N-Site Regulation of Pyridyltriazole in Cp*Ir(N̂N)(H2O) Complexes Achieving Catalytic FA Dehydrogenation.

A series of novel Cp*Ir complexes with nitrogen-rich N̂N bidentate ligands were developed for the catalytic dehydrogenation of formic acid in water under base-free conditions. These complexes were synthesized by using pyridyl 1,2,4-triazole, methylated species, or pyridyl 1,2,3-triazole as a N-site regulation ligand and were fully characterized. Complex 1-H2O bearing 1,2,4-triazole achieved a high turnover frequency of 14192 h-1 at 90 °C in 4 M FA aqueous solution. The terminal and bridged Ir-H intermediates of 1-H2O were successfully detected by 1H NMR and mass spectrometry measurements. Kinetic isotope effect experiments and density functional theory (DFT) calculations were performed; then a plausible mechanism was proposed involving the ß-hydride elimination and formation of H2. Water-assisted H2 release was proven to be the rate-determining step of the reaction. The distribution of Mulliken charges on N atoms of triazole ligand internally revealed that the ortho site N2 of 1-H2O with a higher electron density was conducive to efficient proton transfer. Additionally, the advantage of water-assisted short-range bridge of 1,2,4-triazole moieties led to a higher catalytic activity of 1-H2O. This study demonstrated the effectiveness of nitrogen-rich ligands on FA dehydrogenation and revealed a good strategy for N site regulation in the development of new homogeneous catalysts.

Precisely Controlling Ancillary Ligands to Improve Catalysis of Cp*Ir Complexes for CO2 Hydrogenation.

The regulation of ancillary ligands is critical to improve catalysis of Cp*Ir complexes for CO2 hydrogenation. Herein, a series of Cp*Ir complexes with N^N or N^O ancillary ligands were designed and synthesized. These N^N and N^O donors were derived from the pyridylpyrrole ligand. The solid-state structures of Cp*Ir complexes featured a pendant pyridyl group in 1-Cl and 1-SO4 and a pyridyloxy group in 2-Cl, 3-Cl, 2-SO4, and 3-SO4. These complexes were employed as catalysts for CO2 hydrogenation to formate in the presence of alkali under a pressure range of 0.1-8 MPa and temperature range of 25-120 °C. The catalytic activity of 2-SO4 with a pyridyloxy pendant group dramatically outperformed that of 1-SO4 and 3-SO4. The TOF of conversion of CO2 into formate reached 263 h-1 at 25 °C under a total pressure of 8 MPa (CO2/H2 = 1:1). The experiments and density functional theory calculations revealed that a pendant base in metal complexes plays a key role in the rate-determining heterolytic H2 splitting and enhancing the proton transfer by forming a hydrogen bonding bridge thereby improving the catalytic activity.

A New Practical Method Based on MRI to Individually Localize the Transverse-Sigmoid Sinus Junction in Retrosigmoid Craniotomy: A Retrospective Before-After Study.

Background: Although the asterion has long been used as a skeletal surface marker of the transverse-sigmoid sinuses junction (TSSJ) point in the retrosigmoid approach, abundant evidence shows that the relationship between asterion and TSSJ point varies greatly. In recent years, new technologies have been developed, such as neuronavigation and three-dimensional volume rendering imaging, that can guide in exposing the TSSJ point individually. However, they are not only expensive but also difficult to apply in emergency surgery. Objective: To introduce a quick, practical, and low-cost new method for locating the TSSJ point precisely. Methods: In this retrospective before-after study, the test group located the TSSJ point with our new method during a 6-month period, while the control group used asterion as a surface landmark to estimate the TSSJ during the preceding 6 months. The primary outcome is the immediate exposure rate of the TSSJ point by the initial burr hole. Results: There were 60 patients in both control and test groups as no significant difference in the general clinical characteristics of both groups were observed. The new three-step method significantly increased the TSSJ exposure rate by initial burr hole compared with the control group (96.67% vs. 53.33%, P = 0.0002). Moreover, the total bone loss and craniotomy duration were significantly reduced by the new method. Incidence of sinus injury (10% vs. 6.6%), post-operation infection (3.33% vs. 3.33%), and CSF leakage (3.33% vs. 0%) were similar. Conclusions: The novel three-step approach accurately locates TSSJ points in retrosigmoid craniotomy, reduces bone defects, saves time, and does not increase the risk of sinus injury, infection, and CSF leakage.

Pre-operative external ventricle drainage improves neurological outcomes for patients with traumatic intracerebellar hematomas.

Objectives: Traumatic intracerebellar hematoma (TICH) is a very rare entity with a high morbidity and mortality rate, and there is no consensus on its optimal surgical management. In particular, whether and when to place external ventricle drainage in TICH patients without acute hydrocephalus pre-operation is still controversial. Methods: A single-institutional, retrospective analysis of total of 47 TICH patients with craniectomy hematoma evacuation in a tertiary medical center from January 2009 to October 2020 was performed. Primary outcomes were mortality in hospital and neurological function evaluated by GOS at discharge and 6 months after the ictus. Special attention was paid to the significance of external ventricular drainage (EVD) in TICH patients without acute hydrocephalus on admission. Results: Analysis of the clinical characteristics of the TICH patients revealed that the odds of use of EVD were seen in patients with IVH, fourth ventricle compression, and acute hydrocephalus. Placement of EVD at the bedside can significantly improve the GCS score before craniotomy, as well as the neurological score at discharge and 6 months. Compared with the only hematoma evacuation (HE) group, there is a trend that EVD can reduce hospital mortality and decrease the occurrence of delayed hydrocephalus, although the difference is not statistically significant. In addition, EVD can reduce the average NICU stay time, but has no effect on the total length of stay. Moreover, our data showed that EVD did not increase the risk of associated bleeding and intracranial infection. Interestingly, in terms of neurological function at discharge and 6 month after the ictus, even though without acute hydrocephalus on admission, the TICH patients can still benefit from EVD insertion. Conclusion: For TICH patients, perioperative EVD is safe and can significantly improve neurological prognosis. Especially for patients whose GCS dropped by more than 2 points before the operation, EVD can significantly improve the patient's GCS score, reduce the risk of herniation, and gain more time for surgical preparation. Even for TICH patients without acute hydrocephalus on admission CT scan, EVD placement still has positive clinical significance.

Association between Traumatic Subarachnoid Hemorrhage and Acute Respiratory Failure in Moderate-to-Severe Traumatic Brain Injury Patients.

Acute respiratory failure (ARF) with a high incidence among moderate-to-severe traumatic brain injury (M-STBI) patients plays a pivotal role in worsening neurological outcomes. Traumatic subarachnoid hemorrhage (tSAH) is highly prevalent in M-STBI, which is associated with significant adverse outcomes. In this retrospective cohort study, we aimed to explore the association between the severity of the tSAH and ARF in the M-STBI population. A total of 771 subjects were reviewed. Clinical and neuroimaging data of M-STBI patients were retrospectively collected, and ARF was ascertained retrospectively based on their electronic medical record. The degree of tSAH was classified according to Fisher's criteria, and the grade of tSAH was dichotomized to a low Fisher grade (Fisher grade 1-2) and a high Fisher grade (Fisher grade 3-4). After exclusion procedures, the data of 695 M-STBI patients were analyzed. A total of 284 (30.8%) had a high Fisher grade on admission. The overall rate of ARF within 48 h upon admission was 34.4% (239/695); it was 29.5% (142/481) and 46.3% (99/214) for the low and high Fisher groups, respectively. In a full cohort, a high Fisher grade was associated with ARF after adjusting for age, gender, GCS, smoking history, comorbidities, multiple injuries, characteristics of TBI, and pulmonary factors (OR 1.78; 95% CI, 1.11-2.85, p = 0.016). This result remained robust in the comparisons after PSM (71/132, 42.8% vs. 53/132, 31.9%; OR, 1.59; 95% CI, 1.02-2.49, p = 0.042). A high Fisher SAH grade exposure on admission is associated with ARF in M-STBI patients.

The optimized jugular vein catheterization reinforced cocaine self-administration addictive model for adult male Sprague-Dawley rats.

The self-administration (SA) model represents one of the most important and classic methods for drug addiction, and jugular vein catheterization is one of the most critical techniques in this animal model. We aimed to explore an optimized scheme to improve the success rate of rat jugular vein catheterization and SA model. Our experiment provided an optimized scheme which including numerous details, materials, approaches, updated techniques and protocols. Our experimental group consisted of 120 adult male Sprague-Dawley rats, which were divided into the Traditional Operation group (TO group) and the Optimized Operation group (OO group) by the random number table method and then further individually divided into the Saline Training group and the Cocaine Training group for the following SA training. Our results showed that the success rate of the jugular vein catheterization in the OO group was significantly greater than that in the TO group (93.33% vs 46.67%, χ2 = 31.11, P < 0.001). The optimized jugular vein catheterization could make the SA model more stable, reliable and efficient than the traditional operation. Compared with traditional methods, our optimized scheme made numerous improvements in materials and techniques including uniformity, individualized variability of the S-type positioning nail, the length and connection matching, the shape of the end and low cost. Our optimized scheme could provide a more stable and efficient tool for basic research on drug addiction. Several subtle improvements under our personal experience are usually important for augmenting operational efficiency.

Cerebral fat embolization with paroxysmal sympathetic hyperactivity syndrome and septic shock at high altitude: a case report and literature review.

BACKGROUND: Cerebral fat embolism (CFE) syndrome at high altitude was rare complicated with paroxysmal sympathetic hyperactivity (PSH) syndrome and septic shock. It is a challenge to differential diagnosis and treatment at high altitude. CASE PRESENTATION: This case presents a CFE with PSH and septic shock of a 23-year-old man occurred at high altitude of 3800 m above sea level, transferred by airplane successfully and cured in the department of neurosurgery, Xi'an Tangdu Hospital. CONCLUSIONS: It is key that CFE with PSH can be rapid diagnosed and treatment bundles of septic shock should be initiated as soon as possible. Early neurological rehabilitation played an important role for good outcome.

Effects of Primary Decompressive Craniectomy on the Outcomes of Serious Traumatic Brain Injury with Mass Lesions, and Independent Predictors of Operation Decision.

BACKGROUND: Although operative indications for traumatic brain injury (TBI) are known, neurosurgeons are unsure whether to remove the bone flap after mass lesion extraction, and an efficient scoring system for predicting which patients should undergo decompressive craniectomy (DC) does not exist. METHODS: Nine parameters were assessed. In total, 245 patients with severe TBI were retrospectively assessed from June 2015 to May 2019, who underwent DC or craniotomy to remove mass lesions. The 6-month mortality and Extended Glasgow Outcome Scale scores were compared between the DC and craniotomy groups. Using univariable and multivariable logistic regression equations, receiver operating characteristic curves were obtained for predicting the decision for DC. RESULTS: The overall 6-month mortality in the entire cohort was 11.43% (28/245). Patients undergoing DC had lower mean preoperative Glasgow Coma Scale scores (P = 0.01), and higher amounts of individuals with a Glasgow Coma Scale score of 6 (P = 0.007), unresponsive pupillary light reflex (P < 0.001), closed basal cisterns (P < 0.001), and diffuse injury (P = 0.025), compared with the craniotomy group. Because of high disease severity, individuals administered primary DC showed increased 6-month mortality compared with the craniotomy group. However, in surviving patients, favorable Extended Glasgow Outcome Scale rates were similar in both groups. Pupillary light reflex and basal cisterns were independent predictors of the DC decision. Based on receiver operating characteristic curves, the model had sensitivity and specificity of 81.6% and 84.9%, respectively, in predicting the probability of DC. CONCLUSIONS: These preliminary data showed that primary DC may benefit some patients with severe TBI with mass lesions. In addition, unresponsive preoperative pupil reaction and closed basal cistern could predict the DC decision.

Coexpression of VGLUT1 and VGLUT2 in precerebellar neurons in the lateral reticular nucleus of the rat.

Vesicular glutamate transporter (VGLUT) 1 and VGLUT2 have been reported to distribute complementally in most brain regions and have been assumed to define distinct functional elements. Previous studies have shown the expression of VGLUT1 mRNA and VGLUT2 mRNA in the lateral reticular nucleus (LRN), a key precerebellar nucleus sending mossy fibers to the cerebellum. In the present study, we firstly examined the coexpression of VGLUT1 and VGLUT2 mRNA in the LRN of the rat by dual-fluorescence in situ hybridization. About 81.89 % of glutamatergic LRN neurons coexpressed VGLUT1 and VGLUT2 mRNA, and the others expressed either VGLUT1 or VGLUT2 mRNA. We then injected the retrograde tracer Fluogold (FG) into the vermal cortex of cerebellum, and observed that 95.01 % and 86.80 % of FG-labeled LRN neurons expressed VGLUT1 or VGLUT2 mRNA respectively. We further injected the anterograde tracer biotinylated dextran amine (BDA) into the LRN, and found about 82.6 % of BDA labeled axon terminals in the granular layer of cerebellar cortex showed both VGLUT1- and VGLUT2-immunoreactivities. Afterwards, we observed under electron microscopy that anterogradely labeled axon terminals showing immunoreactivity for VGLUT1 or VGLUT2 made asymmetric synapses with dendritic profiles of cerebellar neurons. Finally, we selectively down-regulated the expression of VGLUT1 mRNA or VGLUT2 mRNA by using viral vector mediated siRNA transfection and detected that the fine movements of the forelimb of rats were disturbed. These results indicated that LRN neurons coexpressing VGLUT1 and VGLUT2 project to the cerebellar cortex and these neurons might be critical in mediating the forelimb movements.

The NAc lesions disrupted the hippocampus-mPFC theta coherence during intravenous cocaine administration in rats.

Synchronization and desynchronization of neuronal oscillatory activities between different brain areas play an important role in effective information communication. The hippocampus-mPFC circuit is well recognized as an important neural circuit pathway involved in drug addiction. We aimed to examine cocaine-related changes in oscillation synchronization in the hippocampus-mPFC circuit and to explore the role of the NAc in oscillation synchronization between the hippocampus and the mPFC during intravenous cocaine administration. In our experiment, adult male Sprague-Dawley rats were divided into the Saline group, Cocaine group and Lesion group by the random number table method. Using an electrophysiological method, we continuously recorded the local field potentials (LFPs) of the hippocampus and the mPFC after pulse intravenous cocaine or saline. Our results showed that theta coherence occurred in the hippocampus-mPFC circuit during intravenous cocaine administration (Coherenceθ, Pre-drug = 0.2212 ±â€¯0.0126, Coherenceθ, Post-drug = 0.3118 ±â€¯0.0149, t = 4.894, P < 0.001), and the NAc Lesions could disrupt hippocampus-mPFC theta coherence (Coherenceθ, Pre-drug = 0.3164 ±â€¯0.0188, Coherenceθ, Post-drug = 0.2628 ±â€¯0.0248, t = 2.408, P < 0.05). These findings indicated that the NAc could influence oscillation synchronization between the hippocampus and mPFC during intravenous cocaine administration, which might help to elucidate the neurophysiological mechanisms of the neural circuits that underlie the function of the NAc during the strengthening of drug addiction.

[Effects of Na2WO4 on 15N absorption and utilization,13C accumulation of apple seedling, and fruit quality]. / é’¨é ¸é’ å¯¹è‹¹æžœå¹¼è‹—15N吸收利用、13C积累及果实品质的影响.

Pot culture and field experiments were carried out with one-year-old apple rootstock M9T337 seedlings and five-year-old 'Yanfu3'/SH6/M. hupehensis Rehd. as test materials respectively. Combined with 15N and 13C isotope tracer technology, we examined the effects of different concentrations of NR inhibitor Na2WO4(0, 0.5, 1, 1.5 mmol·L-1, expressed by CK, T1, T2 and T3 respectively) on 15N absorption and 13C accumulation of seedling and apple quality. The results showed that 0.5-1.0 mmol·L-1 Na2WO4 significantly inhibited shoot growth but not root growth of seedling in the pot experiment. Root growth was significantly inhibited when the concentration of Na2WO4 reached 1.5 mmol·L-1. The NR activity of each treatment was negatively correlated with the concentrations of Na2WO4 in the same period, with an order of CK>T1>T2>T3. The content of nitrate in leaves showed the trend of first rising and then decreasing with the extension of processing time. Nitrate content was positively correlated with Na2WO4 concentration in the same period, with an order of T3>T2>T1>CK. Spraying Na2WO4 reduced the 15N absorption of each organ and 15N utilization rate, with such effects increasing with the amount of spraying. With the increases of Na2WO4 concentration, 13C accumulation on the ground increased first and then decreased, with highest value in T2 treatment. The 13C accumulation of whole plant showed a similar pattern. The results of field experiment showed that Na2WO4 application reduced nitrogen contents of leaves and fruits at maturity stage, and increased the anthocyanin content in peel, soluble solids, soluble sugar content and sugar acid ratio in fruits. The T2 treatment showed the best effect. In summary, T2 treatment (1.0 mmol·L-1 Na2WO4) could inhibit shoot growth of seedlings, reduce 15N absorption and utilization, improve 13C accumulation, which would improve apple quality.

[Effects of potassium levels on translocation of 13C-photoassimilates to fruit in 'Fuji' apple during fruit expanding period].

A field experiment was carried out in a six-year old 'Fuji'3/M26/Malus hupehensis Rehd. apple with the 13C tracer method to examine the changes of chlorophyll fluorescence parameters, photosynthetic characteristics of leaf, sugar transporter gene expression, 13C assimilation capability and the characteristics of translocation and distribution of 13C-photoassimilates to fruit under different levels of potassium addition (K2O 0, 0.5%, 1.0%, 1.5%, 2.0%, expressed by CK, K1, K2, K3, K4, respectively). Potassium aqueous solution smear the leaves within 20 cm around the fruit at fruit enlargement stage. Compared with other treatments, K3 treatment significantly increased Rubisco enzyme activity, net photosynthetic rate, maximal photochemical efficiency of PSII, actual photochemical efficiency of PSII, coefficient of photochemical quenching, sorbitol and sucrose content, sorbitol 6-phosphate dehydrogenase (S6PDH) and sucrose phosphate synthase (SPS) enzyme activities and 13C assimilation capability of leaves. Furthermore, K3 treatment increased gene expression of sorbitol transporter MdSOT1 and MdSOT2 and sucrose transporter MdSUT4, and promoted the unloading of sugar in fruit. The 13C of self retention (self leaves and self branches) was the highest in CK (82.6%) and the lowest in K3 treatment (60.5%). With increasing potassium concentration, the 13C absorption of fruit first increased and then decreased, which was the highest in K3 treatment (1.31 mg·g-1) and the lowest in CK (0.57 mg·g-1). Our results indicated that foliage application of potassium solution improved PSII photochemical efficiency, activities of key enzymes related with carbon assimilation, synthesis ability, and outward transport ability of photosynthates in leaves, and consequently promoted the directional transportation of sugar to fruit. The amount of photoassimilates transported to fruit was the most under 1.5% K2O treatment (K3).

[Effects of different integration of water and fertilizer modes on the absorption and utilization of nitrogen fertilizer and fruit yield and quality of apple trees].

We examined nitrogen use efficiency of 15N-urea of 15-year-old 'Gala' apple trees by broadcast fertilization (T1), nitrogen fertilization with drip irrigation (T2) and nitrogen fertilization with subsurface irrigation (T3), to further improve the water and fertilizer integration technology for apple orchard and to improve nitrogen utilization efficiency. The results showed that leaf area, chlorophyll, and leaf nitrogen content of leaves were significantly higher in T3 treatment than those in T1 and T2 treatments. Soil mineral nitrogen content (20-40 cm) in each period followed the order of T3>T2>T1, while that in 0-20 cm followed an order of T2>T3>T1. The Ndff value at organ level (the contribution rate of the 15N amount absorbed by various organs of the tree to the total nitrogen content of the organ) was the highest in T3 treatment in each period, followed by T2 and T1 treatments. The utilization rate of 15N in the fruit ripening period followed an order of T3>T2>T1. The 15N utilization rate of T3 reached 24.2%, being 1.19 and 1.65 times of T2 and T1, respectively. The 15N distribution rate in the fruits during the fruit maturity stage was the highest in T1 treatment, while that in the storage organs was the highest in T2 treatment and that in the reproduction organs was the highest in T3 treatment. The single fruit weight, yield, soluble solids, hardness, soluble sugar and sugar-acid ratio were the highest in T3 treatment, followed by T2 and T1 treatments. In summary, nitrogen application by percolation irrigation (subsurface application) significantly promoted leaf growth and nitrogen utilization of apple tree, and improved fruit yield and quality.

Strategy for the Biosynthesis of Short Oligopeptides: Green and Sustainable Chemistry.

Short oligopeptides are some of the most promising and functionally important amide bond-containing components, with widespread applications. Biosynthesis of these oligopeptides may potentially become the ultimate strategy because it has better cost efficiency and environmental-friendliness than conventional solid phase peptide synthesis and chemo-enzymatic synthesis. To successfully apply this strategy for the biosynthesis of structurally diverse amide bond-containing components, the identification and selection of specific biocatalysts is extremely important. Given that perspective, this review focuses on the current knowledge about the typical enzymes that might be potentially used for the synthesis of short oligopeptides. Moreover, novel enzymatic methods of producing desired peptides via metabolic engineering are highlighted. It is believed that this review will be helpful for technological innovation in the production of desired peptides.

Characterization of Size-Resolved Hygroscopicity of Black Carbon-Containing Particle in Urban Environment.

The hygroscopic properties of BC-containing particles (BCc) are important to determine their wet scavenging, atmospheric lifetime, and interactions with clouds. Such information is still lacking in the real world because of the challenges in isolating BCc from other aerosols to be directly characterized. In this study, the size-resolved chemical components of BCc including the refractory BC core and associated coatings were measured by a soot particle-aerosol mass spectrometer in suburban Nanjing. The size-resolved hygroscopicity parameter of BCc (κBCc) was obtained based on this full chemical characterization of BCc. We found increased inorganic fraction and more oxidized organic coatings with thicker coatings, which modified κBCc besides the determinant of particle size. The bulk κBCc was observed to range from 0.11 to 0.34. The size-resolved κBCc consistently showed minima at coated diameter (Dcoated) of 100 nm, parametrized as κ(x) = 0.28-0.35 × exp(-0.004 × x), x = Dcoated. Under critical supersaturations (SS) of 0.1% and 0.2%, the D50 values of BCc were 200 ± 20 and 135 ± 18 nm, respectively. On average 33 ± 16% and 59 ± 20% of BCc in number could be activated at SS = 0.1% and 0.2%, respectively. These results provide constraints on surface CCN sources for the light-absorbing BC-containing particles.

[Effects of exogenous ABA on translocation of photosynthate to fruit of Fuji apple during late stage of fruit rapid-swelling.] / å¤–æºè„±è½é ¸å¯¹å¯Œå£«è‹¹æžœæžœå®žè†¨å¤§åŽæœŸå ‰åˆäº§ç‰©å‘æžœå®žè¿è¾“çš„å½±å“.

To clarify the effects and underlying mechanism of ABA on sugar accumulation in apple fruits, 13C trace technique was used to examined the effects of different ABA levels (0, 50, 100 and 150 mg·L-1) and fluoridone (ABA biosynthesis inhibitor) on translocation of photosynthate to fruit during late stage of fruit rapid-swelling in five-year-old 'Yanfu3'/M26/Malus hupehensis Rehd. The results showed that the activities of related enzyme in sugar metabolism, the relative expression of sucrose transporter gene MdSUT1, MdSUT2.2 and sorbitol transporter gene MdSOT3 tended to increase first and then decrease with increasing ABA concentration, with a peak in 100 mg·L-1ABA treatment. Fluridone treatment significantly inhibited the enzymes activities of sugar metabolism and the relative expression of sugar transporters. The treatment of 100 mg·L-1ABA significantly reduced leaf 13C content, increased fruit 13C content and increased the transport rate of photosynthate from leaves to fruits compared with other treatments. Our results indicated that exogenous ABA enhanced sink strength of fruit and promoted the transportation of more photosynthate to fruits, which increased the soluble sugar content in fruits.

[Effects of potassium supply on the growth, photosynthesis and 15N and 13C absorption and utilization of M9T337 seedling.] / ä¾›é’¾æ°´å¹³å¯¹è‹¹æžœç §æœ¨M9T337å¹¼è‹—ç”Ÿé•¿ã€å ‰åˆç‰¹æ€§ä¸Ž15N、13C吸收利用的影响.

Hydroponic experiment was carried out on M9T337 seedlings using 15N and 13C isotope tracer technology to study the effects of different potassium supply levels (K0, K1, K2, K3 and K4 were equivalent to 0, 3, 6, 9 and 12 mmol·L-1, respectively) on the growth, photosynthetic characteristics and 15N and 13C absorption and utilization of M9T337 seedlings. The results showed that dry mass, root length, root surface area, number of tips and root activity of M9T337 seedlings under the K2 level were significantly higher than those under other levels. The net photosynthetic rate (Pn) of leaves increased at low K+ concentration and then decreased with the increases of potassium supply level, and reached the maximum value at K2 treatment (15.5 µmol CO2·m-2·s-1). At the 30th day after treatment, the activities of nitrate reductase (NR) and carbon metabolism enzyme were highest in K2 treatment, and lowest in K0 treatment. With the increases of potassium application rate, the 13C accumulation of seedlings were first increased and then decreased, with the 13C distribution rate of each organ being the most balanced at K2 treatment. There were significant differences in 15N uptake and utilization rate among treatments. 15N uptake and utilization rates of seedlings under K2 treatment were the highest, which were 16.1 mg and 17.9%, respectively. Therefore, too low or too high potassium supply could inhibit seedling root growth and leaf photosynthesis, which was not conducive to carbon and nitrogen absorption. Appropriate potassium supply could improve root activity and net photosynthetic rate, enhance nitrate reductase (NR) and carbon metabolic enzyme activity, and promote carbon and nitrogen metabolism.

[Effects of split combined application of organic-inorganic fertilizers on plant growth, 15N absorption, utilization and loss of Gala apple tree]. / æœ‰æœºæ— æœºè‚¥åˆ†æ¬¡é æ–½å¯¹å˜Žå•¦è‹¹æžœç”Ÿé•¿ã€15N-å°¿ç´ å¸æ”¶åˆ©ç”¨åŠæŸå¤±çš„å½±å“.

Fifteen-year-old 'Gala'/M. hupehensis Rehd. trees and 15N trace technique were used to explore the effects of split combined application of organic-inorganic fertilizers on plant growth, 15N absorption, utilization and loss. The main results were as follows: compared to control, combined application of organic-inorganic fertilizers significantly increased the root-shoot ratio, chlorophyll content, total nitrogen content of leaves and mean fruit mass. The effects of split combined application of organic-inorganic fertilizers treatment were more obvious than one time combined application. Combined application of organic-inorganic fertilizers treatment improved the capacity of 15N derived from fertilizer (Ndff) of different organs, with the effects of split combined application of organic-inorganic fertilizers treatment being more significant. The Ndff value of fruits in different treatments were the highest, followed by leaves, biennial branches, fine roots, large roots and perennial branches, and lowest in trunks. Total N content of plant and 15N-urea utilization rate of the split combined application of organic-inorganic fertilizers treatment were 395.39 g and 28.4% respectively, which were obviously higher than the treatments of one time combined application (342.77 g and 21.1%) and no organic fertilizer application (296.41 g and 14.6%), while 15N loss rate was 51.3%, which was obviously lower than the treatments of one time combined application (57.5%) and no organic fertilizer application (60.6%).

[Effects of nitrogen application levels on translocation and distribution of 13C-photosynthate and 15N to fruit from leaves of apple tree]. / 氮水平对苹果叶片13Cå ‰åˆäº§ç‰©å’Œ15Nå‘æžœå®žè½¬ç§»åˆ†é çš„å½±å“.

A field experiment was carried out in a six-year old 'Fuji3'/M26/Malus hupehensis Rehd. apple with 15N and 13C labeled tracers, to understand 13C assimilation capability and the characteristics of translocation and distribution of 13C-photosynthate and 15N to fruit under different nitrogen application levels (urea 0%, 0.6%, 1.2%, 1.8%, 2.4%, CK, N1, N2, N3, N4, respectively) to smear the leaves within 20 cm around the fruit at late stage of fruit enlargement. The results showed that, with the increases of urea application, the chlorophyll content, nitrogen content, net photosynthetic rate, sorbitol and sucrose content, sorbitol 6-phosphate dehydrogenase (S6PDH) and sucrose phosphate synthase (SPS) activities, 13C assimilation capability of leaves were first increased and then decreased, with the highest value in 1.8% urea smear treatment and the lowest value with the treatment of clear water. The 13C of self retention (self leaves and self branches) was the highest in clear water (81.6%) and the lowest in 1.8% urea smear treatment (63.5%). The 13C was mainly allocated to fruit, followed by unlabeled perennial branch, and the lowest in unlabeled leaves. With the increases of urea application, the 13C absorption of fruit was first increased and then decreased, with the highest value in 1.8% urea smear treatment (1.21 mg·g-1) and the lowest value in clear water (0.51 mg·g-1). The 15N absorption of fruit was enhanced with the increases of urea application. These results indicated that foliage application of urea solution improved translocation and distribution of leaf photosynthate and nitrogen to fruit with varying degrees, which was the highest in 1.8% urea smear treatment and could avoid excessive intake of nitrogen to fruit.

Altered Activity of SK Channel Underpins Morphine Withdrawal Relevant Psychiatric Deficiency in Infralimbic to Accumbens Shell Pathway.

Drug addiction can be viewed as a chronic psychiatric disorder that is related to dysfunction of neural circuits, including reward deficits, stress surfeits, craving changes, and compromised executive function. The nucleus accumbens (NAc) plays a crucial role in regulating craving and relapse, while the medial prefrontal cortex (mPFC) represents a higher cortex projecting into the NAc that is active in the management of executive function. In this study, we investigated the role of the small conductance calcium-activated potassium channels (SK channels) in NAc and mPFC after morphine withdrawal. Action potential (AP) firing of neurons in the NAc shell was enhanced via the downregulations of the SK channels after morphine withdrawal. Furthermore, the expression of SK2 and SK3 subunits in the NAc was significantly reduced after 3 weeks of morphine withdrawal, but was not altered in the dorsal striatum. In mPFC, the SK channel subunits were differentially expressed. To be specific, the expression of SK3 was upregulated, while the expression of SK2 was unchanged. Furthermore, the AP firing in layer 5 pyramidal neurons of the infralimbic (IL) cortex was decreased via the upregulations of the SK channel-related tail current after 3 weeks of morphine withdrawal. These results suggest that the SK channel plays a specific role in reward circuits following morphine exposure and a period of drug withdrawal, making it a potential target for the prevention of relapse.