To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This study aimed to investigate endoscopic revision septoplasty with semi-penetrating straight and circular incisions in patients for whom septoplasty was unsuccessful.
Patients in this study (n = 14) had a deviation of the nasal septum after septoplasty. Pre-operative and post-operative assessments were performed using a visual analogue scale and nasal endoscope. Semi-penetrating straight and circular incisions in front of the caudal septum and at the margin of the nasal septal cartilage–bone defect, respectively, were made. The mucoperichondrium and mucoperiosteum were bilaterally dissected until interlinkage with the cartilage–bone defect was achieved. Mucous membranes within the circular incision as well as the right mucoperichondrium and mucoperiosteal flaps were protected by pushing them to the right. This exposed the osteocartilaginous framework and allowed correction of the residual deviation. The patients were followed up for 30–71 months.
For nasal obstruction and headaches, a significant improvement was noted in post-operative compared to pre-operative visual analogue scale scores. No patients had septal deviations, saddle nose, false hump nose or contracture of the nasal columella.
The technique allowed exposure of the septal osteocartilaginous framework and a broad operational vision, which enabled successful correction of various deformities of the nasal septum.
Dementia is a leading cause of morbidity and mortality without pharmacologic prevention or cure. Mounting evidence suggests that adherence to a Mediterranean dietary pattern may slow cognitive decline, and is important to characterise in at-risk cohorts. Thus, we determined the reliability and validity of the Mediterranean Diet and Culinary Index (MediCul), a new tool, among community-dwelling individuals with mild cognitive impairment (MCI). A total of sixty-eight participants (66 % female) aged 75·9 (sd 6·6) years, from the Study of Mental and Resistance Training study MCI cohort, completed the fifty-item MediCul at two time points, followed by a 3-d food record (FR). MediCul test–retest reliability was assessed using intra-class correlation coefficients (ICC), Bland–Altman plots and κ agreement within seventeen dietary element categories. Validity was assessed against the FR using the Bland–Altman method and nutrient trends across MediCul score tertiles. The mean MediCul score was 54·6/100·0, with few participants reaching thresholds for key Mediterranean foods. MediCul had very good test–retest reliability (ICC=0·93, 95 % CI 0·884, 0·954, P<0·0001) with fair-to-almost-perfect agreement for classifying elements within the same category. Validity was moderate with no systematic bias between methods of measurement, according to the regression coefficient (y=−2·30+0·17x) (95 % CI −0·027, 0·358; P=0·091). MediCul over-estimated the mean FR score by 6 %, with limits of agreement being under- and over-estimated by 11 and 23 %, respectively. Nutrient trends were significantly associated with increased MediCul scoring, consistent with a Mediterranean pattern. MediCul provides reliable and moderately valid information about Mediterranean diet adherence among older individuals with MCI, with potential application in future studies assessing relationships between diet and cognitive function.
The progenitors of many core-collapse supernovae (CCSNe) are expected to be in binary systems. By performing a series of three-dimensional hydrodynamical simulations, we investigate how CCSN explosions affect their binary companion. We find that the amount of removed stellar mass, the resulting impact velocity, and the chemical contamination of the companion that results from the impact of the SN ejecta, strongly increases with decreasing binary separation and increasing explosion energy. Also, it is foud that the impact effects of CCSN ejecta on the structure of main-sequence (MS) companions, and thus their long term post-explosion evolution, are in general not dramatic.
We report the utility of whole-genome sequencing (WGS) conducted in a clinically relevant time frame (ie, sufficient for guiding management decision), in managing a Streptococcus pyogenes outbreak, and present a comparison of its performance with emm typing.
A 2,000-bed tertiary-care psychiatric hospital.
Active surveillance was conducted to identify new cases of S. pyogenes. WGS guided targeted epidemiological investigations, and infection control measures were implemented. Single-nucleotide polymorphism (SNP)–based genome phylogeny, emm typing, and multilocus sequence typing (MLST) were performed. We compared the ability of WGS and emm typing to correctly identify person-to-person transmission and to guide the management of the outbreak.
The study included 204 patients and 152 staff. We identified 35 patients and 2 staff members with S. pyogenes. WGS revealed polyclonal S. pyogenes infections with 3 genetically distinct phylogenetic clusters (C1–C3). Cluster C1 isolates were all emm type 4, sequence type 915 and had pairwise SNP differences of 0–5, which suggested recent person-to-person transmissions. Epidemiological investigation revealed that cluster C1 was mediated by dermal colonization and transmission of S. pyogenes in a male residential ward. Clusters C2 and C3 were genomically diverse, with pairwise SNP differences of 21–45 and 26–58, and emm 11 and mostly emm120, respectively. Clusters C2 and C3, which may have been considered person-to-person transmissions by emm typing, were shown by WGS to be unlikely by integrating pairwise SNP differences with epidemiology.
WGS had higher resolution than emm typing in identifying clusters with recent and ongoing person-to-person transmissions, which allowed implementation of targeted intervention to control the outbreak.
To assess the association of fish consumption with risk of dementia and its dose–response relationship, and investigate variations in the association among low-, middle- and high-income countries.
A new community-based cross-sectional study and a systematic literature review.
Urban and rural communities in China; population-based studies systematically searched from worldwide literature.
Chinese adults aged ≥60 years in six provinces (n 6981) took part in a household health survey of dementia prevalence and risk factors. In addition, 33 964 participants from eleven published and eligible studies were included in the systematic review and meta-analysis.
In the new study in China, 326 participants were diagnosed with dementia (4·7 %); those who consumed any amount of fish in the past two years v. those who consumed no fish had reduced risk of dementia (adjusted OR=0·73, 95 % CI 0·64, 0·99), but the dose–response relationship was not statistically significant. The meta-analysis of available data from the literature and the new study showed relative risk (RR) of dementia of 0·80 (95 % CI 0·74, 0·87) for people with fish consumption; the impact was similar among countries with different levels of income. Pooled dose–response data revealed RR (95 % CI) of 0·84 (0·72, 0·98), 0·78 (0·68, 0·90) and 0·77 (0·61, 0·98) in people with low, middle and high consumption of fish, respectively. Corresponding figures for Alzheimer’s disease were 0·88 (0·74, 1·04), 0·79 (0·65, 0·96) and 0·67 (0·58, 0·78), respectively.
Greater consumption of fish is associated with a lower risk of dementia. Increasing fish consumption may help prevent dementia worldwide regardless of income level.
We report a novel approach to the instantaneous photoinitiated synthesis of mixed anatase-rutile nanocrystalline TiO2 thin films with a three-dimensional nanostructure through pulsed white light irradiation of photosensitive Ti-organic precursor films. Pulsed photoinitiated pyrolysis accompanied by instantaneous self-assembly and crystallization occurred to form graphitic oxides-coated TiO2 nanograins. Subsequent pulsed light irradiation working as in situ pulsed photothermal treatment improved the crystalline quality of TiO2 film despite its low attenuation of light. The non-radiative recombination of photogenerated electrons and holes in TiO2 nanograins, coupled with inefficient heat dissipation due to low thermal conductivity, produces enough heat to provide the thermodynamic driving force for improving the crystalline quality. The graphitic oxides were reduced by pulsed photothermal treatment and can be completely removed by oxygen plasma cleaning. This photoinitiated nanofabrication technology opens a promising way for the low-cost and high-throughput manufacturing of nanostructured metal oxides as well as TiO2 nanocrystalline thin films.
A new approach is proposed to analyze Bremsstrahlung X-rays that are emitted from laser-produced plasmas (LPP) and are measured by a stack type spectrometer. This new method is based on a spectral tomographic reconstruction concept with the variational principle for optimization, without referring to the electron energy distribution of a plasma. This approach is applied to the analysis of some experimental data obtained at a few major laser facilities to demonstrate the applicability of the method. Slope temperatures of X-rays from LPP are determined with a two-temperature model, showing different spectral characteristics of X-rays depending on laser properties used in the experiments.
The study investigates three-dimensional kinematics of lower limb for female Chinese population during normal squatting activity. 25 young female and 25 elder female Chinese subjects were recruited. With each subject's data collected, the means of three-dimensional rotation angles of knee, hip, and ankle joints of those two groups were calculated and analyzed. Measured results showed that the maximal eccentric range of hip flexion/extension of 128.6° for the young female group (P < 0.05) was compared with that of 158.8° for the elder female group. Thus, the elder female undergoes more hip flexion/extension angles than the young female in the posture of squatting. The mean range of motion (ROM) of knee flexion/extension was 140.2° for the young female group and 138.7° (significant level P > 0.05) for the elder female group. The mean ROM of ankle flexion/extension was 47.90° for the young female group and 31.9° (P > 0.05) for the elder female group. The ROMs obtained in the experiment during squatting were greater than the reported ones achieved after joint arthroplasty. These data may be invaluable in providing designers of lower limb prosthesis with basic mechanical parameters, and assessing the effect of kinematics of low limb on rehabilitation for the Chinese population.
We synthesize the literature on Chinese multinational enterprises (MNEs) and find that much of the prior research is based on as few as a dozen case studies of Chinese firms. They are so case-specific that it has led to a misplaced call for new theories to explain Chinese firms’ internationalization. In an attempt to better relate theory with empirical evidence, we examine the largest 500 Chinese manufacturing firms. We aim to find out the number of Chinese manufacturing firms to be true MNEs by definition, and to examine their financial performance relative to global peers using the financial benchmarking method. We develop our theoretical perspectives from new internalization theory. We find that there are only 49 Chinese manufacturing firms to be true MNEs, whereas the rest are purely domestic firms. Their performance is poor relative to global peers. Chinese MNEs have home country bound firm-specific advantages (FSAs), which are built upon home country-specific advantages (home CSAs). They have not yet developed advanced management capabilities through recombination with host CSAs. Essentially, they acquire foreign firms to increase their sales in domestic market, but they fail to be competitive internationally and to achieve superior performance in overseas operations. Our findings have important strategic implications for managers, public policy makers, and academic research.
Hepatitis G virus or GB virus C (GBV-C) is a human virus of the Flaviviridae family that is structurally and epidemiologically closest to hepatitis C virus, but replicates primarily in lymphocytes. Co-infection with GBV-C has been reported to confer beneficial outcomes in some HIV-positive patients. Up to now, however, studies on GBV-C infection in the central nervous system (CNS) of HIV-infected patient have rarely been reported. Herein, we report on a 32-year-old HIV-1-infected patient with cerebral toxoplasmosis and fungal encephalitis. GBV-C viral loads were detected in CSF by quantitative real-time reverse transcription polymerase chain reaction (RT–PCR), and the results showed that GBV-C viral load was 6·5 log copies/ml. We amplified and sequenced the E2 and 5′-untranslated regions from the purified viral RNA from CSF by RT–PCR. Both sequences belong to genotype 3 and there were some minor nucleotide divergence among the E2 sequences from the CSF of the patient. These data suggest that GBV-C may be able to penetrate the blood–brain barrier and colonize the CNS of HIV-infected patients. However, the exact mechanisms and potential effect of the infected GBV-C in CNS on HIV-associated neuropathy needs to be further explored.
The Chinese giant salamander Andrias davidianus is endemic to China and is Critically Endangered, largely because of overexploitation for food. This species is an expensive delicacy in China, and a rapidly growing industry to farm the species has developed throughout much of the country, centred on the Qinling Mountain region of Shaanxi Province. During a 2010 workshop on Chinese giant salamander conservation, which involved a range of stakeholders from across China, it became clear that the conservation community knew little about the salamander farming industry and whether it posed actual or potential threats or opportunities for conservation of the Chinese giant salamander. We therefore conducted a series of investigations to understand the industry better. Our results indicate that although farming of Chinese giant salamanders has the potential to be a positive development for conservation by supplying market demand with farmed animals, it is currently more likely to threaten than support conservation of the species, with continued overexploitation and the potential added impacts of infectious disease and genetic pollution arising from farming practices such as movement of animals across the country and the release of untreated farm wastewater and farmed salamanders to the wild.
Two-step growth method of low pressure chemical vapor deposition(LPCVD) process was employed to fabricate the ZnO:B-TCO film; For the first layer, the seed layer with a heavy doping concentration was deposited on the glass substrate, the film having higher deposition rate were then grown on the top of the first layer; It shows that the doping situations of the seed layer play an important role in electrical and optical performance of the whole ZnO:B-TCO layer, and the combination of this two properties is optimal when the doping ratio (B2H6/DEZ) was 0.4;
The unique properties of silicon oxide materials, no matter intrinsic or doped, utilized in thin film solar cells (TFSCs) in the area of photovoltaic (PV) are making TFSCs one of the most attractive photovoltaic technologies for the development of high-performing electricity production units to be integrated in everyday life. In comparison to other silicon materials, the particular diphasic structure of silicon oxide materials, in which hydrogenated microcrystalline silicon (μc-Si:H) crystallites are surrounded by an oxygen-rich hydrogenated amorphous silicon (a-Si:H) phase, causes them present excellent photoelectrical material properties, such as a low-parasitic absorption in the broadband spectral range, independent controllability of longitudinal and lateral conductivity, refractive indices (3.5-2.0), band gap (2.0-2.6 eV) and conductivity tenability (with orders of 1-10-9 S/cm) with oxygen doping, and so on. Various types of silicon oxide materials, including intrinsic, p- or n- type, further applied in TFSCs have also played significant roles in improving the efficiency of various types of single-, dual-, and triple-junction thin-film solar cells from both the optical and electrical points of view. In this paper, we present our latest progress in studying the performance improvement role of intrinsic or doped silicon oxide materials in pin-type a-Si:H, a-SiGe:H, and μc-Si:H single-junction solar cells. By effectively tuning the band gap values of intrinsic a-SiOx:H materials with oxygen doping and adopting the layers with a suitable band gap (1.86 eV) as the P/I buffer layers of a-Si:H solar cells fabricated on metal organic chemical vapor deposition (MOCVD) boron-doped zinc oxide (ZnO:B) substrates, a significant Voc increases up to 909 mV and an excellent external quantum efficiency (EQE) response of 75% at the 400 nm typical wavelength can be achieved by matching the band gap discontinuity between the p-type nc-SiOx:H window and a-Si:H intrinsic layers. The serious leakage current characteristics of pin-type narrow-gap (Eg<1.5 eV) a-SiGe:H single-junction solar cells can also be finely tuned by integrating an n-type μc-SiOx:H layer with a small oxygen content in addition to improving the long-wavelength response, an effective approach gives rise to the highest FF of 70.62% for pin-type a-SiGe:H single-junction solar cells with an average band gap of 1.48 eV. In addition, our studies proved that the application of p-type μc-SiOx:H window layers in μc-Si:H single-junction solar cells can effectively improve the short-wavelength light coupling by suppressing the parasitic absorption and promoting the anti-reflectivity with a graded refractive index profile. On the basis of the optimum single-junction solar cells with omnipotent silicon oxide materials, an initial efficiency of 16.07% has been achieved for pin-type a-Si:H/a-SiGe:H/μc-Si:H triple-junction solar cells with an active area of 0.25 cm2. The omnipotent properties of silicon oxide layers in TFSCs, including effective optical coupling and trapping, suitability in compensating for the band gap discontinuity, the shunt-quenching capacity, and so on, make them likely to be extended to other types of solar cells such as polycrystalline chalcopyrite Cu(In,Ga)Se2 (CIGS) and perovskite-sensitized solar cells, opening up new opportunities for acquiring solar cells with higher performance.
Lead-containing (Pb-B-X)-2H apatites encompass a number of [AF]4[AT]6[(BO4)6]X2 compounds used for waste stabilization, environmental catalysis and ion conduction, but the influence of the stereochemically active lone-pair electrons of Pb2+ on crystal chemistry and functionality is poorly understood. This article presents a compilation of existing structural data for Pb apatites that demonstrate paired electrons of Pb2+ at both the AF and AT results in substantial adjustments to the PbFO6 metaprism twist angle, φ. New structure refinements are presented for several natural varieties as a function of temperature by single-crystal X-ray diffraction (XRD) of vanadinite-2H (ideally Pb10(VO4)6Cl2), pyromorphite-2H (Pb10(PO4)6Cl2), mimetite-2H/M (Pb10(As5+O4)6Cl2) and finnemanite-2H (Pb10(As3+O3)6Cl2). A supercell for mimetite is confirmed using synchrotron single-crystal XRD. It is suggested the superstructure is necessary to accommodate displacement of the stereochemically active 6s2 lone-pair electrons on the Pb2+ that occupy a volume similar to an O2− anion. We propose that depending on the temperature and concentration of minor substitutional ions, the mimetite superstructure is a structural adaptation common to all Pb-containing apatites and by extension apatite electrolytes, where oxide ion interstitials are found at similar positions to the lonepair electrons. It is also shown that plumbous apatite framework flexes substantially through adjustments of the PbFO6 metaprism twist-angles (φ) as the temperature changes. Finally, crystalchemical  zoning observed at submicron scales will probably impact on the treatment of diffraction data and may account for certain inconsistencies in reported structures.
Grain boundaries (GBs) in polycrystalline silicon (poly-Si) thin film solar cells are frequently found to be detrimental for device performance. Biaxiallytextured silicon with grains that are well-aligned in-plane and out-of-plane can possess fewer GB defects. In this work, we use TCAD Sentaurus device simulator and known experimental work to investigate and quantify the potential performance gains of biaxially-textured silicon. Simulation shows there can be performance gain from well-aligned grains when GB defects dominate carrier recombination or when grains are small. On the other hand, when intra-grain defects dominate recombination and grains are large, well-aligned grains do not lead to much performance gain. Another important result from our simulation is when intra-grain and GB defects are few, Jsc is almost independent of grain size while Voc drops with decreasing grain size.
Thin-film absorber layers for photovoltaics have attracted much attention for their potential for low cost per unit power generation, due both to reduced material consumption and to higher tolerance for defects such as grain boundaries. Cu2ZnGeSe4 (CZGSe) comprises one such material system which has a near-optimal direct band gap of 1.6 eV for absorption of the solar spectrum, and is made primarily from earth-abundant elements.
CZGSe metallic precursor films were sputtered from Cu, Zn, and Ge onto Mo-coated soda lime glass substrates. These were then selenized in a two-zone close-space sublimation furnace using elemental Se as the source, with temperatures in the range of 400 to 500 C, and at a variety of background pressures. Films approximately 1-1.5 µm thick were obtained with the expected stannite crystal structure.
Next, Cu2ZnSnSe4 (CZTSe), which has a direct band gap of 1.0 eV, was prepared in a similar manner and combined with CZGSe as either compositionally homogeneous or layered absorbers. The compositional uniformity of selenide absorbers made by selenizing compositionally homogeneous Cu-Zn-Ge-Sn precursor layers was determined and the band gap as a function of composition was investigated in order to demonstrate that the band gap is tuneable for a range of compositions. For layered Cu-Zn-Ge/Cu-Zn-Sn precursor films, the composition profile was measured before and after selenization to assess the stability of the layered structure, and its applicability for forming a band-gap-graded device for improved current collection.
Chemically deposited thin film stack of SnSe-ZnSe-Cu2-xSe was heated in nitrogen with Se vapor at 350-400 oC to produce Cu2ZnSnSe4 (CZTSe) thin films. For this, a thin film of SnSe with 180 nm thickness was deposited at 26 °C from a chemical bath containing tin(II) chloride, triethanolamine, sodium hydroxide, sodium selenosulfate, and a small quantity of polyvinylpyrrolidone. Thin films of ZnSe and Cu2-xSe were subsequently deposited on this SnSe film, also from chemical bath. The CZTSe thin film produced this way shows X-ray diffraction pattern matching that of Cu2ZnSnSe4 (kesterite/stannite) and have a Zn-rich composition. The film has an optical band gap of 0.9-1.0 eV and p-type electrical conductivity, 0.2-0.06 Ω-1 cm-1.
Fast-electron beam stopping mechanisms in media ranging from solid to warm dense matter have been investigated experimentally and numerically. Laser-driven fast electrons have been transported through solid Al targets and shock-compressed Al and plastic foam targets. Their propagation has been diagnosed via rear-side optical self-emission and Kα X-rays from tracer layers. Comparison between measurements and simulations shows that the transition from collision-dominated to resistive field-dominated energy loss occurs for a fast-electron current density ~5 × 1011 A cm−2. The respective increases in the stopping power with target density and resistivity have been detected in each regime. Self-guided propagation over 200μm has been observed in radially compressed targets due to ~1kT magnetic fields generated by resistivity gradients at the converging shock front.
A study about the achievement of dichromatic white light-emitting diodes (LEDs) was performed. A series of dual wavelength LEDs with different last quantum-well (LQW) structure were fabricated. The bottom seven blue light QWs (close to n-GaN layer) of the four samples were the same. The LQW of sample A was 3 nm, and that of sample B, C and D were 6 nm, a special high In content ultra-thin layer was inserted in the middle of the LQW of sample C and on top of that of sample D. XRD results showed In concentration fluctuation and good interface quality of the four samples. PL measurements showed dual wavelength emitting, the blue light peak position of the four samples were almost the same, sample A with a narrower LQW showed an emission wavelength much shorter than that of sample B, C, D. EL measurement was done at an injection current of 100 mA. Sample A only showed LQW emission due to holes distribution. Because of wider LQW, the emission wavelength of sample B, C and D was longer and peak intensity was weaker. Sample D with insert layer on top of LQW showed strongest yellow light emission with a blue peak. As the injection current increased, sample A showed highest output light power due to narrower LQW. Of the other three samples with wider LQW, sample D showed highest output power. Effective yellow light emission has always been an obstacle to the achievement of dichromatic white LED. Sample D with insert layer close to p-GaN can confine the hole distribution more effectively hence the recombination of holes and electrons was enhanced, the yellow light emission was improved and dichromatic white LED was achieved.
The crystal structure of a-plane GaN/ZnO heterostructures on r-plane sapphire was investigated by using the XRD and TEM measurment. It was found the formation of (220) ZnGa2O4 and crystal orientation of semipolar (10
3) GaN at GaN/ZnO interface. The epitaxial relation of normal surface direction are the sapphire (1
02) // a-GaN (11
0) and ZnGa2O4 (220) // semi-polar GaN (10
). Beside, the emission peak energy of ZnO appears shift about 60 meV in the GaN/ZnO/GaN heterostructures due to the re-crystallization of ZnO layer with Ga or N atom and the formation of the localized state.