogenation of unactivated 1-alkenes. In this DFT-mechanistic work, the origin of the observed ring-size effect is examined in detail using 1-hexene, CH₂ =CH₂ and H₂ as substrates. It is shown that, at room temperature, both the N,N',N'',N''',N''''-stabilized dimer and the monomer are not coordinated by THF in solution, while the corresponding N,N',N'',N'''-stabilized structures are coordinated by one THF molecule mimicking the fifth N-coordination. Catalytic 1-alkene hydrogenation may occur via anti-Markovnikov addition over the terminal Ca-H bonds of transient monomers, followed by faster Ca-C bond hydrogenolysis. The higher catalytic activity of the larger N,N',N'',N''',N''''-stabilized dimer is due to not only easier formation of but also due to the higher reactivity of the catalytic monomeric species. In contrast, despite unfavorable THF-coordination in solution, the smaller N,N',N'',N'''-stabilized dimer shows a 3.2 kcal mol^-1 lower barrier via a dinuclear cooperative Ca-H-Ca bridge for H₂ isotope exchange than the large N,N',N'',N''',N''''-stabilized dimer, mainly due to less steric hindrance. The observed ring-size effect can be understood mainly by a subtle interplay of solvent, steric and cooperative effects that can be resolved in detail by state-of-the-art quantum chemistry calculations.

Reactions of Diethylazo-Dicarboxylate with Frustrated Lewis Pairs

Reactions of PAr₃ /B(C₆ F₅ )₃ (Ar=o-Tol, Mes, Ph) FLPs with diethyl azodicarboxylate (DEAD) afford the corresponding FLP addition products 1-3 in which P-N and B-O linkages are formed. In contrast, the reaction of BPh₃ , PPh₃ and DEAD gave product 4 where P-N and N-B linkages were confirmed. In all cases, other binding modes were computed to be both higher in energy and readily distinguishable by ³¹ P and ¹¹ B NMR parameters. These data illustrate the influence of steric demands and electronic structures on the nature of the products of FLP reactions with DEAD.

Reactions of Frustrated Lewis Pairs with Chloro‐Diazirines: Cleavage of N=N Double Bonds

The reactions of FLPs with diazomethanes leads to the rapid loss of N₂. In contrast, in this work, we reported reactions of phosphine/borane FLPs with chlorodiazirines which led to the reduction of the N=N double bond, affording linked phosphinimide/amidoborate zwitterions of the general form R₃PNC(Ar)NR′BX(C₆F₅)₂. A detailed DFT mechanistic study showed that these reactions proceed via FLP addition to the N=N bond, followed by subsequent group transfer reactions to nitrogen and capture of the halide anion.

The Varied Frustrated Lewis Pair Reactivity of the Germylene Phosphaketene (CH{(CMe)(2,6‐ i Pr 2 C 6 H 3 N)} 2 )GePCO

The germylene species (CH{(CMe)(2,6‐iPr₂C₆H₃N)}₂)GePCO 1 is shown to react with the Lewis acids (E(C₆F₅)₃ E=B, Al). Nonetheless, 1 participates in FLP chemistry with electron deficient alkynes or olefins, acting as an intramolecular FLP. In contrast, in the presence of B(C₆F₅)₃ and an electron rich alkyne, 1 behaves as Ge‐based nucleophile to effect intermolecular FLP addition to the alkyne. This reactivity demonstrates that the reaction pathway is controlled by the nature of the electrophile and nucleophile generated in solution, as revealed by extensive DFT calculations.

The molecular basis of spinocerebellar ataxia type 48 caused by a de novo mutation in the ubiquitin ligase CHIP

The spinocerebellar ataxias (SCAs) are a class of incurable diseases characterized by degeneration of the cerebellum that results in movement disorder. Recently, a new heritable form of SCA, spinocerebellar ataxia type 48 (SCA48), was attributed to dominant mutations in STIP1 homology and U box-containing 1 (STUB1); however, little is known about how these mutations cause SCA48. STUB1 encodes for the protein C terminus of Hsc70 interacting protein (CHIP), an E3 ubiquitin ligase. CHIP is known to regulate proteostasis by recruiting chaperones via a N-terminal tetratricopeptide repeat domain and recruiting E2 ubiquitin-conjugating enzymes via a C-terminal U-box domain. These interactions allow CHIP to mediate the ubiquitination of chaperone-bound, misfolded proteins to promote their degradation via the proteasome. Here we have identified a novel, de novo mutation in STUB1 in a patient with SCA48 encoding for an A52G point mutation in the tetratricopeptide repeat domain of CHIP. Utilizing an array of biophysical, biochemical, and cellular assays, we demonstrate that the CHIPA52G point mutant retains E3-ligase activity but has decreased affinity for chaperones. We further show that this mutant decreases cellular fitness in response to certain cellular stressors and induces neurodegeneration in a transgenic Caenorhabditis elegans model of SCA48. Together, our data identify the A52G mutant as a cause of SCA48 and provide molecular insight into how mutations in STUB1 cause SCA48.

Case Report. Cryoglobulin Hyaline-thrombi Associated Acute Jejunitis in A Patient with Type 2 Cryoglobulinemic Glomerulonephritis

Introduction/Objective

Only one prior case report indicates that mixed positive cryoglobulin in serum can be associated with intestinal vasculitis (Annals of Internal Medicine, 1974).

Methods/Case Report

We report a 63-year old man with history of positive serum cryoglobulin and hepatitis-C 4 years ago and membranoproliferative pattern of glomerulonephritis with possible cryoglobulin type of deposits by electron microscopy on renal biopsy. After treatment, his hepatitis C became negative. But he was recently found to have monoclonal IgM-kappa and positive cryoglobulin in his serum, and the concurrent renal biopsy showed membranoproliferative pattern of glomerulopathy with many hyaline-thrombi (eosinophilic vascular occlusions with no lamination, inflammatory cells or nuclear debris) in the glomerular capillary loops (Figure, left panel). Both immunofluorescent and electron microscopy confirmed a mixed IgG polyclonal and IgM monoclonal type 2 cryglobulinemic glomerulonephritis. The patient also developed abdominal pain and underwent intestinal endoscopy with biopsy. His jejunal biopsy revealed neutrophil infiltration into glands and surface epithelium, with superficial sloughed epithelial cells, consistent with acute jejunitis with features of ischemic etiology. In addition, hyaline-thrombi were identified in the submucosal vessels with surrounding vasculitis (Figure, right panel); the central part of thrombi was morphologically similar to that found in glomerular capillary loops. Therefore, we conclude that cryoglobulin associated hyaline-thrombi were the most likely etiology to cause the acute ischemic jejunitis in this patient.

Results (if a Case Study enter NA)

NA

Conclusion

NA

GATA3 Is a Useful Immunohistochemical Marker to Differentiate Variants of Renal Tubular Lesions from Different Segments of Renal Tubules

Introduction/Objective

GATA3 is found in glomerular mesangial cells, and the distal tubules & collecting ducts in metanephros and eventual kidneys, but not associated with the proximal tubules and loops of Henle. We hypothesize that GATA3 can be used as a marker to identify the origin of tubular differentiation in most renal tumors.

Methods/Case Report

Ten negative controls and 43 renal mass lesions (RCC, papillary, clear cell papillary, and chromophobe carcinomas, oncocytoma, and polycystic kidney disease). GATA3 nuclear stain was graded as negative (absent stain), equivocal and positive (< 5 and > 5% cells, respectively). Details of their GATA3 nuclear expression was analyzed for identifying their tubular segmental origins.

Results (if a Case Study enter NA)

In 10 normal renal parenchyma, GATA3 was positive in mesangial cells, distal tubules, and collecting ducts, but was negative in the proximal tubules and loop of Henle. The cystic lining of glomerulocystic renal disease was stained negatively for GATA3 (proximal tubular origin), whereas pediatric and adult variants of polycystic kidney diseases was positive for GATA3 staining (distal tubular origin). 1/10 ten clear cell RCC and papillary RCC showed focal positive GATA3 stain. GATA3 showed weakly positive staining in some oncocytomas (4/11) and some chromophobe RCC (4/11), indicating that they might be derived from the junctional segment between the loop of Henle and the distal tubules. By contrast, all clear cell papillary RCC (distal tubule origin) were diffusely positive.

Conclusion

Our results indicate that GATA3 is a useful immunohistochemical marker to determine the developmental origin in the specific renal tubular segment for the majority of renal mass lesions. Thus, it may be useful for routine differential diagnosis of these lesions.

Increased Activated Plasma Cells in Inflammatory Bowel Disease When Compared to Ischemic Acute Colitis

Introduction/Objective

Inflammatory bowel disease (IBD) and acute ischemic colitis can both be involved by active colitis. IBD is characterized by crypt architectural distortion, basal lymphoplasmacytosis, and occasional granulomatous changes. However, diagnosis of IBDs is still largely by exclusion of other types of active colitis with similar changes. We previously demonstrated that glucose regulated protein 94 (grp94) is mainly expressed by activated plasma cells. We postulate that increased numbers of grp94-positive plasma cells may support diagnosis of IBDs. Here, we compared IBD and active ischemic colitis for grp94 expression in mucosal plasma cells of colectomy specimens

Methods/Case Report

Tissue sections from colectomy specimens with active IBD (n = 8) and ischemic colitis (n = 7) were examined for grp94 expression by immunohistochemistry (monoclonal antibody clone 9G10 at dilution of 1:200, Enzo Life Science, Inc Farmindale, NY). The staining intensity and highest number of grp94 in plasma cells per high power field was counted and recorded for each case, and combined scores were calculated as # of plasma cells multiplied by staining intensity (ranging from 0 to 3+). Unpaired student T tests were used to compare these indices between the two groups for statistical significance (p value < 0.05 was considered significantly different)

Results (if a Case Study enter NA)

Plasma cells in lamina propria identified by grp94 staining showed higher intensity in IBD than ischemic groups. The number of plasma cells and combined scores were also significantly higher in the IBC group than that of ischemic group

Conclusion

Our data indicates that active plasma cells are much more numerous in IBD than ischemic colitis, supporting the notion that active plasma cells are involved in the development of this disease process. Morphologically, active colitis with increased number of plasma cells appears to be another index favoring the diagnosis of IBD.

Utilization of 2D Barcode Technology to Create Surgical Pathology Reports

Introduction/Objective

After professional transcription service is eliminated, pathologists inevitably undertake the task of diagnostic data entry into pathology repot by adapting a variety of methods such as speech recognition, manual typing, and pre-texted command. Errors and inefficiency in reporting remain common problems, especially for information with unusual syntax such as genotype or nucleotide sequences. To overcome these shortcomings, we introduce here a novel application of a well-established technology as a complementary method, namely 2- dimensional (2D) barcode symbology.

Methods/Case Report

Commonly used diagnostic wordings of pathology reports including specimen type, surgical procedure, diagnosis, and test results are collated and organized by organ (specimen type) and by their frequency of usage/occurrence. Next, 2D data matrix barcodes are created for these diagnostic wordings using a on-line tool (www.free-barcode-generator.net/datamatrix/). The 2D barcodes along with their text are displayed on the computer screen (or printed out as a booklet). A 2D barcode scanner (Symbol LS2208, Motorola) was used to retrieve the text information from the barcodes and transfer into the pathology report. To assess the efficacy of this barcode method, we evaluated the time of data entry into reports for 117 routine cases using an on-line stopwatch and compared with those by other data entry methods.

Results (if a Case Study enter NA)

Unlike manual typing or speech recognition, the barcode method did not introduce typographic or phonosemantic errors since the method simply transferred pre-texted and proof-read text content to report. It was also faster than manual typing or speech recognition, and its speed was comparable to that of the pre-text method integrated in LIS but did not require human memorization of innumerable text commands to retrieve desired diagnosis wordings.

Conclusion

Our preliminary results demonstrated that the diagnostic data entry time was reduced from 28.5% by other methods to 22.1% by the barcode method although due to the small sample size, statistical analysis was not conclusive.

Reactions of B2 (o-tolyl)4 with Boranes: Assembly of the Pentaborane(9), HB[B(o-tolyl)(μ-H)]4

Reactions of the diborane(4) B2 (o-tolyl)4 and monohydridoboranes are shown to give B(o-tolyl)3 and (o-tolyl)BR2 (R2 =(C8 H14 ) 3, cat 4, pin 5, (C6 F5 )2 6) as the major products. The corresponding reaction with BH3 -sources gives complex mixtures, resulting from hydride/aryl exchange, dimerization and borane elimination. This led to the isolation of the first tetra-substituted pentaborane(9) HB[B(o-tolyl)(μ-H)]4 8. The reaction pathways are probed experimentally and by computations.

The Reactivity of Isomeric Nitrenium Lewis Acids with Phosphines, Carbenes, and Phosphide

Alkylation of spiro[fluorene‐9,3’‐indazole] at N(1) and N(2) with tBuCl affords the nitrenium cations [C₆H₄N₂(tBu)C(C₁₂H₈)][BF₄], 1 and 2, respectively. Compound 1 converts to 2 over the temperature range 303–323 K with a free energy barrier of 28±5 kcal mol⁻¹. Reaction of 1 with PMe₃ afforded the N‐bound phosphine adduct [C₆H₄N(tBu)N(PMe₃)C(C₁₂H₈)]BF₄] 3. However, phosphines attack 2 at the para‐carbon atom of the aryl group with concurrent cleavage of N(2)−C(1) bond and proton migration to C(1) affording [(R₃P)C₆H₃NN(tBu)CH(C₁₂H₈)][BF₄] (R=Me 4, nBu 5). Analogous reactions of 1 and 2 with the carbene SIMes prompt attack at the para‐carbon with concurrent loss of H^. affording the radical cation salts [(SIMes)C₆H₃N(tBu)NC(C₁₂H₈)^.][BF₄] 6 and [(SIMes)C₆H₃NN(tBu)C(C₁₂H₈)^.][BF₄] 7, whereas reaction of 2 with BAC gives the Lewis acid‐base adduct, [C₆H₄N(BAC)N(tBu)C(C₁₂H₈)][BF₄] 8. Finally, reactions of 1 and 2 with KPPh₂ result in electron transfer affording (PPh₂)₂ and the persistent radicals C₆H₄N(tBu)NC(C₁₂H₈)^. and C₆H₄NN(tBu)C(C₁₂H₈)^.. The detailed reaction mechanisms are also explored by extensive DFT calculations.

Urinary microRNAs miR-15b and miR-30a as novel noninvasive biomarkers for gentamicin-induced acute kidney injury

MicroRNAs serve as potential biomarkers in various pathological models, and are stable and detectable in biofluids. We investigated the urinary microRNA expression profile in a gentamicin-induced acute kidney injury canine model using RNA sequencing. A total of 234 differentially expressed microRNAs were screened after 12 consecutive days of gentamicin administration (P < 0.05). Six candidate microRNAs (miR-15b, -15b-3p, -16, -30a, -30a-3p, and -30c-2-3p) were selected according to a set criterion, and validated by real-time quantitative PCR. The diagnostic values of these six candidate microRNAs were better than the traditional serum biomarkers (all P < 0.05). Further, using receiver operating characteristic curve analysis, we found that miR-15b and -15b-3p were superior to urinary kidney injury molecule-1 (both P < 0.05). Moreover, miR-15b and -30a levels in the urine samples significantly correlated with their respective levels in the kidney tissue samples (r=0.512 and 0.505, respectively, both P < 0.05). Our data concluded that miR-15b and -30a may be promising biomarkers for renal toxicity.

Management of cN0 papillary thyroid microcarcinoma patients according to risk-scoring model for central lymph node metastasis and predictors of recurrence

BACKGROUND

The role of routine prophylactic central neck dissection (pCND) in clinically lymph node-negative (cN0) papillary thyroid microcarcinoma (PTMC) patients remains controversial. This retrospective study aimed to identify the clinical and pathologic factors of central lymph node metastasis (CLNM) and recurrence in PTMC patients.

METHODS

A total of 371 cN0 PTMC patients from two hospitals were retrospectively analyzed. All patients underwent thyroidectomy plus pCND between January 2010 and January 2018. Clinicopathological features were collected, univariate and multivariate analyses were performed to determine the risk factors of CLNM. A scoring model was constructed on the basis of the results of independent risk factors of CLNM. The Cox proportional hazards model was used to analyze the risk factors of recurrence.

RESULTS

CLNM occurred in 123 (33.2%) patients. Multivariate analysis showed male, tumor size > 0.75 cm, multifocality, extrathyroidal extension (ETE) and tumor in the middle/lower pole were independent risk predictors of CLNM (P < 0.05). A seven-point risk-scoring model was established to predict the stratified CLNM in cN0 PTMC patients. Multivariate Cox regression model showed ETE, vascular invasion and CLNM were independent risk predictors of recurrence (P < 0.05).

CONCLUSION

Our study suggested that routine pCND should be performed for cN0 PTMC patients with score ≥ 3 according to the risk-scoring model. Moreover, patients with risk factors of recurrence should consider more complete treatment and more frequent follow-up.

[Analysis of the hard and soft tissue following immediate and early implant placement in the anterior area of maxilla]

Objective: To compare the difference of soft and hard tissue changes between immediate implant and early implant placement in maxillary anterior region, so as to provide the basis for the selection of implant timing and surgical method for patients in clinical maxillary anterior dental esthetic zone. Methods: From January 2016 to January 2019, 89 patients [48 males and 41 females, aged (38.0±13.3) years] with dentition defect and single tooth implant restoration in the Department of Oral Implantology, Dalian Stomatological Hospital were retrospectively collected. The patients were divided into three groups according to different implant timing and operation methods: immediate implant flapless group (26 cases), immediate implant flap group (30 cases) and early implant group (33 cases, early implant 4-8 weeks after tooth extraction). The operation time, intraoperative and postoperative complications were compared among the three groups. Cone-beam CT was taken before operation, immediately after operation and 6 months after operation. The bone plate thickness immediately after implantation, bone plate thickness at 6 months after operation and absorption amount of bone plate thickness at labial side (immediately after operation minus 6 months after operation) were measured, and the absorption rate of labial bone plate was calculated. Three dimensional quantitative analysis was performed on the lip bone increment, residual bone volume (6 months after operation minus preoperative), and bone volume absorption rate of the three groups immediately after operation by using GuideMia, PlastyCAD and Geomagic engineering software. The pink and white esthetic indexes of the three groups were evaluated at 9 months and 15 months after implant placement. The implant stability quotient (ISQ) value was measured at 6 months after implantation, and the patients' satisfaction with the whole treatment process was investigated at 6 months after implantation. Results: The operation time of immediate implant flapless group was the shortest, the median (lower quartile, upper quartile) was 36.5 (33.3, 38.5) min. At 9 months after operation, PES was relatively high [8.5 (8.0, 9.0)], and the final patient satisfaction was 8.0 (7.3, 8.8), and the difference was statistically significant compared with the other two groups (P<0.05). There was no significant difference in the incidence of intraoperative and postoperative complications among the groups (P>0.05). At 6 months after operation, the thickness of labial bone plate in early group was 3.09 (3.00, 3.25) mm, which was greater than that in the immediate non flap group [1.90 (1.72, 2.33) mm] and that in the immediate implant flap group [2.39 (2.05, 3.06) mm], and the difference was statistically significant (P<0.05). The absorption of labial bone thickness in immediate implant flapless group [0.61 (0.35, 0.98) mm] was significantly lower than that in the immediate implant flap group [1.13 (0.97, 1.53) mm] and that in the early implant group [1.23 (1.07, 1.37) mm] (P<0.05). After 6 months, the residual bone volume of immediate flapless group was 38.7 (31.2, 54.6) mm³ and was significantly different from that in early implant group [109.1 (85.6, 263.1) mm³] (P<0.05), and there was no significant difference in the residual bone volume between immediate implant flapless group and immediate implant flap group (P>0.05). Conclusions: Immediate implant can reduce the treatment time with equal esthetic outcome of implant supported restoration of anterior teeth, and patients prefer it more. The bone volume of lip side was not significantly increased after immediate flap operation, and the bone absorption was less after immediate flap operation. Early implant placement can better maintain the three-dimensional bone mass, and the three groups can obtain good clinical results in the short term, but the long-term effect needs further follow-up study.

[Risk factors of permanent stoma in rectal cancer patients undergoing transabdominal anterior resection with temporary stoma]

Objective: To investigate the risk factors of turning temporary stoma into permanent stoma in rectal cancer patients undergoing transabdominal anterior resection with temporary stoma. Methods: A case-control study was carried out. Data of rectal cancer patients who underwent transabdominal anterior resection with temporary stoma and completed follow-up in Department of General Surgery of Xiangya Hospital of Central South University from June 2008 to June 2018 were collected and analyzed. In this study, temporary stoma included defunctioning stoma (ostomy was made during operation) and salvage stoma (ostomy was made within one month after operation due to anastomotic leakage or severe complications). Cases of multiple intestinal tumors were excluded. A total of 308 rectal cancer patients were enrolled in the study, including 198 males and 110 females with a median age of 56 (48-65) years. Ninety-four patients received intraperitoneal chemotherapy during operation. Among 308 patients, upper rectal cancer was observed in 64 cases, middle rectal cancer in 89 cases and low rectal cancer in 155 cases. Twenty patients underwent transverse colostomy and 288 underwent ileostomy. Phone call following-up was conducted from August to September 2019 to investigate whether stoma was reversed, causes of reversal failure, and tumor relapsed or not in detail. Permanent stoma was defined as that the stoma was still not reversed by the latest follow-up. The univariate analysis was performed with chi-square test or Fisher's exact test, and variables with P value < 0.10 were included in the non-conditional logistic regression model for multivariate analysis. Results: The median follow-up time was 54.3 (32.4-73.8) months. During follow-up, 8 cases had local recurrence and 37 cases had distant metastasis. Among the 308 patients with temporary ostomy, 247 (80.2%) patients had stomas reversed and the median interval time was 4.5 (3.5-6.1) months. The median interval time in 65 patients with salvage stoma was significantly longer that in 182 patients with defunctioning stoma [5.5 (4.3-7.5) vs. 4.2 (3.4-5.5) months; Z=-4.387, P<0.001]. The temporary ostomy was confirmed to become permanent stoma in 61 patients (19.8%), including 45 cases of defunctioning stoma and 16 cases of salvage stoma. Univariate analysis showed that preoperative anemia, intraperitoneal chemotherapy during operation, middle rectal cancer, transverse colostomy, pathological stage, postoperative local recurrence and distant metastasis were associated with permanent stoma (all P<0.10). Multivariate analysis revealed that the intraperitoneal chemotherapy during operation (OR=1.961, 95% CI: 1.029-3.738, P=0.041), middle rectal cancer (OR=2.401, 95% CI: 1.195-4.826, P=0.014), transverse colostomy (OR=3.433, 95% CI: 1.234-9.553, P=0.018), and distant metastasis (OR=8.282, 95% CI:3.820-17.954, P<0.001) were independent risk factors of permanent stoma. Conclusions: There is high risk of turning temporary stoma into permanent stoma among rectal cancer patients undergoing transabdominal anterior resection who receive intraperitoneal chemotherapy during operation, present as the middle rectal cancer, undergo transverse colostomy or develop distant metastasis. Surgeons need to evaluate and balance the risks and benefits thoroughly, and then inform the patients in order to avoid potential conflicts.

The ELFIN Mission

The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or heretoforth simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (∼93^∘ inclination), nearly circular, low-Earth (∼450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (T_orbit ∼ 90 min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50 keV to 5 MeV electrons with Δ E/E < 40% and a fluxgate magnetometer (FGM) on a ∼72 cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5 Hz Nyquist (nominally) with <0.3 nT/sqrt(Hz) noise at 1 Hz. The spinning satellites (T_spin ∼ 3 s) are equipped with magnetorquers (air coils) that permit spin-up or -down and reorientation maneuvers. Using those, the spin axis is placed normal to the orbit plane (nominally), allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250 keV - 5 MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018 and launched by the ELaNa XVIII program on a Delta II rocket (with IceSatII as the primary). Mission operations are currently funded by NASA. Working under experienced UCLA mentors, with advice from The Aerospace Corporation and NASA personnel, more than 250 undergraduates have matured the ELFIN implementation strategy; developed the instruments, satellite, and ground systems and operate the two satellites. ELFIN's already high potential for cutting-edge science return is compounded by concurrent equatorial Heliophysics missions (THEMIS, Arase, Van Allen Probes, MMS) and ground stations. ELFIN's integrated data analysis approach, rapid dissemination strategies via the SPace Environment Data Analysis System (SPEDAS), and data coordination with the Heliophysics/Geospace System Observatory (H/GSO) optimize science yield, enabling the widest community benefits. Several storm-time events have already been captured and are presented herein to demonstrate ELFIN's data analysis methods and potential. These form the basis of on-going studies to resolve the primary mission science objective. Broad energy precipitation events, precipitation bands, and microbursts, clearly seen both at dawn and dusk, extend from tens of keV to >1 MeV. This broad energy range of precipitation indicates that multiple waves are providing scattering concurrently. Many observed events show significant backscattered fluxes, which in the past were hard to resolve by equatorial spacecraft or non-pitch-angle-resolving ionospheric missions. These observations suggest that the ionosphere plays a significant role in modifying magnetospheric electron fluxes and wave-particle interactions. Routine data captures starting in February 2020 and lasting for at least another year, approximately the remainder of the mission lifetime, are expected to provide a very rich dataset to address questions even beyond the primary mission science objective.

Acid-Catalyzed Rearrangements of 3-Aryloxirane-2-Carboxamides: Novel DFT Mechanistic Insights

Efficient synthesis of 3-arylquinolin-2(1H)-ones and N-(2-carboxyaryl)-oxalamides from protic acid-catalyzed rearrangements of 3-aryloxirane-2-carboxamides was achieved recently but not well understood. In contrast to the classical Meinwald rearrangement, extensive DFT calculations reveal that the proximal aryl and amide groups have strong synergetic effects to control the amide-aided and aryl-directed oxirane-opening and further rearrangement sequences. The ortho-nitro substituent of the proximal aryl is directly involved in a nucleophilic oxirane ring-opening, the amide C=O is an important proton shuttle for facile H-shifts, while the N-aryl may act as a potential ring-closing site via Friedel-Crafts alkylation. The mechanistic insights are useful for rational design of novel synthesis by changing the aryl and amide functional groups proximal to the oxirane ring.

Total tumor diameter: the neglected value in papillary thyroid microcarcinoma

BACKGROUND

Tumor multifocality is not uncommon in papillary thyroid carcinoma (PTC), especially in micro-PTC. However, assessing the size of the largest tumor may underestimate effect of additional foci. We aimed to investigate the effect of total tumor diameter (TTD) on clinicopathological features of micro-PTC.

METHODS

Data from 442 patients who underwent thyroidectomy with cervical lymph node dissection for PTC were retrospectively analyzed. Patients were classified into subgroups according to multifocality and TTD. The relationships of clinicopathological features among these groups were analyzed.

RESULTS

Multifocality was observed in 119 patients (26.9%). TTD > 1 cm and presence of extrathyroidal extension (ETE) were significantly higher in multifocal tumors compared to unifocal tumor (P < 0.001, P = 0.016, respectively). When comparing multifocal micro-PTC with TTD > 1 cm to those with unifocal micro-PTC or multifocal micro-PTC with TTD ≤ 1 cm, the proportions of cases with ETE, central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM) were significantly higher (all P < 0.05). There was no significant difference in terms of these parameters between multifocal micro-PTC with TTD > 1 cm and macro-PTC or multifocal macro-PTC. The risk of CLNM was 2.056 (P = 0.044) times higher in multifocal micro-PTC with TTD > 1 cm than in unifocal micro-PTC.

CONCLUSION

For multifocal micro-PTC, TTD can better assess the aggressiveness of the tumor. Multifocal micro-PTC with TTD > 1 cm was more aggressive than unifocal micro-PTC or multifocal micro-PTC with TTD ≤ 1 cm.

[Analysis of misdiagnosis causes of suprasellar arachnoid cysts]

Objective: To investigate the causes of misdiagnosis of suprasellar arachnoid cysts, analyze its characteristics and put forward the diagnostic basis and differential points. Methods: The clinical data fo 97 cases of suprasellar arachnoid cysts diagnosed and treated in the neurosurgery department of Beijing Tiantan Hospital and Hebei General Hospital from March 2015 to March 2019 were analyzed retrospectively. All patients underwent CT and MRI scans with obstructive hydrocephalus. 13 cases were misdiagnosed, including 7 males and 6 females. First visit age 1-31 years old, with an average age of 6.3 years. There were 10 patients younger than 6 years old. The remaining 15-year-old patients, 31-year-old patients and 26-year-old patients each have one case. 11 cases were misdiagnosed as obstructive hydrocephalus, 2 cases as cystic craniopharyngioma. Results: 13 cases were misdiagnosed and mistreated, 11 cases were treated with intraventricular and abdominal shunt, 9 cases were treated with neuroendoscopy and recovered well. One cases of intracranial hematomas underwent craniotomy again, the hematomas were removed again and the bone slise were decompressed. One case had fissured stable after shunt. There were no operative deaths and no complications in this group. After endoscopic reoperation, CT and/or MRI scans showed that the ventricle narrowed in varying degrees, some of them returned to normal size and the flow of cerebrospinal fluid (cerebrospinal fluid) was unobstruct at the end of magnetic resonance cerebrospinal fluid angiography (MRI) fistula after endoscopic reoperation. Conclusions: The incidence of suprasellar arachnoid cysts is low, it is rare in clinic and it is easy to misdiagnose and mistreate. At present, it is recognized that the best treatment methods are partial resection of endoscope cyst wall, cyst ventricle fistula and third ventricle floor fisthla.

Development of ATLID Retrieval Algorithms

ATLID (“ATmospheric LIDar”) is the lidar to be flown on the multi-instrument Earth Clouds and Radiation Explorer (EarthCARE or ECARE) joint ESA/JAXA mission now scheduled for launch in 2022. ATID is a 3 channel linearly polarized High-Spectral Resolution (HSRL) system operating at 355nm. Cloud and aerosol optical properties are key ECARE products. This paper will provide an overview of the ATLID L2a (i.e. single instrument) retrieval algorithms being developed and implemented in order to derive cloud and aerosol optical properties.

[Interpretation of clinical practice guideline for anorectal day surgery 2019 edition]

As the rapid development of minimally invasive techniques, anesthesia, and enhanced recovery after surgery (ERAS), anorectal day surgery receiving more and more attention by improving efficiency of medical care while reducing cost and hospitalized infection. However, day surgery also faces the challenge of completing the whole process from patient admission to discharge within 24 hours. Therefore, establishing a reasonable and detailed day surgery process is the cornerstone to guarantee safe medical practice and patients satisfaction. National Clinical Research Center for Geriatric Disorders (Xiangya), together with China Ambulatory Surgery Alliance formulates the clinical practice guideline for anorectal day surgery 2019 edition. Here we make some interpretations of the guidelines on the detailed process of anorectal day surgery, including indication, preoperative examination, preoperative risk evaluation, health education, assessment of day surgery anesthesia and before leaving postanesthesia care unit (PACU), postoperative management, assessment of discharge and follow-up, for the convenience of various medical centers.

Catalytic Difunctionalization of Unactivated Alkenes with Unreactive Hexamethyldisilane through Regeneration of Silylium Ions

A metal-free, intermolecular syn-addition of hexamethyldisilane across simple alkenes is reported. The catalytic cycle is initiated and propagated by the transfer of a methyl group from the disilane to a silylium-ion-like intermediate, corresponding to the (re)generation of the silylium-ion catalyst. The key feature of the reaction sequence is the cleavage of the Si-Si bond in a 1,3-silyl shift from silicon to carbon. A central intermediate of the catalysis was structurally characterized by X-ray diffraction, and the computed reaction mechanism is fully consistent with the experimental findings.

Anomalous Thermoelectric Effects of ZrTe_{5} in and beyond the Quantum Limit

Thermoelectric effects are more sensitive and promising probes to topological properties of emergent materials, but much less addressed compared to other physical properties. We study the thermoelectric effects of ZrTe_{5} in a magnetic field. The presence of the nontrivial electrons leads to the anomalous Nernst effect and quasilinear field dependence of thermopower below the quantum limit. In the strong-field quantum limit, both the thermopower and Nernst signal exhibit exotic peaks. At higher magnetic fields, the Nernst signal has a sign reversal at a critical field where the thermopower approaches zero. We propose that these anomalous behaviors can be attributed to the gap closing of the zeroth Landau bands in topological materials with the band inversion. Our understanding to the anomalous thermoelectric properties in ZrTe_{5} opens a new avenue for exploring Dirac physics in topological materials.

Fractional Deletion of Compound Kushen Injection Indicates Cytokine Signaling Pathways are Critical for its Perturbation of the Cell Cycle

We used computational and experimental biology approaches to identify candidate mechanisms of action of aTraditional Chinese Medicine, Compound Kushen Injection (CKI), in a breast cancer cell line (MDA-MB-231). Because CKI is a complex mixture of plant secondary metabolites, we used a high-performance liquid chromatography (HPLC) fractionation and reconstitution approach to define chemical fractions required for CKI to induce apoptosis. The initial fractionation separated major from minor compounds, and it showed that major compounds accounted for little of the activity of CKI. Furthermore, removal of no single major compound altered the effect of CKI on cell viability and apoptosis. However, simultaneous removal of two major compounds identified oxymatrine and oxysophocarpine as critical with respect to CKI activity. Transcriptome analysis was used to correlate compound removal with gene expression and phenotype data. Many compounds in CKI are required to trigger apoptosis but significant modulation of its activity is conferred by a small number of compounds. In conclusion, CKI may be typical of many plant based extracts that contain many compounds in that no single compound is responsible for all of the bioactivity of the mixture and that many compounds interact in a complex fashion to influence a network containing many targets.

Acylation Reactions of Dibenzo-7-phosphanorbornadiene: DFT Mechanistic Insights

Extensive DFT calculations provide deep mechanistic insights into the acylation reactions of tert-butyl dibenzo-7-phosphanobornadiene with PhCOX (X=Cl, Br, I, OTf) in CH2Cl2 solution. Such reactions are initialized by the nucleophilic P⋅⋅⋅C attack to the carbonyl group to form the acylphosphonium intermediate A+ together with X- anion, followed either by nucleophilic X-⋅⋅⋅P attack (X=Cl, Br, and I) toward A+ to eliminate anthracene or by slow rearrangement or decomposition of A+ (X=OTf). In contrast to the first case (X=Cl) that is rate-limited by the initial P⋅⋅⋅C attack, other reactions are rate-limited by the second X-⋅⋅⋅P attack for X=Br and I and even thermodynamically prevented for X=OTf, leading to isolable phosphonium salts. The rearrangement of phosphonium A+ is initiated by a P-C bond cleavage, followed either by sequential proton-shifts to form anthracenyl acylphosphonium or by deprotonation with additional base Et3N to form neutral anthracenyl acylphosphine. Our DFT results strongly support the separated acylphosphonium A+ as the key reaction intermediate that may be useful for the transfer of acylphosphenium in general.

Suspended low-loss germanium waveguides for the longwave infrared

Germanium is a material of high interest for mid-infrared (MIR) integrated photonics due to its complementary metal-oxide-semiconductor (CMOS) compatibility and its wide transparency window covering the 2-15 μm spectral region exceeding the 4 and 8 μm limit of the silicon-on-insulator platform and Si material, respectively. In this Letter, we report suspended germanium waveguides operating at a wavelength of 7.67 μm with a propagation loss of 2.6±0.3  dB/cm. To the best of our knowledge, this is the first demonstration of low-loss suspended germanium waveguides at such a long wavelength. Suspension of the waveguide is achieved by defining holes alongside the core providing access to the buried oxide layer and the underlying Si layer so that they can be wet etched using hydrofluoric acid and tetramethylammonium hydroxide, respectively. Our MIR waveguides create a new path toward long wavelength sensing in the fingerprint region.

Suspended silicon waveguides for long-wave infrared wavelengths

In this Letter, we report suspended silicon waveguides operating at a wavelength of 7.67 μm with a propagation loss of 3.1±0.3  dB/cm. To our knowledge, this is the first demonstration of low-loss silicon waveguides at such a long wavelength, with loss comparable to other platforms that use more exotic materials. The suspended Si waveguide core is supported by a sub-wavelength grating that provides lateral optical confinement while also allowing access to the buried oxide layer so that it can be wet etched using hydrofluoric acid. We also demonstrate low-loss waveguide bends and s-bends.