Pain after combat injury in male UK military personnel deployed to Afghanistan

BACKGROUND

Chronic pain after injury poses a serious health burden. As a result of advances in medical technology, ever more military personnel survive severe combat injuries, but long-term pain outcomes are unknown. We aimed to assess rates of pain in a representative sample of UK military personnel with and without combat injuries.

METHODS

We used data from the ADVANCE cohort study (ISRCTN57285353). Individuals deployed as UK armed forces to Afghanistan were recruited to include those with physical combat injuries, and a frequency-matched uninjured comparison group. Participants completed self-reported questionnaires, including 'overall' pain intensity and self-assessment of post-traumatic stress disorder, anxiety, and depression.

RESULTS

A total of 579 participants with combat injury, including 161 with amputations, and 565 uninjured participants were included in the analysis (median 8 yr since injury/deployment). Frequency of moderate or severe pain was 18% (n=202), and was higher in the injured group (n=140, 24%) compared with the uninjured group (n=62, 11%, relative risk: 1.1, 95% confidence interval [CI]: 1.0-1.2, P<0.001), and lower in the amputation injury subgroup (n=31, 19%) compared with the non-amputation injury subgroup (n=109, 26%, relative risk: 0.9, 95% CI: 0.9-1.0, P=0.034). Presence of at least moderate pain was associated with higher rates of post-traumatic stress (RR: 3.7, 95% CI: 2.7-5.0), anxiety (RR: 3.2, 95% CI: 2.4-4.3), and depression (RR: 3.4, 95% CI: 2.7-4.5) after accounting for injury.

CONCLUSION

Combat injury, but not amputation, was associated with a higher frequency of moderate to severe pain intensity in this cohort, and pain was associated with adverse mental health outcomes.

A systematic review of the prevalence of postamputation and chronic neuropathic pain associated with combat injury in military personnel

ABSTRACT

Combat trauma can lead to widespread tissue damage and limb loss. This may result in chronic neuropathic and post amputation pain, including phantom limb pain (PLP) and residual limb pain (RLP). The military population is distinct with respect to demographic, injury, and social characteristics compared with other amputation and trauma cohorts. We undertook a systematic review of studies of military personnel, with a history of combat injury, that reported a prevalence of any type of postamputation pain or chronic neuropathic pain, identified from Embase and MEDLINE databases.Using the inverse variance method with a random-effects model, we undertook a meta-analysis to determine an overall prevalence and performed exploratory analyses to identify the effect of the type of pain, conflict, and time since injury on prevalence. Pain definitions and types of pain measurement tools used in studies were recorded. Thirty-one studies (14,738 participants) were included. The pooled prevalence of PLP, RLP, and chronic neuropathic pain were 57% (95% CI: 46-68), 61% (95% CI: 50-71), and 26% (95% CI: 10-54), respectively. Between-study heterogeneity was high (I 2 : 94%-98%). Characterisation of duration, frequency, and impact of pain was limited. Factors reported by included studies as being associated with PLP included the presence of RLP and psychological comorbidity. The prevalence of postamputation pain and chronic neuropathic pain after combat trauma is high. We highlight inconsistency of case definitions and terminology for pain and the need for consensus in future research of traumatic injury.

Single institution experience with telemedicine for pediatric urology outpatient visits: Adapting to COVID-19 restrictions, patient satisfaction, and future utilization

INTRODUCTION

Widespread utilization of telemedicine in our practice to date has been limited to the evaluation of certain post-surgical patients. The COVID-19 pandemic acutely stressed our established system and required us to enhance our utilization of telemedicine. We hypothesized that expansion of telemedicine to new and follow up patient visits for pediatric urology could be done effectively in a way that satisfied patient and parental expectations.

MATERIALS AND METHODS

Using a pre-COVID-19 established telemedicine program based in our electronic medical record (EMR), patients and providers transitioned to primarily virtual visits when clinically appropriate. Guidelines were formulated to direct patient scheduling, provider and staff education was provided, including a process map designed for multiple providers to complete video visits (VV), and the EMR was redesigned to incorporate telehealth terminology. The number of VV per provider was recorded using the electronic medical record, and patient reported outcomes (PRO) were measured using a standardized questionnaire.

RESULTS

A total of 631 VV met inclusion criteria during the period of May 2018-April 2020. This included 334 follow up, 172 new, and 125 postoperative visits. The median age of patients at time of visit was 7 years (IQR 2-12 years), median visit time was 20 min (IQR 15-30 min), and the median travel distance saved by performing a VV was 12.2 miles (IQR 6.3-26.8 miles). Diagnoses were varied and included the entire breadth of a standard pediatric urology practice. The PRO questionnaire was completed for 325 of those patient visits. Families reported a high overall satisfaction with the video visits (median score of 10 out of 10) and felt that the visit met their child's medical needs. 90% stated that they would strongly recommend a telehealth visit to other families. Patients and parents reported benefits of VV including decreased travel costs and less time taken off from work and school.

CONCLUSION

The EMR enabled nimble redirection of clinical care in the setting of a global pandemic. The enhanced use of telemedicine has proved to be an alternative method to provide care for pediatric urology patients. Families indicate a high degree of satisfaction with this technology in addition to significant time and cost savings. Telemedicine should remain a key aspect of medical care and expanded from post-operative visits to new patient and follow up visits, even as we return to our normal practices as the pandemic restrictions soften.

Immunogenicity and safety of an accelerated hepatitis E vaccination schedule in healthy adults: a randomized, controlled, open-label, phase IV trial

OBJECTIVES

This study aimed to evaluate the immunogenicity and safety of a hepatitis E (HE) vaccine using an accelerated vaccination schedule (vaccine doses at 0, 7 and 21 days).

METHODS

A total of 126 participants aged ≥18 years were randomly assigned to receive the hepatitis E virus vaccine in either the accelerated group (0, 7 and 21 days) or the routine group (0, 1 and 6 months). Serology samples were obtained at 0, 21, 28 and 51 days, and 7 months in the accelerated group, or 0, 1, 2 and 7 months in the routine group after the first vaccine injection. Adverse events (AEs) reported during the whole study were analysed.

RESULTS

A total of 126 participants were randomized, 63 for each group. Sixty-two participants in the accelerated group and 63 in the routine group received at least one dose of vaccine; 57 and 63 participants received all three doses and were included in per-protocol set, respectively. In the per-protocol population, at 1 month after the last dose (accelerated group at 51 days versus routine group at 7 months), the seropositive rates were both 100% (57/57 and 63/63, respectively), and the geometric mean concentrations (GMCs) were 8.51 WHO units/mL (95% CI 6.73-10.76) in the accelerated group and 9.67 WHO units/mL (95% CI 7.67-12.20) in the routine group. The ratio of the accelerated group GMC to the routine group GMC was 0.88 (95% CI 0.61-2.17, lower limit of 95% CI > 0.5), indicating that the accelerated vaccination schedule was non-inferior to the routine one. The overall incidence rates of solicited AEs in the accelerated and routine groups were 32.26% (20/62) and 30.16% (19/63), respectively (p 0.800). Most AEs were moderate.

CONCLUSIONS

An accelerated schedule is safe and provides protective antibodies in a shorter time compared with the routine schedule. The accelerated schedule should be recommended to adults who are travelling on short notice to an HE-endemic area or during an HE outbreak (Clinical Trial Registration. NCT03168412).

Structural and Topological Evolution in SixSe1-x Glasses: Results from 1D and 2D 29Si and 77Se NMR Spectroscopy

The coordination environments of Si and Se atoms and their connectivity in binary Si_xSe_1-x glasses with 0.05 ≤ x ≤ 0.33 are investigated using a combination of one- and two-dimensional ²⁹Si and ⁷⁷Se nuclear magnetic resonance (NMR) and Raman spectroscopy. The high-resolution correlated isotropic and anisotropic ²⁹Si and ⁷⁷Se NMR spectra allow for the identification and quantitation of a variety of Si and Se environments. The results suggest that the structure of these glasses are characterized by a network with essentially perfect short-range chemical order, but with strong clustering at the intermediate range. Initial addition of Si to Se results in cross-linking of Se chain segments with nanoclusters of corner- and edge-shared SiSe_4/2 tetrahedra. These clusters percolate via coalescence near x ≥ 0.2 to finally form a low-dimensional network with high molar volume, at the stoichiometric composition (x = 0.33) that is composed of chains of edge-sharing tetrahedra cross-linked by corner-shared tetrahedra. This structural evolution is shown to be consistent with the compositional variation of the glass transition temperature and the molar volume of these glasses.

Molecular cloning and characterization of lymphocyte cell kinase from humphead snapper (Lutjanus sanguineus)

Lymphocyte cell kinase (LCK) belongs to the Src family of tyrosine kinases, which involves in the proliferation control of lymphocytes. In this study, we cloned the LCK gene of humphead snapper (Lutjanus sanguineus) (designed as LsLCK). Sequence analysis showed that the full-length cDNA of LsLCK was 2279 bp, contained a 1506-bp open reading frame (ORF), encoding a polypeptide of 501 amino acids. The deduced amino acid possessed the typical structural features of known LCK proteins, including four Src homology (SH) domains arranged as the SH1 domain followed by a regulatory C-terminal tail (COOH-domain), SH2 and SH3 adapter domains and SH4 domain which required for membrane attachment and CD4/CD8 binding. Fluorescent quantitative real-time PCR analysis indicated that LsLCK transcripts were expressed mainly in thymus, spleen and head kidney in healthy fish. Moreover, the mRNA expressions in these tissues were significantly up-regulated after challenge with Vibrio harveyi. The results of immunohistochemistry showed that LsLCK protein localized distinctly in cytoplasm of cell in thymus, spleen and head kidney. Taken together, these findings indicated that LsLCK may play an important role in the immune response of humphead snapper against bacterial infection.

A comparison of the clinical characteristics of women with recurrent major depression with and without suicidal symptomatology

BACKGROUND

The relationship between recurrent major depression (MD) in women and suicidality is complex. We investigated the extent to which patients who suffered with various forms of suicidal symptomatology can be distinguished from those subjects without such symptoms.

METHOD

We examined the clinical features of the worst episode in 1970 Han Chinese women with recurrent DSM-IV MD between the ages of 30 and 60 years from across China. Student's t tests, and logistic and multiple logistic regression models were used to determine the association between suicidality and other clinical features of MD.

RESULTS

Suicidal symptomatology is significantly associated with a more severe form of MD, as indexed by both the number of episodes and number of MD symptoms. Patients reporting suicidal thoughts, plans or attempts experienced a significantly greater number of stressful life events. The depressive symptom most strongly associated with lifetime suicide attempt was feelings of worthlessness (odds ratio 4.25, 95% confidence interval 2.9-6.3). Excessive guilt, diminished concentration and impaired decision-making were also significantly associated with a suicide attempt.

CONCLUSIONS

This study contributes to the existing literature on risk factors for suicidal symptomatology in depressed women. Identifying specific depressive symptoms and co-morbid psychiatric disorders may help improve the clinical assessment of suicide risk in depressed patients. These findings could be helpful in identifying those who need more intense treatment strategies in order to prevent suicide.

Childhood sexual abuse and the risk for recurrent major depression in Chinese women

BACKGROUND

Studies in Western countries have repeatedly shown that women with a history of childhood sexual abuse (CSA) are at increased risk for developing major depression (MD). Would this relationship be found in China?

METHOD

Three levels of CSA (non-genital, genital, and intercourse) were assessed by self-report in two groups of Han Chinese women: 1970 clinically ascertained with recurrent MD and 2597 matched controls. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression and regression coefficients by linear or Poisson regression.

RESULTS

Any form of CSA was significantly associated with recurrent MD [OR 3.26, 95% confidence interval (CI) 1.95-5.45]. This association strengthened with increasing CSA severity: non-genital (OR 2.47, 95% CI 1.17-5.23), genital (OR 2.77, 95% CI 1.32-5.83) and intercourse (OR 13.35, 95% CI 1.83-97.42). The association between any form of CSA and MD remained significant after accounting for parental history of depression, childhood emotional neglect (CEN), childhood physical abuse (CPA) and parent-child relationship. Among the depressed women, those with CSA had an earlier age of onset, longer depressive episodes and an increased risk for generalized anxiety disorder (GAD; OR 1.92, 95% CI 1.39-2.66) and dysthymia (OR 2.16, 95% CI 1.52-3.09).

CONCLUSIONS

In Chinese women CSA is strongly associated with MD and this association increases with greater severity of CSA. Depressed women with CSA have an earlier age of onset, longer depressive episodes and increased co-morbidity with GAD and dysthymia. Although reporting biases cannot be ruled out, our results are consistent with the hypothesis that, as in Western countries, CSA substantially increases the risk for MD in China.

Bullying in middle school: results from a 2008 survey

A survey conducted in 2008 among 346 American middle school students in several cities determined that 82.7% of respondents found bullying to be a problem of some degree, with 46.0% rating it a "medium", "bad", or "very bad" problem. It was found that 89% had witnessed an act of bullying and 49.1% said they had been the victim of a bully. Boys were significantly more likely than girls to say that a victim deserved to be bullied (11.1% vs. 1.3%, p = 0.01), whereas girls were significantly more likely than boys to fail to intervene because they did not know what to do (30.3% for girls vs. 11.1%, p < 0.01). There was no significant difference in this study between boys and girls in terms of being a bully: 43.6% admitted they had bullied another (46.2% boys, 41.1% girls, p = 0.34); however, girls were significantly more likely than boys to bully by excluding others and gossiping about them than by hitting, teasing, or threatening. Cyberbullying, surveyed as a distinct entity, had affected 31.1% of respondents directly, with similar results from 2006 to 2007 surveys. Of those who found conventional bullying a "bad" or "very bad" problem at their schools, numbers fell from 17.3% in 2006-2007 vs. 11.3% in 2008.

Through-space R3-HETCOR experiments between spin-1/2 and half-integer quadrupolar nuclei in solid-state NMR

We present several new methods that allow to obtain through-space 2D HETCOR spectra between spin-1/2 and half-integer quadrupolar nuclei in the solid state. These methods use the rotary-resonance concept to create hetero-nuclear coherences through the dipolar interaction instead of scalar coupling into the HMQC and refocused INEPT experiments for spin n/2 (n>1). In opposite to those based on the cross-polarization transfer to quadrupolar nuclei, the methods are very robust and easy to set-up.

Resolution enhancement using a new multiple-pulse decoupling sequence for quadrupolar nuclei

A new decoupling composite pulse sequence is proposed to remove the broadening on spin S=1/2 magic-angle spinning (MAS) spectra arising from the scalar coupling with a quadrupolar nucleus I. It is illustrated on the (31)P spectrum of an aluminophosphate, AlPO(4)-14, which is broadened by the presence of (27)Al/(31)P scalar couplings. The multiple-pulse (MP) sequence has the advantage over the continuous wave (CW) irradiation to efficiently annul the scalar dephasing without reintroducing the dipolar interaction. The MP decoupling sequence is first described in a rotor-synchronised version (RS-MP) where one parameter only needs to be adjusted. It clearly avoids the dipolar recoupling in order to achieve a better resolution than using the CW sequence. In a second improved version, the MP sequence is experimentally studied in the vicinity of the perfect rotor-synchronised conditions. The linewidth at half maximum (FWHM) of 65 Hz using (27)Al CW decoupling decreases to 48 Hz with RS-MP decoupling and to 30 Hz with rotor-asynchronised MP (RA-MP) decoupling. The main phenomena are explained using both experimental results and numerical simulations.

Ultra-wide bore 900 MHz high-resolution NMR at the National High Magnetic Field Laboratory

Access to an ultra-wide bore (105 mm) 21.1 T magnet makes possible numerous advances in NMR spectroscopy and MR imaging, as well as novel applications. This magnet was developed, designed, manufactured and tested at the National High Magnetic Field Laboratory and on July 21, 2004 it was energized to 21.1 T. Commercial and unique homebuilt probes, along with a standard commercial NMR console have been installed and tested with many science applications to develop this spectrometer as a user facility. Solution NMR of membrane proteins with enhanced resolution, new pulse sequences for solid state NMR taking advantage of narrowed proton linewidths, and enhanced spatial resolution and contrast leading to improved animal imaging have been documented. In addition, it is demonstrated that spectroscopy of single site (17)O labeled macromolecules in a hydrated lipid bilayer environment can be recorded in a remarkably short period of time. (17)O spectra of aligned samples show the potential for using this data for orientational restraints and for characterizing unique details of cation binding properties to ion channels. The success of this NHMFL magnet illustrates the potential for using a similar magnet design as an outsert for high temperature superconducting insert coils to achieve an NMR magnet with a field >25 T.

Increasing the sensitivity of 2D high-resolution NMR methods applied to quadrupolar nuclei

Gan and Kwak recently proposed a soft-pulse added mixing (SPAM) idea in the classical two-pulse multiple-quantum magic-angle spinning scheme. In the SPAM method, a soft pi/2 pulse is added after the second hard-pulse (conversion pulse) and all coherence orders in between them are constructively used to obtain the signal. We, here, further extend this idea to distributed samples where the signal mainly results from echo pathways and that from anti-echo pathways dies out after a few t1 increments. We show that, with a combination of SPAM and collection of fewer anti-echoes, an enhancement of the signal to noise ratio by a factor of ca. 3 may be obtained over the z-filtered version. This may prove to be useful even for samples with long T2' relaxation times.

Solid-state microstructures, thermal properties, and crystallization of biodegradable poly(butylene succinate) (PBS) and its copolyesters

Studies of solid-state structures under different crystallization conditions, melting behavior, and crystal growth kinetics are reported for biodegradable aliphatic poly(butylene succinate) (PBS) and its random copolyesters of poly(butylene succinate-co-14 mol %ethylene succinate) [P(BS-co-14 mol %ES)] and poly(butylene succinate-co-15 mol %hexamethylene succinate) [P(BS-co-15 mol %HS)]. The crystal structures of two copolyesters determined by wide-angle X-ray diffraction (WAXD) are the same as that of the PBS homopolymer, suggesting that the second comonomers ES or HS units are excluded from the crystalline core and are in an amorphous state. The further investigations on the crystalline and amorphous phase structures and sizes by small-angle X-ray scattering (SAXS) method have provided quantitative evidence that the existence of second comonomers increases the amorphous thickness of copolyesters but that the influences of comonomers on the lamellar crystal structure and size of copolyesters are complicated. The origin of the complexity and its influences on the equilibrium melting temperature T(m)(0) of copolyester are discussed in the present paper. Gibbs-Thomson and Hoffman-Weeks equations were applied for the determination of T(m)(0) of PBS, P(BS-co-14 mol %ES), and P(BS-co-15 mol %HS)-three samples. Two equations gave different T(m)(0) values for each sample. On the basis of the Gibbs-Thomson equation, the P(BS-co-15 mol %HS) copolyester has the same T(m)(0) value as that of the PBS homopolymer, while the P(BS-co-14 mol %ES) copolyester has a lower one. This is due to the different influences of the second comonomers on the crystalline phase structure indicated by SAXS results, and the Gibbs-Thomson equation has been suggested to be more reliable. The crystal growth kinetics of the three samples was analyzed by using the secondary nucleation theory, and the influences of various parameters on the regime transition and nucleation constant were studied. Meanwhile some interrelations between regime transition temperature and melting behavior were found for the three samples.

Crystallization, melting, and enzymatic degradation of biodegradable poly(butylene succinate-co-14 mol % ethylene succinate) copolyester

The crystal structure and growth kinetics of melt-crystallized poly(butylene succinate-co-14 mol % ethylene succinate) [P(BS-co-14 mol % ES)] copolyester have been investigated at a wide crystallization temperature range of 30 to 90 degrees C. By means of wide-angle X-ray diffraction (WAXD), the copolyester composed of BS and ES units has been identified to have the same crystal structure with that of poly(butylene succinate) (PBS) homopolymer, suggesting that only PBS sequences crystallize while that the ES units are in an amorphous form. On the basis of secondary nucleation theory, two regimes of II and III have been observed and their transition temperature is around 80 degrees C. The spherulitic morphologies of P(BS-co-14 mol % ES) copolyester developed from banded spherulites to the normal ones without banding extinction patterns as the crystallization temperature increased. The melting behavior of P(BS-co-14 mol % ES) copolyester under different conditions has been studied by differential scanning calorimetry (DSC). Four melting peaks and one exothermal peak on the melting curves were observed during heating process, and their origination is discussed. The enzymatic degradation was carried out on the melt-crystallized P(BS-co-14 mol % ES) thin film by an extracellar PHB depolymerase from Pseudomonas stutzeri and the morphologies of lamellar crystals before and after degradation have been examined by atomic force microscopy (AFM). The results have indicated that enzymatically degradable ES units exist on the surface of lamellar crystals and are hydrolyzed by the enzyme, while that the crystalline cores composed of PBS chains are not degraded.

Biodegradable poly(ethylene succinate) (PES). 1. Crystal growth kinetics and morphology

Crystal growth rates of melt-crystallized poly(ethylene succinate) (PES) with a number-average molecular weight Mn of 21,100 and polydispersity of 1.86, respectively, were studied in an extensive temperature range. On the basis of secondary nucleation theory, only one transition between regime III and regime II was found at around 71 degrees C, but no transition of regime II-->I was detected by kinetic analysis. The ratio of nucleation constants KgIII in regime III to KgII in regime II was influenced by the value of activation energy U*, and tended to 2 as predicted by the theory when U* was set as 3688 cal/mol. The morphological changes at spherulitic level and lamellar level in regime II and regime III were examined by using an optical microscope (OM) and atomic force microscope (AFM). Although spherulitic morphologies were found in both regime II and regime III by optical microscopy, further investigations made by following the crystallization process using OM and by checking the lamellar morphology using AFM revealed morphological changes during the crystal growth process and different crystal morphologies in regime II and regime III. Meanwhile by using ultrathin film (approximately 100 nm in thickness), the morphology of lamellar crystals of lozenge-shape outline and composed of single crystals has been studied by AFM technique. The results indicate that there is indeed a transition from regime II to regime III at around 71 degrees C for the isothermal crystallization of PES with an increasing degree of undercooling.

Biodegradable poly(ethylene succinate) (PES). 2. Crystal morphology of melt-crystallized ultrathin film and its change after enzymatic degradation

Poly(ethylene succinate) (PES) ultrathin films with an initial thickness of approximately 100 nm were prepared by the solution cast method on either cover glass or freshly cleaved mica as the substrate. The ultrathin films were then melt-crystallized at a given temperature for a certain period of time. The surface morphologies of these films on the substrates were observed by an atomic force microscope (AFM) and an optical microscope (OM) under ambient conditions. Two different crystal morphologies having fibril-like structure and flat-on lamellar crystals with a certain width were formed, and their growth mechanisms were discussed in association with previous kinetic data. It has been shown that at a higher crystallization temperature such as 85 degrees C (smaller degree of undercooling) the crystal aggregates tend to form lozenge-shaped hedrites which evolved from a single crystal. The enzymatic degradation of PES crystals on the ultrathin films was carried out by using a PHB depolymerase from Pseudomonas stutzeri at room temperature. The crystal morphologies before and after enzymatic degradation were examined by AFM. The lamellar crystals were hydrolyzed into many small fragments, and these fragments had the same thickness as that of the lamellar crystals before enzymatic degradation. The analysis of morphological results for PES lamellar crystals has revealed the existence of many defects on the surface of melt-crystallized lamellar crystals. These defects were preferentially attacked by the enzyme molecules. Hydrolysis starts from the chains folding in crystal defect area and proceeds along the lateral edges, i.e., along the direction perpendicular to the folding chain.

New pillared layered gallium phosphonates in the gallium/1,2-ethylenediphosphonic acid system

1,2-Ethylenediphosphonic acid reacts with gallium nitrate in water to give new pillared layered gallium phosphonates, the structure of which depends on the experimental conditions used for their preparation. Thus, Ga(4)(O(3)PC(2)H(4)PO(3))(3) (1) and Ga(2)(OH)(2)(O(3)PC(2)H(4)PO(3)) (2) were isolated and the structure of 1 was solved by single-crystal X-ray diffraction, while 2 was shown to have the same metal/PO(3) arrangement as the previously described Ga(OH)(O(3)PCH(3)). Ga(4)(O(3)PC(2)H(4)PO(3))(3) (1) is triclinic, with space group P1 with Z = 2, a = 5.1480(4), b = 8.0354(7), and c = 12.383(1) A; alpha = 91.34(1), beta = 101.40(1), and gamma = 90.86(1) degrees; V = 501.9(1) A(3). The structure of 1 is unusual with (i) mixed GaO(4) and GaO(5) sites while a 6-fold coordination is observed for gallium in (2) and (ii) the presence of the organic moiety within both the layers and the interlayer space. The two compounds were fully characterized using (31)P and (71)Ga solid-state NMR.

Structural characterization of MAO and related aluminum complexes. 1. Solid-state (27)Al NMR with comparison to EFG tensors from ab initio molecular orbital calculations

Experimental and ab initio molecular orbital techniques are developed for study of aluminum species with large quadrupole coupling constants to test structural models for methylaluminoxanes (MAO). The techniques are applied to nitrogen- and oxygen-containing complexes of aluminum and to solid MAO isolated from active commercial MAO preparations. (Aminato)- and (propanolato)aluminum clusters with 3-, 4-, and 6-coordinate aluminum sites are studied with three (27)Al NMR techniques optimized for large (27)Al quadrupole coupling constants: field-swept, frequency-stepped, and high-field MAS NMR. Four-membered (aminato)aluminum complexes with AlN(4) coordination yield slightly smaller C(q) values than similar AlN(2)C(2) sites: 12.2 vs 15.8 MHz. Planar 3-coordinate AlN(2)C sites have the largest C(q) values, 37 MHz. In all cases, molecular orbital calculations of the electric field gradient tensors yields C(q) and eta values that match with experiment, even for a large hexameric (aminato)aluminum cage. A D(3d) symmetry hexaaluminum oxane cluster, postulated as a model for MAO, yields a calculated C(q) of -23.7 MHz, eta = 0.7474, and predicts a spectrum that is too broad to match the field-swept NMR of methylaluminoxane, which shows at least three sites, all with C(q) values greater than 15 MHz but less than 21 MHz. Thus, the proposed hexaaluminum cluster, with its strained four-membered rings, is not a major component of MAO. However, calculations for dimers of the cage complex, either edge-bridged or face-bridged, show a much closer match to experiment. Also, MAO preparations differ, with a gel form of MAO having significantly larger (27)Al C(q) values than a nongel form, a conclusion reached on the basis of (27)Al NMR line widths in field-swept NMR spectra acquired from 13 to 24 T.

Distribution of polycyclic aromatic hydrocarbons in aerosols and dustfall in Macao

Polycyclic aromatic hydrocarbons (PAHs), widespread environmental pollutants, have been measured in aerosols and dustfall in Macao. In this paper, we compare concentration distributions and determine the partitioning of PAHs in aerosols and dustfall for different areas, sampling times and sampling heights. The results demonstrate that the concentrations of sigmaPAHs in aerosols and dustfall vary at the different sites and heights. The concentrations of sigmaPAHs and most of the individual PAHs in aerosols at night were higher than those in the daytime when using the unit of microg/g and lower than those when using the unit of microg m(-3). It is shown that the distribution of individual PAHs in aerosols differs significantly from that in dustfall.

High-field high-speed MAS resolution enhancement in 1H NMR spectroscopy of solids

Resolution in 1H NMR spectra of solids can be significantly enhanced with fast magic-angle spinning and high magnetic fields. A variable field and spinning speed study up to 25 T and 40 kHz shows that the homogeneous line broadening is inversely proportional to the product of magnetic field strength and spinning speed. The combination of high field and fast speed yields a 1H linewidth approaching the intrinsic limit determined by anisotropy of magnetic susceptibility. An analysis of the anisotropic magnetic susceptibility line broadening is presented.

[Water distribution and microclimatic effects of sprinkler irrigation on spring wheat field]

Measurements of sprinkler irrigation on spring wheat field indicated that spring wheat canopy could intercept water by 25-30%, and compared with that above canopy in first milking period, the uniformity coefficient below canopy could be increased by 7-9%. Floating and evaporation loss of sprinkler irrigation water could reach 20-25% of the total. In addition, sprinkler irrigation on spring wheat field could decrease air and soil temperature, and increase air actual vapor pressure and relative humidity, which played a definite role in restraining crop transpiration.

Imaging membrane protein helical wheels

Resonance patterns have been observed in 2D solid-state NMR spectra of the transmembrane segment of M2 protein from Influenza A virus in oriented samples reflecting the helical wheel of this alpha-helix. The center of this pattern uniquely defines the helical tilt with respect to the bilayer normal without a need for resonance assignments. The distribution of resonances from amino acid specific labels around the "PISA wheel" defines the rotational orientation of the helix and yields preliminary site-specific assignments. With assignments high-resolution structural detail, such as differences in tilt and rotational orientation along the helical axis leading to an assessment of helical coiling, can be obtained.

Spin dynamics of polarization inversion spin exchange at the magic angle in multiple spin systems

Polarization inversion spin exchange at the magic angle (PISEMA) [J. Magn. Reson. A 109, 270 (1994)] is an important experiment in NMR structural characterization of membrane proteins in oriented lipid bilayers. This paper presents a theoretical and experimental study of the spin dynamics in PISEMA to investigate the line-narrowing mechanism. The study focuses on the effect of neighboring protons on the spin exchange of a strongly coupled spin pair. The spin exchange is solved analytically for simple spin systems and is numerically simulated for many-spin systems. The results show that the dipolar couplings from the neighboring protons of a strongly coupled spin pair perturb the spin exchange only in the second order, therefore it has little contribution to the linewidth of PISEMA spectra in comparison to the separated-local-field spectra. The effects from proton resonance offset and the mismatch of the Hartmann-Hahn condition are also discussed along with experimental results using model single-crystal samples.

Isolation, affinity purification, and identification of piglet small intestine mucosa receptor for enterotoxigenic Escherichia coli k88ac+ fimbriae

An affinity chromatography technique was utilized to isolate and purify the receptors of Escherichia coli K88ac(+) fimbriae from the mucus of the small intestines of newborn piglets. Purified K88ac+ fimbriae were covalently immobilized onto a beaded agarose matrix (Sepharose 4B). The immobilized fimbriae were used for the affinity purification of the K88ac+ receptors. Only two major proteins were tightly and specifically bound to the immobilized fimbriae after the column containing bound receptor was washed exhaustively with a buffer containing a high concentration of salt and a detergent. The receptors were eluted as a single component at a low pH. The isolated proteins were then subjected to enzyme-linked immunosorbent assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blot (immunoblot) analyses. The two proteins were of high purity, were responsible for nearly all of the fimbrial binding capacity of the crude mucus, and had molecular masses of 26 and 41 kDa. The method for isolation of E. coli binding proteins is simple and yields purified intestinal receptors in a single chromatographic run. The intestinal mucus of different piglets has different proportions of the two receptor proteins.

Active-latent glycosylation strategy toward Lewis X pentasaccharide in a form suitable for neoglycoconjugate syntheses

Glycosylation of 4-nitrophenyl 2-acetamido-6-O-tert-butyldiphenylsilyl-2-deoxy-1-thio-beta-D-gluc opyranoside with phenyl 2,3,4,6-tetra-O-benzoyl-1-thio-beta-D-galactopyranoside in the presence of NIS and TfOH as catalyst gave the lactosamine derivative regiospecifically in high yield. Further 3-O-fucosylation with phenyl 2,3,4-tri-O-benzyl-1-thio-beta-L-fucopyranoside using DMTST as promoter afforded the Lex trisaccharide intermediate. The latent glycosyl donor was transformed into its active form (p-acetamidothiophenyl) by reduction with zinc in acetic acid and N-acetylation. Glycosidation with p-nitrothiophenyl lactoside acceptor in the presence of NIS/TfOH as catalyst gave the Lex pentasaccharide in 71% yield.

[Detection of fungi from agricultural commodities with serological method]

The types of fungus antigen and the purification of fungus antigen, the purification of anti-fungus antibody, and the application of serology in detecting fungi from agricultural commodities are introduced. Fungi antigen are mainly from extra-cellular protein and extra-cellular polysaccharide. The method for antigen purification was the same as the common method used to separate and purify proteins and polysaccharides. The specificity of an antibody is the most important parameter for the quality of antibody. As long as the specificity of a antibody is high, the antibody could detect the target fungi from agricultural commodities.

Near-field mapping of the emission distribution in semiconductor microdiscs

We have used a scanning near-field optical microscope to study the fluorescent light distribution in the near- and far-fields with two types of microdiscs, InGaP and GaN, fabricated in our laboratory. The InGaP microdisc has a radius of 2.5-5.0 microm, a thickness of 0.15-0.2 microm and a circular shape and the GaN disc has a radius of 5-8 microm with a thickness of 0.5-2 microm. Spontaneous emission enhancement in these microdiscs has been observed with emitting wavelengths of 650 and 550 nm respectively In both types of microdisc, the whispering-gallery mode (WCM) has been observed on the top surface using near-field optical and far-field microscopic methods. However, due to the different disc structures and optical confinements, the light distributions of the type types of disc are quite different. In the case of the InGaP disc, WGM is the dominant mode with a mixture of other modes. Interference-like ring intensities have been observed both inside the disc surface and outside, with a period ratio of 1:2. In addition, the propagating waves emitted from the side of the disc have been collected for the first time by using near-field optical microscopy. A theoretical calculation based on the theory of optical modes in microdisc lasers confirmed this observation. It also predicted the behaviour of the electric field distribution (transverse electric) inside and outside the disc, as well as the period of the wave propagation. In contrast, the near-field mapping of the GaN fluorescence showed not only a ring-like emission intensity along the circumference of the disc, an indication of WGM, but also an even intensity distribution inside the disc. This can be explained as the combination of the WGM with the Fabry-Perot mode of multi-reflection between the GaN layer and the substrate. The results also demonstrate the potential application of near-field optics to explore the light emission mode of a microdisc on a nanometre scale.

Protease and protease inhibitor assays using biotinylated casein coated on a solid phase

A new type of solid-phase assay for proteases and protease inhibitors has been developed using biotinylated casein. The assay involves coating of titer plate wells with biotinylated casein, hydrolysis of this substrate with a protease such as trypsin, reaction of the biotin from the unhydrolyzed substrate with an alkaline phosphatase-streptavidin complex, and finally quantification of the amount of casein remaining on the plate using alkaline phosphatase activity as the indicator. The activity of the bound indicator enzyme is oppositely related to the protease activity of the sample. In addition, the assay can be modified for quantitating the corresponding amount of protease inhibitor in the sample. The assay is simple, sensitive, accurate, inexpensive, and amenable to automation.

Inhibition of viral adhesion and infection by sialic-acid-conjugated dendritic polymers

Multiple sialic acid (SA) residues conjugated to a linear polyacrylamide backbone are more effective than monomeric SA at inhibiting influenza-induced agglutination of red blood cells. However, "polymeric inhibitors" based on polyacrylamide backbones are cytotoxic. Dendritic polymers offer a nontoxic alternative to polyacrylamide and may provide a variety of potential synthetic inhibitors of influenza virus adhesion due to the wide range of available polymer structures. We evaluated several dendritic polymeric inhibitors, including spheroidal, linear, linear-dendron copolymers, comb-branched, and dendrigraft polymers, for the ability to inhibit virus hemagglutination (HA) and to block infection of mammalian cells in vitro. Four viruses were tested: influenza A H2N2 (selectively propagated two ways), X-31 influenza A H3N2, and sendai. The most potent of the linear and spheroidal inhibitors were 32-256-fold more effective than monomeric SA at inhibiting HA by the H2N2 influenza virus. Linear-dendron copolymers were 1025-8200-fold more effective against H2N2 influenza, X-31 influenza, and sendai viruses. The most effective were the comb-branched and dendrigraft inhibitors, which showed up to 50000-fold increased activity against these viruses. We were able to demonstrate significant (p < 0.001) dose-dependent reduction of influenza infection in mammalian cells by polymeric inhibitors, the first such demonstration for multivalent SA inhibitors. Effective dendrimer polymers were not cytotoxic to mammalian cells at therapeutic levels. Of additional interest, variation in the inhibitory effect was observed with different viruses, suggesting possible differences due to specific growth conditions of virus. SA-conjugated dendritic polymers may provide a new therapeutic modality for viruses that employ SA as their target receptor.

Colorimetric competitive inhibition method for the quantification of avidin, streptavidin and biotin

A colorimetric competitive inhibition assay for avidin, streptavidin and biotin was developed. The method for avidin or streptavidin was based on the competitive binding between avidin or streptavidin and a streptavidin-enzyme conjugate for biotinylated dextrin immobilized on the surface of a microtitre plate. For biotin quantitation the competition is between free biotin and the immobilized biotin for the streptavidin-enzyme conjugate. The limits of detection which was determined as the concentration of competitor required to give 90% of maximal absorbency (100% inhibition) was approximately 20 ng/100 microl per assay for avidin and streptavidin and 0.4 pg/100 microl per assay for biotin. The methods are simple, rapid, highly sensitive and adaptable to high throughput analysis.

Relationships among deoxynivalenol, ergosterol and Fusarium exoantigens in Canadian hard and soft wheat

Soluble extracellular components (exoantigens) from cultures of Fusarium graminearum and F. sporotrichioides were used to produce antisera from chickens for an indirect enzyme immunoassay. This immunoassay was used to estimate Fusarium exoantigen levels in 40 samples of fusarium head blight-infected hard red spring wheat from Manitoba, and in 50 samples of infected soft white winter wheat from Ontario. These wheat samples were also assayed for deoxynivalenol (DON), the predominant Fusarium mycotoxin, and for ergosterol, a metabolite reflecting fungal biomass. Using F. sporotrichioides antisera, the linear correlations between exoantigen level and DON content for the hard and soft wheats had coefficients of 0.80 and 0.76, respectively. With the same antisera, linear correlations between exoantigen level and total ergosterol concentration for the hard and soft wheats had coefficients of 0.66 and 0.81, respectively.

Biotinylated enzyme inhibitorsorbent assay: a specific method for quantitating enzyme and its inhibitor

A biotinylated enzyme inhibitorsorbent assay (BEISA) for quantitating enzyme and its inhibitor has been developed. The assay is based on the competition between unlabeled enzyme and biotin-labeled enzyme for binding by an immobilized inhibitor or between free inhibitor and the immobilized inhibitor for binding by a biotin-labeled enzyme followed by reaction of the biotin-bound complex with a streptavidin-alkaline phosphatase conjugate. The amount of enzyme or inhibitor can be determined from the intensity of color produced by the alkaline phosphatase acting on its substrate. Trypsin and its inhibitor from egg white (ovomucoid) were used as a model for the BEISA. The results indicated that the BEISA is a simple, sensitive, and specific method that can be used to quantitate the amount of an enzyme or its inhibitor and it is amenable to high-throughput analysis and automation. The BEISA can be also applied to any enzyme that has an appropriate inhibitor.

Radiofrequency-Driven and Slow-Magic-Angle-Sample-Spinning Polarization-Transfer Techniques: A Comparative Study

The rate constant of radiofrequency-driven (RF-driven) polarization transfer and that of polarization transfer under slow-magic-angle sample spinning (S-MAS) are compared using a model system, polycrystalline alpha-alpha'-13C2-phthalic acid. While the rate constant under RF irradiation in static samples strongly depends on the orientation of the internuclear vector, the rate constant under S-MAS is hardly sensitive to that orientation and, thus, depends almost exclusively on the internuclear distance. Consequently, polarization-transfer rate constants obtained under S-MAS can be interpreted more simply when used to study local order in polycrystalline or amorphous solids. Copyright 1998 Academic Press.

The characterization of chicken antibodies raised against Fusarium spp. by enzyme-linked immunosorbent assay and immunoblotting

Immunoassays for the detection of three Fusarium species have been developed. Chickens were immunized with the soluble antigens from within the mycelia (mycelia-soluble antigens) and the exoantigens of Fusarium sporotrichioides, Fusarium poae and Fusarium graminearum and the antigens were characterized using enzyme-linked immunosorbent assays, immunoblotting and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The cross-reactivities of antisera with eleven species of Fusarium, eleven species of fungi from other genera and the buffer-extracts of grain were determined. Antisera to the exoantigens and mycelia-soluble antigens did not cross-react with buffer-extracts of grain. The antisera against the mycelia-soluble antigens tended to cross-react with the antigens from other genera whereas the antisera against the exoantigens were genus specific. The antiserum raised against exoantigens from F. poae was species specific. The molecular weights of the immunodominant antigens from the Fusaria were above 28 kilodaltons. Antigens from Fusaria showed specific bands in SDS-PAGE gel that can be used to produce more specific antibodies. The results suggest that exoantigen immunoassay can be developed to identify Fusarium genus, whereas mycelia-soluble antigens are not suitable for immunoidentification among genus.

Frequency- and phase-modulated heteronuclear decoupling in rotating solids

The mechanism of heteronuclear dipolar decoupling by the TPPM sequences, proposed by Bennett et al. (J. Chem. Phys. 103 (1995) 6951) is investigated by comparison with a modified pulse sequence, called TPFM, that uses frequency instead of phase modulation. By combining frequency and phase modulations, circularly modulated sequences are designed. The fact that only the left-handed modulation sequence FMPML leads to improved proton decoupling, while the right-handed modulation sequence FMPMR is ineffective, proves that the efficient decoupling is caused by a secondary resonance effect.