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It is commonly believed that area laws for entanglement entropies imply that a quantum many-body state can be faithfully represented by efficient tensor network states-a conjecture frequently stated in the context of numerical simulations and analytical considerations. In this work, we show that this is in general not the case, except in one-dimension. We prove that the set of quantum many-body states that satisfy an area law for all Renyi entropies contains a subspace of exponential dimension. We then show that there are states satisfying area laws for all Renyi entropies but cannot be approximated by states with a classical description of small Kolmogorov complexity, including polynomial projected entangled pair states or states of multi-scale entanglement renormalisation. Not even a quantum computer with post-selection can efficiently prepare all quantum states fulfilling an area law, and we show that not all area law states can be eigenstates of local Hamiltonians. We also prove translationally and rotationally invariant instances of these results, and show a variation with decaying correlations using quantum error-correcting codes.

摘要目 的通过对成人行走过程中矢状面与冠状面内质心轨迹的分析, 本文探索双足机器人自由、灵活行走的步态规划方法, 并实现对其受意外外力干扰下的稳定行走。方 法在基于线性倒立摆模型的双足机器人运动控制中, 质心、零力矩点和捕获点是实现双足机器人稳定行走的重要因素。 1. 通过对矢状面与冠状面内质心运动轨迹的分析, 建立双足机器人CP-ZMP-COM动力学模型, 由此计算期望的双足机器人质心、零力矩点和捕获点, 进而提出一种改进的双足机器人质心轨迹规划方法; 2. 提出双足机器人在矢状面与冠状面内运动协调的抗扰动反馈补偿控制方法, 对双足机器人质心和捕获点位置进行反馈补偿, 使双足机器人质心和捕获点轨迹能够在后续支撑切换时逼近理想状态; 3. 通过小型双足机器人样机及其仿真模型, 对改进的双足机器人质心轨迹规划方法及抗扰动反馈补偿控制方法进行行走仿真与实验验证。结 论1. 改进的双足机器人质心轨迹规划方法可用于实现小型双足机器人横行、斜行及原地转圈等灵活行走; 2. 基于所提出的抗扰动反馈补偿控制方法, 小型双足机器人受随机脉冲外力下横行、斜行及原地转圈时仍能保持稳定而不摔倒。

Yolk sac tumor (YST) in postmenopausal women is rare and typically presents at an advanced stage including peritoneal involvement and ascites. However, detection of malignant YST cells in ascitic fluid remains exceedingly uncommon. We report a very rare case of metastatic YST initially diagnosed by peritoneal fluid cytology. A 75-year-old woman presented with a large left adnexal mass, thickened endometrium, and large-volume ascites. Cytologic examination of ascites demonstrated abundant malignant cells that were strongly and diffusely positive for SALL4 and Glypican-3, focally positive for AFP, and negative for PAX8, ER, WT-1, p16 and CK7. These findings supported a diagnosis of YST, which was further confirmed by markedly elevated serum AFP and subsequent endometrial curettage. In elderly women with advanced genital tract malignancy and malignant peritoneal fluid, YST is rarely included in the initial differential diagnosis. This case underscores an important clinical implication in the evaluation of diagnostically challenging malignant effusions: when routine morphologic and immunophenotypic findings do not support a common gynecologic or Müllerian neoplasm, germ cell markers—including glypican-3, AFP, and SALL4—as well as measurement of serum AFP should be incorporated into the diagnostic workup. Recognition of this rare possibility is essential for accurate diagnosis and appropriate management, including monitoring serum AFP levels if elevated.

- The diagnosis and grading of acute cellular and antibody-mediated rejection (AMR) in lung allograft biopsies is important because rejection can lead to acute graft dysfunction and/or failure and may contribute to chronic graft failure. While acute cellular rejection is well defined histologically, no reproducible specific features of AMR are currently identified. Therefore, a combination of clinical features, serology, histopathology, and immunologic findings is suggested for the diagnosis of AMR. - To describe the perspective of members of the Pulmonary Pathology Society (PPS) on the workup of lung allograft transbronchial biopsy and the diagnosis of acute cellular rejection and AMR in lung transplant. - Reports by the International Society for Heart and Lung Transplantation (ISHLT), experience of members of PPS who routinely review lung allograft biopsies, and search of literature database (PubMed). - Acute cellular rejection should be assessed and graded according to the 2007 working formulation of the ISHLT. As currently no specific features are known for AMR in lung allografts, the triple test (clinical allograft dysfunction, donor-specific antibodies, pathologic findings) should be used for its diagnosis. C4d staining might be performed when morphologic, clinical, and/or serologic features suggestive of AMR are identified.

- Hypersensitivity pneumonitis (HP) is a lung disease that develops in susceptible individuals after inhalational exposure to an organic antigen or chemical compound. Pathogenesis is attributed to a combination of type III (immune complex-mediated) and type IV (delayed) hypersensitivity reactions to the inciting agent. - To provide an overview of the current status of the medical literature regarding hypersensitivity pneumonitis. - A literature search was performed using PubMed and Google search engines. The terms \"hypersensitivity pneumonitis\" and \"extrinsic allergic alveolitis\" were used, with the search starting on January 9, 2017, and concluding March 8, 2017. - As a pathologist, it is important to consider hypersensitivity pneumonitis when examining lung specimens because it is often clinically and pathologically overlooked. Recognizing the often subtle findings and correlating them with the patient's history or suggesting a thorough clinical investigation of potential exposures can be of help in identifying the underlying condition so that the patient can be appropriately managed.

Routine cervical cancer screening has significantly decreased the incidence and mortality of cervical cancer. As selection of proper screening modalities depends on well-validated clinical decision algorithms, retrospective review correlating cytology and HPV test results with cervical biopsy diagnosis is essential for validating and revising these algorithms to changing technologies, demographics, and optimal clinical practices. However, manual categorization of the free-text biopsy diagnosis into discrete categories is extremely laborious due to the overwhelming number of specimens, which may lead to significant error and bias. Advances in machine learning and natural language processing (NLP), particularly over the last decade, have led to significant accomplishments and impressive performance in computer-based classification tasks. In this work, we apply an efficient version of an NLP framework, FastText™, to an annotated cervical biopsy dataset to create a supervised classifier that can assign accurate biopsy categories to free-text biopsy interpretations with high concordance to manually annotated data (>99.6%). We present cases where the machine-learning classifier disagrees with previous annotations and examine these discrepant cases after referee review by an expert pathologist. We also show that the classifier is robust on an untrained external dataset, achieving a concordance of 97.7%. In conclusion, we demonstrate a useful application of NLP to a real-world pathology classification task and highlight the benefits and limitations of this approach.

Landmark events in the field of lung cancer in the past year have the potential to significantly alter the practice of pathology. Three key events are (1) approval of payment for low-dose computed tomography screening for lung cancer, (2) publication of an extensively revised World Health Organization classification of lung cancers, and (3) approval of immunohistochemistry based companion diagnostics by the US Food and Drug Administration. We briefly review these milestones in the context of their impact on the practice of pathology.

Although Epstein–Barr virus (EBV) is often found in human tonsils, it remains to be precisely determined in what cells and microenvironment the virus is present. Although generally regarded as a B lymphotropic virus, EBV is associated with non-B-cell tumors, for example, NK/T-cell lymphoma, carcinoma, and leiomyosarcoma. To provide a basis for understanding the origin and biology of EBV-infected non-B cells, the immunophenotype of all EBV-infected cells in reactive human tonsils was determined by subjecting tonsil sections to dual/triple EBER in situ hybridization and immunohistochemistry with monoclonal antibodies to T cells (CD3, CD4, CD8, CCR3), B cells (CD20), plasma cells (CD138), natural killer (NK) cells (PEN5), and epithelial cells (cytokeratin), as well as frozen section immunostaining with antibodies to EBV latent proteins EBNA1, EBNA2, LMP1, and EBV early protein BZLF1. Most tonsils contained nearly equal numbers of EBNA1- and LMP1-positive cells (latency program) while only a few contained EBNA2-positive cells (growth program). More than 1000 EBER-positive cells from six tonsils were detected in the interfollicular zone (59%), tonsillar crypts (26%), and follicles (15%). Most (82%) EBER-positive cells are CD20-positive B cells, 7% are CD3-positive T cells, and 11% are cells of indeterminate lineage, often with plasmacytoid morphology. However, no EBER-positive plasma cells were identified. Rare EBER-positive NK cells and EBER/BZLF1-positive epithelial cells were identified. The direct demonstration of EBV within rare T cells, NK cells, and epithelial cells in reactive human tonsils provide a basis for further understanding of the origin of EBV-associated tumors of non-B-cell type.

CD8 + lymphocytes are believed to be important in host defence against the human immunodeficiency virus (HIV)-1, inhibiting HIV-1 replication through both cytolytic and non-cytolytic pathways 1 , 2 , 3 . The cytolytic pathway involves calcium-dependent exocytosis of perforin and granzyme proteases, as well as Fas-mediated programmed cell death 4 , whereas the noncytolytic pathway involves the release of chemokines that prevent viral entry 5 . Using granzyme A as a marker of cytolytic granule proteins, and macrophage inflammatory protein (MIP)-1α and RANTES as markers of HIV-1 inhibitory chemokines, we show that these two very different mediators of viral inhibition are both localized in the cytolytic granules of HIV-1-specific CD8 + cytotoxic T lymphocytes (CTL). Following antigen-specific activation, these mediators are secreted together, facilitating both lysis of virion-producing cells and the inhibition of free virus. In addition, RANTES, MIP-1α and MIP-1β are secreted by CTL as a macromolecular complex containing sulphated proteoglycans. This association appears to have a functional significance, because heparan sulphate facilitates RANTES inhibition of HIV-1 infection of monocytes.