Striatal parvalbumin interneurons, not cholinergic interneurons, are activated in a mouse model of cerebellar dystonia.

Dystonia is supposed to arise from abnormalities in the motor loop of the basal ganglia; however, there is an ongoing debate regarding cerebellar involvement. We adopted the established cerebellar dystonia mice model by injecting ouabain to examine the contribution of the cerebellum. Initially, we examined whether the entopeduncular nucleus (EPN), substantia nigra pars reticulata (SNr), globus pallidus externus (GPe), and striatal neurons were activated in the model. Next, we examined whether dopamine D1 receptor agonists (D1 agonist) and dopamine D2 receptor antagonists (D2 antagonist) or selective ablation of striatal parvalbumin (PV) interneurons could modulate their involuntary movements. The cerebellar dystonia mice had a higher number of c-fos-positive cells in the EPN, SNr, and GPe, as well as a higher positive ratio of c-fos in striatal PV interneurons than the control mice. Furthermore, systemic administration of combined D1 agonist and D2 antagonist and selective ablation of striatal PV interneurons relieved their involuntary movements. Abnormalities in the motor loop of the basal ganglia could be crucially involved in cerebellar dystonia, and modulating PV interneurons might provide a novel treatment strategy.

Analysis of adverse events related to extracorporeal membrane oxygenation from a nationwide database of patient-safety accidents in Japan.

Although adverse events related to extracorporeal membrane oxygenation have been reported, epidemiological data on life-threatening events are insufficient to study the causes of such adverse events. Data from the Japan Council for Quality Health Care database were retrospectively analyzed. The adverse events extracted from this national database included events associated with extracorporeal membrane oxygenation reported between January 2010 and December 2021. We identified 178 adverse events related to extracorporeal membrane oxygenation. At least 41 (23%) and 47 (26%) accidents resulted in death and residual disability, respectively. The most common adverse events were cannula malposition (28%), decannulation (19%), and bleeding (15%). Among patients with cannula malposition, 38% did not undergo fluoroscopy-guided or ultrasound-guided cannulation, 54% required surgical treatment, and 18% required trans-arterial embolization. In this epidemiological study in Japan, 23% of the adverse events related to extracorporeal membrane oxygenation had fatal outcomes. Our findings suggest that a training system for cannulation techniques may be needed, and hospitals offering extracorporeal membrane oxygenation should perform emergency surgeries.

Severe Hyperammonemia Due to Fecal Bowel Obstruction With a Congenital Portosystemic Shunt Resulting in Refractory Status Epilepticus and Cerebral Edema.

Hyperammonemic encephalopathy is a neurological emergency that can lead to seizures and cerebral edema. Although early interventions have been suggested, no clear criteria have been established. Herein, we report a case of severe non-hepatic hyperammonemia resulting in refractory status epilepticus within a day. A 79-year-old woman presented with acute altered mental status. Initial evaluation revealed septic shock and hyperammonemia due to fecal bowel obstruction with congenital portosystemic shunt. The patient was unresponsive to medical treatment and developed refractory status epilepticus. After surgical drainage with colostomy and a decrease in ammonia level, the patient developed cerebral edema and did not recover from the coma. Severe hyperammonemia warrants early intervention, especially in critically ill patients, with treatment of the cause and augmented removal of ammonia with renal replacement therapy.

Effective mechanical potential of cell-cell interaction explains three-dimensional morphologies during early embryogenesis.

Mechanical forces are critical for the emergence of diverse three-dimensional morphologies of multicellular systems. However, it remains unclear what kind of mechanical parameters at cellular level substantially contribute to tissue morphologies. This is largely due to technical limitations of live measurements of cellular forces. Here we developed a framework for inferring and modeling mechanical forces of cell-cell interactions. First, by analogy to coarse-grained models in molecular and colloidal sciences, we approximated cells as particles, where mean forces (i.e. effective forces) of pairwise cell-cell interactions are considered. Then, the forces were statistically inferred by fitting the mathematical model to cell tracking data. This method was validated by using synthetic cell tracking data resembling various in vivo situations. Application of our method to the cells in the early embryos of mice and the nematode Caenorhabditis elegans revealed that cell-cell interaction forces can be written as a pairwise potential energy in a manner dependent on cell-cell distances. Importantly, the profiles of the pairwise potentials were quantitatively different among species and embryonic stages, and the quantitative differences correctly described the differences of their morphological features such as spherical vs. distorted cell aggregates, and tightly vs. non-tightly assembled aggregates. We conclude that the effective pairwise potential of cell-cell interactions is a live measurable parameter whose quantitative differences can be a parameter describing three-dimensional tissue morphologies.

Cranial geometry in patients with dystonia and Parkinson's disease.

Abnormal skull shape has been reported in brain disorders. However, no studies have investigated cranial geometry in neurodegenerative disorders. This study aimed to evaluate the cranial geometry of patients with dystonia or Parkinson's disease (PD). Cranial computed tomography images of 36 patients each with idiopathic dystonia (IDYS), PD, and chronic subdural hematoma (CSDH) were analyzed. Those with IDYS had a significantly higher occipital index (OI) than those with CSDH (p = 0.014). When cephalic index (CI) was divided into the normal and abnormal groups, there was a significant difference between those with IDYS and CSDH (p = 0.000, α = 0.017) and between PD and CSDH (p = 0.031, α = 0.033). The age of onset was significantly correlated with the CI of IDYS (τ = - 0.282, p = 0.016). The Burke-Fahn-Marsden Dystonia Rating Scale motor score (BFMDRS-M) showed a significant correlation with OI in IDYS (τ = 0.372, p = 0.002). The cranial geometry of patients with IDYS was significantly different from that of patients with CSDH. There was a significant correlation between age of onset and CI, as well as between BFMDRS-M and OI, suggesting that short heads in the growth phase and skull balance might be related to the genesis of dystonia and its effect on motor symptoms.

Validation of the prognosis of patients with ER­positive, HER2­negative and node­negative invasive breast cancer classified as low risk by Curebest™ 95GC Breast in a multi­institutional registry study.

Curebest™ 95GC breast (95GC) is a multigene classifier we developed for the prognostic prediction of patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative and node-negative (ER+/HER2-/n0) invasive breast cancer treated with adjuvant endocrine therapy alone. The aim of the preset study was to evaluate the clinical utility of 95GC in a multiinstitutional registry study. Patients (n=215) with ER+/HER2-/n0 invasive breast cancer who had undergone the 95GC assay in seven hospitals were consecutively recruited in the registry study at various postoperative times. At recruitment, no patients had disease recurrences and were prospectively followed up for a median of 62 (range, 6-91) postoperative months. Of the 124 patients classified as 95GC low risk, 118 received adjuvant endocrine therapy alone and six received adjuvant chemo-endocrine therapy. Only two patients developed distant recurrences, and the 5-year distant recurrence-free survival (DRFS) was as high as 98.0%. Of the 91 patients classified as 95GC high risk, 81 received adjuvant chemo-endocrine therapy and 10 received adjuvant endocrine therapy alone. A total of four of these patients developed distant recurrences (5-year DRFS=95.5%). Among the 95GC high-risk patients, prognosis was significantly improved for the 81 treated with adjuvant chemo-endocrine therapy compared with for the 77 (historical controls) treated with adjuvant endocrine therapy alone (P=0.0002; hazard ratio, 0.24). Compared with the St. Gallen 2013 guideline, a significant de-escalation from 73.1% (155/212) to 40.6% (86/212) in adjuvant chemotherapy was achieved. The excellent prognosis of patients with ER+/HER2-/n0 invasive breast cancer classified as 95GC low risk could be validated in the present registry study, indicating that 95GC is useful for safe de-escalation of adjuvant chemotherapy in patients with ER+/HER2-/n0 invasive breast cancer.

Squamous cell carcinoma invading peripheral cerebral blood vessels and causing repeated cerebral hemorrhage : A case report.

Squamous cell carcinoma (SCC) is known to have less brain metastasis, but the reasons are not well established. Herein, we report the case of an 82-year-old man with recurrent cerebral hemorrhage of unknown cause ; upon brain biopsy, SCC was diagnosed infiltrating peripheral blood vessels of the brain and that it was state of micro-metastasis. It is possible that the blood-brain barrier blocked the infiltration of SCC into the brain parenchyma, and it did not form a mass in the brain parenchyma. In addition, because it did not form a mass, it could not be diagnosed as a metastatic brain tumor by contrast-enhanced magnetic resonance imaging or contrast-enhanced computed tomography. Among cases of recurrent cerebral hemorrhage of unknown cause in a short period, there may be cases of vascular infiltration without crossing the blood-brain barrier. Thus, if similar cases of recurrent cerebral hemorrhage of unknown cause is observed, it is necessary to distinguish metastatic brain tumors even if there is no evidence of suspected tumor on contrast-enhanced magnetic resonance imaging scan. J. Med. Invest. 70 : 276-280, February, 2023.

Exploration of advanced cellulosic material for membrane filtration with outstanding antifouling property.

Membranes, at times, have issues due to membrane fouling. The membrane fouling leads to performance deterioration and poses a potential to clog the membrane. Here we present experimental works carried out with emphasis on the antifouling properties, chlorine resistance, and mechanical properties of cellulose triacetate (CTA) and cellulose esters. We present that antifouling performance of cellulose esters evaluated by means of the VCG theory decreases with increasing carbon number in the substituent because of the high electron-donating nature of short aliphatic ester groups. When a long aliphatic ester group is required in terms of other properties such as resistance to chlorine, introducing it together with another substituent with an electron-donating nature such as an ethylene glycol moiety may strike a balance between antifouling and other performances.

Obstructive shock due to a spontaneous haemothorax caused by primary lung cancer.

We describe the case of a 67-year-old man with shock and hypoxemia. Chest X-ray showed bilateral lung mass shadows and left pleural effusion with a mediastinal shift, suggesting malignancy. Physical examination and point-of-care ultrasound findings did not suggest obstructive or cardiac shock, but the patient had prolonged shock refractory to fluid and blood transfusion therapy. We inserted a drain into the left thoracic cavity, which enabled the patient to recover from shock. We diagnosed the patient with obstructive and hypovolemic shock due to spontaneous haemothorax caused by primary lung cancer. Tension haemothorax due to malignancy is rare, and when obstructive shock is combined with haemorrhagic shock, it can be very difficult to determine the cause of shock.

An ImageJ-based tool for three-dimensional registration between different types of microscopic images.

Three-dimensional (3D) registration (i.e., alignment) between two microscopic images is very helpful to study tissues that do not adhere to substrates, such as mouse embryos and organoids, which are often 3D rotated during imaging. However, there is no 3D registration tool easily accessible for experimental biologists. Here we developed an ImageJ-based tool which allows for 3D registration accompanied with both quantitative evaluation of the accuracy and reconstruction of 3D rotated images. In this tool, several landmarks are manually provided in two images to be aligned, and 3D rotation is computed so that the distances between the paired landmarks from the two images are minimized. By simultaneously providing multiple points (e.g., all nuclei in the regions of interest) other than the landmarks in the two images, the correspondence of each point between the two images, i.e., to which nucleus in one image a certain nucleus in another image corresponds, is quantitatively explored. Furthermore, 3D rotation is applied to one of the two images, resulting in reconstruction of 3D rotated images. We demonstrated that this tool successfully achieved 3D registration and reconstruction of images in mouse pre- and post-implantation embryos, where one image was obtained during live imaging and another image was obtained from fixed embryos after live imaging. This approach provides a versatile tool applicable for various tissues and species.

Relationship between the Femoral and Tibial Component Positions and Postoperative Knee Range of Motion after Posterior-Stabilized Total Knee Arthroplasty in Varus-Aligned Knees.

This study aimed to evaluate the relationship between the femoral and tibial component positions and postoperative knee range of motion after posterior-stabilized total knee arthroplasty (TKA). Forty-four patients (48 knees in total: 9 men, 9 knees; 35 women, 39 knees) who underwent posterior-stabilized TKA using a navigation system were included. The femoral and tibial component positions were measured from the preoperative and postoperative computed tomography data with three-dimensional evaluation software. We investigated the relationship between the knee range of motion, including extension restriction and maximum flexion angles at 2 years postoperatively, and the femoral and tibial component positions. Patients with knee extension restriction of 10° or more at 2 years postoperatively showed greater posterior flexion position of the tibial component than those with knee extension restriction less than 10° (6.2° and 3.9°, respectively, p=0.018). The postoperative knee flexion angle was positively associated with the internal rotational position of the femoral component (p=0.032, 95% confidence interval: 0.105-2.178). Patients with a knee flexion angle more than 120° at 2 years postoperatively had greater internal rotational position of the femoral component than those with 120° or less (5.2° and 1.5°, respectively, p=0.002). In conclusions, after posterior-stabilized TKA, the postoperative knee extension restriction angle was associated with the posterior flexion position of the tibial component, and the knee flexion angle was positively related to the internal rotational position of the femoral component.

Successful treatment of invasive tracheobronchial pulmonary aspergillosis with venovenous extracorporeal membrane oxygenation and combined systemic, intratracheal instillation of liposomal amphotericin B: a case report.

BACKGROUND: Invasive pulmonary Aspergillus and invasive bronchial aspergillosis is a life-threatening opportunistic fungal infection that predominantly affects immunocompromised hosts. A case series and review found that the mortality rate of invasive bronchial aspergillosis is high, at about 40%, and 23.7% of invasive bronchial aspergillosis patients require mechanical ventilator management. There are few reports of life-saving cases with venovenous extracorporeal membrane oxygenation as rescue therapy in invasive pulmonary Aspergillus and invasive bronchial aspergillosis. Here, we report a case of invasive bronchial aspergillosis and invasive pulmonary Aspergillus that was successfully treated with venovenous extracorporeal membrane oxygenation, and combined systemic and intratracheal instillation of liposomal amphotericin B. CASE PRESENTATION: We present the case of a 61-year-old Japanese man with invasive tracheobronchial-pulmonary aspergillosis while receiving chemotherapy for malignant lymphoma. Bronchoscopy revealed trachea covered with pseudomembranous necrotizing tissue, the culture revealed Aspergillus fumigatus, and the histological findings of pseudomembranous revealed fungal hyphae. The patient required venovenous extracorporeal membrane oxygenation because of respiratory failure for atelectasis and obstructive pneumoniae. While continuing systemic administration of liposomal amphotericin B, intratracheal instillation liposomal amphotericin B was performed by bronchoscopy three times a week. Although the respiratory conditions improved and the patient was discontinued on venovenous extracorporeal membrane oxygenation, he ultimately died of recurrence of malignant lymphoma. CONCLUSION: Intratracheal instillation of liposomal amphotericin B is safe, and liposomal amphotericin B instillation allowed a targeted high local drug concentration, which led to improvement in the invasive bronchial aspergillosis. In addition, since the patient was supported with venovenous extracorporeal membrane oxygenation, we were able to perform safe bronchoscopic debridement of airway lesions and intratracheal instillation of liposomal amphotericin B.

Determinant factors behind changes in health-seeking behaviour before and after implementation of universal health coverage in Indonesia.

BACKGROUND: The health insurance system in Indonesia was transformed in 2014 to achieve universal health coverage (UHC). The effective implementation of essential primary health services through UHC has resulted in efficient healthcare utilisation, which is reflected in the health-seeking behaviour of the community. Our study aimed to examine the changes in health-seeking behaviour before and after the implementation of UHC in Indonesia and to identify what factors determine these changes. METHODS: We conducted a retrospective cohort study using the recall method and data collected through questionnaire-based interviews in Bandung, Indonesia. We used a two-step sampling technique-randomised sampling and purposive sampling, and a total of 579 respondents with acute or chronic episodes were recruited. [Formula: see text] tests were used to identify the association between factors. Difference in difference model and a logistic regression model for binary outcomes were used to estimate the effect of the implementation of UHC on the health-seeking behaviour. RESULTS: Utilisation of public health facilities increased significantly after implementation of UHC, from 34.9% to 65.4% among the respondents with acute episodes and 33.7% to 65.8% among those with chronic episodes. The odds of respondents going to health facilities when they developed an acute episode increased after the implementation of UHC (OR = 1.22, p = 0.05; AOR = 1.42, p < 0.001). For respondents experiencing chronic episodes, the implementation of UHC increased the odds ratio (OR = 1.74, p < 0.001; AOR = 1.64, p < 0.001) that they would use health facilities. Five years after the implementation of UHC, we still found respondents who did not have health insurance (26 and 19 respondents among those with acute episode and chronic episode, respectively). CONCLUSIONS: The effect of the implementation of UHC seemed greater for those experiencing chronic episodes than for those with an acute episode. Although the implementation of UHC has improved utilisation of public health facilities, the presence of people who are not covered by health insurance is a potential problem that could threaten future improvements in healthcare access and utilisation.

Differential Cellular Stiffness Contributes to Tissue Elongation on an Expanding Surface.

Pattern formation and morphogenesis of cell populations is essential for successful embryogenesis. Steinberg proposed the differential adhesion hypothesis, and differences in cell-cell adhesion and interfacial tension have proven to be critical for cell sorting. Standard theoretical models such as the vertex model consider not only cell-cell adhesion/tension but also area elasticity of apical cell surfaces and viscous friction forces. However, the potential contributions of the latter two parameters to pattern formation and morphogenesis remain to be determined. In this theoretical study, we analyzed the effect of both area elasticity and the coefficient of friction on pattern formation and morphogenesis. We assumed the presence of two cell populations, one population of which is surrounded by the other. Both populations were placed on the surface of a uniformly expanding environment analogous to growing embryos, in which friction forces are exerted between cell populations and their expanding environment. When the area elasticity or friction coefficient in the cell cluster was increased relative to that of the surrounding cell population, the cell cluster was elongated. In comparison with experimental observations, elongation of the notochord in mice is consistent with the hypothesis based on the difference in area elasticity but not the difference in friction coefficient. Because area elasticity is an index of cellular stiffness, we propose that differential cellular stiffness may contribute to tissue elongation within an expanding environment.

Decreased numbers of gastric, colorectal, lung, and breast cancer surgeries performed in 17 cancer-designated hospitals in Gunma Prefecture of Japan during the COVID-19 pandemic.

PURPOSE: This study aims to clarify the influence of the COVID-19 pandemic on cancer surgery in Gunma Prefecture. METHODS: A total of 9839 cases (1406 gastric cancer, 3569 colorectal cancer, 1614 lung cancer, and 3250 breast cancer) from 17 hospitals in Gunma Prefecture were investigated. We compared the number of surgical cases, proportion of cases found by screening, and cStage at the time of the first visit by month in 2020 and 2021 with those in 2019. RESULTS: The rate of decline in cancer surgery was 8.9% in 2020 compared with 2019 (p = 0.0052). Compared with the same month of 2019, in some months of 2020 and 2021, significant decreases were observed in the number of surgeries for gastric and colorectal cancer, the percentage of surgical cases detected by screening in all four cancers, and the proportion of cancers with a relatively early cStage in gastric and breast cancer. CONCLUSIONS: The number of surgical cases of the four cancer types detected by cancer screening decreased in Gunma Prefecture owing to the influence of the COVID-19 pandemic. Furthermore, for some cancer types, the number of operations performed in patients with early-stage cancer is also decreased.

How Worries about Interpersonal Relationships, Academic Performance, Family Support, and Classmate Social Capital Influence Suicidal Ideation among Adolescents in Japan.

Suicide is an important public health issue for adolescents. To investigate the risk and protective factors for adolescent suicide, a cross-sectional questionnaire-based survey was conducted at a junior high school (n = 379) in Japan in 2018. After obtaining survey data, we conducted univariate and logistic regression analyses to test for associations between suicidal ideation and several factors, including worries (i.e., about school life, interpersonal relationships at school, family life, interpersonal relationships at home, and academic performance), perceived support from school staff and family members, and social capital. In this context, the existence of trustful relationships between classmates was used as indicators of social capital. The results showed that the prevalence of suicidal ideation was 10.5%. The risk of suicidal ideation was increased by worries about 1) interpersonal relationships at school, 2) interpersonal relationships at home, and 3) academic performance, but was decreased by social support from family members and trusting relationships. Further, the rate of suicidal ideation was higher among students who expressed all these three worries when compared to those who expressed two or fewer worries. In addition, looking at students who expressed all these three worries simultaneously, the rate of suicidal ideation was higher among those with lower levels of support from family members and fewer trustful relationships. Our results suggest that the prevention of adolescent suicide should include strategies for reducing worries about interpersonal relationships at school/home and academic performance while finding ways to enhance family support and classmate social capital.

Adverse events related to thoracentesis and chest tube insertion: evaluation of the national collection of subject safety incidents in Japan.

PURPOSE: Thoracentesis and chest tube insertion are procedures commonly performed in routine clinical practice and are considered mandatory skills for all physicians. Adverse events secondary to these procedures have been widely reported; however, epidemiology data concerning life-threatening events associated with these procedures are lacking. METHODS: We retrospectively analyzed data from the Japan Council for Quality Health Care open database regarding subject safety incidents involving thoracentesis and chest tube insertion. The adverse events extracted from the database included only events associated with thoracentesis and chest tube insertion reported between January 2010 and April 2020. RESULTS: We identified 137 adverse events due to thoracentesis or chest tube insertion. Our analysis also revealed at least 15 fatal adverse events and 17 cases of left/right misalignment. Not only resident doctors but also physicians with 10 years or more of clinical experience had been mentioned in these reports. The most common complications due to adverse events were lung injury (55%), thoracic vascular injury (21%), and liver injury (10%). Surgical treatment was required for 43 (31%) of the 137 cases, and the mortality risk was significantly higher for thoracic vascular injury than for other complications (p = 0.02). CONCLUSION: We identified at least 15 fatal adverse events and 17 cases of left/right misalignment over a 10-year period in the Japan Council for Quality Health Care open database. Our findings also suggest that care should be taken to avoid thoracic vascular injury during chest tube insertion and that immediate intervention is required should such an injury occur.

Biosorption of different gadolinium (Gd) complexes from water by Eichhornia crassipes (water hyacinth).

Many studies have demonstrated the Eichhornia crassipes (water hyacinth) potency in removing heavy metals, but the plant's potential for sorption of gadolinium (Gd) has not yet been investigated. In this study, water hyacinth was grown in a glass container for 30 days with either GdCl3 or Gd-based contrast agent (GBCA; gadoterate) with water obtained from the Tone River. On the day 30, the Gd concentration in both the water and the plants was measured by mass spectrometry (ICP-MS). After 30 days, 98.5% of GdCl3 in the water had been absorbed by the roots, and 3.5% of Gd was transferred to the leaves. On the other hand, the water hyacinth roots absorbed only 12% of the gadoterate. When exposed to 5 mg/L of GdCl3, the roots of water hyacinth may effectively remove Gd ions in the aquatic environment, with no visible effect on the general health of the plant. However, the water hyacinth roots did not absorb GBCA. This may result in higher accumulation of Gd in the aqueous environment. The GBCA may be broken down by environmental factors and negatively affect the marine ecosystem.

This study highlights the potential capability of water hyacinths in reducing the increasing gadolinium in the environment, which may be of value in optimizing the phytoremediation of medical waste.

Spontaneous pneumothorax with coronavirus disease 2019 in non-ventilated patients: A single-center retrospective case series.

BACKGROUND: Pneumothorax is a rare complication of coronavirus disease 2019, and many of its associated factors are related to mechanical ventilation. We investigated the incidence and clinical features of patients with pneumothorax and coronavirus disease 2019 at a field hospital for patients who did not require intubation. MATERIALS AND METHODS: An isolated field hospital for COVID-19 patients who did not require ventilation was constructed. Patients who developed pneumothorax were extracted and reviewed retrospectively. RESULTS: Between May 2020 and February 2021, 1061 patients were admitted to this field hospital. Among them, eight patients (0.75%, three men and four women) developed pneumothorax. The mean age at incidence was 79.9 (range: 20-96) years; all patients were over the age of 80 years, except one 20-year-old woman. Six of these eight patients (75%) died. CONCLUSION: Although pneumothorax is a rare complication of coronavirus disease-2019, it is predictive of a poor prognosis in older-adult patients.

Social cohesion and quality of life in Bandung: A cross sectional study.

In Bandung, Indonesia, urban expansion, rapid economic growth, and population increase present enormous challenges to the maintenance of a high quality of life (QOL) for its citizens. Moreover, income distribution in the city has become more unequal, thereby threatening social cohesion. Such situations led us to investigate the states and correlation of social cohesion and QOL in Bandung. In 2018, we conducted a questionnaire survey of social cohesion and QOL using 13 and 18 question items, respectively. We employed the Rasch model analysis to analyze the logit measures of 752 responses. The results revealed that the population of Bandung has high social cohesion and decent QOL. Our findings suggest that in Bandung QOL is significantly correlated with social cohesion, therefore strategies that seek to enhance social cohesion may be beneficial to improve the QOL.