Charge Transfer Effects in Naturally Occurring van der Waals Heterostructures (PbSe)_{1.16}(TiSe_{2})_{m} (m=1, 2).

van der Waals heterostructures (VDWHs) exhibit rich properties and thus has potential for applications, and charge transfer between different layers in a heterostructure often dominates its properties and device performance. It is thus critical to reveal and understand the charge transfer effects in VDWHs, for which electronic structure measurements have proven to be effective. Using angle-resolved photoemission spectroscopy, we studied the electronic structures of (PbSe)_{1.16}(TiSe_{2})_{m} (m=1, 2), which are naturally occurring VDWHs, and discovered several striking charge transfer effects. When the thickness of the TiSe_{2} layers is halved from m=2 to m=1, the amount of charge transferred increases unexpectedly by more than 250%. This is accompanied by a dramatic drop in the electron-phonon interaction strength far beyond the prediction by first-principles calculations and, consequently, superconductivity only exists in the m=2 compound with strong electron-phonon interaction, albeit with lower carrier density. Furthermore, we found that the amount of charge transferred in both compounds is nearly halved when warmed from below 10 K to room temperature, due to the different thermal expansion coefficients of the constituent layers of these misfit compounds. These unprecedentedly large charge transfer effects might widely exist in VDWHs composed of metal-semiconductor contacts; thus, our results provide important insights for further understanding and applications of VDWHs.

Coexistence of superconductivity and antiferromagnetism in (Li0.8Fe0.2)OHFeSe.

Iron selenide superconductors exhibit a number of unique characteristics that are helpful for understanding the mechanism of superconductivity in high-Tc iron-based superconductors more generally. However, in the case of AxFe2Se2 (A = K, Rb, Cs), the presence of an intergrown antiferromagnetic insulating phase makes the study of the underlying physics problematic. Moreover, FeSe-based systems intercalated with alkali metal ions, NH3 molecules or organic molecules are extremely sensitive to air, which prevents the further investigation of their physical properties. It is therefore desirable to find a stable and easily accessible FeSe-based superconductor to study its physical properties in detail. Here, we report the synthesis of an air-stable material, (Li0.8Fe0.2)OHFeSe, which remains superconducting at temperatures up to ~40 K, by means of a novel hydrothermal method. The crystal structure is unambiguously determined by a combination of X-ray and neutron powder diffraction and nuclear magnetic resonance. Moreover, antiferromagnetic order is shown to coexist with superconductivity. This synthetic route opens a path for exploring superconductivity in other related systems, and confirms the appeal of iron selenides as a platform for understanding superconductivity in iron pnictides more broadly.

Emergent Kondo Lattice Behavior in Iron-Based Superconductors AFe_{2}As_{2} (A=K, Rb, Cs).

Here, we experimentally study the origin of d-electron heavy fermion (HF) behavior in iron-based superconductors (FeSCs) AFe_{2}As_{2} (A=K, Rb, Cs). Nuclear magnetic resonance on ^{75}As reveals a universal coherent-incoherent crossover with a characteristic temperature T^{*}. Below T^{*}, a so-called "Knight shift anomaly" is first observed in FeSCs, which exhibits a scaling behavior similar to f-electron HF materials. Furthermore, the scaling rule also regulates the manifestation of magnetic fluctuation. These results undoubtedly support an emergent Kondo lattice scenario for the d-electron HF behavior, which qualifies the AFe_{2}As_{2} (A=K, Rb, Cs) as d-electron HF superconductors.

Evolution of High-Temperature Superconductivity from a Low-T_{c} Phase Tuned by Carrier Concentration in FeSe Thin Flakes.

We report the evolution of superconductivity in an FeSe thin flake with systematically regulated carrier concentrations by the liquid-gating technique. With electron doping tuned by the gate voltage, high-temperature superconductivity with an onset at 48 K can be achieved in an FeSe thin flake with T_{c} less than 10 K. This is the first time such high temperature superconductivity in FeSe is achieved without either an epitaxial interface or external pressure, and it definitely proves that the simple electron-doping process is able to induce high-temperature superconductivity with T_{c}^{onset} as high as 48 K in bulk FeSe. Intriguingly, our data also indicate that the superconductivity is suddenly changed from a low-T_{c} phase to a high-T_{c} phase with a Lifshitz transition at a certain carrier concentration. These results help to build a unified picture to understand the high-temperature superconductivity among all FeSe-derived superconductors and shed light on the further pursuit of a higher T_{c} in these materials.

Pressure-Induced Electronic Transition in Black Phosphorus.

In a semimetal, both electrons and holes contribute to the density of states at the Fermi level. The small band overlaps and multiband effects engender novel electronic properties. We show that a moderate hydrostatic pressure effectively suppresses the band gap in the elemental semiconductor black phosphorus. An electronic topological transition takes place at approximately 1.2 GPa, above which black phosphorus evolves into a semimetal state that is characterized by a colossal positive magnetoresistance and a nonlinear field dependence of Hall resistivity. The Shubnikov-de Haas oscillations detected in magnetic field reveal the complex Fermi surface topology of the semimetallic phase. In particular, we find a nontrivial Berry phase in one Fermi surface that emerges in the semimetal state, as evidence of a Dirac-like dispersion. The observed semimetallic behavior greatly enriches the material property of black phosphorus and sets the stage for the exploration of novel electronic states in this material.

Elevated venous lactate level as an early predictive marker of organ failure in acute pancreatitis: a retrospective study.

OBJECTIVE: The aim of this study was to elucidate the relationship between venous lactate levels and the severity of acute pancreatitis (AP). PATIENTS AND METHODS: Retrospective data analysis was conducted on patients diagnosed with acute pancreatitis. The comparative assessment encompassed baseline characteristics, laboratory data, illness severity, local consequences, and organ failure instances. This comparison was performed between patients exhibiting normal serum lactic acid levels (HL) and those displaying elevated HL levels. The association between serum HL levels and other pertinent clinical markers was investigated using linear regression. Logistic regression analysis was employed to evaluate the utility of elevated serum lactate levels in identifying high-risk groups. RESULTS: Significantly elevated serum HL levels were observed in patients with moderately severe acute pancreatitis (MSAP) and severe acute pancreatitis (SAP) in contrast to those with mild acute pancreatitis (MAP) (p<0.01). Multivariate logistic analysis demonstrated that higher lactate levels independently predicted organ failure (95% CI 0.738-0.902, p<0.05). Receiver operating characteristic (ROC) curve analysis indicated that the lactate (LAC) cut-off value of 2.45 mmol/L yielded sensitivity and specificity values of 76.5% and 79.1%, respectively, for predicting AP-associated organ failure. The corresponding area under the curve (AUC) was 0.820. CONCLUSIONS: In AP patients, elevated serum HL levels signify disease severity and hold predictive potential for assessing the risk of organ failure.

Incoherence-coherence crossover and low-temperature Fermi-liquid-like behavior in AFe2As2 (A = K, Rb, Cs): evidence from electrical transport properties.

We study the normal-state transport properties of AFe2As2 (A = K, Rb and Cs) single crystals using Hall coefficient, resistivity and magnetoresistance (MR) measurements. In all three materials, the Hall coefficient R H shows a strong temperature dependence, which is typical for multi-band systems. In particular, R H develops an upturn below a characteristic temperature [Formula: see text], which is in agreement with the incoherence-coherence crossover reported in recent nuclear magnetic resonance studies. A Fermi-liquid-like state, characterized by T (2) behavior of the resistivity and a positive orbital MR obeying Kohler's rule, emerges below T FL ∼0.4 [Formula: see text]. The superconducting transition temperature T c experiences a simultaneous suppression with [Formula: see text] and T FL as the alkali ion's radius increases from A = K to A = Cs, suggesting that the unconventional superconductivity in the AFe2As2 series is related to the strength of the electronic coherence. A phase diagram, similar to that in the heavy fermion Kondo lattice system, is obtained. Based on all the experimental evidence, we argue that the physical properties of this family of heavily hole-doped Fe-based superconductors are controlled by the hybridization between itinerant carriers and localized orbitals, and the Kondo scenario could be effective in such a case.

Physical and performance characteristics of successful high school football players.

The purpose of this investigation was to determine the performance and physiologic characteristics of a "successful" American high school football team, and to compare the present values with values reported for other groups of high school, college, and professional players. For descriptive purposes, players were divided into two groups: backs (N = 8) and linemen (N = 10). Maximal aerobic power (VO2max) was determined from a maximal treadmill test, and body composition was evaluated by hydrostatic weighing. Maximal strength values were evaluated by one-repetition maximum bench press and squat test; the sit-and-reach test was used to measure flexibility. Speed and power were evaluated by a vertical jump and a 36.6-meter sprint. Results indicate that compared with other groups of college and professional players, as the level of competition increases so do height, weight, and fat-free weight of the players. Similar maximum oxygen consumption values were found for the present group when compared with other groups of these players. From the strength and power standpoint, football players at all levels are becoming stronger. Incorporation of strength training programs has greatly improved strength and performance profiles of football players at all levels of competition.

Electrical injury of wrist: classification and treatment--clinical analysis of 90 cases.

Between January 1980 and December 1989, a prospective study was carried out on 114 upper limbs in 90 patients, which were electrically burned with the wrist as the current entrance site. Based upon extensive clinical investigations of arterial injury and its adverse effect on hand circulation, a grading system is suggested for electrically injured wrists based on the severity of injury. The total amputation rate was 39.4 per cent in this group, which was composed of miscellaneous cases with various injuries. However, in subgroups of Type I to Type IV, the amputation rates were 0, 0, 80 and 100 per cent, respectively. A new method to repair the circumferential wound of an electrically burned wrist as well as to bypass the blood flow to the obstructed hand, using a pedicled greater omentum transfer and vascular anastomosis between gastroepiploic artery and the palmar artery, was successfully used in a Type III case.

The use of free flaps in burn patients: experiences with 70 flaps in 65 patients.

A series of 70 microvascular free flaps employed in 65 burn patients is presented. The total survival incidence of the flaps was 87 percent. Satisfactory wound healing was achieved in 80 percent of a total of 54 flaps in fresh burn patients. In the 16 patients with healed burns, flap survival was 100 percent with satisfactory functional and cosmetic results. The cruxes of dealing with difficult fourth-degree burns by using microvascular free flaps and our special considerations about the indications and overall morbidities of the donor site are discussed. This large-series report confirms other occasional reports on the use of free flaps in burn patients. It is our belief that the microvascular free flap is the most expeditious means of dealing with refractory burn wounds, even when more conventional techniques are available. In certain cases, the microvascular procedure is the only method that can salvage an extremity.

[Preliminary study of traditional Chinese medicine-Western medicine treatment of patients with primary liver carcinoma].

In order to improve the therapeutic efficacy for patients with primary liver carcinoma (PLC), the authors treated 30 patients by routine chemotherapy in combination with the immunostimulators Bai Nian Le ( ), levamisole and cimetidine. As a result, the NK activity and percentage of lymphoblast transformation of patients were significantly elevated, expansion of the tumor mass was checked, with clinical conditions obviously improved. So the short term effect of the therapy was satisfactory. The study suggested that Bai Nian Le in combination with levamisole and cimetidine was able to elevate the immune response and therapeutic effect. It may be one of the useful adjuvant therapy for PLC patients.

[Application of skin and soft tissue expansion in treatment of burn injury].

OBJECTIVE: To evaluate the application of skin and soft tissue expansion in the treatment of deformity due to extensive severe burn injury and repair of severe deep electrical burned scalp and skull with fresh wound. METHODS: From 1988, 83 cases of application of skin and soft tissue expansion were reported. In those patients with deformity due to severe burn of large area and with whole nasal defect, soft tissue expander was used under the forehead skin graft and venter frontalis, followed by reconstruction of nose with the expanded vascularized skin flap and carved cartilago costalis as nasal frame. In patients of severe deep electrical burned scalp and skull with fresh wound, skin and soft tissue expansion were used to repair the wound simultaneously with scalp burn alopecia, anesthetics and antibiotics injected into the extracapsular space of the expander in case of pain and infection. RESULTS: All of the cases were successfully treated with little pain and minimized infection. CONCLUSION: Skin and soft tissue expansion in a safe and reliable measure in the treatment of deformity due to extensive severe burn injury and repair of severe deep electrical burned scalp and skull with fresh wound.

[Repair of severe radiation-induced ulcer].

OBJECTIVE: To explore a method to repair severe radiation-induced ulcer and evaluate its clinical effects. METHODS: From August 1988 to December 1998, 12 cases of severe radiation-induced ulcer were treated by muscular or musculocutaneous flap transfer, which included 1 case of pectoralis major muscular flap, 3 cases of three-lobed transverse rectus abdominis musculocutaneous flap, 2 cases of latissimus dorsi musculocutaneous flap, 1 case of tensor fascia lata musculocutaneous flap, 1 case of longitudinal rectus abdominis musculocutaneous and tensor fascia lata musculocutaneous flap, 1 case of gastrocnemius muscular flap, 1 case of gluteus major musculocutaneous flap, huge filleted musculocutaneous flap from lower limbs in 1 case and from upper limbs in 1 cases. RESULTS: All the flaps survived. Primary healing occurred in 9 cases and secondary healing in 3 cases. The extensive multiple ulcers in 2 cases were repaired with filleted limb musculocutaneous flap, and patients were saved. And in other 3 cases, the chest wall defect as the result of radionecrosis were repaired with simultaneous breast reconstruction. CONCLUSION: Muscular or musculocutaneous flaps have abundant blood supply, they are ideal tissue to fill the cavity and repair the defect, especially in repairing severe radiation-induced ulcers.

Tissue deposition of silver following topical use of silver sulphadiazine in extensive burns.

Silver sulphadiazine has been applied to the burn wounds of 509 patients during the past 10 years. Eleven patients with burns covering more than 20 per cent of the body surface showed silver deposits in the mucosa of the lips, gingiva and cheeks. The colour of the burn wound was also slightly darker than in patients not treated with silver compounds. This darker colour spontaneously disappeared during the year following discharge from hospital. The pathogenesis of silver deposition has been discussed in relation to other published studies.

High tension electrical burns of upper arms treated by segmental excision of necrosed humerus. An introduction of a new surgical method.

This paper describes treating high-tension electrical burns of the upper arms by segmental excision of the necrosed humerus. This is a new surgical method of treating local electrical burns. The authors use modification of traditional surgical method, shorten the course of treatment, and preserve the injured limb. However, this surgical method should not be used to treat all high-tension electrical burns of the upper arm, and should be used only under certain conditions. Therefore, it is important to grasp the operative indications.

Iron status in women aerobic dance instructors.

This investigation evaluated the iron and nutritional status of 12 highly trained aerobic dance instructors who did not take iron supplements (ANS) and 8 who did (AS). A control group (C) consisted of 10 age matched controls. The aerobic instructors had exercised for approximately 3.8 days/wk, 56 min/session for the past 7 yrs. There were no significant differences among groups for energy intake, carbohydrate, protein, fat, nonheme iron, heme iron, or total iron intake (excluding supplemental iron). But both exercise groups had lower ferritin values than the control group. There was also a significant difference in mean cell volume (MCV), with both exercise groups having greater values than the control group. There were no differences among groups for serum iron, total iron binding capacity, transferrin saturation, hematocrit, or hemoglobin. One in three aerobic dance instructors had serum ferritin values below 12 micrograms.L-1. Results indicate that women exercise leaders have iron profiles that are similar to other groups of female athletes. The increased MCV values suggest runners' macrocytosis or an exercise induced macrocytosis.

Early surgical treatment of severe electrical injury of bilateral upper extremities: a case report.

A patient with both upper limbs injured by high-voltage current was treated by early wound débridement, segmental excision of the necrosed humerus of the left upper arm, internal screw fixation and vascularized skin free grafting on the right wrist. Functional recovery were satisfactory.