Insight into the Gas-Induced Phase Transformations in a 2D Switching Coordination Network via Coincident Gas Sorption and In Situ PXRD.

Switching coordination networks (CNs) that reversibly transform between narrow or closed pore (cp) and large pore (lp) phases, though fewer than their rigid counterparts, offer opportunities for sorption-related applications. However, their structural transformations and switching mechanisms remain underexplored at the molecular level. In this study, we conducted a systematic investigation into a 2D switching CN, [Ni(bpy)2(NCS)2]n, sql-1-Ni-NCS (1 = bpy = 4,4'-bipyridine), using coincident gas sorption and in situ powder X-ray diffraction (PXRD) under low-temperature conditions. Gas adsorption measurements revealed that C2H4 (169 K) and C2H6 (185 K) exhibited single-step type F-IVs sorption isotherms with sorption uptakes of around 180-185 cm3 g-1, equivalent to four sorbate molecules per formula unit. Furthermore, parallel in situ PXRD experiments provided insight into sorbate-dependent phase switching during the sorption process. Specifically, CO2 sorption induced single-step phase switching (path I) solely between cp and lp phases consistent with the observed single-step type F-IVs sorption isotherm. By contrast, intermediate pore (ip) phases emerged during C2H4 and C2H6 desorption as well as C3H6 adsorption, although they remained undetectable in the sorption isotherms. To our knowledge, such a cp-lp-ip-cp transformation (path II) induced by C2H4/6 and accompanied by single-step type F-IVs sorption isotherms represents a novel type of phase transition mechanism in switching CNs. By virtue of Rietveld refinements and molecular simulations, we elucidated that the phase transformations are governed by cooperative local and global structural changes involving NCS- ligand reorientation, bpy ligand twist and rotation, cavity edge (Ni-bpy-Ni) deformation, and interlayer expansion and sliding.

Ethane/Ethylene Separations in Flexible Diamondoid Coordination Networks via an Ethane-Induced Gate-Opening Mechanism.

Separating ethane (C2H6) from ethylene (C2H4) is an essential and energy-intensive process in the chemical industry. Here, we report two flexible diamondoid coordination networks, X-dia-1-Ni and X-dia-1-Ni0.89Co0.11, that exhibit gate-opening between narrow-pore (NP) and large-pore (LP) phases for C2H6, but not for C2H4. X-dia-1-Ni0.89Co0.11 thereby exhibited a type F-IV isotherm at 273 K with no C2H6 uptake and a high uptake (111 cm3 g-1, 1 atm) for the NP and LP phases, respectively. Conversely, the LP phase exhibited a low uptake of C2H4 (12.2 cm3 g-1). This C2H6/C2H4 uptake ratio of 9.1 for X-dia-1-Ni0.89Co0.11 far surpassed those of previously reported physisorbents, many of which are C2H4-selective. In situ variable-pressure X-ray diffraction and modeling studies provided insight into the abrupt C2H6-induced structural NP to LP transformation. The promise of pure gas isotherms and, more generally, flexible coordination networks for gas separations was validated by dynamic breakthrough studies, which afforded high-purity (99.9%) C2H4 in one step.

Metal Doping to Control Gate Opening and Increase Methane Working Capacity in Isostructural Flexible Diamondoid Networks.

Adsorbed natural gas (ANG) systems involve using porous materials to increase the working capacity and/or reduce the storage pressure compared to compressed natural gas (CNG). Flexible metal-organic materials (FMOMs) are particularly interesting in this context since their stepped isotherms can afford increased working capacity if the adsorption/desorption steps occur within the proper pressure range. We report herein that metal doping in a family of isostructural FMOMs, ML2 (M=Co, Ni or Nix Co1-x , L=4-(4-pyridyl)-biphenyl-4-carboxylic acid), enables control over the gate opening between non-porous (closed) and porous (open) phases at pressures relevant to methane storage. Specifically, methane-induced phase transformations can be fine-tuned by using different Ni/Co ratios to enhance methane working capacity. The optimal working capacity from 5 to 35 bar at 298 K (153 cm3  cm-3 ) was found for Ni0.89 Co0.11 L2 (X-dia-1-Ni0.89 Co0.11 ), which is greater than that of benchmark rigid MOFs.

Amino-Functionalized Microporous MOFs for Capturing Greenhouse Gases CF4 and NF3 with Record Selectivity.

The capture and separation of fluorinated gases (F-gases) from N2 has the potential to not only reduce greenhouse gas emissions but also provide economic benefits for the semiconductor industry. In this work, two Ni-based metal-organic frameworks (MOFs), Ni-MOF (Ni(ina)2, ina = isonicotinic acid) and amine-functionalized NH2-Ni-MOF (Ni(3-ain)2, 3-ain = 3-aminoisonicotinic acid), were constructed for capturing F-gases (CF4 and NF3). At ambient conditions, both materials exhibit very high CF4 sorption capacities (2.92 mmol g-1 for Ni-MOF and 2.69 mmol g-1 for NH2-Ni-MOF). In addition, NH2-Ni-MOF exhibited a record selectivity of 46.3 for the CF4/N2 mixture at 298 K and 100 kPa, surpassing all benchmark adsorbents, including Ni-MOF (34.7). The kinetic adsorption tests demonstrated that Ni-MOF and NH2-Ni-MOF performed well for CF4/N2 and NF3/N2 mixtures. According to grand canonical Monte Carlo (GCMC) simulations, CF4 or NF3 interacts with NH2-Ni-MOF by multiple van der Waals interactions, resulting in stronger interaction than N2. More importantly, dynamic breakthrough experiments verified the practical separation potential of the two materials for CF4/N2 and NF3/N2 mixtures.

Pore-Structure Control in Metal-Organic Frameworks (MOFs) for Capture of the Greenhouse Gas SF6 with Record Separation.

In the electronics industry, the efficient recovery and capture of sulfur hexafluoride (SF6 ) from SF6 /N2 mixtures is of great importance. Herein, three metal-organic frameworks with fine-tuning pore structures, Cu(peba)2 , Ni(pba)2 , and Ni(ina)2 , were designed for SF6 capture. Among them, Ni(ina)2 has perfect pore sizes (6 Å) that are comparable to the kinetic diameter of sulfur hexafluoride (5.2 Å), affording the benchmark binding affinity for SF6 gas. Ni(ina)2 exhibits the highest SF6 /N2 selectivity (375.1 at 298 K and 1 bar) and ultra-high SF6 uptake capacity (53.5 cm3 g-1 at 298 K and 0.1 bar) at ambient conditions. The remarkable separation performance of Ni(ina)2 was verified by dynamic breakthrough experiments. Theoretical calculations and the SF6 -loaded single-crystal structure provided critical insight into the adsorption/separation mechanism. This porous coordination network has the potential to be used in industrial applications.

Complete genome sequence of a novel arlivirus from a yellow spotted stink bug (Erthesina fullo (Thunberg, 1783)).

Arlivirus is currently the only genus in the newly established viral family Lispiviridae. In this study, the complete genome sequence of a novel arlivirus, tentatively named "Nbu stink bug virus 1" (NbuSBV-1), was identified in an individual yellow spotted stink bug, Erthesina fullo (family Pentatomidae, order Hemiptera), which is a widely distributed phytophagous pest in Asia. NbuSBV-1 has a single negative-stranded RNA genome of 13,605 nucleotides in length, and it was predicted to contain six open reading frames (ORFs). Conserved domains of NbuSBV-1 were predicted in ORF1 (a nucleoprotein), ORF4 (a glycoprotein domain), ORF5 (a zinc-finger domain), and ORF6 (an RNA-directed RNA polymerase [RdRP] domain, an mRNA cap domain, and a methyltransferase domain). NbuSBV-1 shares 50.54% amino acid sequence identity in the RdRP region with its closest homolog, Lishì spider virus 2. In RdRP-based phylogenetic analysis, NbuSBV-1 was clearly clustered in a clade with other arliviruses. Furthermore, NbuSBV-1-derived small interfering RNAs (siRNAs) showed typical patterns of virus-derived siRNAs produced by the host antiviral RNA interference pathway. As far as we know, NbuSBV-1 is the first arlivirus identified in an insect of the family Pentatomidae.

Nickel-Based Metal-Organic Frameworks for Coal-Bed Methane Purification with Record CH4 /N2 Selectivity.

The enrichment and purification of coal-bed methane provides a source of energy and helps offset global warming. In this work, we demonstrate a strategy involving the regulation of the pore size and pore chemistry to promote the separation of CH4 /N2 mixtures in four nickel-based coordination networks, named Ni(ina)2 , Ni(3-ain)2 , Ni(2-ain)2 , and Ni(pba)2 , (where ina=isonicotinic acid, 3-ain=3-aminoisonicotinic acid, 2-ain=2-aminoisonicotinic acid, and pba=4-(4-pyridyl)benzoic acid). Among them, Ni(ina)2 and Ni(3-ain)2 can effectively separate CH4 from N2 with top-performing performance because of the suitable pore size (≈0.6 and 0.5 nm) and pore environment. Explicitly, Ni(ina)2 exhibits the highest ever reported CH4 /N2 selectivity of 15.8 and excellent CH4 uptake (40.8 cm3 g-1 ) at ambient conditions, thus setting new benchmarks for all reported MOFs and traditional adsorbents. The exceptional CH4 /N2 separation performance of Ni(ina)2 is confirmed by dynamic breakthrough experiments. Under different CH4 /N2 ratios, Ni(ina)2 selectively extracts methane from the gaseous blend and produces a high purity of CH4 (99 %). Theoretical calculations and CH4 -loading single-crystal structure analysis provide critical insight into the adsorption/separation mechanism. Ni(ina)2 and Ni(3-ain)2 can form rich intermolecular interactions with methane, indicating a strong adsorption affinity between pore walls and CH4 molecules. Importantly, Ni(ina)2 has good thermal and moisture stability and can easily be scaled up at a low cost ($25 per kilogram), which will be valuable for potential industrial applications. Overall, this work provides a powerful approach for the selective adsorption of CH4 from coal-bed methane.

Multiple scalp metastases from colonic neuroendocrine carcinoma: case report and literature review.

BACKGROUND: Colonic neuroendocrine neoplasms (NENs) are relatively rare tumors with an incidence rate of 0.11-0.21/100,000. NENs account for approximately 0.4% of colorectal neoplasms. Cutaneous metastases of colonic neuroendocrine carcinomas (NECs) are very infrequent, while cases of scalp metastasis are even fewer. Cutaneous metastases are more rare than visceral metastases and usually develop later; therefore, cutaneous metastases as initial distant metastases can be easily overlooked. This is the second case report of a colonic NEC with scalp metastasis. Compared with the previous case, in this instance scalp metastasis developed before visceral metastasis, and the cutaneous lesions were confined to the scalp alone. CASE PRESENTATION: A 62-year-old Chinese man, who had undergone radical surgery for a "locoregional" colonic NEC one and half months before, came to our hospital for adjuvant chemotherapy. We found multiple scalp nodules during physical examination. Moreover, these nodules had occurred and had not been detected prior to the patient undergoing radical surgery. The scalp nodules proved to be metastases from colonic NEC as determined using pathological and immunohistochemical examinations following lumpectomy. After one and half months, visceral metastases were detected in this patient. Ultimately, the patient died two months later. CONCLUSIONS: In this report an unusual case of a colonic NEC with initial distant metastasis confined to the scalp is presented. This case is unusual because of the development of cutaneous metastasis before visceral metastasis. The scalp metastasis were initially overlooked, leading to inaccurate staging and radical surgery that was not curative. This demonstrates that distant metastasis can occur during the early phase of tumor growth in these aggressive lesions. Thus, the possibility of distant metastases should be assessed in the initial work up to avoid mistaken clinical staging especially when distant metastases occur only in skin.

Urinary modified nucleosides as novel biomarkers for diagnosis and prognostic monitoring of urothelial bladder cancer.

AIMS AND BACKGROUND: To ascertain the value of the detection of urinary modified nucleosides in the early diagnosis and prognostic monitoring of urothelial bladder cancer. METHODS: One hundred seventeen patients with urothelial bladder carcinoma and 66 healthy volunteers were included in the study. High-performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC/ESI-Q-TOF-MS) was used to measure the levels of urinary modified nucleosides in the bladder cancer and control groups. Postoperative monitoring was done every 3 months in patients with noninvasive carcinoma; 85 patients attended the 1-year follow-up visit. RESULTS: The levels of m1A, ac4C, O6-MeG and 1-MeI were significantly higher in cases than controls (P < 0.05). The highest sensitivity (92.45%) and specificity (87.50%) were obtained when 1-MeI detection was combined with m1A detection. The m1A and 1-MeI levels 3 months after operation in both patient groups were significantly lower than the preoperative levels (P < 0.01). The no-recurrence group subsequently maintained low levels, but in the recurrence group the levels rose again almost to preoperative values. At 6, 9 and 12 months after operation, the m1A and 1-MeI levels of the recurrence group were higher than those of the no-recurrence group and the control group (P < 0.01). CONCLUSIONS: Urinary modified nucleosides might become novel tumor markers that will facilitate the clinical management and will be helpful in the diagnosis and follow-up of urothelial bladder cancer. m1A and 1-MeI appear to be most promising for clinical use and be worthy of further study in the near future.

ESIMS and NMR studies on the selective deprotection of acetylated glucosides by dibutyltin oxide.

The reaction process for the selective deprotection of acetylated glucosides by dibutyltin oxide in methanol is investigated by using methyl 2,3,4,6-tetra-O-acetyl-α-d-glucopyranoside as a model substrate with ESIMS and NMR techniques. According to the results, it is inferred that at first, dimeric 1,3-dimethoxytetrabutyldistannoxane is formed by the reaction of dibutyltin oxide with methanol, and then the tetraorganodistannoxane reacts with the acetylated glucoside to produce glucoside-organotin complex intermediates. Finally, the complex intermediates are hydrolyzed leading to the free-OH glucoside and organotin acetate derivatives. The reaction is affected by neighboring group participation and steric hindrance, which allow for high selectivities among different acetyl groups in acetylated glucosides.

[Effect of COX-2 inhibitor on the expression of BCL-3 and cyclin D1 in human colon cancer cell line SW480].

OBJECTIVE: To study the effects of NS398, a selective cyclooxygenase-2 (COX-2) inhibitor, on the transcription and translation of BCL-3 and its regulatory gene cyclin D1 in colon cancer cell line SW480. METHODS: Human colon cancer cells SW480 were divided into two groups: SW480 cells in experimental group were treated with NS398 in different concentrations(25 micromol/L, 50 micromol/L, 100 micromol/L and 200 micromol/L) for 48 h or 72 h. SW480 cells in control group were treated with media which did not contain NS398. Then the expressions of BCL-3 and cyclin D1 were detected by RT-PCR, Western blot, and immunocytochemistry. RESULTS: At 48 hours RT-PCR showed that BCL-3 mRNA and cyclin D1 mRNA decreased in a dose-dependent manner in the experimental group. However, there were no significant differences in the levels of BCL-3 protein and cyclin D1 protein between two groups (P>0.05). At 72 hours, BCL-3 protein and cyclin D1 protein also decreased in a dose-dependent manner in the experimental group. When the concentration of NS398 reached 100 micromol/L, the differences between the two groups in the expression of BCL-3 mRNA and protein became statistically significant (P<0.01). When the concentration of NS398 reached 50 micromol/L, the differences in the expression of cyclin D1 mRNA and protein were statistically significant (P<0.05). CONCLUSIONS: BCL-3 is expressed in colon cancer cell line SW480. COX-2 inhibitor can inhibit the expression of BCL-3 and cyclin D1 in a dose-dependent manner. NS398 may down-regulate the expression of cyclin D1 through BCL-3.

Separation and characterization of clindamycin phosphate and related impurities in injection by liquid chromatography/electrospray ionization mass spectrometry.

A simple high-performance liquid chromatography/electrospray ionization tandem mass spectrometric (HPLC/ESI-MS/MS) method has been developed for the rapid identification of clindamycin phosphate and its degradation products or related impurities in clindamycin phosphate injection. Detection was performed by quadrupole time-of-flight mass spectrometry (Q-TOFMS) via an ESI source in positive mode. Clindamycin phosphate and its related substances lincomycin, 7-epilincomycin-2-phosphate, lincomycin-2-phosphate, clindamycin B, clindamycin B-2-phosphate, and clindamycin were identified simultaneously by HPLC/ESI-MS/MS results. Based on the MS/MS spectra of their quasi-molecular ions, the fragmentation pathways of clindamycin phosphate and its related substances were compared and proposed, which are specific and useful for the identification of the lincosamide antibiotics and related impurities. The method was rapid, sensitive and specific and can be used to identify clindamycin phosphate and its related impurities in clindamycin phosphate injection without control compounds.

Separation and identification of purine nucleosides in the urine of patients with malignant cancer by reverse phase liquid chromatography/electrospray tandem mass spectrometry.

Urinary-modified nucleosides have a potential role as cancer biomarkers for a number of malignant diseases. High performance liquid chromatography (HPLC) was combined with full-scan mass spectrometry, MS/MS analysis and accurate mass measurements in order to identify purine nucleosides purified from urine. Potential purine nucleosides were assessed by their evident UV absorbance in the HPLC chromatogram and then further examined by the mass spectrometric techniques. In this manner, numerous modified purine nucleosides were identified in the urine samples from cancer patients including xanthine, adenosine, N1-methyladenosine, 5'-deoxy-5'-methylthioadenosine, 2-methyladenosine, N6-threonylcarbamoyladenosine, inosine, N1-methylinosine, guanosine, N1-methylguanosine, N7-methylguanine, N2-methylguanosine, N2,N2-dimethyguanosine, N2,N2,N7-trimethylguanosine. Furthermore, a number of novel purine nucleosides were tentatively identified via critical interpretation of the combined mass spectrometric data including N3-methyladenosine, N7-methyladenine, 5'-dehydro-2'-deoxyinosine, N3-methylguanine, O6-methylguanosine, N1,N2,N7-trimethylguanosine, N1-methyl-N2-ethylguanosine and N7-methyl-N1-ethylguanosine.

Analysis of modified nucleosides in the urine of patients with malignant cancer by liquid chromatography/electrospray ionization mass spectrometry.

As modified nucleosides reflect altered tRNA turnover which seems to be impaired in the body of cancer patients, they have been evaluated as potential tumor markers. High-performance liquid chromatography/electrosprary ionization quadrupole time-of-flight mass spectrometry (HPLC/ESI-Q-TOFMS) was used to identify nucleosides purified from urine in positive ionization mode. Potential nucleosides were assessed by their evident UV absorbance in HPLC and then further examined by mass spectrometric techniques. In this manner, 21 nucleosides were detected in the urine of a patient with lymphoid cancer including three modified nucleosides 5'-dehydro-2-deoxyinosine, N1,N2,N7-trimethylguanosine and N1-methyl-N2-ethylguanosine, which had never been reported previously.

[Effects of low temperature and weak light on the functions of photosystem in Prunus armeniaca L. leaves in solar greenhouse].

In this paper, the net photosynthetic rate (Pn), actual photochemical efficiency of PS II (PhiPSII), photochemical quenching (qp), and maximal photochemical efficiency of PS II in light (Fv'/Fm') of apricot (Prunus armeniaca) leaves in solar greenhouse were measured, and the effects of low temperature (7 degrees C) and weak light (200 micromol x m(-2) x s(-1) PFD) on the photoinhibition of PS I and PS II were investigated. The results showed that the optimal temperature for the photosynthesis of apricot leaves was around 25 degrees C, and the photosynthetic capacity was reduced greatly by the low temperature and weak light, inducing a markedly increased excitation press (1-qp) and in turn, resulting in photoinhibition. The functions of both PS I and PS II were damaged by the low temperature and weak light. Comparing with those only subjected to low temperature, the leaves subjected to both low temperature and weak light had a decreased activity of PS I, with a decrement of 28.26% within 2 h, but their maximal photochemical effeciency of PS II (Fv/Fm) had little change in the same period, suggesting that under low temperature and weak light, PS I was more suffered from photoinhibition than PS II.

Mild and selective deprotection method of acetylated steroids and diterpenes by dibutyltin oxide.

Dibutyltin oxide (DBTO) was first utilized for the deacetylation of steroid and diterpene esters. The results showed the deprotection of acetylated steroids and diterpenes separately with moderate catalysis dibutyltin oxide in methanol selectively removed part acetyl groups of these substrates, whereas several functional groups of the steroids and diterpenes were retained and neither isomerization nor degradation of these substrates was observed. It seems that the acetyl groups with lower steric hindrance or near carbonyl, alkoxy, or hydroxyl groups can be cleaved by the reaction, whereas the acetyl groups with higher steric hindrance or without carbonyl, alkoxy, or hydroxyl groups neighboring were retained under the same conditions. One of the interesting results obtained was the selective hydrolysis of the 3beta-O-acetyl group in the presence of the 6beta group in 3beta,6beta-Di-O-acetyl-5alpha-hydroxypregn-16-en-20-one. This allows for subsequent introduction of one unit at C-3 and the other unit at C-6. This procedure is useful for the synthesis of a series of closely related isomers of 3beta,5alpha,6beta-trihydroxypregn-16-en-20-one and other widespread polyhydroxysteroids in marine organisms and some terrestrial species.

Syntheses of acetylated steroid glycosides and selective cleavage of O-acetyl groups in sugar moiety.

Acetylated 3beta-O-beta-glycosyl steroid derivatives were synthesized by the reaction of a new polyhydroxysteroid 3beta,5alpha,6beta-trihydroxypregn-16-en-20-one (2) with the peracetylated 1-bromo derivatives of d-glucose and d-galactose, respectively. Subsequent protection by excess acetic anhydride in pyridine selectively gave the 6beta-O-acetylated steroid glycosides. Deprotection of the acetylated steroid glycosides separately with moderate catalysis dibutyltin oxide in methanol selectively removed all acetyl groups of sugar moiety, whereas the acetyl group of the steroid part was retained. The structures of the steroid glycosides were confirmed by mass spectrometry, NMR and IR. The complete protocol was shown to be non-destructive at all stages to the sugar moieties and the steroid nucleus. These regioselective reactions open a route to the synthesis of a series of closely related isomers of 2 and other widespread polyhydroxysteroids and steroid glycosides in marine organisms and some terrestrial species.

Characterization of enhancer trap and gene trap harboring Ac/Ds transposon in transgenic rice.

Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-element Ac/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision of Ds element was examined by PCR amplification. The excision frequency of Ds element varied from 0% to 40% among 20 F(2) populations derived from 11 different Ds parents. Southern blot analysis revealed that more than 70% of excised Ds elements reinserted into rice genome and above 70% of the reinserted Ds elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice.